Title: Draft - Water Supply Needs and Sources Assessment - Appendix K - Consultant Responses to Revised Proposed Evaluation Factors
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Title: Draft - Water Supply Needs and Sources Assessment - Appendix K - Consultant Responses to Revised Proposed Evaluation Factors
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Abstract: Jake Varn Collection - Draft - Water Supply Needs and Sources Assessment - Appendix K - Consultant Responses to Revised Proposed Evaluation Factors (JDV Box 70)
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APPENDIX K


CONSULTANT RESPONSES TO REVISED PROPOSED
EVALUATION FACTORS







APPENDIX K

TABLE OF CONTENTS


Response from Peter F. Anderson, P.E.


Response from Peter S. Huyakorn, Ph.D..


Response from Irwin H. Kantrowitz .


Response from Vance W. Kidder, Esq. .


Response from Jerry E. Kubal, P.G...


Response from R. David G. Pyne, P.E..


Response from Peter J. Schreuder, P.G..


Response from Charles H. Tibbals. .


Response from Jake Varn, Esq. . .


Response from Stephen A. Walker, Esq.


. . . . 157


. . . . 162


. . . 167


. . . . 172


. . .. 176


S . . .180


. . .. 185


. . 194


196


Page

146


. o o o o o o .











Georans, inc.
GROUNDWATER SPECIALISTS


46050 Manekin Plaza Suite 100 Sterling. Virginia 20166
703 444 7000




-October 27, 1993



Ms. Barbara Vergara, P.G.
Department of Groundwater Programs and Technical Support
St. Johns River Water Management District
P.O. Box 1429
Palatka, FL 32178-1429


Reference: Water Supply Needs and Sources Criteria Development,
Contract No. 93D277
GeoTrans Project No. 7683-000


Dear Barbara:

Enclosed is my written response to the most recently
(September 28, 1993) proposed evaluation factors for saltwater
intrusion and impact to legal existing users. I have commented on
the factors and proposed an alternative method for defining
thresholds of acceptability and delineating areas of inadequate
sources of water to meet needs.

I will await receipt from you of other panel members'
comments. I look forward to discussing them with the panel,
SJRWMD staff, and other interested parties on December 2. In the
meantime, please do not hesitate to call if you have any questions
or comments.

Sincerely,



Peter F. Andersen, P.E.
Vice President
Principal Engineer


PFA/j

Enclosure as stated


146







Water Supply Needs and Sources Assessment Project


Water Supply Needs and Sources Assessment Project
Discussion of September 28 Proposed Factors

























147


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1 INTRODUCTION

The St. Johns River Water Management District (SJRWMD) is in the
process of developing an assessment of District-wide water supply needs and
sources for the 1990-2010 planning period. As a part of this, the SJRWMD
is attempting to define thresholds of acceptability for water level and
water quality changes. A panel of legal and scientific consultants has
been assembled to comment on SJRWMD proposals for thresholds of
acceptability. An initial series of proposals was developed and submitted
to the panel in mid-June of 1993. Written comments to SJRWMD were provided
by the consultants in late July. A panel discussion on these findings was
held in early September. Based on the comments and discussion, SJiWMD has
subsequently revised the proposals for thresholds of acceptability. This
report provides comments on the most recent proposal and suggests an
alternative proposal for saltwater intrusion factors.



2 PROPOSED EVALUATION FACTORS FOR SALT WATER INTRUSION
IN THE UPPER FLORIDAN AQUIFER

2.1 MOST RECENT SJRWMD PROPOSAL
The five cases SJRWMD has proposed for evaluation factors of salt
water intrusion are actually an expansion of the previously considered
factor 4. The threshold for saltwater intrusion impact was "a change in
spatial distribution of chloride concentrations as follows:


a. water less than 250 mg/l
b. water less than 1200 mg/l
c. water less than 5000 mg/l"


In the new proposal, further detail has been provided on specific
areas within the Upper Floridan where this factor would apply and the
current use of the water for which it would apply. Sulfate and TDS have
also been added as constituents to be considered.
These five cases recognize that the only true indicator of saltwater
intrusion is a change in water concentration. Many of the previously-

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considered evaluation factors were really causal factors. For example, a
change in flow direction or a potentiometric surface below sea-level may
contribute to intrusion, but do not independently indicate that there is or
will be a problem. Other previously proposed factors were more lenient in
defining a threshold (spring discharge, cost of treatment, etc.) The
currently-proposed five cases essentially allow no expansion of zones of
water quality that are in excess of limits for public consumption,
agricultural irrigation, or treatment by reverse osmosis.
While I agree that the only true indicator of intrusion is
concentration change, I disagree that SJRWMD has the database or predictive
capability that will allow them to essentially ignore the causal factors of
intrusion. Although SJRWMD states that both models and trend analysis of
field data will be used to make determinations of future impact, I suspect
that the models will be relied upon most heavily because of sparsity of
field data in critical areas.
Having been involved with the development of the Wekiva River Basin
saltwater transport model, as well as several other saltwater transport
models in Broward, Pinellas, and Pasco Counties, I am familiar with the
assumptions and limitations of these analyses. As a result of having
applied these models to various predictive scenarios, I am also familiar
with the transient response that will be noted through application of these
models. My opinion is that although these models are valuable tools in
understanding the site-specific behavior of saltwater transport, they
should not be used as the sole basis for determining future saltwater
intrusion impact.
A critical assumption in using these models for predictive means is
that future pumpage is accurately quantified. Because the saltwater
interface moves in response to lowering of hydraulic head or reduction in
seaward hydraulic gradient, it is critical that the future water use in
question, as well as the background future water use, be accurately
quantified. Therefore it is very disturbing to note that "a substantial
disparity exists between the projected 1990 and 2010 water use estimates
and projected population growth estimates for the same period" (SJRWMD,
1992). Regardless of how accurate the model is, saltwater intrusion may be
overpredicted because future pumpage is not properly accounted for.

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Because pumpage is arguably the most easily quantified input to the model,
little is gained by running the model with pumpage that is known to be in
error.
Although analysis of water availability to the year 2010 is required
by the Needs and Sources project, it is likely that water quality will
continue to degrade after 2010 as a result of a proposed withdrawal. This
is due to the slow nature of saltwater intrusion; it may take decades for
an equilibrium to be attained following imposition of a new stress.
Therefore, the ultimate magnitude of a saltwater intrusion problem may be
underestimated by using the 2010 concentrations as the basis for
comparison. Areas that are unaffected in 2010 by a stress imposed in 1995
could become degraded by 2015.
One of the assumptions in the model is that concentrations are
currently (1990) in a state of equilibrium. This may not be true in all
areas, and could have some implications on conclusions derived from the
modeling. Also, it appears to me that SJRWMD wishes to use the model or
field data to decide if a withdrawal is acceptable or not. However, in
most instances, intrusion is not the result of a single withdrawal, but
rather the composite result of several withdrawals. It is unclear to me
how this method will distinguish between individual withdrawals, enabling
SJRWMD to decide if a withdrawal is acceptable or not.
The proposal by SJRWMD is such that expansion of zones of poor
quality water within the Upper Floridan aquifer is not allowed. Although
degradation within zones is allowed (it is theoretically permissible to
degrade a zone from 251 mg/l to 999 mg/l chloride), the proposal does not
recognize that any degradation within a zone will nearly always result in
some lateral or vertical movement of the 250 mg/l, 1000 mg/l, or 5000 mg/l
isochlors. Movement of isochlors will constitute a change in the extent of
concentration zones. It is nearly impossible to treat current
concentration zones as independent packets of water that will not change in
extent with the introduction of a solute of higher concentration.
By setting the standard as no expansion of concentration zones within
the Upper Floridan aquifer, SJRWMD may unintentionally be putting-a
moratorium on additional future water use. Any new withdrawal will have an
effect (perhaps not monitorable) on the movement of the saltwater

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interface. Perhaps a tolerance (or threshold) other than no movement needs
to be established.
Several approximations in the models that result in inaccuracies in
the computed concentrations preclude their use to this level of detail and
certainty. The difference between computed and observed concentration,
referred to as the residual, may be fairly large in some areas. The model
may in fact indicate a different concentration zone than is actually
observed. It is, therefore, difficult to justify the results of a model
that may have a residual of several hundred or even a thousand mg/l in
deciding whether a zone will be degraded sufficiently to classify the
withdrawal as unacceptable.
In summary, I do not believe that the current proposal by SJRWMD
should be adopted. It relies too much on the modeling that has or is being
performed. Although a threshold for degradation within a zone is proposed,
it is not clear under which circumstances the degradation will not create
an expansion of the zone. It appears that this proposal is geared toward
vertical movement of saltwater without much consideration to lateral
movement.


2.2 AN ALTERNATE PROPOSAL-THE SWISS SYSTEM
In attempting to set thresholds for acceptable water degradation by
saltwater intrusion, we must distinguish between indicators of degradation,
causes of degradation, and factors that make geographic areas prone to
degradation. As mentioned earlier, the only true indicator of saltwater
intrusion is a change in water concentration. Because the data base
contains only a limited time history and geographical coverage of
concentrations, some reliance must be placed on numerical models to fill in
the gaps for current data and to predict future changes. I do not believe
that SJRWMD should rely solely on the limited database and models with a
fairly high degree of uncertainty associated with them for establishing
thresholds.
I propose that SJRWMD should use additional data, as well as direct
indicators, to establish thresholds for acceptable water degradation and to
delineate areas of inadequate water resources to meet future demand. These
other data include causes of saltwater intrusion (upward hydraulic

51 GeoTrans,inc.










gradients, landward hydraulic gradients, decrease in seaward hydraulic
gradient, decrease in downward hydraulic gradient, and creation of a direct
hydraulic gradient from a source of poor quality water such as a river) and
factors that make an area prone to saltwater intrusion (low leakance of the
upper confining unit, high leakance of the middle confining unit, proximity
to the interface, significant drawdown,'deep pumpage, areas that are
already fully developed).
The method I propose is similar to the U.S. Environmental Protection
Agency's Hazard Ranking System (HRS) for hazardous waste sites. The HRS
involves summing individual scores for each potential hazard at a site to
obtain a composite hazard score. The method I propose, referred to as the
Salt Water Intrusion Susceptibility Score (SWISS), involves assignring to
each geographic area a score or rank for each direct indicator, causal
factor, and factor that makes areas prone to intrusion. These scores are
then summed to provide a composite SWISS for each geographical-area. Areas
with a high SWISS would be considered to have inadequate water resources to
meet demand.
In practice, this would be an ideal application for a Geographic
Information System (GIS). A series of overlays, one for each factor, with
a ranking or score for each square mile (for example) of the SJRWMD could
be developed. The score would pertain to that square mile area's
susceptibility to salt water intrusion as defined by a single factor. The
overlays would then be summed to give a composite score. The composite map
would give a clear indication of critical areas. An example of factors to
be included and how they would be scored is given in Table 1.
The advantage of the SWISS system is that it relies on the
preponderance of evidence rather than a single piece of data. Uncertainty
in data is not as critical because the problem is looked upon with many
different types of data. Most of the initial potential evaluation factors
that were discussed in the July 27 reports are included in the SWISS
method. However, because a single factor cannot "condemn" an area, it
becomes less critical that all exceptions to a particular factor are
identified. For example, an area may be penalized for having a landward
gradient; however if it is far from the interface and there are no



152 GeoTrans,inc.










Table 1. Factors and basis for ranking for the SWISS Method.


Factor High Rank Low Rank

Documented increase in
1 TDS, C1, or SO4 Significant trend No increase
concentration over a increase (decrease)
7-year period
Current horizontal
2 distance to 250 mg/L Hundreds of feet Miles
isochlor (or TDS, SO4
equivalent)
Current depth to 250
.3 mg/L isochlor (or TDS, 50 ft 1000 ft
SO, equivalent)

4 Upper confining bed Thick Thin
thickness

5 Middle confining bed High Low
leakance
Strong seaward
6 Landward gradient seaward
Seaward gradient gradient
Downward
7 Upward gradient Downward
Upward gradient gradient
Percent decline in
8 available artesian head 100% 0%
from redevelopment to
present
Predicted percent
9 decline in available 100% 0%
artesian head from
1990-2010
Predicted increase in
10 chloride (TDS, S04)
10 chloride (DS, SO Large increase 0
concentration from
1990-2010


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7

documented changes in contaminant concentrations, the area will not be
classified as a critical area when the composite score is determined.
To prevent too much subjectivity from being present in the method,
quantitative assignments should be made for all factors. For example, the
score for upper confining bed thickness could be proportional to thickness:
a 100-foot thick bed would get a score df 10, a 10-foot thick bed would get
a score of 1.
The method presented here should be considered a prototype: many
details need to be worked out before implementation. For example, should
more relative weight be assigned to some factors?, what composite score
constitutes a problem?, can quantitative assignment mechanisms be developed
for all factors?, are there any other factors that may be appropriate?



3 PROPOSED EXISTING LEGAL USER IMPACT CRITERIA


SJRWMD has proposed three existing legal user impact criteria. These
are described and commented upon below.
Criteria 1. In areas where the potentiometric surface of the
Floridan aquifer is higher than land surface year round, but is projected
to decline below land surface in response to projected increases in water
use, the impact to existing legal users would be considered unacceptable.
Note: this would provide limited protection to users of groundwater
supplied by free flowing wells.
This proposal establishes a baseline for impact that is tied to a
datum rather than a specific value or percent decline. This seems like a
good concept, except it protects areas that are not realizing their full
development potential. It also gives the impression that current
conditions should be maintained. The note that this proposal will provide
limited protection of users of groundwater supplied by free flowing wells
is true, but the word limited must be underscored. A decline in pressure
may be considered an impact by an affected water user.
Criteria 2. In areas where the Floridan aquifer water levels are
currently less than 20 feet below land surface, but are projected to be
greater than 20 feet below land surface in response to projected increases

154 GeoTrans,inc.








8

in water use, the impact to legal existing users would be considered
unacceptable. Note: this would provide protection to users of groundwater
withdrawing from wells equipped with centrifugal pumps that cannot pump
from depths greater than 25 feet.
This proposal is very similar to the first, but sets a threshold for
maintaining heads that are higher than 20 feet below land surface from
falling below this depth. Again, this proposal seems to protect areas that
may not be fully realizing their development potential. Proposals 1 and 2,
in concert, do not address areas that may be truly stressed. In concept,
the idea of establishing maximum drawdown based on a datum, rather than an
individuals particular pumping system, seems sound. I would like to see
something more scientifically based than trying to protect certainetypes of
pumping systems.
Criteria 3. In areas where the quality of groundwater in the
Floridan aquifer is projected to exceed the limits described (as saltwater
intrusion factors), the impact to existing legal users would be considered
unacceptable.
This proposal merely carries over what was set forth earlier into the
category of impact to legal existing users. Therefore my comments related
to saltwater intrusion factors also apply here.



4 SUMMARY


The SJRWMD has proposed a new set of criteria for establishing
thresholds for saltwater intrusion and impact to legal existing users. The
ideas all have merit and are based on logical thought. However, I believe
that the SJRWMD has not considered all potential factors for determining
degree of saltwater intrusion. Given the sparsity of the data base and
consequent relative uncertainty in the models, it is not appropriate to
base determinations solely on these considerations. I have, therefore,
offered an alternative method. The current SJRWMD proposal, the previous
SJRWMD proposals, and the current alternative should not be considered
exclusive of one another. It is likely that the best solution is a
combination of all three. With regard to impact to legal existing users,

155 GeoTrans,inc.










the SJRWMD has identified two methods that essentially place limits on the
amount of acceptable drawdown from land surface. These methods appear to
protect areas that are most suited for development of water resources.
Although maximum drawdown from land surface may be an appropriate criteria,
it should be based on preventing additional undesirable results.










































156 GeoTrans, inc.







eN.DRO
Leobgic-


October 27, 1993


Ms. Barbara A. Vergara, Director
Department of Ground-Water Programs
and Technical Support
St. Johns River Water Management District
P.O. Box 1429
Palatka, FL 32078-1429


Dear Barbara:

We have reviewed the District's revised saltwater intrusion and impacts to existing legal
user's criteria, and our comments are enclosed. In summary, we generally concur with the
proposed criteria as they are stated, but we foresee potential problems with the implementation
of the saltwater intrusion criteria. Our thoughts are summarized on the attached pages.

Please call if you have any questions.


Sincerely,



Peter S. Huyakorn
President


PSH;sh
Attachments


1165 Herndon Parkway, Suite 900, e7rndon. Virginia 22070 USA
(703) 478-5186 FAX (703) 471-4180


ST. JOINS RTIiE WATERi WA7 OiSThc'Ti

Nn\ -- i 1993
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PROPOSED EVALUATION FACTORS FOR SALTWATER INTRUSION
IN THE UPPER FLORIDAN AQUIFER


General

1) In order to implement the proposed criteria, it will be necessary to delineate the present
location of the 250 mg/C; 1000 mg/C; 2,500 mg/e and 5000 mg/f chloride and/or sulfate
isopleths throughout the District, or at least in regions of potential concern. This task
could prove problematic due to insufficient observation data. In areas that have been
extensively studied, such as eastern Orange and Seminole Counties, the 250 mg/f
isochlor is fairly well known (the uncertainty could, however, be on the order of 2-3
miles in many places). Other isochlors, however, are generally not known particularly
well. Although it is possible to construct generalized regional mappings, it is not clear
if that level of detail is sufficient for the intended purpose. Substantial additional field
investigations may be necessary to adequately complete this item.

2) The time value under consideration during which "the concentrations of these constituents
are projected to rise above these limits" for the various criterion is not specified. This
is a key issue since saltwater intrusion occurs over very large time scales; once a
condition conducive to saltwater intrusion exists, it may take several tens of years for
increased ion concentrations to be detected and mapped. In other words, a clear planning
horizon for saltwater intrusion impacts should be decided upon and stated.

Related to this issue is the projection of increases in ionic concentrations due to increases
in groundwater withdrawals; this approach implies that it will be necessary to somehow
separate saltwater intrusion due to existing withdrawals from that expected to occur due
to future withdrawals. This task can be accomplished using density-dependent transport
models (where appropriate), but is more difficult (or impossible) to accomplish using
trend analysis unless detailed data is gathered over some definitive time period.

3) i., our opinion, the District should reconsider implementing as a backup criterion "the
reversed regional hydraulic gradient near the transition zone" to delineate regions of
potential saltwater intrusion. We recommend this for two reasons:

1) In general, wherever the direction of groundwater flow is reversed, or the
magnitude of flow is reduced, in the vicinity of the transition zone, the
stage for saltwater intrusion is set and intrusion will eventually occur.

2) Groundwater flow directions and magnitudes are more readily and
accurately obtained from field data and modeling projections that are
estimates of water quality.

It seems that this criterion should at least be used in a regional, or first-cut, approach to
determine areas of potential concern and regions of enhanced data collection.









Potential Problems with Model Predictions


1) There is some degree of uncertainty and calibration error associated with all model
predictions; simulated, or "calibrated", isochlors will not match precisely with those
observed in the field. When a model is used for predictive purposes, therefore, the
initial isochlor position may be biased towards a zone of lesser or higher concentration.
This bias in initial location will have to be accounted for. Exceptions to this may be
local modeling efforts (such as the Geneva lens model) or model subdomains that were
focused upon during model calibration (such as the Cocoa well field in the east-central
Florida model).

2) The focus of most modeling efforts is correct simulation of the 250 mg/e isochlor. Other
isochlors are generally not focused upon during calibration, and they tend to follow
general regional trends as opposed to local (but potentially significant) irregularities.

3) Sulfate (S04) and total dissolved solids (TDS) concentrations are not simulated in most
(if not all) of the District's modeling studies. TDS may be inferred if it is asumed that
ions in solution vary in direct proportion to chloride (Cl) as is observed in the standard
chemical composition of seawater. Sulfate concentrations will have to be determined
from trend analysis if additional modeling work is not conducted.


Potential Problems with Predictions Using Trend Analysis

1) To conduct appropriate trend analysis, data sets with a sufficient number of monitoring
wells and data points, to yield statistically valid results will have to be identified.
Although the District chloride data base covers a large number of wells, many of these
wells do not have a large number of chloride measurements through time.

2) A methodology for treating nearby wells with different trends (due to local anomalies
and/or measurement error) will need to be devised. This problem is currently being
faced by the SWFWMD, where certain observation wells indicate increasing chloride
concentrations, and other wells (in the immediate vicinity) do not.


Attached Figure

We have constructed a conceptual figure depicting various parts of the transition zone
that correspond to the proposed saltwater intrusion criteria. The figures provided in the
District's October 22 correspondence illustrate the conceptualization for upcoming, but
not for lateral intrusion or combined lateral/upconing intrusion.









PROPOSED EXISTING LEGAL USER IMPACT CRITERIA


In general we concur with the proposed criteria as stated. Our only comment concerns
criterion one, which states that the potentiometric surface cannot be drawn down below land
surface year round. This criterion neglects decreases in flow rates due to lowering of heads
prior to dropping below land surface. For example, if a user is obtaining 100 gpm from an
artesian well with no pump, according to the proposed criterion the well yield could be
decreased to 5 gpm due to lowering of the potentiometric surface with "no impact".








Proposed Evaluation Factors for Saltwater Intrusion
in the Upper Floridan Aquifer






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REVISED EVALUATION FACTORS -- NEEDS AND SOURCES ASSESSMENT


Comments by Irwin H. Kantrowitz


Salt Water Intrusion Evaluation Factors

The overall concept of the revised factors is on target; by eliminating
references to gradients and head, the hydraulic inconsistencies of the
original version have likewise been eliminated. Too, the revisions have
been made objective, thus eliminating many of the uncertainties found in the
original. Unfortunately, these improvements came at the expense of clarity.

I found the factors very difficult to follow because of the convoluted
structure required by the format. I found Factor 4 impossible to follow and
believe there is an error. As we discussed, this factor, designed to
protect agricultural irrigation water, should have quality bounds of 250,
250, 1000 and 1000, 1000, 5000 (Cl, SO4 and TDS) and all my following
comments are based on that revision. Also, as I understand our discussion,
the correct values for Factor 5 are 1000, 1000, 5000 and 2500, 2500, and
10,000, and apply to the entire thickness of the aquifer.

Because I found the factors to be so confusing, I resorted to drawing a
diagrammatic cross section using the 250, 1000, and 2500 isochlors and
indicating each zone described in the factors. (It was this exercise that
convinced me of the impossibility of Factor 4 as originally presented.)
This cross section (attached) points out that there are large parts of the
aquifer with water suitable for irrigation and RO that are not included in
the zones defined by the Factors. There is a zone beneath zone 2 and
between zones 2 and 3 where the aquifer contains water suitable for
irrigation that is excluded from zone 3 (or 4?). There is a similar zone
underlying zone 4 and between zones 4 and 5 where the aquifer contains water
suitable for RO that is excluded from zone 5 and another zone beyond zone 5
that contains a considerable thickness of water with less than 2500 mg/l
that is not included in any zone (it should be included in zone 5).

These inconsistencies, plus the convoluted language, led me to try my
hand at a revision of these factors. First, I defined some terms up front
so that they didn't need to be spelled out repeatedly within the factors.
In developing the factorss, I adhered to the District's intent of
protecting drinking water, agricultural irrigation water, and water for RO.
There are two alternate sets of factors; one that more closely parallels the
structure of the District's factors, and another (my personal choice) that
combines everything into one factor. Both sets are attached.


Legal User Impact Criteria

I see nothing technically wrong with the three criteria. However, the
need to install or change a pump (Criteria 1 and 2) seems relatively
insignificant when compared to possible irreparable damage to the aquifer
(Criteria 3) -- unless of course, its your well.






































Diagrammatic cross section showing zones of the Upper Floridan aquifer
protected by Factors 1 through 5 (based on the 250, 1000, and 2500
isochlors.










EVALUATION FACTORS FOR SALT WATER INTRUSION IN THE UPPER FLORIDAN AQUIFER
--ALTERNATE ONE--


DEFINITIONS

Drinking Water -- water containing less than 250, 250, and 500 milligrams
per liter (mg/l) of dissolved chloride (Cl), dissolved sulfate (S04), and
total dissolved solids (TDS), respectively.

Agricultural Irrigation Water -- water containing less than 1000, 1000, and
5000 mg/l of Cl, S04, and TDS, respectively.

Reverse-Osmosis Feed Water -- water containing less than 2500, 2500, and
10,000 mg/l of Cl, S04, and TDS, respectively.

Sufficient Thickness -- a vertical zone within the aquifer that can serve as
a dependable source of water to wells designed to produce water for the
purposes of drinking supply, agricultural irrigation, or reverse osmosis.

Projected -- Projections of ground water quality changes based on ground
water models and trend analysis of ground water quality data.


EVALUATION CRITERIA


1. Where the Upper Floridan aquifer contains water in sufficient thickness
to constitute a source of drinking water to public supply or individual
domestic wells, any proposed increase in ground water withdrawal that is
projected to increase concentrations of Cl, S04, or TDS above the upper
limits for such use will be considered unacceptable.

2. Where the Upper Floridan aquifer contains water in sufficient thickness
to constitute a source of agricultural irrigation water, any proposed
increase in ground water withdrawal that is projected to increase
concentrations of Cl, S04, or TDS above the upper limits for such use will
be considered unacceptable.

3. Where the Upper Floridan aquifer contains water in sufficient thickness
to constitute a source of reverse osmosis feed water, any proposed increase
in ground water withdrawal that is projected to increase concentrations of
Cl, SO4, or TDS above the upper limits for such use will be considered
unacceptable.










EVALUATION FACTORS FOR SALT WATER INTRUSION IN THE UPPER FLORIDAN AQUIFER
--ALTERNATE TWO--


DEFINITIONS

Drinking Water -- water containing less than 250, 250, and 500 milligrams
per liter (mg/1) of dissolved chloride (Cl), dissolved sulfate (S04), and
total dissolved solids (TDS), respectively.

Agricultural Irrigation Water -- water containing less than 1000, 1000, and
5000 mg/1 of Cl, S04, and TDS, respectively.

Reverse-Osmosis Feed Water -- water containing less than 2500, 2500, and
10,000 mg/l of Cl, S04, and TDS, respectively.

Sufficient Thickness -- a vertical zone within the aquifer that can serve as
a dependable source of water to wells designed to produce water for the
purposes of drinking supply, agricultural irrigation, or reverse osmosis.

Projected -- Projections of ground water quality changes based on ground
water models and trend analysis of ground water quality data.


EVALUATION FACTOR

Where the Upper Floridan aquifer contains water in sufficient thickness
to constitute a source of 1) drinking water for public supply or individual
domestic wells, 2) agricultural irrigation water, or 3) reverse osmosis feed
water, a proposed increase in ground water withdrawal that is projected to
increase concentrations of Cl, S04, or TDS above the upper limits for any of
these uses will be considered unacceptable.







VINCE W. KIDDER
'ST. )OHNS TW:. WxtiR BIA1 DOShiC^
i ,0

October 27, 1993

Ms. Barbara A. Vergara, P.G., Director
Dept. of Ground Water Programs & Technical Support
St. Johns River Water Management District
Po Box 1429
Palatka, Fl 32178-1429

Re: Needs & Sources Assessment Criteria

Dear Barbara:

I have reviewed the evaluation factors for salt water intrusion and
existing legal users that have been proposed since mid-September 1993.
To do so I have re-organized salt water intrusion so that I could more
easily follow what was intended. Please find my re-organized version
attached. I hope it accurately reflects the text I was sent.

My over-all comments pertain to the "will be considered unacceptable"
phrase in each of the five cases. It is my understanding that the
evaluation criteria are being developed pursuant to Section 17-40.501,
Fla.Admin.Code. As such the criteria are to be used to identify
specific geographical areas which have become critical water resource
problem areas or are anticipated to become critical within the next 20
years. Of course the rule provision then requires consideration of
remedial or preventative measures among the district and local
government. Thus I have assumed that the "considered unacceptable"
language is intended to mean or be synonymous with the rule's language
about critical water resource problem areas. Consequently in my re-
organization I so indicated.

I also believe that the language in cases 2 and 4 that pertain to
thickness of water precluding reasonable development needs to be
clarified to be more pointed and informative. Accordingly I have made
an attempt to do so. I am not sure it is what is needed but I believe
it illustrates what needs to be and can be done in terms of
clarification.

The text provided us did not address the frequency of analysis and the
projected period of analysis. The rule indicates a 20 year projection.
Is the frequency of analysis annual every two years or what? I would
expect this information to come out in the Needs & Sources publication.

The current proposed evaluation criteria are an improvement in concept
as well as clarity. I will leave it to those who are technically
oriented to decide whether that portion of the water resource that needs
protecting is addressed. At this juncture I see my role as a word-smith
and that is the nature of my comments.

Sincerely,


Vance W. Kidder
VWK/ss















UPPER FLORIDIAN


CASE 1. Where water in the aquifer has concentrations throughout
of:

CL- less than 250 mg/l
S04- less than 250 mg/l
TDS less than 500 mg/l

AND

projected ground water withdrawal would cause
concentrations to increase

CL- above 250 mg/l
S04- above 250 mg/l
TDS above 500 mg/l

THEN

the area where concentrations are so projected to
increase is a critical water problem area that will be
subject to the measures set out in Section 17-40. 501 so
as to prevent such a change



CASE 2. Where water in the aquifer contains concentrations of:

CL- less than 250 mg/l
S04- less than 250 mg/l
TDS less than 500 mg/l

BUT

greater than these concentrations at depth

AND

projected ground water withdrawal would cause
concentrations of CL-, S04- and TDS to increase to 250,
250, and 500 mg/1, respectively, in areas currently
supplying water for public supply and individual domestic
use where the water has concentrations less than 250, 250
and 500 mg/l

THEN

The area where concentrations are so projected to
increase is a critical water problem area that will be
subject to the measures set out in Section 17-40. 501 so
as to prevent such a change














UNLESS


water with concentrations of CL-, S04-, or TDS that are
less than 250, 250 or 500 mg/l, respectfully, is not
recharged or recharged so minimally that to preserve the
area of water at concentrations below these amounts is
tantamount to not putting the water to use.



CASE 3. Where water in the aquifer contains concentrations of:

CL- between 250 and 1,000 mg/l
S04- between 250 and 1,000 mg/l
TDS between 500 and 5,000 mg/l

AND

projected ground water withdrawals would cause
concentrations of CL-, S04- or TDS to rise above 1,000
CL-, 1,000 S04- or 5,000 TDS, respectively

THEN

the area where concentrations are so projected to
increase is a critical water problem area that will be
subject to the measures set out in Section 17-40. 501 so
as to prevent such a change



CASE 4. Where water in the aquifer contains concentrations of:

CL- between 250 and 1,000 mg/l
S04- between 250 and 1,000 mg/l
TDS between 500 and 5,000 mg/l

AND

where the Upper Floridan aquifer is underlain by water
with concentration greater than

CL- greater than 1,000 mg/l
S04- greater than 1,000 mg/l
TDS greater than 5,000 mg/l

AND

projected ground water withdrawals would cause
concentrations of these constituents to increase:
















CL- above 1,000 mg/l
504- above 1,000 mg/l
TDS above 5,000 mg/l

in areas where concentrations of these constituents do
not exceed:

CL- 1,000 mg/l
S04- 1,000 mg/l
TDS 5,000 mg/l

THEN

the area where concentrations so projected to increase is
a critical water problem area that will be subject to the
measures set out in Section 17-40. 501 so as to prevent
such a change

UNLESS

water with concentrations of CL-, S04- or TDS that are
greater than 250, 250, 500 mg/l and less than 1,000,
1,000 or 5,000 mg/l, respectfully, is not recharged or so
minimally recharged that to preserve the area of water at
concentrations below these amounts is tantamount to not
putting the water to use



CASE 5. Where water in the aquifer contains concentrations
throughout of:

CL- greater than 1,000 mg/i but less than 2,500 mg/l
S04- greater than 1,000 mg/l but less than 2,500 mg/l
TDS greater than 5,000 mg/l but less than 10,000 mg/l

AND

projected ground water withdrawals would cause
concentrations of CL-, S04- or TDS to rise above 2,500
mg/l CL-, 2,500 mg/l S04- or 10,000 mg/l TDS

THEN

the area where concentrations are so projected to
increase is a critical water problem area that will be
subject to the measures set out in Section 17-40. 501 so
as to prevent such a change






































































171





ST 2 3 F R I 1 6 -a- K -9 E f`:4 L- F U R R & S S 0 1


Kubal-Furr & Associates
Environmental Consultants
P.O. Box 273210 P.O. Box 846
Tampa, FL 33688-3210 Greenville, SC 29602
813/931-7730 803/370-0470
FAX/931-8039 FAX/370-9798


29 October 1993



Via Facsimile


Ms. Barbara A. Vergara
St. Johns River Water
Management District
Post Office Box 1429
Palatka, Florida 32178-1429

Dear Ms. Vergara:

I have looked at the salt water intrusion and existing legal user criteria developed since our last
meeting in September and I think the District staff has done a good job of presenting the various
water resource conditions into which most of the water use requests will fall

Although I do have some reservations about these factors which I'll present later, I think the
basic: approach is workable and I have prepared the attached flow chart (Attachment A) which helps
me understand how these criteria might be incorporated into the existing permit evaluation process.
As I see it, one way to go about it would be as follows:
The consultants group and District staff agree on the evaluation criteria which is
presented to the Governing Board for adoption. These criteria include water quality
considerations such as the existing and projected concentrations of chlorides, total
dissolved solids, and sulfates; general aquifer characteristics/scenarios as presented by
the staff in the example cases; and, projected declines in water levels as-they affect
existing users.

After the evaluation criteria are adopted, the staff should generally divide the District
into discrete areas exhibiting the aquifer characteristics presented in the example cases.
Once subdivided, implement a monitor well installation program in the discrete areas
with the intent of providing data which will allow the staff to analyze water quality
trends. While ground-water quality data from an applicant or permitted is useful, the
District's monitoring program needs to be more focused in order to better define
horizontal or vertical movement of an interface.

As the ground-water quality monitoring network is being established, the District needs
to merge, or somehow manage, the different flow and transport models which have
been developed for selected areas.









Ms. Barbara A. Vergara


*Following this, the District needs to estimate the potential water resource availability in
each of the subdivided areas, either by applying the models or through manual
calculation. The resource availability should then be compared to both existing
allocations and projected needs to establish a baseline or benchmark upon which permit
requests and renewals can be evaluated.

It's going to be time-consuming and not all that easy to get to this point but it involves mostly
technical evaluation of resource potential and comparison of this potential to actual and projected
demands. The bulk of this work has already been accomplished by the District staff, with the
exception of changing orientation to the subdivided areas as established by the example cases.

The next part of the process involves evaluation of water use permits against the criteria
established above:

First, determine if any impacts to existing legal users are expected. If there are
unacceptable impacts, the permit is denied, whether or not the other criteria are met. An
option at this point is for the applicant to modify the permit or mitigate the impacts.

If no impacts to existing users are predicted, the permit is subjected to the other criteria
concerning water quality. The comparison indicates either acceptable or unacceptable
impacts and the permit is issued, denied, modified.

In the absence of any attempt to optimize the use of the water resources available within the
district, the permitting process can become a rather perfunctory exercise at this point. The impacts
are either acceptable or unacceptable and the permit is either issued or denied.

The gross water resources available in the District appear more than adequate for the
foreseeable future; however, municipalities are not all going to be located over abundant sources of
high quality ground water and the best places to grow citrus and other crops won't always be
situated in poorer quality areas. The District's most valuable mission, in my mind, is to proactively
match the needs to the sources and to develop ways to optimize the utilization of the resource. I
don't see the permitting process as it currently exists as being the most effective way to go about
this.

Having said all this, and proposing one way to incorporate the evaluation factors into the
permit process, I still have a number of questions and concerns about proceeding this way:

The water quality parameters selected (i.e., chlorides, sulfates and total dissolved
solids) are all on the list of secondary drinking water standards. The example cases
presented for drinking water quality in the Floridan aquifer apply the secondary
standards to these parameters, which are based principally on aesthetic rather than
health-based criteria. How much difficulty do the attorneys foresee enforcing these
standards?

SI think the use of the flow and transport models to predict impacts is perfectly
acceptable, particularly early in the program before a satisfactory water quality database
is developed. I would expect that through time the empirical data would become more
important than predictive modeling for no other reason than it's harder to argue against
actual data.


Kubal-Furr & Associates
173


29 October 1993









Ms. Barbara A. Vergara


I don't think there are that many more typical examples, but, there are areas of the
District which do not fit any of the cases presented. For example, the Floridan may be
unconfined or semiconfined in parts of the District; a convenient distinction between
upper and lower Floridan may not exist; and, poor quality water could intrude
horizontally as well as vertically. These cases seem to exist more along the edges of the
District and probably do not affect the basic approach being presented here.
Subdividing the district into distinct hydrogeologic areas will identify any exceptions to
the example cases already presented.

I don't think the District can limit impacts just to free flowing areas and to owners of
centrifugal pumps. Why wouldn't it be unacceptable to cause a drawdown which
lowers the water level below the lift limits of my pump regardless of pump type?
All in all, I'm still not completely sure I understand how the District would intend to
implement these criteria assuming we all agree on the numbers. These criteria would
have to be applied on a first-come, first-served basis. If all the criteria are satisfactorily
metby the first 99 applicants but number 100 gets snagged by this regulatory trip wire,
do we just stop things at that point? "I know this may be the best place in the State to
grow citrus, but you're ten milligrams per liter too late and now you need to go 100
miles north of the frost line where there is plenty of available water, OK"?

If the criteria are implemented in this fashion, is there anything to stop me from
obtaining permits speculatively based on a proposed land use? I would think this would
be a very attractive feature to potential buyers of my property, especially when we get
down to the last few permits being issued.

In conclusion, I think the evaluation criteria are of value in protecting the resource and their
adoption would produce an added benefit-if the criteria are adopted, people will eventually start to
be turned down when they request a permit even though the total resource is more than adequate to
satisfy the need. Ultimately, the laws of supply and demand will force the District, and/or private
industry to develop creative ways to optimize allocation of the resource and to match needs to any
number of potential sources of supply.

I'm'looking forward to discussing these evaluation factors at the next meeting and in working
through several example cases demonstrating how the criteria could be applied. I hope you have a
Happy Thanksgiving and I'll see you on the 2nd of December.

Sincerely,

Kubal-Furr & Associates


Jerry Kubal





Kubal-Furr & Associates
174


29 October 1993


-3-






Attachment A.

Incorporation of Evaluation Factors into Permitting Process




'.. Establish Evaluation Crieri ..ria l. .


Kubal-Furr & Associates
175


Evaluate

Ways

to

Opimize

Resource

Allocations;









Engineers NOV 31993
Planners
E'r1ISHE Economists
Scientists

October 28, 1993





Ms. Barbara A. Vergara, P.G., Director
Dept of Ground Water Programs and
Technical Support
St. Johns River Water Management District
PO Box 1429, Palatka, Florida 32178-1429

Subject: Water Supply Needs and Sources Assessment Criteria

Dear Ms. Vergara:

Following are my review comments on the second round of proposed evaluation factors
for salt water intrusion in the Upper Floridan Aquifer, received October 25 by fax.

Water Use Permitting Procedures

The proposed evaluation criteria represent a different approach than that provided to us
previously. They appear to follow a format designed to facilitate evaluation according to
solute transport computer model analysis. They are general and relatively easy to
understand. Such generality would provide the District with some flexibility in their
implementation to respond to site-specific needs and opportunities. However the same
generality may tend to reduce the applicant's confidence in the predictability of the
outcome of any particular water use permit application.

I am reasonably comfortable with having general criteria so long as the procedures for
their implementation incorporate a strong element of real data analysis, common sense,
good judgement and experience at the staff level instead of a computer model driven
"black box" that is assumed to be irrefutable. This judgement should incorporate the
computer model procedures along with hard data on water levels, water quality, trends,
flow rates, hydrogeology and other factors. The District appears to have a strong
commitment toward developing a regulatory program to control salt water intrusion. I
hope that the District has an equally strong commitment to obtaining such data,
particularly in areas more sensitive to salt water intrusion, and to incorporating such data
into the decision process for water use permitting.



Miami Office 2828 Coral Way. Suite 440 305 443-6401
Miami, FL 33145-3214 176 Fax No. 305 443-8856









Ms. Barbara A. Vergara
Page 2
October 28, 1993



The data required to drive such a 3-dimensional solute transport model is generally
lacking throughout the District. Perhaps the best data set is available for the Cocoa
wellfield, with which I am quite familiar. The minimal amount of information regarding
water quality and hydraulic variability with depth at this site is a constraint upon full
confidence in current solute transport modelling for this area. Even less data is available
in other areas.

My suggestion is that areas considered more likely to experience salt water intrusion
problems should first be identified. Major water users in these areas should then be
notified of this designation and a program should be planned and initiated to collect the
necessary data, along with normal records of flow, water levels and water quality. The
focus would be on collecting high quality data along a number of transects and at selected
monitor wells designed and operated to detect upward movement of the interface. The
schedule for this data collection program should parallel the water use permit renewal
cycle for major water users so that the amount and quality of data available is reasonably
matched to the regulatory issues being addressed and the urgency of those issues.

Such a program will be expensive, however the adverse impact of inappropriate
regulatory decision-making can be far more expensive to water users. I do not have the
impression that the salt water intrusion risk within the District is extremely urgent,
although there are some areas that bear watching. A proper program can and should be
implemented to collect data over a period of several years to support appropriate
regulatory action.

Location of Unacceptable Impact

The criteria are sufficiently general that they make no reference to location of the
projected adverse impact. Any groundwater withdrawal, particularly near the coast, will
tend to move the equilibrium location of the salt water interface. If the District were to
take the position that any interface movement is unacceptable, then for many parts of the
District no groundwater production would be permitted. On the other extreme, if the
District took the position that adverse impacts would be considered only for the
applicant's wells, then many other water users could be adversely impacted by lateral salt
water movement. Clearly these extremes would be inappropriate, however both are
consistent with the proposed evaluation factors.

If this range of generality were deemed to be too great, the range could be narrowed by
adding qualifying language. For example: "Where the Upper Floridan Aquifer within a
reasonable radius of influence around the applicant's wells contains water with ..." The
radius of influence could be defined according to the average production rate in the








Ms. Barbara A. Vergara
Page 3
October 28, 1993



permit application and could be established to reflect different radii for different parts of
the District, depending upon the severity of the salinity intrusion potential in each part.

Except for withdrawals immediately adjacent to the coast, effects upon salt water
interface movement tend to be cumulative, representing the combined influence of all
users rather than the individual influence of a single user. The radius of influence may
need to be greater in areas of more concentrated production by multiple users.

Time of Unacceptable Impact

The proposed criteria also lack specificity with regard to time of any adverse impact.
Since the rate at which the interface adjusts to a new equilibrium may require several
years or decades, it would be appropriate to indicate the time associated with an
unacceptable impact. A time frame somewhat longer than the permit duration seems
appropriate, due to the slow response of the aquifer system. For example: "...the change
in water quality will be considered unacceptable if it occurs within a projected duration of
25 years. The conclusion regarding interface movement could be based upon computer
modelling combined with trends of water quality change and gradient reductions along
transects established for this purpose, or at identified wells monitoring upward movement
of the interface at depth.

Case 1 Comment

It is not uncommon for water utilities to utilize water from wells that slightly exceed
drinking water standards, so long as the blend entering the distribution system meets
these standards. I suggest that the District align its water quality criteria to match FDEP
criteria for public drinking water systems. Suggested revisions are Cl 350 mg/1; S04 -
350 mg/1; TDS 750 mg/1. According to FDEP, drinking water can exceed the
standards for one parameter but not two. The suggested values provide some flexibility
in this regard, without compromising the District's intent.

Case 3 Comment

I am not aware of agricultural operations in Florida that can make effective utilization of
water with TDS in excess of about 3500 mg/1 without adversely impacting crop
productivity. Chloride concentrations are more pertinent for agriculture.








Ms. Barbara A. Vergara
Page 4
October 28, 1993



Case 4 Comment

The data to support this solute transport simulation model is generally lacking, as
discussed above, and is unlikely to be generated by agricultural interests. Is the District
willing to fund this data collection effort. The Hastings agricultural area, with its
deterioration in quality due to chronic upcoming of brackish water, is a good example.
Crop yields are already being adversely affected in this area due to the higher salinity of
irrigation water.

Case 5 Comment

Reverse osmosis water treatment of brackish groundwater is far more likely to be
implemented with much lower TDS concentrations in the range of 700 to 2000 mg/1.
The cost of treating water with high TDS concentrations is substantial compared to other
water supply alternatives available within the District. Reserving high TDS water for RO
supplies, particularly along the coast, probably will provide little benefit to anyone.

Summary

The proposed regulatory approach is a step in the right direction. It needs to add some
specificity with regards to location and timing of any unacceptable adverse affects. It
also needs to incorporate a clear commitment to obtaining and relying upon reliable
hydrologic and water quality data, and consideration of trends in this data, to support
regulatory actions.

Very truly yours,

CH2M HIL



R. David G. Pyne, PE


r







HYnROSC ENCES


Via Facsimile


Ms. Barbara A. Vergara, P.G.
Director
Department of Ground Water Programs
and Technical Support
St Johns Water Management District
Post Office Box 1429
Palatka, Florida 32178-1429



RE: Evaluation factors Saltwater Intrusion; SDR Project SJRF 010; Contract #93D250

Dear Ms. Vergara:

I am pleased to provide you with my comments on the "Proposed Evaluation
factors for Saltwater Intrusion In the Upper Floridan Aquifer". My response consists of
two parts: 1) comments on the evaluation factors; and 2) suggested changes im th6
language.

I hope that my comments may help you and your staff and the committee to arrive
at a very reasonable and acceptable set of evaluation criteria.


Sincerely yours,
SCHREUDER, INC.


-- .


Peter J. Schreuder P.G.
President


PJS/mm
SJRFIvergranv.ltr 1-10-93



13412 N. LNCOLS AVF-NI'F TAMP., HIORIDA 33618 TELEPHONE (813) 902-6600 FAX (813) 962-6601


GEOTECHNOLOGY
November 11, 1993


- R---











Ms. Barbara Vergara P.G
November 11, 1993
Page 2


Comments on Proposed.Evauation Factors


Introduction

If the concentrations of Chloride (CI-) or Sulfate (SO4=) in the groundwater are
higher than background (generally greater than 20 50 mg, movement of mineralized
groundwater has occurred. The concentration limits of 250 mg/I have been adopted as
health based standards. If concentrations of chloride or sufate in the groundwater are
above background at a particular point in the aquifers, t indicates the presence of an
InienaceU. i rte y uu iuwat: quay~~ ~rr rn kiteface iS qene/r')Y P. 80l)Ai'-yM. Any 1,..n ge
in the potentiometric surface in response to groundwater wihdrawals witi cause a snit
in the equilibrium resulting In a shift in groundwater quality.

If one wishes to regulate groundwater withdrawals based on these health
standards, it is useful to recognize that saltwater intrusion has already occurred and that
an attempt is made to limit the expected shift in the water-quality equilibrium to a certain
level. I am not certain that this can be reliably predicted based on my experience even
with the use of trend analyses and groundwater quality models. I therefore suggest an
approach that recognizes the uncertainty involved. It may be useful to consider a range
of values in combination with a rate of change in any one of the water quality parameters.
Fcr example, if the water quality already exceeds 200 mg/1 for chloride and/or sulfate, it
may not take much to bring it to 250 mg/1. I would suggest that the District consider
increasing their vigilance in protecting the resource by requiring applicants to install
monitor wells and determine water quality parameters more frequently. For example in
Case 1, it is necessary to know what the upward migration rate is of the more mineralized
groundwater In the lower Floridan Aquifer. This may require the applicant to construct
three or more short screen monitor wells in the first majorflow zone in the Upper Floridan
Aquifer above the middle confining layer. It would also require the collection and
analyses of their water quality samples in the screen area of the monitor wells and a
sample of the pumped water.on a quarterly basis. Because anisotropy may play a key
role in the migration of mineralized groundwater, The District may require a pumping test
using the three monitor wells in hope of determining the preferred direction of
groundwater migration in the first significant flow zone above the middle confining layer.

This monitoring approach will only detect the intrusion after it has already taken
place because more mineralized groundwater has migrated upward through the
underlying middle camping unit It would be very helpful to have one short screen
monitor well in the middle confining unit near the pumping well to evaluate the vertical


I




P Fj-


Ms. Barbara Vergara P.G.
November 11, 1993
Page 3


migration velocity. Based on my experience rehabilitating well fields in the coastal zones
in Florida, a danger is the existence of unplugged but abandoned wells open to botn ne
upper and lower Floridan Aquifers.

Spedllc Comments


Case 1) I believe that the District needs to be more specific in setting up the
evaluation factors The assumptions underlying Figure 1 are of an isotropic,
homogeneous aquifer system. This too is simplified compared to the reality
of saltwater intrusion. Preferred flow zones exist in the Upper Floridan.
Their existence and potential for allowing a relatively rapid migration of
mineralized water should be considered. The proposed changes In the
language are shown in the attached texts as strikeouts and underlined
additions.

Case 2) The only difference between Case 1 and 2 is the absence of a well defined
confining zone between the lower quality groundwater at the bottom of the
Upper Floridan aquifer and the better quality in the upper part. It has been
my experience that in this case, it is nearly Impossible to meet the
objectives of this case as stated in the "note". I suggest to delete this
evaluation factor, because it seems already covered by the language in
Case 1.

Case 3) From an agricultural viewpoint, I believe that irrigation water with a TDS
greater than 1500 mg/1 would pose significant restrictions because of the
potential for soil salinity problems. I therefore suggest to only look at the
TDS concentration as an upper limit criterion.

Case 4) As mentioned in my comments on case 2, I believe that this is not easy
from a physical point of view to meet the intent of the District as discussed
in the "Note". I suggest to delete this evaluation factor because it is already
covered by case 3.

Case 5) It seems that cost effectiveness for reverse osmosis processes using
brackish groundwater charges at about the 4000 mg/i TDS level. This
would therefore again suggest a graduated approach. For example, i the
TDS concentration rises and a new equilibrium is established at 5000 mg/I
of TDS. It may pose a severe risk to the economic viability of the reverse
osmosis plant.


182










Ms. Barbara Vergara P.G.
November 11, 1993
Page 4



PROPOSED EVALUATION FACTORS FOR SALT WATER INTRUSION
IN THE UPPER FLORIDAN AQUIFER

Case 1. Where the Upper Floridan aquifer contains tar ith crWcetra tiona
ut vvie lit: 11 u ipcpi roluai a o
chloride (CI-) or sulfate (SO4-) or total dissolved solids (TDS) less than 250
200 mg/i, 250 200 mg/I, and 500 400 mg/1 respectively in equilibrium
conditions throughout, and the rate of change in the concentrations of these
constituents are is projected to rise above drinking water standards these
limits in response to projected increases in ground water withdrawals, the
change in water quality will be considered unacceptable.

Case 2. Where the Upper Floridan aquifer contains water with concentrations of Cl-
or SO, or and TDS geae than 250 mg/n, 250 mg/l, and 500 mg/I respectively
and groateo than these concentrations at dep. e within the Upp'12 mForidan
and concentrations of thoe cons tit uent ae projected to riinrac se theoe
limits In portions o, the aquifer crrently flying water it, h conntra 1700 mq/
of thoo constituents leos than these limits to pubic--supply and ridividua'2
domestic wells, the change in water quality will be considered unacceptable.
However, if th the sickness of water with concentrations tGee than thes limItss
is so thin that water of drinking water quality cannot-be-reasonaby
dnreaopsed from wit, within the change in water quality wil nwill berd
coacceptable.

Case 3. Where the Upper Flordan aquifer contains water with concentrations of Cl-
or S04- or TDS greater than 250 mg/i, 250 mg/, and 500 mg/I respectively
throughout, and less than 1-00 mg- 14000 mgA and .5000 1200 mg/l TDS
espetiey in equilibrium conditions throughout, and the rate of change in
the TDS concentrations of these constituents ar is projected to rise to
concentrations above 1000 rngl (fCIl) or 1000 mFgA(S )or 5000 1700 mo/li
(TDS) anywhere within the Upper Floridan aquifer in response to projected
increases in ground water withdrawals, the change in water quality will be
considered unacceptable.

Case 4. \Whmere the Upper Floridan aquifer-contains water with concentrations of Gl
or $04- or TDS greater than 250 mql, 250 m/I and2 500 mq/l respectivelY
and 'e65 than 1000 mg/l, 100m mgg and 500 m@A respectively, underlain
within the Upper Floridan aquifer b? Water with concentrations greater than
1000 mq%, 1000 mqAl and 5M000 mq/l respctively,-and- loe than 9-m25




P 86


Ms. Barbara Vergara P.G.
November 11, 1993
Page 5


..Qg,?500 mg! ?In d 0\ ,00 -r rnp rn'.'olY ; and conCA ntr..rtin of.thoIo
Sn titO de to^^r Incrons an 100 m/ PC!/ r 100 g,,I

with concntrtionS 2 less than 1000 mg/I (GCI) or 1000 mg/ (SQ4-) o -50
Vg/I (TDS) for agiculturol irrigation, the change in water qua&iy will bo
considered unacceptable-. ow.er-, if the th.cknesS of water with
concentrations greater than 250 mq/1 (Cl), 250-MqA-S 04;,- or 500 q1
(T-DS) an l4es than 1000 mg9A (Cl) or 1000 mgA1 ($04) or 5000 ml; TDS
is BO thin that watr for agricultural irgation purposes cannot be reasonabty
developed from it without causing the supply wells to produce water-with
concontrations of thco conStituent greater than these limits 1000 mq/1 (Cl)
or 1000 m;Al (SO ) or 5000 m%4l (TDS), the change In water aualitv wil-lbo


.considered accptabl.


Case 5. Where the Upper Floridan aquifer contains water with concentrations of Gl-
~-S04--or TDS greater than 400 2000 mg/, 1000 mg/n, and 5000 mgW
reepegtivel but less than 2600 3500 mg/, 230 M. or "0.ln mI
respective in equilibrium conditions throughout, and the concentrations of
these TDS constituents are Is projected to rise above these imitl .600 mq,
(CGI). 250 m0.n SO and .0An n0 4000 mg/(TS) in response to projected
increases in ground water withdrawals; the change in water quality will be
considered unacceptable.










GEOLOGICAL SURVEY
WATER RESOURCES DIVISION
224 West Central Parkway, Suite 1006
Altamonte Springs, Florida 32714
(407) 648-6191 Octob




Ms. Barbara Vergara
St. Johns River Water Management District
P.O. Box 1429 i
Palatka, FL 32078-1429


TAKE
PRIDE IN
AMERKA
Im
UE


er 25, 1993




.. ......1
i..,


Dear Barbara:

Per your request of September 28, 1993, I have reviewed the second
edition of the District's proposed Needs and Sources Assessment
Criteria. Thank you for making it available on disk -- that saved me
some typing!

The latest versions of evaluation factors for salt water intrusion and
that for existing legal user criteria are derived, in part, from the
discussions held by the group of consultants that met in Palatka on
September 10, 1993. I believe the consultants did a good job of
airing out the first versions as well as pointing up the need to zero-
in on certain elements and to deemphasize others.

In responding, I have repeated the wording of each element and
followed with my own comments.


185






PROPOSED EVALUATION FACTORS FOR SALT WATER INTRUSION
IN THE UPPER FLORIDAN AQUIFER


1. Where the Upper Floridan aquifer contains water with
concentrations of chloride (Cl-) or sulfate (S04-) or total
dissolved solids (TDS) less than 250 mg/l, 250 mg/l, and 500
mg/l respectively throughout, and the concentrations of
these constituents are projected to rise above these limits
in response to projected increases in ground water
withdrawals, the change in water quality will be considered
unacceptable.

Note: This is intended to maintain ground water of
drinking water quality in the Upper Floridan
aquifer. Projections of ground water quality
changes will be made using ground water quality
models and trend analysis of ground water quality
data.

My feeling is that the breakpoint criteria are o.k. but that the
initial classification is too coarse. In other words, could the
initial classification criteria be changed to, say, 50 mg/L, 50 mg/L,
and 100 mg/L for Cl-, S04, and TDS but still maintain the threshold of
unacceptability at 250 mg/L, 250 mg/L, and 500 mg/L? This would make
for a more conservative initial condition and recognize the existence
of ground water of good-to-excellent quality, yet it would allow for a
certain amount of interface movement at the base of the aquifer. This
compromises water quality at the base of the Upper Floridan but it
really is no different than the condition in #2 whereby degradation of
water quality is allowed in a thin section of fresh water at the top
of the aquifer.

In areas where the top-to-bottom Cl- and S04- concentrations are
already 51-249 mg/l and where TDS is already 101-499 mg/L,
precautionary water-use restrictions could be in effect at the very
outset. If the initial classification is as originally outlined,
there would be virtually no margin for interface movement, even where
there is a substantial thickness of good-quality water. The total
area that would qualify for this treatment would be relatively small,
and might be called a lateral buffer zone.


186





2. Where the Upper Floridan aquifer contains water with
concentrations of Cl- or S04- or and TDS less than 250 mg/l,
250 mg/1, and 500 mg/1 respectively and greater than these
concentrations at depths within the Upper Floridan, and
concentrations of these constituents are projected to
increase to these limits in portions of the aquifer
currently supplying water with concentrations of these
constituents less than these limits to public supply and
individual domestic wells, the change in water quality will
be considered unacceptable. However, if the thickness of
water with concentrations less than these limits is so thin
that water of drinking water quality cannot be reasonably
developed from it, then the change in water quality will be
considered acceptable.

Note: This is intended to maintain water of drinking
water quality in the Upper Floridan aquifer to
supply water to public supply and individual
domestic wells in areas where the Upper Floridan
aquifer already contains some water which does not
meet drinking water standards. This criteria
recognizes that, in some areas, the Upper Floridan
contains relatively thin layers of fresh water
which are not dependable sources of water to wells
designed to produce water which meets drinking
water standards. Projections of ground water
quality changes will be made using ground water
quality models and trend analysis of ground water
quality data.


This criterion seems to be pretty straight-forward but it allows
interface movement only at the top of the aquifer where the majority
of relatively shallow domestic Floridan wells are finished. Would it
be possible to allow for some degradation in, say, the bottom few
percent of aquifer thickness? This is the interval least likely to be
tapped by either domestic or public supply wells. That would remove
some of the apparent incongruity in approach.






3. Where the Upper Floridan aquifer contains water with
concentrations of Cl- or S04- or TDS greater than 250 mg/l,
250 mg/l, and 500 mg/l respectively throughout, and less
than 1000 mg/l, 1000 mg/l and 5000 mg/l respectively
throughout, and the concentrations of these constituents are
projected to rise to concentrations above 1000 mg/l (Cl-) or
1000 mg/l (S04-) or 5000 (TDS) anywhere within the Upper
Floridan aquifer in response to projected increases in
ground water withdrawals, the change in water quality will
be considered unacceptable.

Note: This is intended to maintain water in the Upper
Floridan aquifer of suitable quality for
agricultural irrigation. Projections of ground
water quality changes will be made using ground
water quality models and trend analysis of ground
water quality data.


If I am interpreting this criterion correctly, the water quality in
the entire thickness of the aquifer will be allowed to degrade only to
the upper limits described. Again, perhaps some degradation might be
allowed in the bottom few percent of aquifer thickness.





4. Where the Upper Floridan aquifer contains water with
concentrations of Cl- or S04- or TDS greater than 250 mg/l,
250 mg/1 and 500 mg/1 respectively, and less than 1000
mg/1, 1000 mg/l, and 5,000 mg/1 respectively, underlain within
the Upper Floridan aquifer by water with concentrations greater
than 1000 mg/L, 1000 mg/L, and 5000 mg/L respectively; and
concentrations of these constituents are projected to
increase above 1000 mg/1 (Cl-) or 1000 mg/1 (S04-) or 5000
mg/1 (TDS) in portions of the aquifer currently supplying
water with concentrations less than 1000 mg/1 (Cl-) or 1000
mg/1 (S04-) or 5000 mg/1 (TDS) for agricultural irrigation,
the change in water quality will be considered unacceptable.
However, if the thickness of water with concentrations less
than 250 mg/1 (Cl-), 250 mg/l .(S04-), or 500 mg/1 TDS and less
than 1000 mg/L (Cl-) or 1000 mg/L (S04-) or 5000 mg/L (TDS) is
so thin that water for agricultural irrigation purposes
cannot be reasonably developed from it without causing the
supply wells to produce water with concentrations of these
constituents greater than 1000 mg/L (Cl-) or 1000 mg/L (S04-) or
5000 mg/L (TDS), the change in water quality will be considered
acceptable.

Note: This is intended to maintain water in the Upper
Floridan with a quality suitable for agricultural
irrigation in areas where the Upper Floridan
aquifer already contains some water which is not
acceptable for agricultural irrigation. This
criteria recognizes that, in some areas, the Upper
Floridan aquifer may contain relatively thin
layers of water suitable for agricultural
irrigation which may not be dependable sources of
water to wells designed to produce water for this
purpose. Projections of ground water quality
changes will be made using ground water quality
models and trend analysis of ground water quality
data.


Though wordy and difficult to interpret, once grasped, this criterion
becomes a fairly well-reasoned proposition except for the same
arguments I posed in my comments regarding #2. That is, the only part
of the aquifer in which the water quality is allowed to degrade is the
upper part in areas where the section of better-quality water is thin.
It still seems to me as though the bottom part could be allowed to
degrade to some extent, especially if the top part is allowed to
degrade.






5. Where the Upper Floridan aquifer contains water with
concentrations of Cl- or S04- or TDS greater than 1000 mg/l,
1000 mg/l, and 5000 mg/1 respectively but less than 2500 mg/L,
2500 mg/L, or 10,000 mg/L respectively throughout, and the
concentrations of these constituents are projected to rise
above 2500 mg/L (Cl-), 2500 mg/L (S04-), and 10,000 mg/L (TDS)
in response to projected increases in ground water withdrawals;
the change in water quality will be considered unacceptable.

Note: This is intended to provide for development of
ground water supplies for reverse osmosis from the
Upper Floridan aquifer in areas where the quality
of water is currently not suitable as drinking
water or agricultural irrigation supply.
Projections of ground water quality changes will
be made using ground water quality models and
trend analysis of ground water quality data.


This criterion allows the water in the entire thickness of the Upper
Floridan to degrade to the upper limit stated. O.K. as written..



General comments:

o The wording of the elements is ponderous and could provide many
hours of arguing as to just what is meant. However, most of the
wording could be cleared up with a set of keyword definitions that
would describe the limits of the constituents and then refer only
to the keywords in the text. That would remove all of the
repetitious numbers and parenthetical items that clutter the
wording.

o Violations of the threshold criteria will probably occur at the
base of the aquifer regardless of the producing interval of the
pumping wells. If that occurs, or is projected to occur, will the
entire thickness of the aquifer be declared off-limits to further
withdrawals? Will withdrawals for existing uses be curtailed?

o I have serious reservations about the ability of existing ground-
water flow and solute-transport model codes to allow models to be
constructed that will predict interface movements and concentration
gradients to the degree that will be necessary to support
regulatory action. Now, this does not mean that models should not
be used. Rather, they could be used in gaining insight as to how
the aquifer system functions and in learning where data could be
collected in order to rectify a data deficiency.

o I believe that modeling technology will evolve so that suitable
models can be constructed. However, in the near term, I would
prefer to rely upon the use of nests specific-purpose monitoring
wells in key locations and at several isolated depths to help index
the water-quality trends in the Upper Floridan.





PROPOSED EXISTING LEGAL USER IMPACT CRITERIA


Objective to limit the impacts of proposed ground water
withdrawals on the quantity and quality of ground water sources
supplying existing legal uses of ground water


Proposed Criteria

1. In areas where the potentiometric surface of the Floridan
aquifer is higher than land surface year round, but is
projected to decline below land surface in response to
projected increases in water use, the impact to existing
legal users would be considered unacceptable.

Note: This would provide limited protection to users of
ground water supplied by free-flowing wells.


As ground-water withdrawals increase, whether by an increase in
flowing wells or by increased local or nearby pumping, the
potentiometric surface will probably decline below land surface
seasonally at first, and then more persistently as time goes on,
especially in drought years. When does the impact become
unacceptable? The instant that wells cease to flow or when they
seasonally or persistently cease to flow?

Most flowing wells have discharge pipes that are above land surface.
I believe that the District requires newly-constructed flowing (and
non-flowing) wells to have casings that extend at least 1 foot above
land surface. So, recently-constructed flowing wells will cease to
flow before the potentiometric surface declines below land surface.
So, what will be the limiting criterion? Heads below land surface or
wells that cease to flow?

Further, the utility of many flowing wells will be effectively zero
even before they cease to flow entirely. Stock-watering wells might
be the exception, especially if the wells discharge directly to the
land surface and are not required to discharge into a tank that would
be above land surface.

Would you not allow a user of a flowing well to put a pump on his well
in order to meet his needs, especially if he is not going to exceed
his permitted consumptive use limits?






2. In areas where Floridan aquifer water levels are currently
less than 20 feet below land surface, but are projected to be
greater than 20 feet below land surface in response to
projected increases in water use, the impact to existing
legal users would be considered unacceptable.

Note: This would provide protection to users of ground
water withdrawing from wells equipped with
centrifugal pumps that cannot pump water from
depths greater than 25 feet.


O.K. as written, but one of the questions raised by #1 is also
applicable here in modified form:

As ground-water withdrawals increase, the potentiometric surface will
probably decline below the 20-foot-deep threshold seasonally at first,
and then more persistently as time goes on, especially in drought
years. When does the impact become unacceptable? The instant that
the first centrifugal pump breaks suction or when the problem occurs
persistently?





3. In areas where the quality of ground water in the Floridan
aquifer is projected to exceed the limits described in the
proposed evaluation factors for salt water intrusion in the Upper
Floridan aquifer, the impact to existing legal users would be
considered unacceptable.


I don't see any need for this criterion.
part, by the previous criteria unless you
between existing legal and illegal users.
intent, however.


It is covered, all or in
are making a distinction
I don't think this is the


Overall assessment:

My feeling is that this latest edition of all the criteria is much-
improved, fairly well-crafted, and reasonably defensible assuming that
the District can actually predict and project the changes to the
water-quality regimen and potentiometric heads in the Floridan aquifer
system. Current state-of-the-art ground-water flow modeling is
sufficient to predict heads but it is woefully inadequate to predict
water-quality changes, especially in a complex aquifer system such as
the Floridan. Now, that doesn't mean that modeling technology will
remain static. It will evolve and improve but, in the near term,
field monitoring will be required --and it will be expensive.

Barbara, if you have any questions, please call me.



Sincerely,




Charles H. Tibbals
Subdistrict Chief


cc: Doug Munch, SJRWMD
Bob Schultz, SJRWMD




'U V-1''1 -:Q% 1 :.-' 1. 1IU : L-HK L I UN r l .- l .l'3 wrir L'L


CARLTON, FIELDS, WARD, EMMANUEL, SMITH & CUTLER, P. A.
ATTORNCYvS A LAW

One HAmeoLA PLACC PFIRSTATE TO*ER .ARIouBvlbrw U -t6 VIRT rLORQ' P-LKVU9lObNS CESPCRAtETf ashCNTI 1OECs
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PLEASc REPLY TO
VIA TELECOPY & U.S. MAIL Tallahassee

November 8, 1993
MEMORANDUM

TO Barbara A. Vergara

FROM: Jake Varn J"A

RE: Proposed Evaluation Factors

As requested, I have reviewed the proposed evaluation
factors on salt water intrusion and impact on existing legal
users and offer the following comments on the proposed factors.

With respect to the five cases dealing with salt water
intrusion:

1. A prime consideration in establishing the criteria for
each of the five cases is making sure that the District
can justify the concentrations used in each of the five
cases. This is a technical issue, but the District
must have sufficient data and justification for
establishing these limits otherwise the District's
determinations are subject to being attacked as
arbitrary. It would be worthwhile to discuss the basis
for these concentrations at our meeting.

2. The language for each case needs to be clarified.
After reading the current language, it is not clear to
me what is unacceptable. Is it unacceptable to
increase the concentration of a single constituent
above the established level or do you have to increase
the concentrations of all of the constituents above the
established levels?

3. I would also revise the proposed language to indicate
that when the effect of all withdrawals are projected
to have the described impact, such change is
unacceptable. It is the combination of all of the
withdrawals that create the unacceptable condition.
One user should not be viewed as the one causing or
creating the unacceptable condition. I have serious
concerns about how the District intends to implement
these criteria.


I L- I itL-.L- t .lJ DO




NLI~'U ~- ~2 i' I -.J1L II,[ rL:c L ; 'JHr)1LI IttL INU :; ---'-7--'





MEMORANDUM
November 8, 1993
Page Two


4. In case 4, the criteria appears to be designed to
protect agricultural irrigation, Why is this limited
to protecting agricultural irrigation? I would suggest
deleting the phrases "for agricultural irrigation
purposes" and "for agricultural irrigation." The
current language would appear to limit the use of this
water to agricultural irrigation. Why are other uses
unacceptable?

With respect to the criteria for impacts on existing legal
users:

1. As to Criteria 1 and 2, I have a number of concerns
about each of these criterion. Initially, each of
these criterion appear to be very arbitrary. I have a
strong feeling that neither of these criterion can be
justified technically legally.

2. As to Criteria 1 and 2, neither of the proposed
criteria take into account the nature of the new use or
the existing use. In my opinion, the nature of the new
use and the existing use are major considerations in
determining whether a use unreasonably interferes with
an existing use.

3. As a general comment, I don't believe that the proposed
criteria will provide meaningful guidance to the
District or water users.

4. Considerable time and attention needs to be devoted to
developing meaningful criteria on this subject.

5. I would propose revising the objective to read as
tollows: Objective to (insure that the inipauct of
proposed groundwater withdrawals do not unreasonably
interfere with or adversely affect the quantity and
quality of ground water sources supplying existing
legal uses of ground water.

If there are any questions or should you care to discuss any
of these comments, please let me know.

JDV:dgb




V.,I( L I I~j .


LAW OFFICES
MESSER, VICKERS, CAPARELLO. MADSEN, LEWIS, GOLDMAN & METZ
A PROFESSIONAL ASSOCIATION
SUITE 7Q1
215 50UTH MONROE STREET SUITE 900
POST OFFICE 60X 1876 2000 PALM BEACH LAKr S BOULEVARD
T.A.LLAuIAS',r, FLOhRIo. 32300-187G WEST PALM BEACH, FLOnIDA 33409
TELEPHONE (904) 222-0720 TELEPHONE (407) 640-0820
TELECODICR (90-) 224-4359 TELECOPER (407) 640-8Z0O

REPLY TO: WEST PALM BEACH


October 27, 1993

VIA TELEFACSIMILE


Ms. Barbara A. Vergara, P.G.
Director, Department of Groundwater Programs
and Technical Support
St. Johns River Water Management District
P.O. Box 1429
Palatka, FL 32178-1429

RE: Water Supply Needs and Sources Assessment Criteria Development,
"Agreement for Professional Services", Contract No. 93D253

Dear Ms. Vergara:

I have reviewed the materials provided to me by the District in its letters of
September 28, September 30, and October 22, 1993. The following are my general
comments regarding the District's proposals. Specific comments on the individual
criteria are included in the notes accompanying the attached revised Objectives and
Criteria.

General Comments

1. The Objectives and Criteria for both impacts on existing legal users
and saltwater intrusion are phrased in terms of "acceptable" or "unacceptable"
impacts. This phrasing suggests a regulatory program rather than a "needs and
sources assessment". I suggest that the objectives be rewritten consistent with the
languageand requirements of Rule 17-40.501, F.A.C., specifically subsections (1) and
(4). This approach will tie the objectives directly to the purpose for doing the needs
and sources assessmrent, and will provide a clear focus for the specific criteria to
follow. I have rewritten the objectives for the existing legal user impact criteria in the
attachment.




*'j U ri-I 2.


Ms. Barbara A. Vergara, P.G.
St. Johns River Water Management District
October 27, 1993
Page 2




2. A set of objectives for the saltwater intrusion criteria section
should be developed. I like the idea of objectives for these factors. As described
above, they help keep the focus on the purpose of the assessment, and should help
resist the natural urge to think of these factors and criteria in regulatory terms. I have
suggested some objectives for the saltwater intrusion criteria section in the
attachment.

3. The criteria/evaluation factors should be rewritten to reflect the
new or revised objectives. Once the objectives are rewritten, rewriting the
criteria/evaluation factors is relatively easy. Once rephrased, it becomes clear that
these criteria/evaluation factors are for purposes of identifying specific geographic
areas where critical water supply problems are projected to develop, not for regulating
specific users. My suggested revisiBons are included in the attachment.

4. The District should consider adding a time element to the
criteria/evaluation factors. Rule 17-40.501, F.A.C., requires the District to look at a
twenty-year planning horizon. When the modeling is completed, however, it is likely
that these criteria/evaluation factors will be met at different times for different areas
within the District. Thus, the District may find it useful to identify and separately
address areas where problems are expected to arise within a five, ten or fifteen year
planning horizon as well. This will enable the District to separate the shorter term
critical areas from the longer term critical areas, which may be useful for developing
action plans within the planning process to follow. For purposes of this exercise, I
have just included a twenty year horizon in the attachment.

5. Saltwater intrusion criteria should relate in some fashion to DEP's
groundwater classifications. See Rule 17-520.410, F.A.C. DEP's classifications are
intended to identify and protect present and future most beneficial uses of
groundwaters in the State. Rule 17-520.100(2).(7), F.A.C. DEP classifies
groundwaters as "potable water use" (F-I, G-l, G-II), and "non-potable water use" (G-
III, G-IV), based on total dissolved solids. The DEP's breakpoints for TDS are 3,000
and 10,000 mg/I TDS, which do not match .with the 500, and 5,000 mg/I TDS criteria
proposed by the District. I suggest that another criteria be developed for the 3,000
mg/I TDS scenario. I have included an additional criteria in the attachment to address
this issue.


197


') 'I;r'_1


0 ". 1 I )" '-









Ms. Barbara A. Vergara, P.G.
St. Johns River Water Management District
October 27, 1993
Page 3



Groundwaters are also classified as single source (F-I, G-l). In fact, the only
designated single source aquifer in the State is located within the surficial aquifer in
Flagler County. See Rule 17-520.460(1) F.A.C. As written, the District saltwater
intrusion criteria would not identify this surficial aquifer as a critical area, I believe
that anything you could do to mesh the State's groundwater classification system
with your critical area designation process would be a positive step towards avoiding
even more confusion in this area in the future.

The attached revised Objectives and Criteria/Evaluation Factors have been
rewritten to address the general comments above, as well as some specific comments
unique to each individual criteria. As stated above, specific comments are included
in notes with each of the revised objectives or criteria~/valuation factors.

Thank you for the opportunity to work on this project. I look forward to
reviewing the other consultants' remarks and seeing you on December 2nd in Palatka.
If you have any comments or questions in the interim, please don't hesitate to call.

Since 'y, <



Ste hen A. Walker



SAW/bt
Attachment







PROPOSED EXISTING LEGAL USER IMPACT CRITERIA


Objectives: to identify specific geographical area where the impacts of present
ground water withdrawals on the quantity and quality of ground water sources
supplying existing legal uses of around water have begomre critical.

to identify specific geographical areas where limj the impacts of
projected pr4epeed ground water withdrawals on the quantity and quality of ground
water sources supplying existing legal uses of ground water are anticipated to become
critical within the next 20 years,

to identify areas where collection of data, water resource investigations,
water resource projects or the implementation of regulatory programs are necessary
To prevent the impacts of projected ground water withdrawals on the quantity and
quality of ground water sources suDplving existing legal uses of ground water from
becoming critical.

Note: The proposed objective was stated in regulatory or solution oriented
terms rather that needs and sources terms. The relevant rules and
statutes suggest that our focus ought to be identifying geographic areas
for further study and action, not attempting to eliminate or limit specific
impacts. I suggest the objectives be reworded to parallel s. 17-
40.601(1), (4) FAC.


Proposed Criteria

The following areas ore or are anticipated to become critical water supply areas in the
next 20 years:

1. If areas where a significant number of existing leaal uses rely upon free
flowing wells and the potentiornetric surface of the Floridan aquifer is
higher theft-lend au' s.f.c. oun.d, b-ut is projected to decline below
land surface in response to pr-jected in"oreos in wotcr ue for all or any
portion of the year within the next 20 years the impaet*o testing legal
users would be considered unWAGcOtabio.

Note: As edited, this criteria directly measures the impact to be
identified as a problem. It doesn't catch areas where free flowing
wells do not presently exist. If users are not already relying on
free flowing walls in an area, there may not be a good resource
reason to protect heads. The reason why heads decline doesn't
seem relevant to the question of whether its a problem to existing
users, so I eliminated this constraint. Also, I added a phrase to
deal with time and duration to give it some bounds. Finally, the
criteria is restated as a means of identifying problem areas, rather








than ascribing terms like "unacceptable" to them. Closer
examination in the planning process may reveal that declining
heads are acceptable. For example, projected land use changes
make continued reliance on free flowing wells unlikely in any
event.

2. tf areas where a significant number of existing legal uses rely upon
centrifugal Dumps and Floridan aquifer water levels aro ucrrntly lss
tha.n 20 foot blow, land .urfac, but are projected to be greater than 20
feet below land surface if Les e t projFe:ted inarge ..n water usa
for all or any portion of the year within the next 20 years .-titne
oxicting legal uacrs would be concidorpd unaoeaptablo.

Note: See note above. Same comments for centrifugal pumps as for
free flowing wells.

3. Jt areas where a significant number of existing leaal uses rely upon the
Floridan aquifer and the quality of ground water in the Floridan aquifer
is projected to exceed the limits described in the proposed evaluation
factors for salt water Intrusion In the Upper Floridan Aquifer, the-impaet
Notei: Stig lesgl uabo, ad notes for salted unoeccptrusio

Note: See notes above, and notes for salt water intrusion criteria.


__







PROPOSED EVALUATION FACTORS FOR SALT WATER INTRUSION
IN THE UPPER FLORIDAN AQUIFER

Objectives: to identify specific georaphical areas where the impacts of present salt
water intrusion on the entity and quality of ground water sources applying existing
legal uses of ground water have become critical.

to identify specific aeographicalareas where the impacts of projected salt
water intrusion on the quantity and quality of ground water sources supplying existing
legal uses of ground wator are anticipated to become critical within the next 20 years.

to identify areas where collection of data, water resource investigations,
water resource projects or the implementation of regulatory programs are necessary
to prevent the impacts of projected salt water intrusion on the quantity and quality of
ground water sources supplying existing legal uses of around, water from becoming
critical.


Note: These suggested objectives have been stated in terms parallel to Rule
17-40.501(1) and (4), FAC. See note for existing legal user objectives
for comparison.


Proposed Criteria

The following areas are or are anticipated to become critical water suoolv areas in the
next 20 years:

Case 1. areas where the Upper Floridan aquifer contains water with
concentrations of chloride (CI) or sulfate (SO4) or total dissolved solids
(TDS) less than 250 mg/I, 250 mg/l, and 500 mg/l respectively
throughout, and the concentrations of these constituents are projected
to rise above these limits for all or any portion of the year within the
next 20 years rospon to projected increase n ground wate

tneeeeptable.

Note: Rephrased to identify geographic areas rather than levels of
acceptability. Since salt water intrusion can occur for reasons
other than ground water withdrawals, that limitation has been
eliminated from the criteria.

Case 2. areas where the Upper Floridan aquifer contains water with
concentrations of CI- or S04 or TOS less that 250 mg/I, 250 mg/I, and
500 mg/l respectively and greater than these concentrations at depths
within the Upper Floridan, and concentrations of these constituents are



201









projected to increase to these limits in portions of the aquifer currently
supplying water with concentrations of these constituents less than
these limits to public supply and individual domestic wells for all or any
portion of the year within the next 20 vears,-tho -hang to watr allt,
will be considered uffo cptal~c. Hewevo., if the thiefics eof watef
with .con.cntr.ti.na less than those lim-its is so thin that water ef
drinking .water quality can not be roaoeably developed from it, the ktho
.ohn.g in water utility will be -onsidr..d ao. pt blc.

Note: Same comments as previous criteria. In addition this criteria
suggests that the aquifer is presently being used as a source of
drinking water, either from domestic or public water supply wells.
If it is already a source of drinking water, the last sentence seems
inappropriate. If an existing supply is that tenuous, it would
certainly qualify as critical In the needs and sources assessment.
Whether or not such a source should be protected is a resource
decision that should be made in the planning process, not in the
problem identification process.

Case 2A, areas where the aquifer contains water with concentrations Ot Cr or SO,
or TDS less than mn/l, rnma/ and 3.000 ma/1 respectively
throughout, and the concentrations of these constituents are projected
to rise to concentrations above mog/I CI' or mg/I SO'( or
3,000 ma/1 TDS in portions of the aquifer currently supplyina water with
concentrations of these constituents less than these limits to public
suDDlv wells for all or any portion of.the year within the next 20 years.

Note: This new criteria has been added to match up with the DEP TDS
limit for F-I and G-I aquifers. It has been made generic, applying
to any aquifer, so as to catch the F-I aquifer in Flagler County. I
don't know what the appropriate CI' and SO4 concentrations
should be.

Case 3. areas where the Upper Floridan aquifer contains water with
concentrations of CF or SO or TDS greater than 250 mg/I, 250 mg/I,
and 500 mg/I respectively throughout, and less than 1000 mg/I, 1000
mg/I and 5000 mg/I respectively throughout, and the concentrations of
these constituents are projected to rise to concentrations above 1000
mg/I C- or 1000 mg/I S04 or 5000 mg/I TOS anywhere within the Upper
Floridan aquifer for all or any portion of the year within the next 20 years
:in rcpcnao tC projected-ncos incoaGz i groun d wnWrI withdr:awlS, the
change in wator 'Quolity will be eensidcrcd unaeeeptobla.

Note: This factor has been rewritten to address issues discussed in
previous notes.








Case 4. areas where the Upper Floridan aquifer contains water with
concentrations of Cl' or SO or TDS greater than 250 mg/l. 250 mg/l,
and 500 mg/1 respectively and less than 1000 mg/I, 1000 rng/l and 5000
mgil respectively, underlain within the Upper Floridan aquifer by water
with c ;nentrations greater than 1000 mg/l, 1000 mg/I, and 5000 mg/!
respectively; and concentrations of these constituents are projected to
increase above 1000 mog/ CIl or 1000 mg/l SO, or 5000 mg/I TDS in
portions of the aquifer currently supplying water with concentrations less
than 1000 mg/l Cl or 1000 mg/I SO4 or 5000 mg/I TDS for agricultural
Irrigation for all or any portion of rhe year within the next 20 vears-he
hange inr wa.tcr quaiit w.ll b. o..nsidorod uno..pt ob.l. However, if
the thierss ,f water wth oRoe CntrtOleas ghe ator thIem 250 mrg/i C
260 M9.11 CD-O OF 500 migil TDlSofess thean 1000 m/i Q1;,y 1000 g
o A^./ Tr\C *0 9^ #>.: 1.-.< + c 4 1. f j^^, l~fr,lf 1-lt>> !.


VYWV--rlrcrr-ri;2 w vi i" YTV V V UF a~j W VVILmr M
purpcl,~ ~k CI a ~not bz rInnye!OPcd fromR it Without eaufing t
pwpees awit beFeaenalyd V VW
cueppi wells tW Producc Wt00 with concentrations of thezc ecnstiftuOn46
Qrcatcr th8n 1000 Mg/I CU, 1 000 Mg/I StQ-, or OF000 moil TOG, thie


ctU-e in w: t r quMlt, i comaimeree 0eeeptuagte

Note: See the note for Case 2.

Case 5. areas where the Upper Roridon aquifer contains water with
concentrations of CI- or SO; or TDS greater than 1000 mg/I, 1000 mg/I,
and 5000 mg/l respectively but less than 2500 mg/I, 2500 mg/I and
10,000 mg/I respectively throughout, and the concentrations of these
constituents are projected to rise above 2500 mg/I Ce, 2500 mg/I SO ,
or 10,000 mg/i TDS for all or eny portion of the year within the next 20
years in ruMpurdlc to projected InoroCase In ground watr withdrawals,
thio change in water quality will bo considered unac-eptab o.

Note: See the note for Case 1.


1:\S319\5923\MISC\PHASE2.ATT




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