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 Title Page
 Table of Contents
 List of Figures
 Abstract
 Executive summary
 Introduction and background
 Water quality problems in Wakulla...
 Sources of the problem
 Solutions to the problem
 Acknowledgement
 Reference
 Appendices














Solving water pollution problems in the Wakulla Springshed of North Florida
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 Material Information
Title: Solving water pollution problems in the Wakulla Springshed of North Florida science and technology at work for a better Florida
Series Title: Special publication (Florida Geological Survey)
Physical Description: 1 computer disk : ill., col., charts, maps ; 4 3/4 in.
Language: English
Creator: Florida -- Dept. of Environmental Protection
Florida Geological Survey
Hydrogeology Consortium (Fla.)
Conference: Hydrogeology Consortium Workshop, May 11-13, 2005
Publisher: The Consortium
Place of Publication: Tallahassee Fla
Tallahassee Fla
Publication Date: 2005
 Subjects
Subjects / Keywords: Water quality -- Florida -- Wakulla Spring   ( lcsh )
Hydrogeology -- Florida -- Wakulla Spring   ( lcsh )
Groundwater flow -- Florida -- Wakulla Spring   ( lcsh )
Water -- Pollution -- Florida -- Wakulla Spring   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
 Notes
Summary: Purpose of workshop: To present an overview of the broad and growing scientific evidence linking water quality decline at Wakulla Spring with land use practices in the region.
System Details: System requirements: PC or Mac, CD-ROM reader, Adobe Acrobat Reader.
General Note: Title from: Title screen.
 Record Information
Source Institution: University of Florida
Holding Location: University of Florida
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The author dedicated the work to the public domain by waiving all of his or her rights to the work worldwide under copyright law and all related or neighboring legal rights he or she had in the work, to the extent allowable by law.
Resource Identifier: oclc - 70203207
System ID: UF00094056:00002

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Table of Contents
    Title Page
        Page i
        Page i-a
    Table of Contents
        Page ii
        Page iii
    List of Figures
        Page iv
    Abstract
        Page v
    Executive summary
        Page vi
        Page vii
        Page viii
        Page ix
        Page x
        Page xi
        Page xii
        Page xiii
    Introduction and background
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
    Water quality problems in Wakulla Springs and River
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
    Sources of the problem
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
        Page 36
        Page 37
        Page 38
    Solutions to the problem
        Page 39
        Page 40
        Page 41
    Acknowledgement
        Page 42
    Reference
        Page 43
        Page 44
        Page 45
        Page 46
    Appendices
        Page 47
        Page 48
        Page 49
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Full Text



DEGRADATION OF WATER

QUALITY AT

WAKULLA SPRINGS, FLORIDA:

ASSESSMENT AND

RECOMMENDATIONS




Report of the Peer Review Committee
on the Workshop
Solving Water Pollution Problems
in the Wakulla Springshed of North Florida
May 12-13, 2005
Tallahassee, Florida


December 2005












PEER REVIEWERS


David E. Loper, Ph. D., Chair
Professor Emeritus
Department of Geological Sciences
and Geophysical Fluid Dynamics Institute
18 Keen Building, MC 4360
Florida State University
Tallahassee, FL 32306-4320

William M. Landing, Ph. D.
Professor of Environmental and Marine Chemistry
Department of Oceanography, 325 OSB
Florida State University
Tallahassee, FL 32306-4320

Curtis D. Pollman, Ph. D.
Principal Scientist
Tetra Tech, Inc.
Research & Development Division
408 W. University Ave., Suite 301
Gainesville, FL 32601

Amy B. Chan Hilton, Ph. D.
Assistant Professor
Florida A&M University-Florida State University
College of Engineering
Department of Civil and Environmental Engineering
Associate, Geophysical Fluid Dynamics Institute
2525 Pottsdamer Street
Tallahassee, FL 32310-6046











CONTENTS

Peer Review ers................................................................................................................................. i
A BSTRA CT.................................................................... ...................................................... v
EXECU TIVE SUM M A RY ................................. ......................... ................. .................... vi
Introduction............................................................................. .......................... vi
Nutrient Loading ....................................................................... .............................................. vii
D ark Water..................................................................... .................................................. ix
Other Comm ents......................................................... ................................................... ix
Recomm endations.......................................................... ...................................................... x
CHA PTER 1. Introduction and Background ................................................. ......................... 1
1.1 Purpose of this Report................................................................................ .................... 1
1.2 Other Reports ......................................................................................... ......................... 2
1.2.1. Nitrate Loading and Non-point Source Pollution in the Lower St. Marks Wakulla
Rivers Watershed............................................................................................................................ 2
1.2.2. Woodville Recharge Basin Aquifer Protection Siml Phases I and II................................... 5
1.2.3. A Sn ai, g for Water Quality Protection: Wastewater Treatment in the Wekiva
Springs Area............................................................................................................. ...................... 7
1.2.4. Florida's Springs: Strategies for Protection & Restoration.......................... ............ 9
1.2.5. Protecting Florida's Springs: Land Use Planning Strategies and Best Management
P ra ctices ...................................................................................................................... .... ............ 1 0
1.3 Regulatory Fram ew ork ........................................................................ ................... 10
1.4 Physical Setting.................................................................................................................. 11
1.4.1 Surface Water Features.............................................................................. ......................... 13
1.4.2 Groundwater Features .................................................................... .................................... 14
Chapter 2: Water Quality Problems in Wakulla Springs and River ......................................... 19
2.1 N itrate Loading ................................................................................... ......................... 19
2.1.1 Nitrate and the Nitrogen Cycle.................................................................. ................... 19
2.1.2 Extent and Causes of Nitrate Contamination........................................... 19
2.1.3 Extent and Causes of nvasive Exotic Aquatic Plant Growth ...................................... 22
2.2 Extent and Causes of Loss of Water Clarity ......................................... .................... 24
CHA PTER 3: Sources of the Problem s ....................................................... .......................... 26
3.1 Summary and Evaluation of Nitrogen Limitation ................................. ................. ... 26
3.2 Sources of N itrate............................................................................................................... 26









3.3 Wastewater Treatment Facilities. ...................................................... .......................... 29
3.3.1 Trend of Groundwater Flow........................................................................ .................. 30
3.4 N itrate D ata...................................................................... ............ ............. ............ 31
3.5 Fertilizer and Livestock.................................................................................................... 37
3 .6 S ep tic Sy stem s .................................................................................... .......................... 3 7
3.7 Sources of D ark W after ...................................................................................................... 38
CHAPTER 4: Solutions to the Problems................................................................................... 39
4.1 Mitigation Strategies for Nutrient Loading................................................................... 39
4.1.1 Wastewater Treatment Facilities............................................................... ................... 40
4.1.2 Sep tic System s............................................................................ ......................................... 41
4.1.3 F fertilizers and L livestock ........................................................................... ............. .......... 41
4.2 Mitigation Strategies for the Loss of Water Clarity...................................................... 41
A C K N O W LED G M EN T S ............................................................................. ......................... 42
R eferen ces .............................................................. ................................................................ ...... 4 3
T able 1: L ist of acronym s ............................................................................... .............. .......... 45
W eb sites of interest ......................................................... ............................. ................ ............. 46
A PPEN D IC E S ............................................................................................... .......................... 47
Appendix A: Questions for the Peer Review Committee........... ........... .. .................... 47.
Appendix B: Key Peer Review Committee Questions and Answers......................................... 49
App endix C L ist of R review ers........................................................................ .................... 51
Appendix D. History of Hydrilla Removal Efforts at Wakulla Springs.................................... 53
E.1 The Case against NLimitation ......................................................................... .................. 55
E .2 The C ase for N Lim itation.............................................................................. ....................... 55
E.3 The Case for Reducing Plant Growth by Limiting Nitrate Loading to the Springshed ............. 56
Appendix F: Phosphate in the Floridan Aquifer and Wakulla Springs ............................... 60
Appendix G. Specific Slg',",'c tiI,/ \ for Research on Nutrients and Biota............................. 67
Appendix H. Speculation on the Origin of Dark Water ................... ....... ........... .. 68
Appendix I: Ongoing Programs, City of Tallahassee Water Utility ....................................... 69










LIST OF FIGURES

Figure 1: Aerial photo of Wakulla Spring and River............................. ............... ..... vi
Figure 2: Average nitrate concentrations in ground water sampled from the SESF
m monitoring w ells .......................................................................... ................. . 6
Figure 3: Nitrate data from 1986 to 2004 for the SESF well with the highest average
nitrate concentration s.................................................... ....................... .................... 6
Figure 5: Florida portion of the Wakulla-St. Marks watershed ...................................... 12
Figure 6: A m ap of the W K P ........................................................................ ......................... 16
Figure 7: Three-dimensional rendering of the Wakulla cave system ..................................... 17
Figure 8: Estimated water budget for the Wakulla Springs contributory area ........................ 18
Figure 9: A schematic illustration of sources, reservoirs, and pathways of nitrogen in the
unconfined portion of the Wakulla springshed......................... ......................... 20
Figure 10: FDEP's Stream Condition Index (SCI) scores and ratings .................................... 21
Figure 11: Variation with time of concentrations of phytoplankton chlorophyll a and
nutrients in W akulla Springs, 1965-present ............................................................ 23
Figure 12. Annual percentage of down days for the glass-bottom boats and annual
rainfall in inches, 1994-2004. ................................................... .................... 25
Figure 13. Total phosphorus in Florida's first-magnitude springs ............................................ 27
Figure 14. Pie chart of nitrate contributions to Wakulla Springs ................... ................ 27
Figure 15. Potentiometric surface map of the upper Floridan aquifer........................................ 31
Figure 16. Nitrate levels in COT drinking-water well 12.............................. .................... 33
Figure 17. Measured nitrate trends in monitoring wells at the SESF ..................................... 34
Figure El: TN:TP ratios (by mass) over time at Wakulla Springs, 1996-2004...................... 57
Figure E2. Variations of concentrations of TN and TP in the Wakulla River with distance
downstream of the springhead........... ..... ........................................................... 58
Figure E3. TN:TP mass uptake ratios and changes in algal (phytoplankton) chlorophyll a
concentrations in Wakulla Springs and the Wakulla River....................................... 59
Figure F Sampling stations for the Leon County Lake Henrietta/Lake Munson
stormwater m monitoring program ..................................................... ..................... 61
Figure F2. Total-P and ortho-P in the city of Tallahassee drinking water well CW12 ............ 61
Figure F3. Total P data from the Wakulla Springs boil........................................................ 62
Figure F4. Nitrate concentrations north and south of the sprayfield ........................................ 63
Figure F5: Relationship between total nitrogen and total phosphorus concentration and
discharge at W akulla Springs .................................................... .................... 65










ABSTRACT

Wakulla Springs, a natural resource of great ecological and recreational value, is suffering from
two problems: (1) ecological decline due to excess nitrate loading and (2) dark water. While the
source of dark water and the remedy for this problem remain uncertain, the situation regarding
nitrate is reasonably clear. Currently the largest single source of nitrate appears to be the
Southeast Sprayfield operated by the city of Tallahassee, but nitrate from septic tanks in Leon
and northern Wakulla Counties is a looming problem. The long-term success of efforts to restore
Wakulla Springs will depend on a continuing, coordinated research program into the sources of
and solutions to the problems facing this unique natural resource.

In order to address these problems and possibly reverse the decline that has occurred at Wakulla
Springs, the following six recommendations are intended to serve as guides for future actions by
local and state governments:
Recommendation 1. Goal of Wastewater Disposal Activities
A primary goal of all wastewater disposal activities in Leon and Wakulla Counties should be to
reduce nutrient loading (nitrogen and phosphorus) to the aquifer.
Recommendation 2. Wastewater Utility
A wastewater utility should be established and charged with improving the operation of all onsite
sewage treatment and disposal systems (OSTDSs or septic systems), in accordance with the goal
stated in Recommendation 1.
Recommendation 3. Regulate Fertilizers
The amounts and types of fertilizer used in the catchment basin of Wakulla Springs should be
limited and regulated through a combination of public education and targeted ordinances.
Recommendation 4. Expedite the Total Maximum Daily Load Process
The Florida Department of Environmental Protection should expedite the establishment of total
maximum daily loads and pollutant load reduction goals for Wakulla Springs and River.
Recommendation 5. Hydrologic Observatory
A Hydrologic Observatory should be established and charged with coordinating and facilitating
research activities into a number of issues related to the health of Wakulla Springs and River.
Recommendation 6. Public Education
A concerted, prolonged and properly funded effort should be made to educate the public on the
importance of the previous recommendations to the long-term health of Wakulla Springs and its
ecosystems.










EXECUTIVE SUMMARY

Introduction
Wakulla Springs is the centerpiece of Wakulla Springs State Park and one of the crown
jewels of the Florida state park system. On average, 250 million gallons per day (mgd) of water
flow from the spring, creating the Wakulla River, which joins the St Marks River some 10 miles
downstream. The combined rivers form an estuary at the edge of Apalachee Bay in the Gulf of
Mexico. The spring is the above-ground representation of a vast underground water resource, the
Floridan aquifer a thick, water-bearing layer of porous limestone. The springs, river and
estuary have historically had exceptional ecological and recreational value; the state park
receives about 200,000 visitors per year.


Figure 1: Aerial photo of Wakulla Spring and River Courtesy of Joe Hand, FDEP

In recent years, there has been a striking change in the basin, illustrated in Figure 1, and in
the upper reaches of the river. Native aquatic vegetation has been almost entirely replaced by
invasive exotic species, most notably hydrilla and algae. This apparently has led to other
changes in biota, as many native animals and birds are in decline, and in some instances have
disappeared altogether. In addition, there seems to have been an increase in the frequency of
dark-water days, during which the water in the basin is too dark to permit the glass-bottom boats
to operate.









A workshop, entitled Solving Water Pollution Problems in the Wakulla Springshed of
North Florida: Science and Technology at Work for a Better Florida, was convened on May
12 and 13, 2005, in Tallahassee, Florida. At this workshop scientific and engineering experts
from government agencies, academia and private industry assessed water-quality problems in
Wakulla Springs and River, explored their causes and consequences, and proposed solutions or
mitigating strategies. Attention at the workshop was focused on two issues: increased nutrient
loading in the water emanating from Wakulla Springs and the increasing frequency of dark-water
days.

A peer review committee was charged with synthesizing the research findings of several
major studies of Wakulla Springs and summarizing the workshop's conclusions and
recommendations. In particular, the committee was charged with developing answers, using the
best available data, to the following set of five key questions:
1. What does the preponderance of evidence indicate are the sources of nutrients (nitrogen and
phosphorus) reaching Wakulla Springs, and which are the most important sources?
2. Are nutrients (nitrogen and/or phosphorus) responsible for the ecological "imbalance of
the Wakulla River (imbalance as defined by Florida DEP)?
3. What are the solutions that should be implemented presently to reduce nutrient loading to
Wakulla Springs?
4. What are the future threats (say 50 years into the future) regarding nutrient loading to
Wakulla Springs, and what planning is now necessary to avoid these threats?
5. What additional research, if any, is necessary to provide adequate certainty regarding
effective actions to eliminate the Wakulla Springs and River nutrient pollution problem?

A more complete list of questions posed to the committee is found in Appendix A, and its
preliminary answers (prior to the development of this report) are in Appendix B. A list of
experts who were consulted during the preparation of this report is found in Appendix C. This
document is the report of the committee.

Nutrient Loading
Non-native hydrilla now chokes the spring basin and the upper mile of the river and,
together with algal blooms, reduces dissolved-oxygen levels in the water. As a result, the
ecosystem has been degraded, and the river's ecological and recreational value has diminished.
A number of sensitive species have all but disappeared. In recent years, the Wakulla River has
averaged in the lowest 20th percentile for water quality of Florida's rivers, with the ecological
health of the upper reaches of the Wakulla River on average being rated as "poor" for the past
five years.
Increasing nitrate levels over the past several decades in the waters flowing from Wakulla
Springs has caused a decline in water quality and has seriously disrupted the ecology of the basin
and river. The nitrate level rose from about 0.2 milligrams per liter (mg-N/L) during the 1970s
to about 1 mg-N/L by the end of the 1990s, a fivefold increase in less than 30 years.
The conclusion that nitrogen (in the form of nitrate) is the key nutrient fueling this growth is
substantiated by two facts:









Nitrogen in the upper Wakulla River decreases more rapidly than phosphorus with
distance down river and
The concentration of nitrate in Wakulla's waters has increased substantially in the past
30 years, whereas the concentration ofphosphorus has not.
Further, since phosphorus is buffered by natural processes (particularly leaching from the P-rich
Hawthorne group clays that overly the Floridan aquifer north of the Cody Scarp and the
adsorptive equilibration of dissolved ortho-P with the limestone matrix of the aquifer), the
control of its concentration is not practically possible.
The weight of evidence presented at the workshop, and collected and assessed since the
workshop, indicates that the most significant sources of nitrate are as follows:

Nitrogen in wastewater applied at the COT's Siinthei t Sprayfield (SESF),
Septic systems in the unconfined portion of the Wakulla springshed,1
Fertilizer (a portion of which is attributable to the SESF operations) and
Residual sludge applied at the airport.

Data indicate that the SESF, which receives the great majority of the city's wastewater (17 -
22 mgd), is a significant source (70% by one estimate) of the total nitrate load to Wakulla
Springs, excluding atmospheric deposition (most of which is taken up by plants) and residual
sludge application (which is being phased out as a disposal practice). Additionally, Wakulla
Springs and River are vulnerable to pollution from land-use practices because in a significant
portion of the springshed (the southern portion) the aquifer lies below porous soils (i.e., the
aquifer is unconfined). Specifically, the SESF is located on the Woodville Karst Plain, an
unconfined portion of the Floridan aquifer. Thus the nutrients that are not taken up by crops
grown on the SESF readily percolate through the permeable, sandy soil and flow directly into the
upper portions of the Floridan aquifer system. From there, a significant fraction of the
groundwater flows southwest toward Wakulla Springs, as demonstrated by potentiometric-
surface data. Tracing experiments, sponsored by the Florida Department of Environmental
Protection (FDEP), will be conducted in the coming year to clarify the pathways and travel times
for groundwater flowing from the SESF.
Since the SESF is a point source operated by a responsible entity, it is more amenable to
rapid modification than other sources. The COT should be commended for making
modifications in the operation of its wastewater facilities in recent years that have reduced the
release of nitrate into the aquifer (see Appendix I). However, further modification of SESF
operations may be necessary if the biological and ecological degradation at Wakulla Springs are
to be reversed.
In the larger portion of the Wakulla springshed, lying north of the Cody Scarp, the aquifer
lies below relatively impermeable soils. Surface runoff in this area is collected and channeled to
the sinkhole lakes Lafayette, Jackson, lamonia and Miccosukee and to other open sinkholes.


1 A springshed is the land area that contributes rainfall and runoff to a spring; it is also called the capture zone, catchment basin
or contributory area.









Thus, pollutants on the land surface (such as fertilizers) can move rapidly into the aquifer that
supplies the flow to Wakulla Springs and River.
Septic systems are a growing problem as the region's population continues to increase. This
source, having multiple points of origin, will be difficult to address without change in the
administrative structure of local governments. Other sources of concern are fertilizers and
livestock. The former is likely to increase as the population in the springshed continues to grow.
The adverse impact of fertilizers can be mitigated by suitable storm-water regulation and public
awareness campaigns. The contribution from livestock is small, and is anticipated to remain so.
There is no evidence that a significant flux of nitrate originating in southern Georgia reaches
Wakulla Springs.
It is doubtful that a reduction in nitrate alone will allow the ecology of the Wakulla Springs
basin and upper river to recover to a "pristine" state, because it is exceedingly difficult to
eradicate invasive plants such as hydrilla. However, it is reasonable to expect that the balance of
competition will shift in favor of the native plants as the nitrate concentration is decreased
toward natural levels. Reduction of the nitrate loading will slow the rate of growth of hydrilla
and algae and facilitate their control by various means. A crucial first step to recovery is a
reduction of nitrate loading; if nothing is done, the ecology of Wakulla Springs will remain
severely degraded.

Dark Water
Another Wakulla Springs problem presented and discussed at the workshop involves the
dark (tea-colored) water frequently evident in the spring basin, which has resulted in a recent
increase in the number of days when the state park's glass-bottom boats cannot operate. The
periods of dark water in Wakulla Springs are variable and appear to be the result of natural
processes. The dark water probably results from tannic surface waters (stained brown in color
from percolating through leaf litter) being carried to the aquifer by surface runoff following
rainfall. Current understanding of the dark-water problem is insufficient to allow any remedies
to be proposed at this time. The development of the requisite understanding will require a
concerted, properly funded research effort.

Other Comments
Several of the more specific recommendations presented in the Wekiva Study Report2 might
be applicable to Wakulla Springs, but such specificity is beyond the scope of this report.
Further, it may be premature to establish protection zones for Wakulla Springs; at present there is
insufficient understanding of the structure of the aquifer and the specific flow paths within the
springshed of Wakulla Springs to delineate such zones. However, it is reasonable to expect that
such zones could be identified in the not-too-distant future (-5 years), assuming that the research
program recommended below is implemented and properly funded.
The FDEP is to be commended for purchasing, and maintaining in a natural state, 11,000
acres of springshed in Wakulla County in order to protect water quality in Wakulla Springs. The
continued purchase of land in the springshed is a desirable policy, especially for areas close to
the spring or for major aquifer-recharge areas.


2 FDEP. December, 2004. A strategyfor water quality protection: Wastewater treatment in the Wekiva study area.









Wakulla Springs and River has rightly been designated by FDEP as an Outstanding Florida
Water. This unique system is under severe stress due to population growth in the springshed. If
it is to be preserved for future generations, a suitable suite of protective measures and
administrative structures need to be put in place, beyond the efforts to control nitrate and dark
water, including the following:
Suitable regulation and oversight by responsible state agencies (e.g. FDEP and the
Florida Department of Community Affairs [DCA])
A continuing coordinated program of monitoring, data collection and analysis by
researchers, perhaps within the auspices of a hydrologic observatory or research station and
The coordinated involvement of community andpublic-interest groups, such as the
Friends of Wakulla Springs, the Wakulla Springs Working Group, the Trust for Public Lands,
1000 Friends ofFlorida, the Hydrogeology Consortium, etc.

Recommendations
The six recommendations of the peer review committee, presented below, are addressed
principally to state and local governments. Several of the commentaries on these
recommendations list specific actions that were mentioned by participants at the workshop.
These are presented as illustrations; the committee is not endorsing any specific actions.
Recommendation 1. Goal of Wastewater Disposal Activities
A primary goal of all wastewater disposal activities in Leon and Wakulla Counties should be
to reduce nutrient (nitrogen and phosphorus) loading to the aquifer.
Commentary: The COT and Leon and Wakulla Counties should, by cooperative and joint
agreements, institute means to facilitate and monitor realistic progress toward this goal.
Immediate progress may be made by the following:
Review and modify practices and activities at the COT's wastewater treatment facilities.
In particular, the application offertilizer to the SESF should be minimized, consistent with
maximizing nutrient removal by sprayfield plants. The planned upgrade of the T. P. Smith
(and Lake Bradford Road) facilities to improve sewage treatment capabilities should be
completed as soon as practicable; tertiary treatment (nutrient reduction) and/or other
means of reducing nitrogen (and phosphorus) loading to the Wakulla Springs springshed
should be implemented; and
Cessation of the application of wastewater residuals in the Wakulla Springs springshed
(if not previously implemented).
Fertilizer applications at the sprayfield, which have decreased substantially in the last few
years, should be further reduced, and the goal of the sprayfield operations should be primarily to
remove nutrients from wastewater, rather than to achieve reuse for agricultural production (hay
and cattle). Further, the rate of treated sewage application currently about 120 inches per year
vs. 68 inches per year of rainfall should not exceed the capacity of crops at the sprayfield
crops to efficiently remove nutrients before they enter the groundwater.
Consideration should be given to procuring additional land for applying Tallahassee's
treated sewage, especially land outside the Wakulla springshed. The reduced application rate of









wastewater per acre of land will improve the efficiency of nutrient removal by crop plants, and in
addition, land application outside the springshed will decrease overall nitrate loading to the
springs. Alternatives would be to remove a greater portion of the nitrate at the treatment plant,
increase the reuse of wastewater and/or to pipe wastewater to alternate discharge points. Land
costs associated with several of these options are of course a significant factor, and these costs
should be compared with other options that do not entail such costs, such as the removal of
nutrients via tertiary treatment at the T. P. Smith plant or at the SESF. (A $73 million upgrade to
the T. P. Smith plant is planned; tertiary treatment for nitrogen removal at the plant would add
about $30 million to the cost.)
Recommendation 2. Wastewater Utility
A wastewater utility should be established and charged with improving the operation of all
onsite sewage treatment and disposal systems (OSTDSs or septic systems), in accordance with
the goal stated in Recommendation 1.
Commentary: This utility should encompass those areas of Leon and Wakulla Counties not
currently served by a wastewater treatment facility (WWTF) and should be funded by an
appropriate utility fee. Data from the workshop and our continuing assessment indicate the need
for the improved management of septic systems in Leon County and the portion of Wakulla
County in the springshed, because nutrient loading from these systems is a critical threat to the
future ecological and recreational value of Wakulla Springs and River. In particular, assessment
of growth-management options suggests that limits should be placed on numbers, and numbers
per acre, of septic systems in the unconfined portion of the springshed.
The workshop's panel of experts strongly recommended the establishment of a wastewater
utility, and the committee has adopted that recommendation. The utility should be led by the
governments of the COT and Leon and Wakulla Counties, with the assistance of FDEP, the
Florida Department of Health, and the DCA. This utility could be initially funded by grants from
the US Environmental Protection Agency and sustained over the long term by fees charged to
septic-system owners. The most attractive feature of this utility is that it could be responsible for
maintaining and monitoring performance-based septic systems (with heightened nitrate-treatment
requirements) in the environmentally sensitive, unsewered portions of the springshed, providing
a uniform means of ensuring that these systems are operated in an environmentally sound fashion
to minimize impacts on Wakulla Springs and River.
Recommendation 3. Regulate Fertilizers
The amounts and types offertilizer (e.g., slow-release only) used in the catchment basin of
Wakulla Springs should be limited and regulated through a combination of public education and
targeted ordinances.
Commentary: This recommendation applies to the entire catchment basin, because fertilizer,
mobilized by rainwater, can reach the aquifer by percolation in the unconfined portion of the
basin or as stormwater from the confined portions. To be successful, public education would
need to be properly funded and supervised by a responsible entity. One possible entity to be
responsible for public education related to fertilizer usage and application is the Hydrologic
Observatory proposed in Recommendation 5.









Recommendation 4. Expedite the Total Maximum Daily Load Process
The Florida Department of Environmental Protection should expedite the establishment of total
maximum daily loads and pollutant load reduction goals for Wakulla Springs and River.
Commentary: The TMDL process for Wakulla Springs should address all sources of nitrogen
to the springshed, including, but not limited to, fertilizer use in southern Georgia and north
Florida, atmospheric deposition, stormwater recharge, septic systems, and sprayfield disposal of
treated wastewater. These criteria should be put into practice as soon as practicable, guiding
decisions on land use, pollution permits, remedial actions, etc.
Recommendation 5. Hydrologic Observatory and Research
A Hydrologic Observatory should be established and charged with coordinating and facilitating
research activities into a number of issues related to the health of Wakulla Springs and River,
including the following:
The contributing areas, flow paths, and travel times of water and pollutants (including
nitrate and dark water) discharging at Wakulla Springs;
The nature and fate ofpollutants introduced by various sources in the springshed;
The effect ofpollutants and nutrients on the biota in the spring basin and upper reaches
of the Wakulla River (Appendix Gprovides specific \l'gc.\_tin iifor research); and
Best management practices (BMPs)for the treatment and disposal ofwastewater,
retention and treatment of stormwater, and design and operation of septic systems.
Commentary: There are two types of research that can provide a greater degree of
confidence that a given course of restoration is likely to meet with success; the first addresses
ecological cause and effect and the second defines the sources that govern that causative factor.
Well-designed process and synoptic monitoring studies can help address the cause-and-effect
question, while the source relationship with the causative factor is best addressed through the
development of a well-defined mass balance. It would be helpful if this research could be
conducted within the 12-to-18-month time horizon over which other studies are being conducted
on behalf of the COT and Leon County, to confirm the flow linkage between the SESF and
Wakulla Springs.
Further, the state should seriously consider designating Wakulla Springs and River as an
Aquatic Preserve (a state designation) to protect the ecosystem's esthetic, biological, and
scientific values for the enjoyment of future generations, and/or a National Estuarine Research
Reserve (a national designation) to establish the area for long-term research, education and
stewardship. Such designations would promote the protection of the springs, river, and estuary,
and would encourage research efforts to generate data that can be extrapolated to other important
spring ecosystems in Florida and the rest of the country. Wakulla Springs and River, and the St.
Marks estuary, represent an opportunity to study systematically the effects of land use changes
and water quality; this information would be useful in addressing water quality issues in the
state's many other springs. Alternative strategies include making the springs, river, and estuary a
working case study to promote scientific research, or to apply for a broader research designation
through the National Science Foundation. Whatever designation the Wakulla Springs ecosystem
is afforded, there is a need to provide a high level of water-quality protection to this unique and
valuable ecosystem and, to assist in achieving this, there is a need to develop a Wakulla Springs









research station on site to investigate springs water-quality issues using the staffing resources
of the nearby FDEP, US Geological Survey and Northwest Florida Water Management District
offices, together with faculty and staff of Florida State University, Florida A&M University and
the FAMU-FSU College of Engineering.
Recommendation 6. Public Education
A concerted, prolonged and properly funded effort should be made to educate the public on the
importance of the previous recommendations to the long-term health of Wakulla Springs and its
ecosystems.
Commentary: This effort should involve state and local governments and agencies, public-
interest groups and the geotechnical community. Coordination of public-outreach and education
activities could be made part of the charge of the Hydrologic Observatory proposed in
Recommendation 5.











CHAPTER 1. INTRODUCTION AND BACKGROUND

1.1 Purpose of this Report
This document is an outgrowth of a workshop entitled Solving Water Pollution Problems in
the Wakulla Springshed of North Florida: Science and Technology at Work for a Better
Florida that was held at the Center for Professional Development at Florida State University on
May 12 and 13, 2005. The workshop was sponsored by 1000 Friends of Florida, Hydrogeology
Consortium, Florida Department of Environmental Protection (FDEP), Florida Geological
Survey (FGS), Florida Department of Health, Florida Department of Community Affairs,
Hazlett-Kincaid, Inc., Northwest Florida Water Management District (NWFWMD), city of
Tallahassee (COT), and Leon and Wakulla Counties.
The workshop focused on two major issues in Wakulla Springs and the upper reaches of the
Wakulla River: nutrient loading, which is believed to be responsible for the rampant growth of
invasive exotic plants and algae, and the loss of water clarity.
A recent report by the NWFWMD (Chelette et al., 2002) identified seven sources of nitrate
to the lower St. Marks-Wakulla Rivers watershed: atmospheric deposition, wastewater
(generated by wastewater treatment facilities, or WWTFs), residuals (sewage sludge), septic
systems (onsite sewage treatment and disposal systems, or OSTDSs), commercial fertilizer,
sinking streams, and livestock. The present report considers in detail the following sources:
WWTFs including sprayfield operations and the disposal of residuals,
Septic systems and
Stormwater and fertilizers.

Note: the COT is phasing out the disposal of residuals within the springshed and will
eliminate this source of nutrient entirely in the near future.
Atmospheric deposition was not considered at the workshop because it is not specifically a
local source, and resolving the issue will require a fundamental change in our national technical
infrastructure. In addition, a large percentage of the nitrogen from this source is taken up by
plants or otherwise lost, so that little, if any, enters the aquifer. Similarly, livestock are not
considered in the present report, as they are a minor nitrogen source in the Wakulla springshed.
To explore further and to provide an understanding of the information presented in the
workshop, the organizers charged a peer review committee (consisting of the four authors of this
document) to assess the state of Wakulla Springs and to recommend actions aimed at improving
the spring basin and the upper reaches of the Wakulla River, focusing on nutrient loading and the
loss of water clarity. Part of this charge consisted of a set of key questions to be answered by the
committee. Appendices A and B list the questions posed and the committee's answers,
respectively.
This report is based on information presented at the workshop, together with pertinent
information obtained from other sources both prior to and following the workshop. Earlier drafts
of this report were circulated to a number of specialists for their comments (Appendix C) to









ensure that the assessment and recommendations presented here are based on the best available
scientific information.
The remainder of this chapter discusses the findings of other major reports on the issue of
nitrate contamination and provides background information on the physical setting of the
Wakulla springshed (including surface water and groundwater). Chapter 2 describes the extent
and causes of the nitrate loading and water clarity issues. Chapter 3 contains an evaluation of the
sources of the problems and Chapter 4 discusses potential solutions and mitigating strategies.
The summary of the findings and specific recommendations of the peer review committee are
found in the Executive Summary.

1.2 Other Reports
A great deal of work has already been carried out in terms of scientific research, assessments of issues
affecting springs and springsheds statewide, and discussions on the best approaches to restoring and
protecting Florida's springs. This section summarizes recent major reports that are useful in
understanding and addressing the water-quality problems in Wakulla Springs and River.

1.2.1. Nitrate Loading and Non-point Source Pollution in the Lower St. Marks-Wakulla
Rivers Watershed

This subsection summarizes the principal findings of a comprehensive report (Chelette et al,
2002) that was developed as a component of the NWFWMD's St. Marks Surface Water
Improvement and Management Program, assessing the risk to drinking-water wells and surface
waterbodies from nitrate contamination in the lower St. Marks-Wakulla watershed. While the
report provides detailed information on the hydrology of the watershed, water quality in the
Floridan aquifer, sources of nitrogen, a nitrogen budget, and the results of nitrogen-fate
modeling, it stops short of providing specific solutions to the problem of nitrate contamination.
The report's principal conclusions and recommendations for the Wakulla springshed are as
follows:
The quality of water discharged from Wakulla Springs is predominantly determined by
the quality of groundwater in the Floridan aquifer. Under low-flow conditions,
discharge from Wakulla Springs is composed almost entirely of groundwater from the
Floridan aquifer.
Under high-flow conditions, discharge from Wakulla Springs is still primarily composed
ofFloridan-aquifer groundwater. Surface-water inputs (via sinking streams and other
direct, conduit-type inputs to the Floridan aquifer) at all times constitute a relatively
smallfraction of the total discharge from the spring.
The capture zone (or springshed) for springs within the Woodville Karst Plain (WKP)
extends as far north as Mitchell County in southwest Georgia. Volumetrically, most of
the water discharged through Wakulla Springs is recharge that occurs on the WKP near
the spring or farther north in Leon County. The spring is imbedded in a zone of very high
hydraulic conductivity that funnels water to the spring from the northwest, north and
northeast. The COT, suburbanized Leon County and developing portions of Wakulla
County overlie the spring capture zone.









* Given its proximity to both the spring and to the zone of high hydraulic conductivity lying
north of the spring, it is a virtual certainty that Ames Sink contributes water to Wakulla
Springs. (This conjecture has subsequently been confirmed by tracing studies.) Fisher
and Black Creeks, which lie near the presumptive western edge of the capture zone,
probably contribute water to Wakulla Springs. Lost Creek sinks too far south to
contribute water to the spring; this water likely discharges through the Spring Creek
group.
* Potentiometric surface mapping indicates a significant flow of groundwater from the
Leon Sinks area bypassing west of Wakulla Springs. (However, since this report was
written, groundwater tracing has demonstrated a connection between the Big Dismal
Turner Sink conduit system and Wakulla Springs.)
* Based on Stream-Condition-Index measurements and other observations, the biota of
Wakulla Springs and the upper river have been adversely perturbed by anthropogenic
impacts. These appear to have resulted from the introduction of invasive exotic plants
and increased nutrient discharge from the spring. Effective efforts to manage Wakulla
Springs as an aesthetic and recreational resource require an improved understanding of
the complex interrelationship between nutrient concentrations in spring water and
attendant biological perturbations.
* Nitrate concentrations in waters discharging from Wakulla Springs have increased
threefold in the past 25 year, from roughly 80,000 kilograms of nitrogen per year (kg-
N/yr) in the mid- to late 1970s to 270,000 kg-N/yr currently. Isotopic analyses indicate
that both inorganic and organic sources contribute to the nitrogen load discharged by
the spring.
* Assuming that removal efficiencies remain at present levels, the nitrogen load discharged
through the spring will increase as the populations ofLeon and Wakulla Counties
increase.
* Nitrate concentrations in Floridan-aquifer groundwaters beneath the semiconfined
potion ofLeon County have been constant or slightly increasing over the past 20 years.
This implies that the flux of nitrate from the semiconfined Floridan aquifer into the
unconfined Floridan aquifer (along the Cody Scarp) has been relatively constant over
this period. The estimated nitrate-N mass flux across this boundary under present
conditions is 73, 000 kg-N/yr. (Note that the fraction of this flux reaching Wakulla
Springs is uncertain.)
* The increase in nitrate output from Wakulla Springs over the past 25 years is largely
attributable to inputs that have occurred south of the Cody Scarp.
* At the scale of the entire study area and under current conditions, atmospheric deposition
accounts for about half the total nitrogen load applied to the landscape. OSTDSs,
WWTFs, commercial fertilizer, livestock, and sinking streams account for the other half.
Ignoring atmospheric deposition and sinking-stream inputs, OSTDSs, livestock and
commercial fertilizers are estimated to contribute about 60 percent of the total nitrogen
load applied to the landscape, with WWTFs contributing the remaining 40percent.









* At the scale of the Wakulla Springs contributory area and under current conditions,
WWTFs are estimated to contribute just over half of the nitrogen load applied to the
landscape. Atmospheric deposition, OSTDSs, livestock, commercial fertilizer, and
sinking streams contribute the remainder.
* The analysis presented here presumes a state of quasi-equilibrium between nitrogen
applications to the landscape and nitrogen loads discharged through down-gradient
springs. Assuming that the ability of the landscape and hydrosphere to provide
denitrification is more or less constant, decreasing the nutrient discharge from springs
will require reducing nitrogen loads to the landscape.
* Technologies that provide for denitrification in OSTDSs (beyond currently applied
technologies) should be encouraged, particularly south of the Cody Scarp and in the
Wakulla Springs contributory area. To the extent that they reduce the potential numbers
of OSTDSs (or other pollution sources), land acquisitions provide positive water-quality
benefits.
* If additional denitrification of large, more concentrated sources (e.g., WWTFs) is
contemplated, this should be preceded by consideration of the benefit likely to be derived.
Effective cost-benefit analysis requires a better understanding of both the fate and
transport of nutrients originating at these facilities and the adverse effect of elevated
nutrient levels on receiving surface waters.
* Nitrogen introduced to the environment via WWTF effluent and residuals disposal
comprises a relatively large fraction of the total nutrient budget of the study area. The
fate of nitrogen introduced to groundwater from these sites is poorly understood, beyond
the immediate site perimeters. While the nitrogen budget presented here assumes this
nitrogen is reaching Wakulla Springs, there is no direct evidence for this. Additional
data collection and monitoring will be required to prove this hypothesis. Monitoring the
evolution of nutrient plumes emanating from concentrated points of application is not a
trivial undertaking. The effort is significantly complicated by the distances involved and
by the cryptic way in which conduit flow in a karst environment influences contaminant
transport. (Several studies are ongoing or planned to resolve this question.)
* Continuing, long-term monitoring ofstream flow and water quality (potentially Munson
Slough; Black, Fisher and Lost Creeks; and the St. Marks River) and spring flow
(Wakulla Springs and St. Marks Rise) will provide a better understanding of
groundwater-surface water interactions on the WKP.
* The age dating of ground and surface waters is an important tool in identifying
groundwater-surface water interactions (and associated time scales). The continued
speciation of nitrogen isotopes willfurther elucidate the significance of various inputs of
organic and inorganic nitrogen to groundwaters.
* This study greatly benefited from accurate and precise data on effluent and residual
loads. Future studies in this (and other areas) will benefit from similar high-quality data
for other nitrogen streams, in addition to data on effluent and residuals.









1.2.2. Woodville Recharge Basin Aquifer Protection Study, Phases I and I


This report was prepared for Leon County in April 2005 by McGlynn Laboratories Inc (Prime
Consultant), Tallahassee-Leon County GIS (Subconsultant), URS Corp. (Subconsultant) and
AE&R Group (Subconsultant).
1.2.2.1 The Impact of the Southeast Sprayfield on Wakulla Springs.
The Southeast Sprayfield (SESF) appears to contaminate the shallow surficial sand aquifer
only on the SESF property and areas immediately thereto; most of the nutrients sink rapidly to
the deeper parts of the aquifer. Karst windows, open to the aquifer, between the SESF and
Wakulla Springs have nitrate concentrations significantly elevated above background levels.
When nitrate concentrations in these karst features are plotted versus downstream distance, a
dilution factor of approximately 10% per mile is evident, indicating that flow occurs primarily
within conduits. This data, together with the piezometric elevations and the lack of nitrate in the
St. Marks Rise, indicates that the nitrate-laden groundwater flows from the SESF in the direction
of Wakulla Springs. Wakulla Springs is enriched with nitrate. Nitrogen/phosphorus ratios
suggest that Wakulla Springs is phosphate limited; the enhanced growth of submerged aquatic
vegetation and aquatic algae at the spring could be the result of phosphate enrichment (but see
Appendix E). While nitrate derives from wastewater inputs to the aquifer (SESF and OSTDSs),
phosphate could originate from urban storm water entering open karst features. This phosphate
is probably rapidly transported via subterranean conduits to the spring. Lakes Lafayette, Jackson
and Munson, which contain open karst features, are likely sources of phosphate loading.
1.2.2.2 Monitoring and Permit Data Reviewed
Data obtained from the SESF monitoring wells shows that the nitrate is occurring primarily
in deeper (between 100 and 125 feet) wells near the southern boundary of the SESF. The soils at
the SESF are very permeable, and the SESF effluent descends locally, rather than mounds, and
may travel south at even greater depths. Water samples from two of the wells on the southern
boundary of the SESF have averaged over 6 milligrams per liter (mg/L) nitrate over the last 4
years (see Figure 2).
Select historical graphs of the SESF well data for nitrate, all with rather high nitrate
concentrations, show maximum nitrate concentrations occurring in 1989. This appears to be due
to fertilizers applied to the SESF through the center-pivot irrigation system. The subsequent
reduction in nitrate concentrations occurred when the farmer switched to a time-release fertilizer.
After 1989, monitoring-well nitrate concentrations dropped several mg/L and have remained
rather constant except for a few incidents of elevated nitrate levels caused by problems with the
SESF effluent quality in 2002 when the SESF was holding back residuals (see Figure 3). This
data has been independently compiled by William Landing; see 3.3.2.







CoT Sprayfield Wells, 2000-2004, Average Nitrate
7.0
6.0
m 5.0-
S4.0
a 3.0
2.0
1.0-
0.0 -
CO CO C14 C- CO I-- C n 0D 0) c OI Z MO CM CQ co
m M M m [ m m, M M mJ' co

Well

Figure 2: Average nitrate concentrations in ground water sampled from the SESF monitoring wells
Nitrate analyzed by the COT's Water Quality Laboratory. Graphics produced and analyzed by MLI.
Prepared for Leon County by McGlynn Laboratories Inc. See Figure 4for well I,, aI ,ill i


CoT Sprayfield Well Data, SE53, Nitrate
12

10

l S l

6-

4

2






Figure 3: Nitrate datafrom 1986 to 2004for the SESF well with the highest average nitrate
concentratiions
Well SE53 is on the ,,iih, ii boundary of the SESF (see Figure 4) and is about 100feet deep. Mstands
for the month ofMarch. Nitrate w (n ii i ail "i s in August 2002 exceeded 10 mg/L in one instance. Nitrate
analyzed by the COT Water Quality Laboratory. Graphics produced and analyzed by ML. Preparedfor
Leon County by McGlynn Laboratories Inc.
z 4g 02z -,,, ,*, r' zz-,












Leon County by McGlynn Laboratories Inc.





































Figure 4: Well locations on the SESF

From Chelette et al., 2002. Prepared for Leon County by McGlynn Laboratories Inc.

1.2.3. A Strategy for Water Quality Protection: Wastewater Treatment in the Wekiva
Springs Area

This 2004 FDEP report focuses on developing a strategy to reduce nutrient loading to
surface water and groundwater in the Wekiva springshed from wastewater facilities regulated by
FDEP (other contributing sources of nitrogen in the springshed are being addressed by other
agencies or in different time frames).3 The report's conclusions are useful for the purposes of
this analysis because the aquifer vulnerability in the Wekiva area is comparable to that of the
Wakulla Springs area, and because specific and detailed strategies for addressing the nitrate
contamination issue are provided.
The Wekiva springshed, which covers about 300,000 acres, contains 27 named springs that
discharge an average of 71 mgd. Like the Wakulla springshed, the Wekiva region is underlain
by karst geology and characterized by sinkholes, caves, and springs. Generally, higher
topographic regions to the west and south of Wekiva Springs recharge the Floridan aquifer
system, which in turn feeds the springs and wetlands at lower elevations.


FDEP. December 2004. A strategy for water quality protection: Wastewater treatment in the Wekiva Study Area. Available at
http://www.dep.state.fl.us/central/Home/Admin/WekivaReportDecember2004.pdf.
gr7,_













1.23.A trtegfo Wte Quliy roecton Wstwatr retmnt n heWeiv









FDEP reviewed existing treatment at the 48 WWTFs (large and small) in the Wekiva River
springshed, as well as more advanced nitrogen-removal technologies and associated costs. To
focus on reducing nutrient loading from facilities that would most directly affect current or future
water quality in Wekiva Springs, the statewide Florida Aquifer Vulnerability Assessment was
applied to the Wekiva area.
The report provides a number of recommendations involving more stringent requirements
for wastewater treatment. FDEP would not be able to implement these requirements through
rulemaking under its existing authorities. However, these could be adopted by crafting a
legislative bill; this has already been done for the Tampa Bay Estuary, the Indian River Lagoon,
and most recently, the Florida Keys. Local governments might also need state assistance in
implementing the requirements and identifying funding sources.
FDEP's specific conclusions and recommendations for reducing nutrient loading in the
Wekiva springshed are as follows:
Adopt three protection zones tailored to the specific aquifer vulnerability of the Wekiva area.
Adopt three levels of enhanced wastewater-treatment requirements for groundwater discharges:

Primary Protection Zone (requiring the highest level of wastewater treatment)
No new rapid-rate or restricted-access slow-rate land application systems.
Existing large WWTFs4 with rapid-rate systems as theprimary reuse method would be
required to reduce nitrogen in applied reclaimed water to 3 mg/L total nitrogen as N
within 5 years. Where rapid-rate systems were used only as backup to the regional reuse
irrigation system, they would be considered to be part of the regional system.
Existing large WWTFs with regional reuse irrigation systems or restricted-access
irrigation systems would be required to reduce nitrogen in the applied reclaimed water
to 10 mg/L total nitrogen as N within 5 years.
Existing small WWTFs5 would be required to connect to a regional WWTF within 5
years, or reduce nitrogen in reclaimed water to 10 mg/L total nitrogen as N.
No land application of wastewater residuals.

Secondary Protection Zone
Existing large WWTFs with rapid-rate systems as the primary reuse method would be
required to reduce nitrogen in applied reclaimed water to 6 mg/L total nitrogen as N
within 5 years. New systems would have to meet this requirement. Where rapid-rate
systems were used only as backup to the regional reuse irrigation system, they would be
considered to be part of the regional reuse system.
Existing large WWTFs with regional reuse irrigation systems or restricted-access
irrigation systems would be required to reduce nitrogen in the applied reclaimed water



4 Large wastewater treatment facilities are those with a permitted capacity of 100,000 gallons per day (gpd) and greater.
5 Small wastewater treatment facilities are those with a permitted capacity of less than 100,000 gpd.









to 10 mg/L total nitrogen as N within 5 years. New systems would be required to meet
this requirement.
Existing small WWTFs would be required to connect to a regional WWTF within 10
years or reduce nitrogen in reclaimed water to 10 mg/L total nitrogen as N.
No land application of wastewater residuals.

Tertiary Protection Zone
Facilities must meet the existing regulations, with the possibility of requiring an increased
monitoring program. The following enhanced wastewater-treatment requirements would be
adopted for surface-water discharges:
New surface-water discharges would only be permitted as backup to a regional reuse
system and would have to comply with the provisions of the APRICOT Act, as codified in
Section 403.086(5), Florida Statutes (F.S.).
Existing surface-water discharges would be limited to a backup to a regional reuse
system, and would constitute no more than 30% of the wastewater-treatment-plant flow
on an annual average basis. Facilities in this category would be required to be in
compliance within 5 years.

1.2.4. Florida's Springs: Strategies for Protection & Restoration

This report6 by the Florida Springs Task Force presents a number of broad-based strategies
for preserving and restoring Florida's springs statewide. These focus on four different areas, as
follows:
Outreach strategies center on education (including the development of an up-to-date
database of water-quality parameters) and the development of spring-basin working
groups composed ofstakeholders from all levels ofgovernment, agricultural and
commercial interests, environmental groups, and citizens.
Information strategies include springs-monitoring programs and scientific research to
support decision making.
Regulation strategies include the following:
Enforcing and strengthening existing regulations and groundwater standards,
Applying a nutrient managementplan that includes water-quality-based best
management practices (BMPs),
Expanding Outstanding Florida Water (OFW) designations to include streams and
karst features that have hydrologic connections to OFWs,
Identifying and designating additional springs as OFWs,
Creating special protection and regulation for springs and spring-recharge basins by
rule,



6 Florida Springs Task Force. November 2000. Florida's Springs: Strategies for Protection & Restoration. Available at
http://www.dep.state.fl.us/sprinas/reports/FloridaSprinqsReport.pdf.









Establishing and applying quantifiable ground-water quality standards for nutrients
that protect the ecological quality and health of surface water systems,
Protecting springflows and aquifers by establishing minimumflows and levels,
Implementing and expanding water conservation measures and requirements,
Developing alternative water sources,
Evaluating and implementing aquifer recharge and storage technologies, and
Protecting rare, threatened, and endangered species.
SFunding strategies include creating a Springs Protection and Restoration Fund,
increasing funding for water quality and biological monitoring, funding a springs-
research grant program, funding educational programs, and providing funding to help
landowners and businesses implement BMPs and clean up sinkholes.

1.2.5. Protecting Florida's Springs: Land Use Planning Strategies and Best
Management Practices

This report7 provides a wide range of detailed information and guidance on the following:
Developing and implementing comprehensive planning strategies by using Florida's
comprehensive-planning process, establishing a working group, adopting a resolution of
support for springshed protection, collecting data and mapping resources, establishing
springshed protection zones, creating an overlay protection district, using other land-use
planning tools, using acquisition and easement strategies to protect sensitive areas,
establishing voluntary stewardship programs, and adopting Comprehensive Plan policies
for protecting springsheds.
Managing development impacts by choosing appropriate sites, designing sites
appropriately, using sensitive landscape design and management strategies, using
effective erosion and sediment controls, addressing stormwater and wastewater
management issues, using a combination of BMPs, encouraging water conservation
measures, and increasing public awareness. The report also includes information on
specific policy and permitting considerations for karst areas.
For golf courses, using a springshed-based approach to siting and development,
selecting appropriate sites, integrating environmental planning, establishing a
construction management program, and creating a natural resource management plan.
Implementing agricultural and silvicultural BMPs.
Developing a management plan for public recreation and controlling the impacts of
public use.

1.3 Regulatory Framework
The nutrient enrichment of surface waterbodies can result from point-source and non-point-
source pollution. Nutrient enrichment from nitrogen and phosphorus can disrupt ecosystems by


7 Florida Department of Community Affairs and FDEP. November 2002. Protecting Florida's Springs: Land Use Planning
Strategies and Best Management Practices. Available at
http://www.dca.state.fl.us/fdcp/DCP/publications/sprinqsmanual.pdf.









fueling the rampant growth of aquatic plants. The Surface Water Quality Standards Rule,
Chapter 62-302, Florida Administrative Code (FAC), states that excessive nutrients (total
nitrogen and total phosphorus) constitute one of the most serious threats to water quality in
Florida and that it is FDEP's policy to limit the introduction of nutrients of anthropogenic origin
into Florida's waters. This legislation requires that particular consideration be given to
protecting waters with high nutrient concentrations, or sensitivity to nutrient loadings, from
further nutrient enrichment. Chapter 62-302, FAC, also requires that particular consideration be
given to protecting waters currently containing very low nutrient concentrations (less than 0.3
mg/L total nitrogen or less than 0.04 mg/L total phosphorus) from nutrient enrichment.
Section 62-302.530, FAC, lists the following narrative surface water quality criteria for
nutrients:
Limit discharges of nutrients as needed to prevent violations of other surface-water
quality standards contained in Chapter 62-302. Anthropogenic nutrient enrichment
(total nitrogen or total phosphorus) is considered degradation in relation to the
provisions of Sections 62-302.300 (antidegradation policy), 62-302.700 (OFWs), and 62-
4.242 (antidegradation permitting requirements).
In no case shall the nutrient concentration of a body of water be altered so as to cause an
imbalance in natural populations of aquatic flora or fauna.

1.4 Physical Setting
The Wakulla-St. Marks Basin, located in the Big Bend region of the Florida Panhandle
(Figure 5), drains 1,204 square miles.8 One of the more pristine areas of Florida, it has a much
lower population density and fewer stresses on the environment than many other parts of the
state. Large areas remain relatively undeveloped, and many waterbodies have not been
significantly modified (see Figure 7).
The Wakulla Springs and River have historically had exceptional ecological and recreational
value. The river, with its shallow marshes, old-growth floodplain forest, upland hardwood
forest, and longleaf pine forest, provides habitat for numerous native animal and plant species.
Tallahassee, the region's largest city in size and in population (Tallahassee's 2004
population was estimated at 169,000; Leon County's at 264,000), is located between the
Ochlockonee and St. Marks Rivers, and its urban and suburban areas lie in both basins. Other,
much smaller population centers in the area include Woodville and Bradfordville in Leon
County and Crawfordville, Sopchoppy, St. Marks, Medart, Panacea, and Ochlockonee Bay in
Wakulla County. Many of those centers in Wakulla County lie to the south of the Wakulla
springshed.






8 Portions of the text in this section are excerpted or adapted from the St. Marks River watershed pilot
project report (unpublished), Hand, J., D. Tterlikkis, P. Lee, T. Singleton, and L. Lord (Tallahassee,
Florida: FDEP); and the Ochlochonee-St. Marks Basin assessment report, August 2003 (Tallahassee,
Florida: FDEP).











Figure 5: Florida portion of the Wakulla-St. Marks watershed
From Chelette et al., 2002


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1.4.1 Surface Water Features


The surface-water hydrology of the Wakulla-St. Marks Basin is disjointed, with no
integrated drainage from most of the northern part of the basin, a short coastal drainage system
composed of local streams draining coastal regions, and the St. Marks River being the only
somewhat continuous integrated drainage system. There are more than 590 total river miles in
the basin, of which more than 460 miles are perennial rivers and streams.
The 40-mile-long St. Marks River, which originates as an intermittent stream in the
Tallahassee Hills, in northeastern Leon County near U. S. Highway 90, drains about 871 square
miles. From its headwaters, the St. Marks remains swampy and poorly defined as it flows
southward to the Cody Scarp through low-density residential areas, pine plantations, and
wetlands, receiving direct flow from a few tributaries.
Downstream, the Limestone Creek system, Gum Creek, and Willow Creek feed the river.
Below this area, the Horn Spring group and Chicken Branch contribute appreciably to the flow
of the St. Marks River. From just north of the Leon-Wakulla County line, the St. Marks River
enters the WKP and is fed by Floridan aquifer springs, becoming wider and clearer as more
groundwater enters from spring flows.
To the south, at Natural Bridge, the St. Marks River disappears underground. It reemerges a
mile downstream at St. Marks Spring (also known as St. Marks Rise) as a spring-run river that is
considerably larger, and with different chemical characteristics, than the stream that disappears at
Natural Bridge. After emerging at St. Marks Spring, the St. Marks River flows southward as a
well-defined spring-run river, flowing at an average rate of 460 mgd (21 m3/s). Along its course
south of the St. Marks Rise, many small springs contribute to the river's flow.
The St. Marks joins the Wakulla River, its largest tributary, in east-central Wakulla County.
The Wakulla, a spring-run river fed mainly by the Floridan aquifer, originates at Wakulla
Springs and flows south for approximately 10 miles to its confluence with the St. Marks River.
From the confluence, the St. Marks widens into an estuary, with most river flow confined to a
dredged channel out into Apalachee Bay, approximately 3 miles to the south.
South of Tallahassee in the Sandhills Region, Munson Slough flows into Lake Munson, a
255-acre, cypress-rimmed freshwater lake. The lake is located at the Cody Scarp, the transition
between the Tallahassee Hills and the coastal lowlands known as the Lake Munson Hills. The
Lake-Munson watershed is the largest and most urbanized in the Wakulla-St. Marks Basin.
Formerly a cypress swamp formed in a solution depression, Lake Munson was impounded
decades ago as a mill pond. In the early 1950s, a new dam structure and control valves were
installed to control flooding in the area to the south.
Because Lake Munson has historically received treated wastewater, as well as urban
stormwater from more than half of the COT, through a network of channelized urban streams
and ditches, nutrient loading and sedimentation have caused serious problems. By 1973,
Munson was the most polluted lake in the southeastern United States and was experiencing fish
kills, algal blooms, floating aquatic vegetation, high nutrient and bacteria levels, low game-fish
productivity, and depressed oxygen levels. The outfall from the lake discharges downstream to
Eight Mile Pond and Ames Sink, where it disappears underground into the Floridan aquifer. In
1982, the city began eliminating wastewater effluent discharges to the lake, upgrading









wastewater treatment, and correcting sewage-spill problems. As Chapter 2 of this report makes
clear, however, good intentions may have unintended consequences that is, addressing the
surface-water-quality issue in Lake Munson has created a groundwater-surface water issue in
Wakulla Springs and River.
Other significant sinking streams in the Wakulla/St. Marks Basin include Lost Creek, Fisher
Creek, and Black Creek. These originate in flatwood swamps in the southwestern part of the
basin and, like the St. Marks River, disappear underground into sinkholes after they enter the
WKP, becoming "lost." Recent tracing studies have shown that water in Fisher and Black
Creeks flows to Leon Sinks, with a portion continuing on to Wakulla Springs. Lost Creek is not
believed to contribute to Wakulla Springs. According to Chelette et al. (2002), nitrogen loading
to these streams totals about 72,600 kg-N/yr, with Lost Creek contributing more than half of this
amount, at 39,600 kg-N/yr.
Closer to the coast, numerous tidal streams (creeks) discharge directly to the Gulf of
Mexico. The largest of these, East River and Stoney Bayou, originate at impounded wetlands in
the St. Marks Wildlife Refuge and flow into Apalachee Bay near the mouth of the St. Marks
River, contributing to the Wakulla-St. Marks estuary. Farther to the west is Spring Creek, a
local creek associated with the largest-magnitude spring system in Florida. Tidal fluctuations
dominate flow in these coastal creeks to varying extents.
Apalachee Bay, a large, open, shallow bay in the northern Gulf of Mexico, supports
numerous aquatic habitats and is an important recreational and commercial fishery in the region.
It also contains part of the Big Bend Seagrasses Aquatic Preserve, the most extensive span of
seagrass beds in the country, encompassing about 450,000 acres of seagrass beds and salt marsh.

1.4.2 Groundwater Features

In the Wakulla springshed, and in the surrounding St. Marks Basin, groundwater occurs
primarily in the Floridan aquifer, a vast carbonate aquifer system that is present throughout
virtually all of Florida, as well as southern parts of Alabama, Georgia, and the Carolinas. The
Floridan is the source of water for potable supply, irrigation, and industrial uses throughout most
of the region. The Tallahassee municipal wellfield is the primary user of groundwater from this
aquifer within the Wakulla springshed.
In the Tifton Uplands/Tallahassee Hills, north of the Cody Scarp, the Floridan aquifer is
confined by a thick overburden of sediment that helps to protect against contamination.
However, breaches in the confining layer, mainly sinkholes, provide pathways for recharge and
the introduction of contaminants. The unconfined or poorly confined regions of the Floridan
aquifer (regions with less than 25 feet of sediment cover) extend well north of the Cody Scarp
into the southern part of the Tallahassee urban area.
Woodville Karst Plain
The 288,000-acre WKP, which is part of the Gulf Coastal Lowland physiographic region,
extends from the southern edge of Tallahassee to the Gulf of Mexico, in southeastern Leon
County and eastern Wakulla County. Its northern border, the Cody Scarp, formed about 100,000
years when ocean levels rose. The WKP is bounded on the west by the Apalachicola Lowlands
(which begin west of U. S. Highway 319) and on the east by the Wacissa River in Jefferson
County; see Figure 6.









Capped by less than 20 feet of quartz sands, the WKP gently slopes toward the Gulf. Relict
dunes and terraces associated with ancient sea stands now mantle St. Marks (early Miocene) and
Suwannee (Oligocene) Limestones. The porous sands allow water to move rapidly to the
underlying soluble carbonates (limestone) that are present at or near the land surface, recharging
the Floridan aquifer in the area. Over time, this acidic water has dissolved the limestone,
resulting in karst terrain characterized by abundant springs, sinks, sinking streams, dolines, karst
windows (collapsed segments of underground streams), swallets (caves or holes that swallow a
stream), and dolines (collapsed caves), as well as a well-developed system of tunnels or conduits.
As discussed earlier in this chapter, a number of "lost" rivers in the area flow a short way before
being captured by subterranean conduits. Dissolution continues to wear down the entire
foundation of the WKP.
While some of these hundreds of depressions remain dry, most hold water, forming lakes
and swamps. If confined to the surface, the water is typically tannic, while depressions that
breach the aquifer are often filled with clear groundwater-unless fouled by murky runoff or
topped with algae-laden thermoclines. These waters provide recharge to groundwater, the
conduit network, springs, and eventually the rivers.
Of Florida's 27 first-magnitude springs (i.e., discharging more than 64.6 mgd) about one-
fourth are found in the WKP. These include Spring Creek Springs, St. Marks Spring, Wakulla
Springs, Wacissa Springs, Kini Spring, River Sink Spring, and Natural Bridge Spring. Nine
other named springs and numerous unnamed, smaller springs and seeps are also found in the
WKP. Springs provide most of the flow in the St. Marks River (downstream of Tram Road) and
virtually all of the flow in the Wakulla River.
Currently, more than 37 miles of conduits in the WKP have been physically mapped by
cave-diving explorers. The Leon Sinks Cave system, with 58,444 feet (more than 11 miles) of
mapped groundwater passages, is the longest surveyed underwater cave in the United States.
This cave stream, which is exposed to the surface by 26 karst windows, probably contributes
flow at both Wakulla Springs and the Spring Creek group.
In Figure 6, note that water from the disappearing streams (Fisher Creek, Black Creek,
and Munson Slough) flows to Wakulla Springs either directly or via a flow path that intersects
Wakulla Cave somewhere in the southernmost region of the cave system, and that groundwater
flow directions, as predicted by the potentiometric surface contours (flow is perpendicular to the
contours in the down-gradient direction), in the region between Wakulla Springs and the SESF is
also toward Wakulla Springs.
Wakulla Springs
Wakulla Springs is the centerpiece of the 2,680-acre Edward Ball Wakulla Springs State
Park. One of the largest and deepest freshwater springs in the world, its surface expression
covers about 3 acres. On average, 250 mgd of water flow from the spring vent, creating the
Wakulla River. The spring is the above-ground representation of a vast underground water
resource, the Floridan aquifer-a thick, subterranean, water-bearing layer of porous limestone.









1 "-- . . , .'T ,
.1,_. .. ; ,.. .. .,

;^i~ 1 .iL*'; pL!c -,
:'.,.' -M^ .. ... ..' *''_*i *... B i _; X ... '
S .. ., ^ i f . .,


S. -- ... SESF









.' .-' .j > _. .., ^ ^. ^g.







Sprisf r
g'?1 Q N., N








Figure 6: A map of the







showingthe distribution andthickness of confining material, tracer-defined ground water flow i and
position of the major springs and aves in the a at Mars Basin
-pnngs '" -. r-t+... .r9












Fi 6: A mapof teWK




showing the distribution and thickness of confining material, tracer-defined ground waterflow I I, ii' and
the potentiometric surface of the upper Floridan aquifer, as defined by water level in wells relative to the
position of the major springs and caves in the Wakulla St. Marks Basin










Figure 7 shows a projection view (looking southwestward) of the cave system beneath
Wakulla Springs. In this figure distance northward is shown on the left-hand side of the graphic,
with distance eastward shown to the right. The upper portion shows a color-filled contour map
of the land surface and channel bottom in the Wakulla River (in blue). Part of a US Geological
Survey (USGS) topographic quadrangle (Crawfordville East USGS 7.5 min) is projected beneath
the cave system (shown in gray). It has been modified to show the approximate location of an
east-west groundwater divide (the pink band across the center of the graphic), as defined by flow
directions in the cave reported by Woodville Karst Plain Project explorers. The largest tunnels
trend south, away from Wakulla Springs, while the smaller tunnels trend north toward the
projected recharge area. Note that the groundwater divide crosses the cave south of Wakulla
Springs in the largest tunnels, suggesting that the spring's base flow is derived primarily from
water flowing south through the smaller tunnels.


Wakulla Cave: Woodville Karst Plain, North Florida


Elevation -iee rr lii
Kl i[ I I ,'1. ll 1 I -IEU II l
12 li i6 E. I .i pIJj .90
Z exaggeration: 5.0
Azimuth: 132.39
Inclination: 21.09


Figure 7: Three-dimensional rendering of the Wakulla cave system
as defined by 1999 survey data. Courtesy ofHazlett-Kincaid, Inc
Figure 8 depicts a water budget for the portion of the Wakulla springshed in the WKP; the
blue line in the center of the map outlines this zone, which covers 95,898 acres. A computer-
modeling program was used to estimate groundwater inflows and outflows to the area around









Wakulla Springs.9 The zone consists of the Floridan aquifer bounded by the Cody Scarp on the
north, the boundary between the confined and unconfined Floridan aquifer in Wakulla County on
the west, and a "no-flow" boundary on the south and east. Wakulla Springs lies at the southern
boundary of the contributory area. The eastern boundary was positioned on the basis of
potentiometric surface maps. The no-flow boundary west of Wakulla Springs is based on the
assumption that the Big Dismal-Turner Sink conduit system eventually flows to Wakulla
Springs, and also that it completely captures Floridan aquifer groundwater flow in its vicinity.
The numbers shown are illustrative; the actual flows are quite variable.


9 The computer program used was Zonebudget (Harbaugh, 1990). The map is taken from Chelette et al., (2002). The text
explaining the graphic was also adapted from this report.


Figure 8: E\inmated water budget for the Wakulla Springs contributory area










CHAPTER 2: WATER QUALITY PROBLEMS IN WAKULLA
SPRINGS AND RIVER

2.1 Nitrate Loading

2.1.1 Nitrate and the Nitrogen Cycle

Nitrate (NO3 ) is a common form of combined nitrogen in most natural surface (fresh)
waters and some groundwater in Florida.10 Nitrate occurs naturally and is also produced by
human activities. Most plants cannot directly use nitrogen in its molecular form (N2), but instead
use nitrogen in the form of either nitrate or ammonium. The primary natural sources of nitrate
on the earth's surface include volcanic activity, lightning, and biological fixation. In biological
fixation, molecular nitrogen is fixed by a special bacterium associated with certain plants, most
notably legumes, sugarcane, and some ferns, and may be further oxidized to nitrate by other
bacteria. Nitrate is also produced from the breakdown of animal manure and dead plants.

According to Vitousek et al. (1997) "Human activities are greatly increasing the amount of
nitrogen cycling between the living world and the soil, water, and atmosphere. In fact, humans
have already doubled the rate of nitrogen entering the land-based nitrogen cycle, and that rate is
continuing to climb." Elevated concentrations of nitrate in groundwater commonly result from
agricultural and urban land-use practices in groundwater recharge areas. The proximity of these
areas to points of discharge (i.e., springs) can result in elevated nitrate levels in surface waters.
Nitrate ions are quite mobile in groundwater and surface water. There are essentially no
solubility constraints on the amounts found in groundwater. The nitrate ion does not sorb to
soils or rock, and thus nitrate can move freely through the soil and the groundwater system.
Groundwater in highly permeable sediment or fractured rock generally contains dissolved
oxygen, as does most surface water. In this aerobic environment, nitrate ions can migrate long
distances.
In surface waters, nitrate acts as a fertilizer for aquatic plants. Nitrate levels much less than
1 mg/L can cause a significant shift in the balance of springs' ecological communities. With an
overly abundant supply of nutrients, aquatic plants and algae grow rapidly, filling the water with
thick masses of green vegetation. Oxygen in the water is used up, leading to the depletion of
fish, and other species.

2.1.2 Extent and Causes of Nitrate Contamination

Nitrate does not naturally occur in Florida's groundwater at concentrations higher than 0.1
mg/L. Increasing nitrate levels in the Floridan aquifer in the WKP in Leon and Wakulla
Counties, as well as in water emanating from Wakulla Springs, are a significant ecological
concern. Because a spring is a discharge point, the quality of spring water can be considered
characteristic of a large cross-section of the aquifer. Water comes to Wakulla Springs from a
number of sources. An increase in nitrate concentration in Wakulla Springs can be interpreted

10 Portions of the text in this chapter are adapted from the St. Marks River watershed pilot project report (unpublished), by J.
Hand, D. Tterlikkis, P. Lee, T. Singleton, and L. Lord (Tallahassee, Florida: FDEP).









either as a widespread increase in nitrate concentration in the groundwater from a large area of
the aquifer (resulting, for example, from septic tanks) or as a significant increase in one or a few
specific inputs (such as a WWTF). Nitrate sources for Wakulla Springs appear to be a
combination of both types, with the latter making the larger contribution.
Figure 9 illustrates the sources, reservoirs, and pathways of nitrogen in the unconfined
portion of the Wakulla springshed. In this figure the black horizontal line denotes the land
surface. Ignoring the thin veneer of sand, below this is a limestone matrix, the voids of which
are saturated with groundwater below the water table, indicated by the blue horizontal line. The
horizontal striping indicates the water-filled conduit that conveys water and pollutants to
Wakulla Springs. The large checkered arrow denotes stormwater and sinking streams. Inputs of
nitrate consist of atmospheric deposition, fertilizers, septic systems, land spraying, and residuals.
Reservoirs consist of soils, vegetation, and livestock. Brown arrows indicate transfers of
nitrogen. Sinks of nitrogen (not illustrated) include the harvesting and decay of vegetation and
removal of livestock. The nitrogen that enters groundwater finds its way to Wakulla Springs.

Instorm water and atmospheric
spraying and sinkig str eams deposition
residuals |




Figure 9: A s i illustration ofsources, reservoirs, and path s ofnitrogen in the f












portion of the Wakulla springshed



1970 and 1975, and from about 0.6 mg/L to more than 1 mg/L between 1995 and the late 1990's
niae wa dveod to o t dnn ae liestockv vegetation










currently cause no public health concerns, except in isolated instances. However, the
groun r standard for nitrate does nt a ress te fact that, i lorda, ro undwater becoe
Springs


Figure 9: A scheinatic illustration of sources, reservoirs, andpathorays of nitrogen in the iiin on fined
portion of the Wakulla springshed
Coincident with the shifts in the plant community in the Wakulla River described in 2.1.3
(below), concentrations of total nitrogen increased from about 0.2 mg/L to 0.6 mg/L between
1970 and 1975, and from about 0.6 mg/L to more than 1 mg/L between 1995 and the late 1990's
- a fivefold increase in 30 years. The current groundwater quality standard of 10 mg/L of
nitrate was developed to protect drinking-water supplies. Overall, nitrate levels in wells of the
Wakulla-St. Marks Basin are considerably lower than Florida's drinking-water standard and
currently cause no public health concerns, except in isolated instances. However, the
groundwater standard for nitrate does not address the fact that, in Florida, groundwater becomes
surface water when it flows from springs. What is safe for human consumption is, in the case of
nitrate, often detrimental to the ecological health of receiving surface-water bodies. As










discussed in the preceding subsection, nitrate levels far less than 1 mg/L can cause the
degradation of spring ecosystems.

FDEP has rated the ecological health of the upper reaches of the Wakulla River, on average,
as "poor" for the past five years.11 Figure 10 provides these ratings in graphical form. The red
lines on this graph indicate the first three times that herbicide was dispensed in the spring waters
(April 16-18, 2002; November 19-21, 2002; November 12-14, 2003; the last two applications -
May 4-6, 2004 and April 27-29, 2005 occurred later than the timeline on the graph), in an
attempt to reduce the amount of invasive exotic aquatic plants. In addition, the bird count on the
Wakulla River has sharply declined; the number seen in the annual Christmas bird survey
dropped from an average of 1,893 between 1987 and 2002, to less than half that average
recently. In 2003, 888 birds were seen, and 914 in 2004.


30 ewdlert



20




10-

--- ----------------
b + +
:-+ +- i i _ _ - h i -- h _




+ + '


Figure 10: FDEP's Stream Condition Index (SCI) scores and ratings

for the Wakulla River, 2000-04 (above), and stream health wim-n-. January 31, 2005 (/. / 'ir


Data were taken from FDEP's Wakulla Springs' Ecosummaries, available at http:/
bin/reports/search.asp.


depstateflus/1a i-


. .v .vd saef sl sci


vv vv vy









2.1.3 Extent and Causes of Invasive Exotic Aquatic Plant Growth


The Wakulla Springs basin and upper river have seen a progressive shift in both community
structure and the standing crop of primary producers since before at least 1990.12 In 1990,
invasive growths of Brazilian elodea (Egeria densa) and parrot's feather (Myriophyllum
brasiliense) became a concern. Elodea was particularly problematic, extending from the springs
downriver at least 2 miles. Since then, both elodea and parrot's feather, as well as native
eelgrass (Vallisneria), have been increasingly displaced by the macrophyte Hydrilla verticillata,
which has also been accompanied by increases in attached algae (periphyton), although a thick
infestation of elodea continues in Sally Ward Spring and Slough. Hydrilla was first discovered
at the park in April 1997, although its occurrence may not have been detected earlier because it
closely resembles Brazilian elodea. By December 1997, it had spread down the river to the first
turn, approximately one quarter mile past the tour boat dock. During 1998 it invaded the spring
basin, the swimming area, and the area behind the spring. In 1999 it continued to invade
downriver past the first turn and began to occupy large areas in the middle and on the west side
of the river. It also infested the spring to a depth of 60 feet and affected the features on the glass-
bottom boat tour. The channel from the spring to the boat dock had also become infested with
hydrilla. In 2000 hydrilla continued its spread downriver, going beyond the boat tour turnaround
and continuing into the upper edge of the tree islands. With the growth of hydrilla, there was a
drastic decrease in the presence of eelgrass and elodea. Appendix D describes the extensive
efforts undertaken since 1990 to control these undesirable aquatic plants, first by mechanical
harvesting and then by herbicides.
Nitrate values measured in the Wakulla River decrease with distance downstream from the
springs, reflecting the uptake of nitrate by aquatic vegetation, now consisting principally of
hydrilla and algae. An important question is how the changing nitrogen or phosphorus
concentrations in the Wakulla River influence the structure of the plant community. The goal of
restoration is not merely to reduce the standing crop; rather, restoration must also induce a shift
in the dominant macrophytes from hydrilla to a more typical structure (e.g., Vallisneria) that
dominated the springs historically.
No estimates of changes in plant community standing crop or structural dynamics were
presented at the workshop, and thus one of the objectives of this section is to examine the
available data and determine to the extent possible whether nitrogen is the limiting nutrient
governing the primary producer community dynamics. Appendix E presents the cases for and
against nitrogen limitation; these are summarized and evaluated in Chapter 3.
Figures lla and lib compare the variation in the concentrations of chlorophyll a and the
nutrients nitrogen and phosphorus, respectively, in Wakulla Springs between 1965 and the
present. A comparison of the two figures shows that while a shift has occurred in nitrogen
(Figure lla), a similar shift in total phosphorus concentrations in the spring is not apparent
(Figure llb),13 causing many to hypothesize that nitrogen availability is controlling primary
(plant) production rates and community dynamics in Wakulla Springs basin and immediately
downstream. Since mid-1996, when more intensive routine monitoring was initiated, nitrogen

12 This summary is based in large part on reports contributed by S. Savery, Park Biologist.
13 It should be noted that, as part of his presentation, J. Hand of the FDEP indicated that historical concentrations of total
phosphorus measured during -i. ..,iil 1970s may be unreliable because of comparatively insensitive detection limits.












concentrations have clearly declined (see Figure 17), while phosphorus concentrations show no
clear pattern of either an overall increase or decline.



I II1


12 . . . . . . . . . . . . 1.200

10 ," 1.000
hlorophyll a
8- 0.800
-O
6 -. 0.600 "

o 4 0.400

2 Tr 0.200

0 * * * 0.000
1965 1970 1975 1980 1985 1990 1995 2000 2005
Time

10 , . . . . . . 0.100


8 ." 0.080
C, * N
Chlorophy a
O 6 -. . 0.060 -

Q- -
o 4 0.040
0

2 0.020
TP


0 . . . . . . . . . . . . . . . . 0.000
1965 1970 1975 1980 1985 1990 1995 2000 2005
Time




Data courtesy of J. Hand, FDEP.


Figure 11: Variation with time of concentrations ofphytoplankton chlorophyll a and nutrients in
Wakulla Springs, 1965-present

Upper panel (a): chlorophyll a and total nitrogen. Lower panel (b): chlorophyll a and total phosphorus.











2.2 Extent and Causes of Loss of Water Clarity
Wakulla Springs is known for the outstanding clarity of its water. For years, a major
attraction at the park has been the glass-bottom boat ride, where visitors can observe fish and see
down over 100 feet into the main vent of the spring.
However, periodic variations in water clarity have been a problem at Wakulla Springs for as
long as it has operated as a tourist attraction. When dark water is present in the spring basin, the
glass-bottom boats do not operate, because there is not enough visibility (these periods are called
"down days"). There has been some concern that the episodes of dark water are increasing in
number and duration, and that they may be tied to human activity and changes in land use in the
spring recharge area.
To understand the problem, it is first necessary to understand the nature and origin of the
dark water. There are two major causes of reduced transparency in natural waters. The first is
turbidity, which is caused by the suspension of sediment or other materials such as bacteria,
organic debris, and algae in the water. The second is color, a staining of the water that is
naturally occurring, and that is usually caused by dissolved or colloidal organic materials leached
from decaying leaves and other organic materials. The darkness of the water at Wakulla Springs
is believed to be caused by color. The water is dark, but still clear, rather like a glass of iced tea.
Boat operators at Wakulla Springs have noticed that there seemed to be a connection
between the amount of rain and the arrival of dark water in the springs. Often, there would be a
lag time of several days between rainfall and the darkening of the springs. Sometimes, the
springs would darken even when there was only light rain locally (at the springs). At other
times, the springs remained clear when it rained locally. Although daily records of the operation
of the glass-bottom boats had been kept sporadically since the 1940s, in 1987 park personnel
started to record rainfall totals at the park and the days of dark water in the springs.
Figure 12 shows that the amount of dark water and the resulting loss of clarity in the spring
basin, as quantified by the annual percentage of down days for the glass-bottom boats, appear to
be related to rainfall for the period from 1987 through 2004, although the correlation is far from
perfect. Although the percentage of down days has exceeded 80% for the past 3 years, this
recent trend toward more down days is not yet statistically significant.
During periods of low rainfall, most of the water in Wakulla Springs is provided by "base
flow", which is the slow, long-term steady flow of clear water from the rock matrix of the
Floridan aquifer. After heavy rains, flow in Wakulla Springs increases. This initial increase
comes from increased base flow created by the physical, downward pressure of rainwater on the
top of the aquifer, and flow from rainfall that has entered the aquifer immediately adjacent to the
springs. If sufficient rain falls, surface runoff will flow into sinkholes and ponds, and water
levels will start to rise throughout the unconfined Floridan aquifer. As time passes, flow from
the springs continues to increase as more of the recent rainwater flows through the aquifer from
farther away, and as water starts to enter the springs from sinkholes and other surface drainage
features connected to the springs by conduits. Colored water from overflowing swamps and
forested areas enters the aquifer through these sinkholes and, if present in a large enough
quantity, colors the water flowing from the springs.


















100






80





I Oa0 D Days(%
40

30

20




1994 INSn 1n99 1997 1998 1999 2000 2001 2092 2003 2004


Figure 12. Annual percentage of down days for the glass-bottom boats and annual rainfall in inches,
1994-2004.

In each pair of bars, the percentage of down days is on the left (maroon) and annual rainfall (blue) is on
the right.










CHAPTER 3: SOURCES OF THE PROBLEMS

In this chapter the sources of the nutrients (particularly nitrate) are discussed, beginning with
a discussion in 3.1 of the case for nitrogen limitation, followed in 3.2 by a summary of the
sources of nitrate. The history of WWTFs operated by the COT is presented in 3.3. Key
measurements of nitrate concentrations related to the SESF are presented in 3.4. Nitrate
sources due to fertilizer, livestock and septic systems are briefly summarized in 3.5 and 3.6.
Finally, the dark water that emanates from the main vent of Wakulla Springs is briefly discussed
in 3.7.

3.1 Summary and Evaluation of Nitrogen Limitation
Whether the plant growth rate in Wakulla Springs is nitrogen (N) or phosphorus (P) limited
is not completely certain at this time, but on balance, it appears that N is more likely the limiting
nutrient (see Appendix E for a detailed discussion of this issue). The high N:P ratio in Wakulla
River water suggests that the spring is P limited, but these ratios are imperfect indicators of
nutrient limitation. While algal assay results conducted by Stevenson et al. (2004) appear to
corroborate P limitation for most Florida springs, the comparatively rapid uptake of N compared
with P with distance downstream from the springhead suggests that nitrogen supply is more
critical. Moreover, the striking changes in trophic state observed in Wakulla Springs basin and
immediately downstream are contemporaneous with significant increases in nitrogen (nitrate),
while increases in phosphorus concentrations have been far more modest or not evident. Based
on the in situ dynamics of N, P, and the primary producer community, N limitation is more likely
than P limitation.
Whether the plant growth rate in Wakulla Springs is N or P limited may not affect options for
reducing plant overabundance in the Wakulla River. There is little evidence that Tallahassee is
contributing P to Wakulla Springs (Appendix F), and it appears that phosphate loading to the springs is
determined by both sorption of phosphate by soils and release of phosphate by clays and sands of the
Hawthorn Group, a soil formation found in the Wakulla springshed. The result is an equilibrium
concentration of P in the water that is very difficult to alter. Figure 13 shows the effect of the overlying
Hawthorn Group on phosphorus concentration in springs; Gainer and Jackson Blue Springs have no
overlying Hawthorn Group, while the other springs do.

3.2 Sources of Nitrate
It appears that nitrate is the crucial nutrient feeding the growth of hydrilla and algae in
Wakulla Springs and River. Chelette et al. (2002) provided the most authoritative and complete
study of nitrate sources in the Wakulla springshed. According to Figure 58 of that study
(reproduced here as Figure 14a), the principal nitrate sources from 1990-99 were as follows:
City of Tallahassee wastewater effluent and residuals (sewage sludge), average loads of
360,000 and 130,000 kg-N/yr, respectively, or about 55% of total sources;
Atmospheric deposition, average load of 232,000 kg-N/yr, or 26%;
Fertilizer and livestock, average loads of 60,000 and 14,000 kg-N/yr, respectively, or
9%;












* Septic systems, 56,000 kg-N/yr, or 6%; and

* Sinking streams, estimated annual load of 33,000 kg-N/yr, or 4%.


Figure 13. Total phosphorus in Florida's first-magnitude springs


OSDS
6%


Atmospheric Deposition
26%


WWTF
40%


Sinking Streams
4%
Livestock
2%

Commercial Fertilizer
7%


Figure 58. Relative Contribution from Inventoried Nitrogen Sources to
1990-1999 Average N Loading in the Wakulla Springs Contributory Area.


Figure 14a. Pie chart of nitrate contrihutions to Wakulla Springs

including atmospheric deposition and residual sludge applications, 1990-99 (from Chelette et al., 2002)










The average aggregate loading from these sources totals approximately 885,000 kg-N/yr.
Estimates produced by the City of Tallahassee differ somewhat from these, however, reflecting
the uncertainty in the estimation process and changes in practices for disposal of residuals.

Chelette et al. (2002) found that the sources of nitrate are predominantly local, with 73%
(197,000 kg-N/year) originating south of the Cody Scarp. Much of the remaining 27% (73,000
kg-N/year) can be attributed to septic systems and fertilizer applications in Leon County. The
committee could find no evidence that a significant flux of nitrate originating in southern
Georgia reaches Wakulla Springs. Davis (1996) estimated aquifer flow across the Georgia-
Florida border to be 45 cubic feet per second (cfs). However, not all of that flows to Wakulla
Springs. The nitrate concentrations (typically 0.2 mg-N/L) from the Tallahassee drinking water
wells north of the city should reflect the aquifer input from Georgia. Thus by this estimate the N
loading from Georgia that makes it south across the Cody Scarp is less than 45 cfs x 0.2 mg-N/L
= 8000 kg-N/year. This is less than 3% of the total nitrate load at Wakulla Springs. Although
this number is somewhat uncertain, it is difficult to construct a model in which significant nitrate
is coming to Wakulla Springs from Georgia.

Fertilizer and livestock, as well as septic systems, are non-point sources (that is, there are a
very large number of inputs to the aquifer distributed over a wide geographic area). In contrast,
sewage operations are point sources, and thus are much more easily managed. It should be noted
that within the contributory area identified by the NWFWMD that was used for Figure 14b,
fertilizer application at the city's sprayfield is a large portion of the fertilizer input.

Figure 14b shows the relative nitrate contributions to Wakulla Springs, over and above the
background nitrate delivered to the spring in the Floridan aquifer (reported as 0.33 mg-N/L in the



Nitrate Inputs Wakulla Springshed Livestock3%


Nitrate Loading as an Indicator
of Nonpoint Source Pollution in
the Lower St. Marks-Wakulla
Rivers Watershed Commercial
NWFWMD, April 2002 Fertilizer
13%






Represents input within the
contributory zone as defined in
the NWFWMD nitrate report. It WWTF 72%
is the portion of the
unconfined area determined to
be directly contributing to
Wakulla Springs instead of to
St. Marks or Spring Creek.
Atmospheric inputs not
included. Residual Sludge
Application Removed


Figure 14b: Relative nitrate contributions to Wakulla Springs









southern conduits in 2004; consistent with 0.2 to 0.4 mg-N/L reported in the late 1970s for the
spring). Taking atmospheric deposition, sinking streams and residual-sludge applications out of
the accounting, the percentages are as follows: sewage treatment operations 72, fertilizer and
livestock 16 and septic systems 12%. Even allowing for some uncertainty in these numbers, it is
clear that sewage operations are the dominant contributor to nutrient loading at Wakulla Springs.

3.3 Wastewater Treatment Facilities.
Historically, starting in the 1950s, the COT's treated wastewater was discharged to Lake
Munson. Beginning in 1966, however, the city became one of the few municipalities in the
country to experiment with using treated effluent water to irrigate crops. By the early 1970s,
Lake Munson had become the most polluted lake in the southeastern United States (see 1.4.1).
Water quality in Lake Munson began to improve dramatically in the 1980s when the city built a
pipeline, diverting treated effluent from the lake and applying it to the land surface.
The COT's sewer system carries raw sewage from homes and businesses to one of two
wastewater treatment plants. The T. P. Smith Facility, the city's primary sewage treatment
facility, can treat 27.5 mgd and can handle peak flows up to 55 mgd. The Lake Bradford plant
can treat 4.5 mgd. After treatment, about 2 mgd are reused for plant operations and landscaping
irrigation. The rest is pumped to the Southwest Sprayfield, adjoining the plant, and to the 2,163-
acre Southeast Farm Wastewater Reuse Facility (referred to as the SESF in this report), 8 miles
to the east. Ongoing programs related to wastewater treatment conducted by the city's Water
Utility are described in Appendix I.
The SESF is one of the largest and most advanced facilities of its type anywhere in the
world and has won a number of awards for its design and operation. At the facility, 13 center-
pivot sprinkler systems distribute the treated wastewater to the land surface. Crops such as
canola, corn, soybeans, hay (Bermuda grass), and sorghum are grown year-round. Crop rotation
ensures that some fields are available as pasture year-round. The crops, which remove nutrients,
are then sold or put up for silage to supplement cattle that graze on the pastureland at the farm
year-round (about 300 head during the summer and 2,000 head during the winter). Because the
cattle receive no grain or other food from offsite while grazing at the sprayfield farm, they act as
a sink for nutrients. The system was designed to serve as a huge biological filtration system,
aimed at removing excess nitrogen and phosphorus from the treated wastewater. The nutrients
are removed from the water in four ways:

1. Much of the (ammonia) nitrogen volatilizes into the atmosphere during irrigation,
2. Sprayfield crops take up nutrients from the treated sewage,
3. Phosphorus not used by the crops is physically adsorbed onto the surface of soil particles
and
4. Naturally occurring bacteria in soils assimilate nitrogenous compounds in the treated
sewage.

When the SESF was created some 25 years ago, it was state of the art. Since then, however,
much more has been learned about the nature of the aquifer in the region and the direction of
groundwater flow. Nitrate levels in groundwater under the sprayfield rose from less than 1 mg/L
in 1982 to 10 mg/L (the drinking water standard) by the late 1980s. Concurrently, nitrate levels









in Wakulla Springs, 9 miles south of the sprayfield, increased by a factor of five times over the
values prior to the establishment of the SESF.
The SESF lies above the unconfined portion of the Floridan aquifer and potentiometric
contour maps produced by the NWFWMD and USGS (Figure 15) indicate that this facility lies
directly up-gradient of Wakulla Springs. That is, treated sewage with its nitrate load applied at
the sprayfield rapidly sinks into the ground and flows southwest, directly toward Wakulla
Springs. In this regard, it is important to note that the levels of nitrate measured at St. Marks
Spring, located south of the sprayfield, are low, indicating that nitrate of sprayfield origin is not
moving southeastward. It is not yet known what fraction of the sprayfield effluent reaches
Wakulla Springs and how long it takes to travel there. Tracing experiments are to be conducted
in the coming year, with funding from the Hydrogeology Program of the FDEP and the Florida
Springs Initiative, to provide this information.
The COT is in the process of phasing out the disposal of sewage sludge in the Wakulla
springshed, so that the contribution from that source (27% of sewage operations) is diminishing
and will cease in the near future. A new sludge-drying system, which became fully operational
in March 2005 at the T. P. Smith WWTF, produces reusable "Class A" biosolids, which can be
sold as a beneficial fertilizer and soil conditioner to commercial nurseries, agricultural markets
and other businesses. This unique, single-pass drying system reduces the plant's sludge volume
by 75%, virtually eliminating the need for spreading biosolids on land. Eighty-five percent of
the sludge that used to be spread is now dried and removed from the system. Work continues to
further reduce sludge spreading.
Tallahassee's water utility plans to construct at a cost of $3 million a new water-reuse
treatment plant in the Southwood area that will take water directly away from the sprayfield.
This new Tram Road Reuse Facility, with a capacity of 1.2 mgd, will use highly treated
wastewater to irrigate the Southwood Country Club golf course, the extensive landscaping at the
state's Capital Circle Office Complex, and the Blueprint 2000 Capital Circle Southeast
improvement project.
Two high schools in the Southwood development have also expressed an interest in using
the reclaimed water to irrigate their athletic fields. The treated water will be sent via a pipeline
from the T. P. Smith plant and then will receive additional treatment at the new facility before
being used for irrigation. The additional treatment at the new facility will include filtration and
disinfection, making the water safe for irrigation ponds at the golf course. The non-potable
water can also be used for fire control or controlling dust during dry periods.

3.3.1 Trend of Groundwater Flow

Trends of groundwater are shown in Figure 15, with gray lines showing the potentiometric
(water level) surface, with the contour interval being 1 foot. Groundwater flow in the aquifer is
generally perpendicular to these lines. Blue lines indicate the surface positions of the St. Marks
(east) and Wakulla (west) Rivers and blue circles indicate major springs. Red lines mark the
positions of the major underwater caves in the basin, with the Leon Sinks and Chips Hole
systems to the north and the Wakulla cave system to the south. Green circles indicate center
pivots at the sprayfield, and the red area at the sprayfield shows where nitrate levels in
groundwater are greater than 5 mg/L.
















Iwest 1prayfl -.d
....... .. 0--


Figure 15. Potentiometric surface map of the upper Floridan aquifer


3.4 Nitrate Data
In this subsection, data on nitrate concentrations collected at key locations near the
sprayfield and at Wakulla Springs over the past several decades are presented and discussed.
Specifically nitrate trends at COT drinking water well #12 are shown in Figure 16, at monitoring
wells 02, 15, 19 and 53 in the four panels (labeled a d) of Figure 17, and at Wakulla Springs
boil in Figure 18.
Nitrate concentrations in Tallahassee's drinking-water well #12 (located near the
intersection of Orange Avenue and South Monroe Street, roughly six miles northwest of the
sprayfield and 10 miles north of Wakulla Springs), illustrated in Figure 16, have increased
gradually from 0.4 mg-N/L to about 0.5 mg-N/L since 1980. Similar nitrate concentrations are
reported from COT wells #17 and #27 in the southeastern quadrant of the city. This likely
reflects the "background" nitrate concentration in the aquifer leading toward Wakulla Springs
from the north. "Natural" levels of nitrate are less than 0.1 mg-N/L, and possibly as low as 0.01
mg-N/L (e.g., measurements at monitoring wells SE-82, 83, 84 and 85 on the eastern edge of the
SESF; see also nitrate levels at COT wsells #19 and 26, shown in Figure 44 of Chelette et al,
2002; Katz, 1992; Upchurch, 1993). The somewhat higher levels seen in this figure are likely









due to inputs (fertilizer and septic systems) within the urban area of Tallahassee, but are not due
to the SESF, which lies downgradient of this well.
Figure 17 shows the time history of groundwater nitrate concentrations from 1980 to the
present measured at four monitoring wells at the sprayfield: one (SE-19; Panel a) in the middle
of the field, one on the western edge (SE-15; Panel b) and two on the southern edge (SE-53;
Panel c and SE-02; Panel d). The locations of these wells are shown in Figure 4. Concentrations
at well SE-19 (near the center of the sprayfield) have increased twenty-fold since 1983, as shown
in Figure 17a. Note the change in scale from Figure 16; nitrate concentrations at the SESF are
far higher than to the north. Nitrate concentrations in SE-19 peaked in 1992-1993, then declined
roughly 35% by 1996, and have remained relatively uniform to the present. Nitrate
concentrations on the western boundary of the SESF (SE-15; Figure 17b) have increased
gradually by roughly a factor of five since 1983 and, although the concentration trend appears to
be accelerating over the last few years, values remain significantly lower than in the middle of
the SESF. Nitrate concentrations on the southeastern boundary of the SESF (SE-53; Figure 17c;
this panel is equivalent to Figure 3) show a trend that is nearly identical to that seen in the center
of the SESF (SE-19), increasing from 1983 through 1992, then decreasing by roughly 40% to the
present. The trend measured at a nearby well (SE-52; not shown here) is virtually identical to
that at SE- 53, verifying the consistency of the data. On the southwestern boundary of the SESF,
well SE- 02 (Figure 17d) shows only an intermediate nitrate peak in 1990-1992. Concentrations
at SE-02 continued to increase after 1992, until stabilizing from 1997 to the present at levels
consistent with the interior wells and the other southern boundary wells. These data trends
support the conclusion that the groundwater underneath and to the south of the SESF has been
significantly contaminated with nitrate.













City Drinking Water Well 12
Southeastern quadrant; 365' depth; 192' casing


S0.8
Z

E 0.6
2)

0.4
z

0.2

0.0


E]

. . .


CU C EU CU CU C CC c- CU CUC C C C C E CU C CU C C (- CU C


A COT o COT-NWFWMD



Figure 16. Nitrate levels in COT drinking-water well 12
COT = City of Tallahassee, NWFWMD = Northwest Florida Water Management District. The closed
symbols indicate measurements that are deemed not accurate.








Figure 17a:


SESF Monitoring Well SE-19
Interior; South of center; 74' depth; 52' casing


z 6.0
5.0
E

S3.0
Z
2.0
1.0
0.0
0 C4 CO Ic LD CO I- CO M C 04 M C9 U) (D 1I- OD CD M 19 M I I I

aU CU C CU CQ (0 (C C( (U CO C (U CG C U G C CU Co (G CO CO CG CO CO 1O CO C


A COT o COT-NWFWMD

Figure 17. Measured nitrate trends in monitoring wells at the SESF
The closed symbols in this and other panels indicate measurements that are deemed not accurate. Note
the change of scale from Figure 16 and from panel to panel.


Figure 17b:


SESF Monitoring Well SE-15
Western boundary; North of center; 102' depth; 96' casing


1.2

2 1.0
z
0 0.8 8 i
E
4 0.6
-I O
2 0.4 II L

0.2 f~ iff] -1 O
El [ O E


0 0 00 00 0 I 0 0 0 0 I 0 0 0 T- T 9 0
cc c cc c c cc c c c c c C C c c C c CC ~C
S, -, -, -, -, -, -, - -, -7 -, -7 0, -, -, -, -, o, -,


A COT 1 COT-NWFWMD









Figure 17c:


SESF Monitoring Well SE-53
Southern boundary; East of center; 100' depth; 93' casing


14.0

12.0


. 10.0
z
8.0
E
S 6.0

z 4.0


AA


S c t co- O O M tO n co q O O- C O M i
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(O r~~O cO ra r~O cro or or or o oc oc sr o r r
_^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ _ _ _ _ _ _


A COT ] COT-NWFWMD


Figure 17d:


SESF Monitoring Well SE-02
Southern boundary; West of center; 46' depth; 42' casing


7.0


S6.0
-j


E 4.0
*I-


3.0

2.0

1.0 ..
0.0
C CNM eC L O to t- W Mo C
0? ? 0 CC CCC CCC
a, a, a, a, a, a, a, a, a, a, -


) r-Nmq LMc OC q'' LO
aC C C C C C C C C C C C C C
, aO a, a, a, a a, a, a, a, a, a, a, a, a,
> - - - - - - -


A COT El COT-NWFWMD


Z










Measured concentrations of nitrate, nitrate+nitrite, and total N in the Wakulla Springs boil
are shown in Figure 18. The data indicate that the majority of the total nitrogen is in fact
dissolved nitrate. Note that the duration of measurements extends 10 years earlier than those
shown in Figure 17; unfortunately nitrate concentrations in Wakulla Springs were not regularly
monitored between 1978 and 1989. Also, note that the nitrate concentrations measured at
Wakulla Springs are considerably lower than in the monitoring wells. Prior to 1980,
concentrations were about 0.3 mg/L, a level comparable to that inferred from COT well 12,
shown in Figure 16. The concentrations began to increase between 1977 and 1985, peaked from
1990-94, and have declined by roughly 35% to the present, mirroring the trend seen in
monitoring wells SE-19 and SE-53 (see Figure 17a, c).

Wakulla Springs (boil); FDEP Data Set

1.4

1.2 o .

1.0 E9 10 El










NO3 NO3+NO2 TN
)0.4 0 S0) 0 0
04 N

5, ^ o5 c o m

o N03 o N03+N02 TN
Figure 18. Nitrate time series trends at Wakulla Springs
The discharge at Wakulla Springs is highly variable and is known to come from at least two
distinct sources. The scatter in the data since 1989 seen in Figure 18 is likely the result of a
time-varying mixture of two waters, one high in nitrate and one low in nitrate, driven by
variations in rainfall. It is possible that the downtrend of nitrate concentration since 1990 is due
to an increase in the low-nitrate component as rainfall and net discharge have increased. This
hypothesis is supported by Figure F5, which shows a negative correlation between nutrient
concentrations and discharge. However, annual rainfall for the relevant period (see Figure 12)
shows no clear trend. A more likely explanation is that the downward trend of nitrate
concentrations in the past decade reflects, and is the result of, the decrease in nitrate
concentrations in the groundwater beneath the sprayfield. This latter explanation is supported by
the similarity in the timing of the nitrate concentration increases and decreases between the
sprayfield and Wakulla Springs and the magnitude of the decrease (35-40%). This correlation
between variations of nitrate concentrations at the sprayfield and Wakulla Springs strongly
suggests that the SESF has been a major contributor to the nitrate loading at Wakulla Springs.









Nitrate loading from the other significant nitrogen source in the springshed (septic systems)
would have shown an increase in proportion to population growth between the Cody Scarp and
the spring, and there is no reason to expect that source to have declined since 1992-93.
Several studies are expected to be completed in the next 1-2 years that will help clarify the
nitrate sources. The COT will complete its SESF Nutrient Management Report in early 2006.
This report should provide accurate net nitrogen loading values for the SESF over time. In
addition, the FGS is funding a set of tracing studies, to be conducted starting in 2006, to
determine definitively whether groundwater is flowing from the SESF to Wakulla Springs.
Successful completion of these tracing studies will remove any lingering doubt about the flow of
nitrate-laden groundwater from the sprayfield to Wakulla Springs.

It is very likely that improvements in wastewater management practices by the City of
Tallahassee during the past decade have led to the decrease in nitrate at Wakulla Springs. These
improvements included reducing the spreading of residuals (sewage sludge), reducing the
application of fertilizer at the sprayfield, and improving wastewater treatment processes. This
provides hope that further improvements in sprayfield operations will result in beneficial changes
at Wakulla Springs.

3.5 Fertilizer and Livestock

Chelette et al. (2002, pp. 92-94) presented information on commercial fertilizer use and
livestock in the springshed prior to 2002. Fertilizer, which is used in agricultural and residential
applications, is a significant source of inorganic nitrogen. Agricultural land use grew from the
early 1900s to the 1980s, when land uses changed with population growth. The authors note that
in 1999, fertilizer use at the SESF (44,000 kg-N/yr) was about 21% of the total used in both Leon
and Wakulla Counties (212,000 kg-N/yr). About 70% (150,000 kg-N/yr) is applied to the semi-
confined areas of the aquifer in Leon County, and about 8% (18,000 kg-N/yr) is applied to
unconfined areas in Wakulla County. Livestock operations in Leon and Wakulla Counties are
small. Chelette et al. (2002) estimated that in Wakulla County, 82% of the acreage in pasture
and cropland lies in the unconfined portion of the aquifer and contributes 23,000 kg-N/yr. In
Leon County, 91% of this acreage is in the semi-confined portion of the aquifer (124,000 kg-
N/yr), and about 7.5% is in the unconfined portion.

3.6 Septic Systems
A conventional septic system consists of a tank and a drainfield. Wastewater from a house
enters the tank, where bacterial action partially breaks down organic materials. As the tank fills,
effluent drains from the tank to the drainfield. This effluent still contains solid materials,
partially treated organic matter, bacteria and viruses, and soluble organic and inorganic
compounds. As the effluent slowly seeps out through the drainfield, the surrounding soil
continues the treatment process. Bacterial action further breaks down the solid and soluble
organic compounds, some of the inorganic compounds bind to the soil particles, and the soil
filters out the remaining solids, including bacteria. The remaining liquid then drains to
groundwater, where any remaining impurities are diluted and possibly further attenuated.
A well-sited, well-functioning, and well-maintained septic system can treat and remove most
potential contaminants from wastewater before it reaches groundwater. Successful treatment
requires clean, unsaturated soil material around the drainfield to effectively filter and clean the









effluent. Septic systems must also be spaced widely enough to allow for the dilution and
attenuation of any effluent that may reach groundwater. Septic systems in areas prone to
flooding, or located too close together, may not meet these requirements.
Even a well-sited and well-constructed septic system, however, can create problems if it is
poorly maintained and operated. Household cleaners, most notably bleach, can kill the beneficial
bacteria that digest the waste in the septic tank. A septic system cannot break down common
household substances, such as solvents or pesticides, that are disposed of down the drain. Septic
systems also require regular maintenance. If the accumulated solids are not periodically
removed, over time they may plug the drainfield, reducing contaminant removal.
Contributions from septic systems in the Wakulla springshed, although relatively small at
present, constitute a looming problem. Wakulla County is one of the fastest-growing counties in
the state, with a 26.9% increase in population between 1990 and 1996. The 1990 US Census
counted 14,202 people in Wakulla County. The projected county population in 2005 is 20,000
people, but some estimate that the current population already exceeds this number. Most homes
in Wakulla County use septic systems for their sewage waste disposal. The locations of septic
systems in Leon and Wakulla Counties as of 2002 are shown in Figure 53 of Chelette et al
(2002).
Although public water is available in some parts of the county, many homeowners also use
domestic wells for their household water supply. With an increase in population, there is
concern that ever-increasing numbers and densities of septic systems will affect the quality of
water in the Floridan aquifer, the primary source of drinking water for both the domestic and
public supply wells in the county.
As discussed earlier, much of the eastern portion of Wakulla County lies within the WKP -
an area characterized by a thin, sandy soil overlying karst features such as sinkholes, springs,
disappearing rivers, and underwater caves and conduits. The water table lies close to the land
surface, and the geology of this area makes it highly susceptible to groundwater contamination
from sources such as septic systems at the land surface.

3.7 Sources of Dark Water
The dark (tannic) water causing the loss of water clarity is believed to originate in the Leon
Sinks area. Recent tracing studies show that water from several sinking streams in that area
(primarily Fisher Creek and Black Creek) rapidly enters the Leon Sinks cave system and soon
appears at Wakulla Springs. Samples of water from several tunnels that convey water to the
spring from the west, collected by the NWFWMD, are dark and low in nitrate, confirming the
conclusions of the tracing studies.
Jim Stevenson has hypothesized that before the early 1900s, the lands west of the WKP
were burned frequently by fires, reducing the amount of organic leaf litter and underbrush that
could contribute tannin to surface water (and ultimately groundwater). This condition persisted
until the establishment of the Apalachicola National Forest in 1936, when fires were largely
suppressed and the land was replanted in pine trees. In subsequent years the amount of organic
matter-and thus the amount of tannin that can eventually reach groundwater-has gradually
increased. A more complete description of this hypothesis is found in Appendix H.











CHAPTER 4: SOLUTIONS TO THE PROBLEMS

The motivation for the workshop and the goal of this report is to identify solutions to the
problems of nutrient loading and the associated degradation of biota in Wakulla Springs and
River, as well as the loss of water clarity caused by dark water flowing to the springs. This
chapter assesses whether the degradation can be stemmed and reversed and enumerates a number
of possible mitigation strategies.14 The peer review committee makes no recommendations
regarding specific actions.

4.1 Mitigation Strategies for Nutrient Loading
Although it does not appear possible to eliminate undesired species entirely, it appears
possible to limit the rapid growth of both hydrilla and algae. The flux of nitrate (the limiting
nutrient) from the main vent of Wakulla Springs is about 750 kg-N/day, and the change in nitrate
down the river (Figure E2, Appendix E) is due almost entirely to uptake by plants (380 kg-
N/day plant uptake). Since 1 kg-N produces 16 kg of vegetation (dry weight), this translates into
6,080 kg of aquatic vegetation added to the spring basin and upper river each day.
The high levels of nitrate (and to some extent phosphorus) favor the growth of vegetation
such as hydrilla and algae, which derive nutrients directly from the water, as opposed to native
vegetation, which derives nutrients primarily from the river bottom, via root systems. If the
levels of nitrogen and phosphorus are reduced, the rate of production of hydrilla and algae will
likely be reduced and the fraction of native vegetation will increase. However, it is very likely
that regular intervention, such as herbicide treatments, will need to be continued to keep the
levels of hydrilla and algae in check.
Even if there are other factors affecting the growth of hydrilla and algae, there seems little
hope of reversing the degradation without reducing the concentration of nitrate in the water.
Currently, a statewide technical workgroup is examining the feasibility of establishing a spring
nutrient standard, and is scheduled to complete its work in 2005. The water-quality standard for
nitrate in springs is currently the drinking-water standard: 10 mg/L. While this level is designed
to protect human health, it is fifty times the recommended FDEP target concentration necessary
to protect the ecological integrity of the system. In this regard, recall that Section 62-302.530,
FAC, states that "In no case shall nutrient concentration of a body of water be altered so as to
cause an imbalance in natural populations of aquatic flora or fauna."
In the Wakulla system, it is important that FDEP water-quality criteria be developed to
provide direction for the control of nutrient sources that contribute to surface water and
groundwater pollution; the agency must use these criteria to set acceptable limits on pollution, in
order to protect the natural system's ecological integrity. Implementing the TMDL Program and
establishing ecologically based water-quality criteria for nutrients and thus, more stringent FDEP
permit requirements, are essential to protecting the spring and river; however, these steps will
take time. Given the urgency of the situation, it is sensible to give priority to the TMDL process
for the Wakulla River.


14 Portions of the text in this chapter are adapted from the FDEP document, A strategyfor water quality protection: Wastewater
treatment in the Wekiva Study Area (December 2004).









Further, it is clear that Wakulla Springs, River, and estuary represent an opportunity to study
systematically the hydrology of an important karst system and the effects of land-use changes
and water quality on the state's many other springs. To facilitate and coordinate such studies
two things are needed: special designation and funding. Regarding special designation, Wakulla
Springs and River are currently designated as an OFW, a designation meant to prevent declines
in water quality, and the FGS is promoting the establishment of a Hydrologic Observatory
focusing on the WKP. Another step the state could take is to designate Wakulla Springs and
River as an Aquatic Preserve15 with the specifically qualified intent of using the Wakulla
ecosystem as a "living laboratory" to be used to more fully study and thus better understand the
nutrient and ecosystem dynamics associated with Florida springsheds. The numerous springs of
Florida could benefit by having several "living laboratories" established to identify and frame the
long-term research, educational and stewardship needs. In concert with these designations, there
needs to be adequate funding of research focused on developing practical answers to critical
questions bearing on the quality of groundwater and the health of ecosystems near springs; see
Recommendation 5 in the Executive Summary and Appendix G.

4.1.1 Wastewater Treatment Facilities

Strategies for mitigating input of nutrients to the aquifer are aimed principally at the SESF,
since it seems to be the largest contributor to nitrate at Wakulla Springs, but these strategies
apply to other WWTFs as well. The overall strategy recommended by the committee is to
manage all facilities with the goal of minimizing the addition of nutrients and other pollutants to
surface water or groundwater. Specific strategies include the following:
Stop spreading sludge in the basin (this stfl//c'r V is being implemented at the SESF),
Minimize fertilizer use at the SESF (fertilizer usage at the SESF has been reduced
significantly in recent years) and
Improve nutrient removal at the wastewater treatment plants and/or move the treated
wastewater to be disposed of through land application either much farther up in the basin
(north of the Cody Scarp) or out of the basin completely.

The recently published report on protecting water quality in the Wekiva area of central
Florida provides a useful approach to mitigating wastewater impacts.16 Like the Wakulla
springshed, the aquifer in the Wekiva region is comparable in terms of its vulnerability to nitrate
contamination.
Using information on "natural" spring conditions in the Wekiva region, including nitrogen
concentrations, FDEP concluded that the target concentration should be about 0.2 mg/L of
nitrate-nitrogen. This is in agreement with the concentration recommended by the State Springs
Task Force. Having this target of 0.2 mg/L of nitrate-nitrogen allowed FDEP to recommend a
minimum-treatment-level strategy for wastewater treatment systems based on the zone (primary,
secondary, or tertiary) and the volume of the discharge (greater than 0.1 mgd or less). The 0.2


15 A state designation. Information is available at: http://www.dep.state.fl.us/coastal/proqrams/aquatic.htm.
16 FDEP. December 2004. A strategy for water quality protection: Wastewater treatment in the Wekiva Study Area. Available at
http://www.dep.state.fl.us/central/Home/AdminN/ekivaReportDecember2004.pdf.









mg/L target is a starting point; however, any future TMDLs developed for the Wakulla
springshed will be crucial in evaluating site-specific impacts of nutrients on surface waters and
establishing specific limits to be achieved. The Wekiva report is summarized in 1.2.3 (p. 7).

4.1.2 Septic Systems

Septic systems present a difficult problem for two reasons. First, they are out of sight, and
hence out of mind, for the vast majority of the population, and second, the number of such
systems in the springshed is projected to increase dramatically in the coming years.
The only sustainable remedy to this looming problem is to establish a wastewater utility and
charge it with maintaining all on-site disposal systems and facilitating the necessary
environmental education of septic-tank owners. The activities of this utility should be in
accordance with the goal of minimizing the input of nitrate and other pollutants to groundwater.
This utility should encompass those areas of Leon and Wakulla Counties not currently served by
a WWTF and should be funded by an appropriate utility fee. The advantages of a utility would
be as follows:
Failing systems would get prompt attention,
Advanced systems would be employed where necessary to protect the aquifer and
The cost of maintenance and improvement would be distributed, rather than falling on the
individual homeowner.

4.1.3 Fertilizers and Livestock

Although the peer review committee did not investigate this issue in much depth, it appears
that altering fertilizer use could reduce the input of nitrogen to the aquifer. Proactive public
education efforts are an essential part of achieving this goal. As noted above, one immediate
step is to minimize the use of fertilizer at the SESF. Additionally, the types of fertilizers used
elsewhere in the springshed could be regulated by ordinance, permitting only those (e.g., time
release) that minimize nutrient inputs to the aquifer.

4.2 Mitigation Strategies for the Loss of Water Clarity
One possible strategy to improve water clarity would be to prevent dark water on the surface
from entering the aquifer, perhaps by the impoundment or diversion of streams or by burning
leaf litter in key locations. However, more needs to be learned regarding the sources,
concentrations, and volumes of dark water before seriously considering this strategy. The
committee recommends that the origin and mode of transport of the dark water be systematically
investigated.










ACKNOWLEDGMENTS

This workshop and the studies that helped frame the opinions and scientific judgment of the
Peer Reviewers was the collaborative product of many individuals and agencies, including 1000
Friends of Florida, city of Tallahassee, Florida Department of Environmental Protection, North
Florida Water Management District, US Geological Survey, Florida Department of Community
Affairs, Leon County, Wakulla County, Florida LakeWatch, Hazlett Kincaid Inc., and McGlynn
Laboratories Inc.
The efforts of two individuals, however, deserve special consideration. First, this workshop
was conceived by Dr. Donald Axelrad of the FDEP. Dr. Axelrad also helped organize and
promote the workshop, recruited the peer reviewers, assisted in obtaining data critical for the
reviewers' analyses, and provided critical comment on earlier drafts. Second, Dan Pennington of
1000 Friends of Florida played a key role in organizing and coordinating the workshop and
helped shepherd the report through the production process. Without the concerted efforts of both
these individuals, this report and our consensus recommendations for the restoration of Wakulla
Springs would not exist.











REFERENCES

Canfield, D. E. Jr., E. Philips, and C. M. Duarte. 1989. Factors influencing the abundance of
blue-green algae in Florida lakes. Can. J. Fish. Aquat. Sci. 46: 1132-1137.
Chelette A., T. R. Pratt, and B. G. Katz. 2002. Nitrate loading as an indicator ofnonpoint
source pollution in the lower St. Marks-Wakulla Rivers watershed. Northwest Florida
Water Management District, Water Resources Special Report 02-1. Available:
http://www.nwfwmd.state.fl.us/pubs/nitrate/wrsp02-1.htm.
Davis, H. 1996. Hydrogeologic investigation and simulation of ground-water flow in the upper
Floridan aquifer of north-central Florida and delineation of contributing areas for selected
city of Tallahassee, Florida, water supply wells. U. S. Geological Survey Water Resources
Investigation Report 95-4296.
Dillon K., W. Bumett, G. J. Kim, J. Chanton, D. R. Corbett, K. Elliott, and L. Kump. 2003.
Groundwater flow and phosphate dynamics surrounding a high discharge wastewater
disposal well in the Florida Keys. Journal of Hydrology 284 (1-4): 193-210.
Elliot, K. 1999. The fate of wastewater phosphate in saline carbonate groundwater, Key Colony
Beach, Florida. Master's Thesis, Pennsylvania State University.
Florida Department of Community Affairs and Florida Department of Environmental Protection.
November 2002. Protecting Florida's springs: Land use planning strategies and best
management practices. Available:
http://www.dca.state.fl.us/fdcp/DCP/publications/springsmanual.pdf.
Florida Department of Environmental Protection. August 2003. Ochlochonee-St. Marks Basin
assessment report. Tallahassee, Florida. Bureau of Watershed Management.
Florida Department of Environmental Protection. December 1, 2004. A /stirIg/ for water
quality protection: Wastewater treatment in the Wekiva study area.
Florida Department of Environmental Protection. 2005. Florida's Aquatic Preserves.
Available: http://www.dep.state.fl.us/coastal/programs/aquatic.htm.
Florida Department of Environmental Protection. Various dates. Wakulla Springs
ecosummaries. Available: http://www.dep.state.fl.us/labs/cgi-bin/reports/search.asp.
Florida Springs Task Force. November 2000. Florida's springs: Strategies for protection &
restoration. Available:
http://www.dep.state.fl.us/springs/reports/FloridaSpringsReport.pdf.
Gerami, A. 1984. Hydrogeology of the St. Marks River Basin, northwest Florida. M.S. Thesis.
Tallahassee, Florida: Florida State University.
Hand, J., D. Tterlikkis, P. Lee, T. Singleton, and L. Lord. St. Marks River watershed pilot
project report (unpublished). Tallahassee, Florida: Florida Department of Environmental
Protection.









Harbaugh, A. W. 1990. A computer program for calculating subregional water budgets using
results from the U. S. Geological Survey modular three-dimensional ground-water flow
model. U.S. Geological Survey Open-File Report 90-392.
Hendry, C. W. Jr., and C. R. Sproul. 1966. Geology and groundwater resources ofLeon
County, Florida, Bulletin No. 47. Florida Geological Survey, Tallahassee, Florida.
Katz, B. G. 1992 Hydrochemistry of the upper Floridan aquifer, Florida. U.S. Geological
Survey Water Resources Investigation Report 91-4196.
Hydrogeochemistry, Florida Geological Survey, Special Publication No. 34.
Kincaid, T. R. 1999. Morphologic and fractal characterization of saturated karstic caves. Ph
D Dissertation, University of Wyoming, Laramie.
Lane, E. 1986. Karst in Florida. Special Publication No. 29. Tallahassee, Florida: Florida
Geological Survey.
McGlynn, S. 2005. Woodville recharge basin aquifer protection study. Phases I and II.
Prepared for Leon County Growth and Environmental Management.
National Estuarine Research Reserve System. 2005. Available: http://nerrs.noaa.gov/
Rosenau, J. C., G. L. Faulkner, C. W. Hendry, Jr., and R. W. Hull. 1977. Springs ofFlorida.
Bulletin No. 31 (revised). Tallahassee, Florida: Florida Geological Survey.
Rupert, F. 1988. The geology of Wakulla Springs. Open File Report No. 22. Tallahassee,
Florida: Florida Geological Survey.
Scott, T. M., G. H. Means, R. C. Means, and R. P. Meegan. 2002. First magnitude springs of
Florida. Open File Report No. 85. Tallahassee, Florida: Florida Geological Survey.
Scott, T. M., G. H. Means, R. P. Meegan, R. C. Means, S. B. Upchurch, R. E. Copeland, J. Jones,
T. Roberts, and A. Willet. October 12, 2004. Springs ofFlorida. Version 1.1, Revised.
Published for the Florida Geological Survey, Tallahassee, Florida.
Smith, V. H. 1983. Low nitrogen to phosphorus ratios favor dominance by blue-green algae
inlake phytoplankton. Science 221: 669-671.
Stevenson, J. A. 2005. Wakulla Springs dark water hypothesis. Tallahassee, Florida.
Stevenson, R. J., A. Pinowska, and Y. K. Wang. 2004. Ecological condition of algae and
nutrients in Florida springs. FDEP Contract Number WM858. Final report. Tallahassee,
Florida: Florida Department of Environmental Protection.
Stumm, W., and J. J. Morgan. 1996. Aquatic C//milu/\ny, 3rd Edition. New York: Wiley
Interscience.
Upchurch, S. B. 1993 Quality of waters in Florida's aquifers. In Maddox, G. L., J. M. Lloyd, T.
M. Scott, S. B. Upchurch, and R. Copeland (eds.), Florida Ground Water Quality
Monitoring Program Volume 2, Background
Vitousek P. M., R. W. Howarth, G. E. Likens, P. A. Matson, D Schindler., W. H. Schlesinger
and G. D. Tilman 1997. Human alteration of the global nitrogen cycle: causes and
consequences. Issue Ecol. 1: 1-17.









Werner, C. L. 2001. Preferential flow paths in soluble porous media and conduit system
development in carbonates of the Woodville Karst Plain, Florida. M.S. Thesis.
Tallahassee, Florida: Florida State University.

TABLE 1: LIST OF ACRONYMS


AWT
BMP
CoT
FAC
FDEP
mgd
mg/L
NWFWMD
OFW
OSTDS
SESF
TMDL
USGS
WKP
WWTF


Advanced wastewater treatment
Best management practice
City of Tallahassee
Florida Administrative Code
Florida Department of Environmental Protection
million gallons per day
milligrams per liter
Northwest Florida Water Management District
Outstanding Florida Water
Onsite sewage treatment and disposal system
Southeast Sprayfield
Total maximum daily load
U. S. Geological Survey
Woodville Karst Plain
Wastewater treatment facility











WEB SITES OF INTEREST

http://www.floridastateparks.org/wakullasprings/default.cfm
http://www.wakullasprings.org/
http://www.wkpp.org/
http://www.hazlett-kincaid.com/FGS/
http://www.tfn.net/springs/
http://www.dep.state.fl.us/labs/cgi-bin/reports/search.asp
http://www.floridasprings.org/
http://www.thiswaytothe.net/springs/
http://www.cafwn.org/
http://www.dep.state.fl.us/coastal/programs/aquatic.htm
http://nerrs.noaa.gov/










APPENDICES


Appendix A: Questions for the Peer Review Committee
May 9, 2005
Dear Drs. Chan Hilton, Pollman, Loper, and Landing,
After additional review, the Wakulla Springshed Workshop Planning Committee has
produced the following 5 general questions for the Peer Review Committee to draft answers to
from information available at the workshop, namely:
1. What does the preponderance of evidence indicate are the sources of nutrients (nitrogen and
phosphorus) reaching Wakulla Springs, and which are the most important sources?
2. Are nutrients (nitrogen and/or phosphorus) responsible for the ecological "imbalance" of
the Wakulla River (imbalance as defined by FDEP)?
3. What are the solutions that should be implemented presently to reduce nutrient loading to
Wakulla Springs?
4. What are the future threats (say 50 years into the future) regarding nutrient loading to
Wakulla Springs, and what planning is now necessary to avoid these threats?
5. What additional research, if any, is necessary to provide adequate certainty regarding
effective actions to eliminate the Wakulla Springs and River nutrient pollution problem?
The following 15 detailed questions, some of which we may not yet have answers to, can
serve as guidance for answering the 5 general questions. It may not be necessary to answer all of
these detailed questions in full to answer the general questions.
6. Is Wakulla Springs especially vulnerable to pollutant inputs from groundwater? If so, why?
7. How are pollutants transported to Wakulla Springs via groundwater, from where, and what
is the time-of-passage from pollutant sources to Wakulla Springs?
8. What were the historical versus present levels of nitrogen and phosphorus in Wakulla
Springs and River waters?
9. How has the plant community in the Wakulla River changed over time with increased
nutrient concentration?
10. What is the ecological "imbalance" of the Wakulla River as defined by FDEP that has
resulted in the river being listed on the state's "impaired waters" list?
11. What are the present sources of nutrients nitrogen and phosphorus-to Wakulla Springs?
Quantify these to the extent possible.
12. Are nitrogen and/or phosphorus responsible for the "imbalance" offlora and fauna in the
Wakulla River?
13. Does nitrogen, or does phosphorus, or do both equally limit the growth rate and biomass of
plants (e.g., hydrilla, lyngbya, sagittaria, vallisneria, filamentous greens, etc.) in the Wakulla
River?









14. What are the likely ecological changes to the Wakulla River that would result from continued
increases of nutrient loading to Wakulla Springs?
15. Will nitrogen and/or phosphorus load reduction to Wakulla Springs restore the Wakulla
River to a "balanced" state or to a more "balanced" state?
16. Which nutrient load to Wakulla Springs is it more effective and feasible to control
nitrogen or phosphorus? Nutrient loads from which sources are most feasible to control?
17. If nitrogen is the limiting nutrient, or if it will become so with nutrient loading reductions,
will controlling nitrogen loading achieve restoration of Wakulla Springs and River, or will it
merely impose selective pressure favoring nitrogen-fixing algae, leaving the ecosystem
"imbalanced"?
18. How much must the nitrogen or phosphorus load to Wakulla Springs be reduced to restore
the Wakulla River to a "balanced" state?
19. What additional research if any is needed to allow decision making on necessary actions for
restoring the Wakulla River to a "balanced" state?
20. What are the future threats (say 50 years into the future) to Wakulla Springs and River and
what planning is now necessary to avoid these?

Donald M. Axelrad, Ph.D.
Florida Department of Environmental Protection










Appendix B: Key Peer Review Committee Questions and Answers
The following answers were prepared by the peer review committee immediately following the
workshop. Any changes between these responses and equivalent responses found in the main
body of this report reflect the input of additional data and information received subsequent to the
workshop.
A. Is Wakulla Springs especially vulnerable to pollutant inputs from ground water? If so, why?
Yes. A significant portion of the catchment basin of Wakulla Springs consists of an
unconfined aquifer; pollutants applied to the land surface in such areas typically move rapidly
into the Floridan aquifer with little natural attenuation, compared with areas where the aquifer is
confined. Unfortunately, the Southeast Sprayfield (SESF) operated by the City of Tallahassee, is
located within an unconfined region, so that the nutrients in the sprayed water quickly enter the
aquifer and pose a particular danger to Wakulla Springs. Further information on the
hydrogeology of the aquifer may be found at http://www.wkpp.org/ and http://www.hazlett-
kincaid.com/FGS/.
B. What are the main water quality issues affecting the Wakulla River and what are the
consequent ecological or aesthetic impairments?
The main water quality issues are nutrient loading (nitrogen and phosphorus) and dark
water. The nutrient loading is the direct cause of the excessive growth of hydrilla and algae that
is plaguing the spring basin and upper reaches of the Wakulla River. This growth is choking out
native vegetation and is severely stressing many aquatic species.
It is unclear at this time whether the increased density of hydrilla is contributing to the
decline in the number of birds observed in the park and has contributed to the disappearance of
the apple snails and limpkins in the park. It has been proposed that the apple snails were
drowned out in the flood event of August 18 to 22, 1994, when the river stage (elevation above
NAVD88 sea level) exceeded 9.3 feet, compared with an average stage of 5.4 feet for the
interval from 1987 to 2005. The flood hypothesis is supported by the fact that recent efforts to
reintroduce the apple snail seem to be succeeding (Scott Savery, personal communication).
The presence of invasive aquatic plants and dark water, the decline in bird counts and the
absence of apple snails and limpkins are strongly impairing the aesthetic quality of the Springs
and State Park.
Cl. What does the preponderance of evidence indicate are the sources of nutrients (nitrogen
and phosphorus) reaching Wakulla Springs, and which are the most important sources?
Several independent lines of evidence (the temporal history of nitrate in the spring and in the
wells south of the SESF and model calculations of water flow and pollution transport) indicate
that the SESF accounts for between one-third and one-half the nitrate in Wakulla Springs. Other
nutrient sources of concern include septic systems, fertilizers and municipal waste-disposal
activities (other than the SESF).
C2. What does the preponderance of evidence indicate are the sources of dark water reaching
Wakulla Springs, and which are the most important sources?
Although the precise source has not been identified, it seems very likely that the dark water
originates in the swamps within the Apalachicola National Forest to the west and north of









Wakulla Springs. After rain in that area, this dark water flows to sinkholes on the western edge
of the Woodville Karst Plain (e.g., Black Creek and Fisher Sinks), and is conveyed fairly rapidly
to the springs by means of a system of natural conduits.
D. Are nutrients (nitrogen and/or phosphorus) responsiblefor the ecological "imbalance of the
Wakulla River (imbalance as defined by FDEP)?
While both nitrogen and phosphorus contribute to the growth of hydrilla, algae and other
undesirable aquatic plants, the limiting nutrient is nitrogen, in the form of dissolved nitrate.
E. What are the solutions that should be implemented presently to reduce nutrient loading to Wakulla
Springs?
An immediate and obvious remedy to the excess nitrate in Wakulla Springs' waters is a
modification of practices and activities at the Southeast Sprayfield, with a goal of reducing
nutrient loading to the aquifer. In particular, the application of fertilizer to the sprayfield should
be suspended, until a thorough review is made of its effect on the nutrient load to the aquifer. In
addition, the types and amounts of fertilizers used elsewhere in the springshed of Wakulla
Springs should be reduced, insofar as is practicable, by regulation and/or public education.
F. What are the future threats (say 50 years into the future) regarding nutrient loading to Wakulla
Springs, and what planning is now necessary to avoid these threats?
All future threats are a direct result of the projected growth and development in the
springshed of Wakulla Springs, particularly in Leon and Wakulla Counties. Looming problems
are the projected rise in the volumes of treated wastewater and septic-tank effluent and in the
amount of storm water runoff, as the currently rural areas of Leon and Wakulla Counties become
progressively more developed and populated. The projected increase in septic systems is
particularly worrisome.
To address the looming problem of septic system effluents, it is strongly recommended that
a waste-water utility, encompass those areas of Leon and Wakulla Counties not currently served
by a wastewater treatment facility, be established and charged with improving the operation of
all on-site disposal systems, with the goal of reducing nutrient loading to the aquifer.
G. What additional research, if any, is necessary to provide adequate certainty regarding effective
actions to eliminate the Wakulla Springs and River nutrient pollution and dark water problems?
Although some aspects of the problems facing Wakulla Springs are now beyond a
reasonable doubt and lead to recommendations for specific actions (see the answers to questions
E and F above), further research is necessary because our knowledge and understanding of other
aspects of the problems remain incomplete, and problems that are minor at the present time can
become much worse as the population in the springshed continues to grow. Specifically,
research is necessary to better quantify primary contributing regions, flow paths and travel times
for water and pollutants (including nitrate and dark water) in the springshed of Wakulla Springs.
Also, specific research is necessary to:
Better understand the nature and fate ofpollutants introduced by various sources within
the springshed;
Better understand and quantify the effect thatpollutants have on the biota in the spring
basin and upper reaches of the Wakulla River; and,









Identify BMPsfor the treatment and disposal ofwastewater, retention and treatment of
stormwater and design and operation of septic systems.


Appendix C. List of Reviewers
A draft of the report was sent to the following people for their review and comment
Jonathan Arthur, Florida Department of Environmental Protection-Florida Geological Survey
Don Axelrad, Florida Department of Environmental Protection
Michael Bascom, Florida Department of Environmental Protection
Commissioner Ed Brimner, Wakulla County
Paul Booher, Florida Department of Health
John Buss, City of Tallahassee
Angela Chelette, Northwest Florida Water Management District
Rick Copeland, Florida Department of Environmental Protection-Florida Geological Survey
Brian Crawford, Wakulla County Health Department
Hal Davis, United States Geological Survey
Richard Deadman, Florida Department of Community Affairs
Rodney DeHan, Florida Department of Environmental Protection-Florida Geological Survey
Richard Drew, Florida Department of Environmental Protection
Dick Fancher, Florida Department of Environmental Protection, Northwest District Director
Russel Frydenborg, Florida Department Of Environmental Protection
Joe Hand, Florida Department of Environmental Protection
Tim Hazlett, Hazlett Kincaid Inc.
Theresa Heiker, Leon County
Val Hubbard, Florida Department of Community Affairs
Todd Kincaid, Hazlett Kincaid Inc.
Commissioner Debbie Lightsey, City of Tallahassee
Eric Livingston, Florida Department of Environmental Protection
Linda Lord, Florida Department of Environmental Protection
Gary Maddox, Florida Department of Environmental Protection
Alex Mahon, Leon County Health Department
Sean McGlynn, McGlynn Laboratories, Inc.
Jim Oskowis, City of Tallahassee









Dan Pennington, 1000 Friends of Florida
Tom Pratt, Northwest Florida Water Management District
Lynn Putnam, City of Tallahassee
Mark Repasky, Sustainable Design, Inc.
Eberhard Roeder, Florida Department of Health
Scott Savery, Wakulla Springs State Park
Walt Schmidt, Florida Department of Environmental Protection-Florida Geological Survey
Mark Sees, City of Orlando
Jamie Shakar, City of Tallahassee
Tom Singleton, Florida Department of Environmental Protection
Jim Stevenson, Wakulla Springs Working Group Coordinator
Commissioner Cliff Thaell, Leon County Florida
Karth Vaith, CDM, Jacksonville
Jessie VanDyke, Florida Department of Environmental Protection
Marty Wanielista, University of Central Florida, Florida Stormwater Academy
Ellie Whitney, Friends of the Wakulla, Tallahassee










Appendix D. History of Hydrilla Removal Efforts at Wakulla Springs
by Scott Savery, FDEP, Wakulla Springs, State Park Biologist

Soon after its discovery, attempts were made to remove hydrilla from the spring and river.
Removal by hand was the first method used. The extent of the hydrilla infestation became
apparent when it invaded the swimming area and complaints were made about an abrasive plant
that was entangling some swimmers. Hydrilla was now a major problem at Wakulla Springs
State Park. In February 1998, a full-time OPS position was created and an individual was hired
to help in the control and removal of hydrilla. Swimmers and volunteers were first used in the
swimming area to help hand-pull the hydrilla and load it onto dump trucks. Shortly after this,
divers were used to pull it out of the deeper areas of the spring and swimming area. Tarps were
put down to shade out the hydrilla in parts of the spring basin and the area directly behind the
floating dock. Shading with tarps can kill hydrilla. However, the tarps must be down for over
80 days or the hydrilla can resprout from the roots and tubers. In April 1998, the approved
aquatic herbicide Aquathal was applied to a portion of the swimming area. The hydrilla was
observed to turn brown but did not die from this herbicide application. None of these efforts was
successful in controlling the spread of hydrilla. At the end of 1998, despite an estimated 260,000
kg removed, involving 4,265 man-hours at an estimated cost of $33,500, hydrilla continued its
invasion of the spring and river.
Late in 1998, Prism Ecological Services, Inc. was contracted to remove hydrilla from certain
parts of the river by the use of a mechanical plant harvester. In 10 days of cutting during March
1999, totaling 282 man-hours, a total of 100,000 kg of hydrilla was removed from the river.
Prism returned 4 times in 1999 and removed 280,000 additional kg of hydrilla. Until October
1999, Prism was cutting hydrilla and harvesting the clippings that were being hauled to a dump
site in the park. This method was improved upon; in October 1999, Prism developed a way to
mechanically pull hydrilla from the river while leaving some of the native Tapegrass (Vallisneria
americana). In five days, 64,000 kg of hydrilla were pulled from the river.
Between December 1999 and January 2000, 19 volunteers completed 40 dives and park
personnel completed 28 dives. This totaled 24 volunteer man-hours and 21 man-hours for park
personnel. Done in coordination with the Prism mechanical harvesting, this massive dive effort
greatly increased the efficiency of the hydrilla removal effort. In 11 days a total of 120,000 kg of
hydrilla was removed. Some of the hydrilla was being removed off site, but most was still being
hauled to the on-site dump. In May 2000, a second loading area was developed at the
Warehouse/Railroad area downriver. This new loading site allowed hydrilla removal from
farther downriver with a shorter travel time. A third loading site was built between the swim
area and the Warehouse/Railroad area.
In May 1999, an attempt at biological control was made in conjunction with Dr. O'Brien
from Florida A&M University. Specimens of the fly Hydrellia pakistane were collected from
central Florida. Approximately 20,000 flies were introduced to a small section of the river near
the boat drydock area. In November 1999, several specimens were collected in the area in which
they were released. A small population appears to have been established. No other control
methods were used in this area designated for biological control. There has never been any
evidence of the flies having any negative impacts to the hydrilla and we are not sure if they are
present today.









Hydrilla removal by mechanical harvesting and diving (in the swim area and spring)
continued until April 2002. This method of treatment was somewhat successful for short-term
control of the hydrilla in the swim area, the spring, and the boat tour route. A total of over
2,000,000 kg of hydrilla was removed at a cost of over $400,000. But the infestation was getting
worse in areas that were not being used and downriver past the tour route. In 2002 it was
determined that alternative treatments were needed. A herbicide application of Aquathol K was
done on April 16, 2002, for 52 hours at a rate of 4.25 parts per million (ppm) (a total of 1,750
gallons). The results were remarkable. Since then herbicide treatments at lesser rates (1.5-2.15
ppm) were completed in November 2002, November 2003, May 2004, and April 2005. The
treatments cost about $80,000 each.
Since the herbicide treatments of hydrilla, the vegetation of the river has changed. There has
been a decrease in most plants, most notably hydrilla, musk-grass and Sagittara kurziana. There
have also been some increases and spread of Illinois pondweed, Southern naiad (Najas
guadalupensis), and Vallisneria americana. The system acts like a yo-yo; after the herbicide
treatment there is much less vegetation and algae covers most everything in the water. As the
system recovers, the natives pondweedd, naiad, Sagittaria, and Vallisneria) grow back faster than
the hydrilla, but over time the hydrilla grows back and overtakes the natives. This yo-yo effect
takes 6 to 8 months to occur. But there has been improvement. We do now have large areas
with good native growth and little hydrilla, but we also have large areas where hydrilla continues
to dominate.









Appendix E: The Case Against and For Nitrogen (N) Limitation in the Upper
Reaches of the Wakulla River

E.1 The Case against N Limitation

For Florida springs and rivers, the evidence for N limitation of aquatic plant production is
scant. In a study of 28 springs of north and central Florida, Stevenson et al. (2004) found mixed
evidence supporting N limitation of algal growth. Most spring sites, including Wakulla Springs,
were deemed as phosphorus (P) limited (56%), or N and P limited (22%), whereas N limitation
occurred at only 19% of the sites and was species specific. The study did not address
successional dynamics of macrophytes in relation to changing nutrient regimes, which is perhaps
arguably the more important ecological question confronting Wakulla Springs. Other factors
related to disturbance in the springshed other than nutrient supply can also influence primary
producer dynamics. For example, despite recent increases in N concentrations, Hoyer and
colleagues (M. Hoyer, personal communication) concluded that eutrophication changes in
Wekiva Springs were related to changes in substrate dynamics and an increase in light
penetration due to the removal of the terrestrial canopy.
Traditionally, the Redfield stoichiometric ratio ofN to P concentrations in phytoplankton
has been used to help identify N or P limited regimes. This ratio is 16:1 when expressed on a
molar basis (7.2 on a mass basis) and is best evaluated using dissolved inorganic N and P
concentrations. The N:P mass ratio for Wakulla Springs which is calculated from total
nitrogen (TN) and total phosphorus (TP) concentrations, since there are limited if any data on
dissolved inorganic phosphorus concentrations for the spring has generally declined since
1996, ranging between 22 and 34 (Figure El). These results follow from the overall decline in
TN concentrations, but not TP during the same period. For lacustrine systems, Smith (1983)
found that blue-green algae tended to become more dominant and bloom when TN:TP mass
ratios fell below 29:1, although this ratio has not been found to be a reliable indicator of
cyanobacterial dominance in Florida lakes (Canfield et al., 1989). Stevenson et al. (2004),
however, indicate that N may be limiting algal growth in streams when water column N:P ratios
are greater than 16:1, because P is probably more efficiently recycled than N.

E.2 The Case for N Limitation

One approach to elucidating whether N or P limitation is controlling primary production in
Wakulla Springs is to examine the relative loss rates of both nutrients as water moves
downstream from the spring boil. Assuming that continued inputs of groundwater downstream
are not appreciably contributing to the riverine flux within the first mile of the boil, a more rapid
decline in the concentration of one nutrient relative to the other indicates that its availability is in
more short supply. Figure E2 shows the change in average concentration of both TN and TP in
the Wakulla Springs and River system with distance downstream from the spring boil. The plot
also shows predicted concentrations of TN and TP derived by assuming that both nutrients are
taken up stoichiometrically according to the Redfield ratio. In other words, using TP as an
example, predicted TP concentrations were calculated as a function of the measured uptake of
TN downstream (relative to average TN concentrations in the spring boil) and assuming that the
stoichiometric equivalent mass of TP was also consumed. A comparison of predicted with
observed values (Figure E2) clearly shows that TN is consumed preferentially to TP. For









example, predicted TN concentrations are much higher than observed, while predicted TP
concentrations are much lower than observed. This is also clearly evident in the molar mass
uptake ratios of TN relative to TP computed for sites downstream from the boil. The uptake
ratios increase monotonically with distance downstream and are all in excess of 29.
The temporal history of nitrate in the wells south of the SESF and in Wakulla Springs, and
the timing of excessive growth of aquatic plants in Wakulla Springs and River, also indicate that
nitrate is likely responsible for the problem (see Figures 17 and 18).

E.3 The Case for Reducing Plant Growth by Limiting Nitrate Loading to the Springshed

Most data indicate that nitrate, rather than phosphate, is responsible for the proliferation of
hydrilla and algae in the Wakulla River. Control of either nitrate or phosphate loading to the
springshed could be used to control the excessive plant growth rate in the Wakulla River. It may
be more feasible, however, to limit nitrate loading to the springshed to reduce the growth of
nuisance plants in the river. A larger proportion of nitrate than phosphate loading to the
springshed comes from point sources, which means nitrate inputs may be more readily controlled
Also, the phosphate-rich rock, known as the Hawthorn Group, that overlies the Floridan aquifer
in areas of the springshed may represent a significant and unabatable source of phosphate to
Wakulla Springs. FDEP is using 0.2 mg/L of nitrate as a target concentration for the spring-fed
Wekiva River to control undesirable aquatic plant growth. Nitrate concentrations in the Wakulla
River are 3 to 5 times this target.
Several hypotheses can be proposed to explain the differential rate of uptake of nitrogen
relative to phosphorus. A first hypothesis is nitrogen is in critical short supply and thus is taken
up more rapidly than phosphorus, despite the fact that TN:TP ratios are indicative of P limitation.
[Note: Algal mat N:P ratios reported by Stevenson et al. (2004) appear to be greater than 30:1,
which would be indicative of higher N uptake, but need to be verified (see Stevenson, Figure
2.22)].
A second hypothesis is that nitrogen is not solely limiting, and phosphorus is more rapidly
mineralized than nitrogen by upstream plants. This would account for a higher relative net
uptake of nitrogen compared with phosphorus. A third hypothesis is differential dilution rates of
nitrogen and phosphorus downstream of the boil also could potentially explain the results. This
hypothesis would require that additional sources of groundwater continue to discharge into the
Wakulla River below the spring boil, but at ratios of N:P that are lower than waters exiting the
boil. This last hypothesis is unlikely, as the inputs by Sally Ward and McBride Springs are
relatively small and very likely derived from the same source as the main vent.
Water-column concentrations of chlorophyll a increase from less than 0 to approximately
3.4 micrograms per liter ([tg/L) approximately 9.2 km downstream from the boil (Figure E4).
This increase is a kinetic effect related to the time of travel (algae need to time to grow once
exposed to sunlight) in concert with an excess nutrient supply. Because P concentrations are so
high relative to the rate of suspended algal uptake, it would take a very large decrease to
effectively reduce chlorophyll a levels below current levels.






































1996


1998


2UUU

Time


2UU2


2UU4


Figure El: TN:TP ratios (by mass) over time at Wakulla Springs, 1996-2004

Data courtesy ofJ. Hand. Plots by Cm it, Pollman. This plot also shows the Redfield ratio of
algal N:P (mass basis; Snimm and Morgan, 1996)


y = 9E 3.56- 0.46253x R= 0.26379




0 00* e 0
IF--- ------- 41 -- -- -- -- -- -

*P*
S I




Redfel, I N P Ratio


I I I I I I I I I I I I





















































Figure E2. Variations of concentrations of TN and TP in the Wakulla River with distance downstream
of the springhead
(upper panel: TP concentrations; lower panel: N concentrations)
The blue lines show average concentrations at a given location measured between 1999 and 2002. Error
bars are standard error of the mean. The red lines show the predicted concentrations of, for example, N,
assuming that observed changes in P are matched by a stoichiometrically equivalent (I,,~, J on the
Redfield ratio) amount of uptake in N.




58



















































Figure E3. TN:TP mass uptake ratios and changes in algal (phYloplahnkon) chlorophyll a
concentrations in Wakulla Springs and the Wakulla River as a function of distance downstream from
the spring boil
(upper panel: TN:TP mass uptake ratios; lower panel: chlorophyll a c(- ', Ii, mil 'ii%)
Data are site averages from 1999 through the present. Error bars are standard error of the mean. Data
are from LakeWatch and FDEP routine monitoring sites (J Terrell, LakeWatch, personal
communication.)







59












Appendix F: Phosphate in the Floridan Aquifer and Wakulla Springs


Summary: The goals of these analyses were to collect phosphate data on stormwater,
groundwater, and springs in the Leon and Wakulla County areas and to search for regional and
temporal trends as indications of the influence of the city of Tallahassee (COT) on phosphorus
loading to Wakulla Springs. Analyses suggest that neither stormwater nor the Southeast
Sprayfield (SESF) are a significant source of phosphorus to Wakulla Spring, but that Hawthorn
Group sediments in the springshed control phosphate concentrations in groundwaters entering
the spring via the kinetics of phosphate dissolution and desorption.

This data summary is based on data received from the COT (Jamie Shakar), Leon County
(Melissa Hughes), the Northwest Florida Water Management District (NWFWMD; Tom Pratt),
Florida Geological Survey (2004 Springs Report), and LakeWatch (Sean McGlynn).

For this data summary, OP stands for ortho-P. TP stands for unfiltered total P (presumably
measured following persulfate/autoclave oxidation of unfiltered samples). All concentrations are
expressed as milligrams of phosphorous per liter (mg-P/L = ppm-P).

Stormwater:

Leon County has begun measuring OP in stormwater running into Lakes Henrietta and
Munson, and leaving Lake Munson. The concentrations reported for 2005 are all close to the
detection limit of 0.014 ppm-P.


City of Tallahassee Drinking Water Well CW12:

CW12 is located NE of the intersection of Orange Avenue and South Monroe Street. The
total depth of the well is 365 feet, and it is cased to 192 feet. OP concentrations for February 12,
2002 through august 1, 2005 ranged from 0.02 to 0.04 ppm-P with no significant time trend.


Name StationID Description


LCLM3040384307 Lake Henrietta 1
LCLM3040384307 Lake Henrietta 1
LCLM3040184306 Lake Henrietta 2
LCLM3040184306 Lake Henrietta 2
LCLM3039584309 Lake Henrietta 3
LCLM3039584309 Lake Henrietta 3
LCLM3039084312 Lake Henrietta 4
LCLM3039084312 Lake Henrietta 4
LCLM3039084312 Lake Henrietta 4
LCLM3037584313 Munson Slough 1 above Lake Munson
LCLM3037584313 Munson Slough 1 above Lake Munson
LCLM3036484301 Munson Slough 2 belowdam
LCLM3036484301 Munson Slough 2 belowdam
LCLM3034884301 Munson Slough 3 Gas Rpeline Road
LCLM3034884301 Munson Slough 3 Gas Rpeline Road
LCLM3034484302 Munson Slough 4 on forest rd 30031
LCLM3034484302 Munson Slough 4 on forest rd 30031


Latitude Longitude Original Sample_ Parameter


30.40366
30.40366
30.40155
30.40155
30.39514
30.39514
30.39084
30.39084
30.39084
30.37522
30.37522
30.36396
30.36396
30.34843
30.34843
30.34443
30.34443


-84.30789
-84.30789
-84.30673
-84.30673
-84.30947
-84.30947
-84.31271
-84.31271
-84.31271
-84.31391
-84.31391
-84.30181
-84.30181
-84.30175
-84.30175
-84.30246
-84.30246


Sample_ Time
02/04/05 14:00
05/01/05 12:30
02/04/05 14:00
05/01/05 12:50
02/04/05 14:00
05/01/05 18:50
02/04/05 14:00
05/01/05 19:50
05/01/05 19:50
01/31/05 14:45
04/20/05 10:12
01/31/05 15:20
04/20/05 10:47
01/31/05 15:34
04/20/05 11:05
01/31/05 16:00
04/20/05 11:35


Orthophosphate
Orthophosphate
Orthophosphate
Orthophosphate
Orthophosphate
Orthophosphate
Orthophosphate
Orthophosphate
Orthophosphate
Orthophosphate
Orthophosphate
Orthophosphate
Orthophosphate
Orthophosphate
Orthophosphate
Orthophosphate
Orthophosphate


Method Sampling Result


_Type
surface
surface
surface
surface
surface
surface
surface
surface
surface
surface
surface
surface
surface
surface
surface
surface
surface


0.014
0.014
0.014
0.014
0.014
0.014
0.014
0.014
0.014
0.014
0.014
0.014
0.014
0.014
0.014
0.026
0.014


Original_
Units
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L








































Figure Fl. Sampling stations for the Leon County Lake Henrietta/Lake Munson stormwater
monitoring program


Total and Ortho P in CW12


*OP TP


r 0.12
. 0.10
0.08-
0.04


0.02 !
S0.00
-0.02
-0.04


MN- C O C
3 35


i I


1 0) Q


0~ CO N 0) CO (0 LO (0 (0 CN C
N CN 4 (0 CO CN 4 (0 CO C\1 4 2
0000 Coco Coco-0


Date

Figure F2. Total-P and ortho-P in the city of Tallahassee drinking water well CW12

Error bars for TP represent the Method Detection Limit (MDL) =0.04 ppm-P. Error bars for OP
represent the MDL 0.004 ppm-P. Two OP data points were anomalously much higher than the
corresponding TP data and are highlighted in red.









Florida Geological Survey Southeast Leon and Wakulla County Springs:
Natural Bridges Spring (0.03 ppm-P) and St. Marks River Rise (0.05 ppm-P) were sampled
in 1972. Samples were taken in 2002 from Horn Spring (0.045 ppm-P), Natural Bridges Spring
(0.046 ppm-P), Rhodes Spring (0.045 ppm-P), and St. Marks River Rise (0.041 ppm-P). These
data are inadequate to demonstrate any time series, but provide an estimate for OP in this portion
of the Floridan aquifer.
In Wakulla County, Wakulla Spring was sampled in 1972 and 2002, showing 0.03 ppm-P
OP both times. Newport Spring (southeast of Wakulla Spring near the St. Marks River) was also
sampled in 1972 (0.01 ppm-P TP) and again in 2002 (0.014 ppm-P OP). Once again, there is no
obvious time trend, but the time series is not adequate to be conclusive.
NWFWMD Aquifer Data:
In 1999-2000, the NWFWMD measured 0.02 to 0.03 ppm-P OP in the Floridan aquifer
north of the Cody Scarp. In 2004, the concentrations were 0.013 to 0.057 ppm-P OP. No
samples were taken under the SESF (sprayfield) in 1999, but the value in 2004 was 0.013 ppm-P
OP.
Northeast of Wakulla Spring, between the spring and the SESF, OP concentrations in 1999-
2000 were 0.02 to 0.05 ppm-P. In 2004, the concentrations in this area were 0.004 to 0.029 ppm-
P. In 2004, the wells around the spring showed 0.021 to 0.034 ppm-P OP.


Total Phosphorus, Wakulla Springs, LAKEWATCH


1'- OM

C) C) C


Date

Figure F3. Total P data from the Wakulla Springs boil
The error bars represent the method detection limit =6 ppb-P. The data are not significantly correlated
with time.











LakeWatch Data:

TP concentrations at the Wakulla Spring boil from 1996-2004 range from 0.02 to 0.04 ppm-
P and show a very slight, statistically insignificant, decrease with time. Because the samples are
taken so soon after the water exits the cavern mouth, it is unlikely that a significant portion of the
TP is present as particulate P (phytoplankton or detritus). Therefore, it is likely that the OP
concentrations are very close to these TP concentrations, although they must in fact be less than
or equal to the TP concentrations.



Above and below sprayfield

Nitrates and chloride are more than
3J [r,1n I.iHIii ueIu pl o i U [j I iLJ Lj.



bo 7I


S
-= =f p S
E L
AR Q R 0 Z Ee

S~ 032
~u I C S g
a BA I D


Figure F4. Nitrate concentrations north and south of the sprayfield

Nitrate concentrations south of the sprayfield are 300% of values north of the sprayfield,
while total phosphorus concentration is unchanged north to south (J. Hand, FDEP). These data
suggest that the sprayfield is not a source of total phosphorus to Wakulla Springs, and support
the hypothesis that phosphorus concentration in groundwater in the springshed is controlled by
the kinetics of dissolution or desorption with Hawthorn Group sediments.






























































64





































TP vsSpring Discharge


1000
900
800

700
600
500
400
300

200
100
0


0 5 10 15 20
TP (ug/L)


25 30 35


Figure F5: Relationship between total nitrogen and total phosphorus concentration and discharge at
Wakulla Springs
at station 1 "Henry 's Pole" 50feet downstream from the Wakulla Spring boil


TN vs Spring Discharge


1000
900

800 y --*-0.8874x + 1061 .3

700 R2 = 0.3997
.S 600 *
500 *

4 00 *----
S500.

S* *




0
0 200 400 600 800 1000 1200
0 ---- i ----,---- i ----,---- i ---- I
0 200 400 600 800 1000 1200


*
**.
*
** *


Si i


: :









Data from Lakewatch (McGlynn Laboratories Inc., April 10, 2005, Revision 3. Woodville
Recharge Basin Aquifer Protection Study. BC-07-19-02-29. Phase I and II Summary, p. 33.) TN
shows an inverse relationship with discharge; suggesting rainwater dilution of an unvarying TN
load to the watershed. TP showed no statistically significant relationship with discharge;
suggesting that stormwater TP inputs, which should peak at times of high rainfall/high discharge,
are not significant relative to other TP sources.
The TN vs. spring water discharge plot is a classic inverse relationship that occurs when the
pollutant source is limited and becomes diluted with increased (rainfall-driven) flow. In contrast,
the independence of concentration of TP from flow is indicative of a dissolution type source
such as the Hawthorn Group (i.e., an essentially infinite phosphorus source over the time scales
of interest and where the kinetics of dissolution or desorption reaching equilibrium is faster than
the kinetics of increased flow.

Conclusions:
Conclusions from these data, and from literature regarding the behavior of OP in limestone
aquifers, are as follows:
OP rapidly equilibrates/adsorbs in limestone aquifers. The equilibrium concentration is
a function of the water chemistry (mainly the ionic strength) and the limestone matrix.
High OP concentrations in low ionic \i engili 'feed" water lead to adsorption yielding
lower equilibrium concentrations. Low OP concentrations in higher ionic strength feed
water can lead to de-sorption and a higher equilibrium OP concentration. These
processes reach equilibrium within 10 to 50 days in the Key Largo Limestone (Dillon et
al., 2003; Elliot, 1999). Thus, it appears that OP concentrations in the 0.01 to 0.04 ppm-
P range (NWFWMD aquifer data) may represent the equilibrium concentration one
expects from the interaction of stormwater and treated sewage water with the limestone
aquifer. It may take decades or centuries to some day exhaust the adsorption capacity of
the aquifer between the city of Tallahassee and Wakulla Springs. To avoid this, OP input
should be minimized as much as possible.
Aquifer samples taken on the southern edge of the SESF in 2004 (0.013 ppm-P) are lower
than the concentrations in Wakulla Springs. This is less than or equal to OP
concentrations in the aquifer in this region, \,l,'uc'/tin,' that higher OP concentrations in
the aquifer could be due to desorption of OP from the limestone matrix.
OP in stormwater reaching Lake Munson, and leaving Lake Munson, is very close to the
detection limit (0.014 ppm-P) and is lower than the OP concentrations in the aquifer and
coming from the spring itself Therefore, stormwater does not appear to be a significant
source of OP to the spring.
None of the available aquifer data shows any significant time trend, although the data set is
too limited to conclude whether OP concentrations in the aquifer or Wakulla Springs have
increased or decreased with time. The LakeWatch TP time series from Wakulla Spring (1996-
2004) is by far the most extensive data set from the region. It shows no significant trend with
time.










Appendix G. Specific Suggestions for Research on Nutrients and Biota


If additional confirmation is needed of the link between nitrate inputs to the springshed and
excessive plant biomass in Wakulla Springs and River, further research could be conducted
within the 12-to-18-month period over which other studies are being conducted on behalf of the
city of Tallahassee and Leon County, to confirm the flow linkage between the Southeast
Sprayfield and Wakulla Springs.
If doubts remain regarding whether nitrogen or phosphorus is more important as regards
controlling nuisance plant growth in the Wakulla River (our conclusions support nitrogen control
both from the limiting-nutrient standpoint and because we are better able to control nitrogen
loading), we recommend that an in situ nutrient-dosing study be conducted in the Wakulla River.
This could be conducted downstream of the spring boil in a reach that has been relatively un-
impacted based on its primary producer (plant) community structure. Like studies conducted by
Stevenson et al. (2004) in other Florida springs, this study should involve a controlled flume that
provides quantitative control of nutrient fluxes, and should include two components: (1)
controlled-addition studies to help define the thresholds of change for an extended period, and
(2) continued studies on the same experimental sites with nutrient reductions to define whether
the relationship between the primary producer community and ambient nutrient fluxes is the
same, regardless of whether the system is becoming progressively eutrophic or is being
remediated. This latter type of study is critical to ensuring that a new, essentially irreversible
alternative stable state has not developed downstream from the spring boil that will be
unresponsive to mitigative measures. For example, Hydrilla is said to grow well under low-
nutrient conditions and, once present in a system, is almost impossible to eradicate.
Synoptic monitoring of changes in nutrient concentrations downstream of the Wakulla
Springs boil, in concert with monitoring of the structure and density of the primary producer
community, should also help define the threshold points where shifts occur in response to
increasing nutrient concentrations. There is already in place monitoring of the spring boil
concentrations (conducted by LakeWatch) and concentrations at a series of stations located
downstream from approximately 5.4 through 9.2 km from the springhead. What is unknown at
this point is the degree of vegetative monitoring at the downstream locations (if any). In
addition, if the region of most rapid shift in the primary producer community lies less than 5.4
km from the springhead, then additional monitoring stations for both water chemistry and plant
community structure need to be established.
The mass balance studies should have two fundamental components the measurement of
loads and source attribution. Load measurements involve quantifying both the flux of water and
concentrations of the contaminant associated with the flux. Perhaps even more difficult for the
Wakulla Springs problem is quantifying the contribution from a possible source to the measured
fluxes in Wakulla Springs. Tracer studies (both those planned and those already conducted) are
critical in helping to define these relationships. What is critically lacking in the current studies is
any assessment of error in source contributions. Errors inherent in our understanding of source
contributions and also in our understanding of the critical endpoint (i.e., primary producer
community structure) cause-and-effect relationship need to be quantitatively analyzed to assess
the likelihood of the degree of success and cost benefit of a given management option. Given the
appropriate error measurements, a Monte-Carlo-type analysis would be quite useful in defining
the probability of success.









The planned USGS study on sampling for pharmaceuticals at locations down gradient of the
SESF will help indicate the direction of groundwater flow from the sprayfield.

Appendix H. Speculation on the Origin of Dark Water
contributed by Jim Stevenson
Occasional dark water flowing from Wakulla Springs is a natural phenomenon. In the
1890's, Henry Beadel wrote that heavy rain reduced water clarity. During the 1940's, the
manager of the Wakulla Spring Lodge occasionally wrote to Ed Ball commenting on the periodic
dark water days that kept the glass-bottom boats from operating. However, we don't know the
frequency with which this condition occurred.
The lands west of the Woodville Karst Plain are drained by Lost, Black and Jump Creeks.
These creeks flow into sinks that are connected to the cave system conducting water to Wakulla
Spring. The watershed of these creeks was burned frequently by lightning and human-caused
fires for centuries, thereby substantially reducing leaf litter and underbrush. The natural
landscape was an open forest of widely spaced longleaf pines and the ground was carpeted with
native grasses and wildflowers. During the dry season, fires burned into creek bottoms
eliminating organic debris.
During the 1920's, the forest was logged and the land was burned annually to replenish the
grasses for open-range livestock grazing. Logging, burning and grazing substantially reduced
the amount of vegetation that could contribute tannin to the creeks and sinks.
After the establishment of the Apalachicola National Forest in 1936, all fires were suppressed
and the land was replanted in pine trees. With the absence of fire, the density of pine trees and
underbrush increased as did titi and other hardwood trees along the creeks and bordering
wetlands. Livestock grazing was eventually phased-out in the 1970's and prescribed burning
was resumed at intervals of three or more years. The pine trees have steadily increased in size
producing more needles which add to the mass of leaf litter.
Therefore, during the last 50 years, the management of this watershed has resulted in a
substantial increase in vegetation and leaf litter compared with the condition during the 1920s
and 1930s. During periods of rain, the leaf litter releases tannin to surface waters resulting in an
increase of dark-water days at Wakulla Springs.
Water clarity is exacerbated by turbid stormwater flowing from Tallahassee through Munson
Slough into Ames Sink.










Appendix I: Ongoing Programs, City of Tallahassee Water Utility


Master Wastewater Treatment Plan:
The project entails the development of a 20-year master plan for the treatment and disposal
of the city's wastewater. The plan will consider needed treatment/ disposal capacities to meet the
20-year growth; advanced treatment processes for nutrient removal; alternative disposal
methods, particularly public access reuse; and potential locations for the new treatment/ disposal
facility. The project will look at the feasibility to upgrade the Lake Bradford Road Treatment
Plant (LBRTP), which has a capacity of 4.5 million gallons per day to a reclaimed water
treatment plant that can produce public access reuse water for primary irrigation and cooling
needs. Due to its location, the LBRTP could provide reuse water the downtown area, Florida
State University, including the National High Magnetic Laboratory and Seminole Golf course,
and the Florida A&M University. Converting the LBRTP to a reclaimed water treatment plant
would reduce the treated wastewater disposed at the Southeast Farm Facility and thus mitigating
any possible impact on the Floridan Aquifer and Wakulla Springs. Also, the reuse plant would
correspondingly reduce the amount of water pumped from the Floridan Aquifer, thus preserving
that amount for future drinking water needs.
Phase I of the Master Treatment Plan was completed in May 2005 and entailed a
comprehensive review of the operations and facilities at the T.P. Smith Water Reclamation
Facility (TPS Plant). The resulting report recommended a 5-year Capital Improvement Plan to
upgrade the existing facilities and processes to improve reliability and treatment quality. The
treatment improvements would upgrade the secondary treatment process to remove
approximately 30% more nitrate-nitrogen and provide additional treatment capacity of 1.5
million gallons per day. The estimated cost for the TPS Plant improvements is $74 million that
is subject to City Commission approval.

Reuse Facility:
The Tram Road Reuse Facility (TRRF) is designed with a capacity of 1.2 million gallons per
day to provide Part III Public Access Reuse water for irrigation to nearby users including the
Southwood golf course, State Office Complex, two high schools, and the Capital Circle
Southeast Widening Project. The FDEP permit has been obtained, and the project will be
advertised for construction in early 2006. Future expansion of the reuse system may include the
City's Hilaman golf course and landscaping for Blairstone Road and the planned Orange Avenue
extension. The total estimated cost for the reclaimed water treatment plant and the reuse
distribution system is $2,500,000 $3,000,000. The TRRF will withdraw a portion of the treated
wastewater effluent being pumped to the Southeast Farm Facility (SEF) from the T.P. Smith
Water Reclamation Facility, which is the city's major wastewater treatment plant. Every gallon
of wastewater treated at the TRRF and reused as irrigation is one less gallon disposed at the
farm. Moreover, a dual environmental benefit is realized as the wastewater reuse also results in
avoided pumping from the Floridan Aquifer and thus preserving the aquifer for future drinking
water needs.

Biosolids:
The end products of a wastewater treatment process are treated wastewater or effluent and
treated biosolids. The biosolids from the treatment process had been land applied locally to City









owned property. In March 2004, the Utility installed a heat drying system to upgrade biosolid
quality from Class B to Class AA. The resulting product, which can be used as fertilizer and soil
amendments, is sold through a broker to commercial nurseries and other agricultural outlets. By
utilizing this advanced technology, the City has reduced land application of biosolids by 90
percent. With planned addition of a new dryer in the next 2 to 3 years, the utility will achieve a
100% (or total) reduction. This corresponds to a significant reduction in the amount of nitrogen
that can seep into the ground and potentially impact the Floridan Aquifer and surface waters
within the lower St. Marks-Wakulla Springs Watershed.

Nutrient Management Plan

The Utility is conducting an evaluation of the nutrient usage or a Nutrient Management Plan
(NMP) at the Southeast Farm Facility with expected completion by January 2006. As part of the
NMP various nitrogen and phosphorus sources will be evaluated with the goal of reducing
overloading to the system without any detrimental effects to groundwater quality.
Fertilizer is used at the Southeast Farm Facility to ensure healthy plant growth and thereby
ensure optimum plant uptake of nutrients. Healthy plants remove more nutrients than unhealthy
plants. The fertilizer also maintains healthy plants throughout the year and prevents any surface
water runoff, which would have an immediate detrimental effect on area lakes and streams.
Fertilizer usage has decrease by 68% since 2000 and for the last two years averages under
8% of the total nitrogen load at the irrigation pivots, indicating fertilizer usage is not a major
contributor of nitrogen to the system at the Southeast Farm Facility.

USGS Study:

In response to concerns of water quality issues at Wakulla Springs and the Northwest Florida
Water Management District's report indicating the SEF Facility is a large potential source of
nitrogen in the contributing area, the City of Tallahassee Water Utility and the United States
Geological Survey have combined efforts into a three-year study, which began in the summer of
2003, to investigate the path and evolution of reclaimed water as it moves from the SEF Facility.

Nitrate alone is a poor indicator of human activity due to the many sources of nitrogen in the
natural environment. The study will analyze samples for many of the typical human wastewater
chemical parameters including heavy metals, pesticides and herbicides. Two biological methods
will help to 'fingerprint" and assist in determining specific contribution groundwater from the
SEF Facility. he process should be able to differentiate the contributing nutrient sources;
fertilizer, treated wastewater and livestock operations. Effects from the cattle operation versus
human contribution should be further determined.
The joint study will also model the groundwater flow leaving the SEF Facility. Although
previous reports indicate groundwater flow in a southwesterly direction, monitoring wells at the
far southwest comer of the Facility, SE16 & 17, have shown no increase in nitrogen levels both
total and nitrate, over the life of the Facility. These wells by their location should indicate
varying trends in groundwater quality. The USGS/Cityjoint study will help to answer additional
aspects of groundwater flow.