Title: Draft - Water Supply Needs and Sources Assessment - Summary and Conclusion
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 Material Information
Title: Draft - Water Supply Needs and Sources Assessment - Summary and Conclusion
Physical Description: Book
Language: English
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Spatial Coverage: North America -- United States of America -- Florida
 Notes
Abstract: Jake Varn Collection - Draft - Water Supply Needs and Sources Assessment - Summary and Conclusion (JDV Box 90)
General Note: Box 24, Folder 2 ( Emerging Issues and Conflicts - 1976-1994 ), Item 3
Funding: Digitized by the Legal Technology Institute in the Levin College of Law at the University of Florida.
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Bibliographic ID: WL00004576
Volume ID: VID00001
Source Institution: Levin College of Law, University of Florida
Holding Location: Levin College of Law, University of Florida
Rights Management: All rights reserved by the source institution and holding location.

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Summary and Conclusion


The consultants individually offered a variety of comments on various
water resource management subjects and on both sets of evaluation
factors provided by SJRWMD staff. Several of these comments were
generally agreed upon by the consultant group. The comments that were
generally agreed upon, along with others considered particularly
significant to the success of the Water Supply Needs and Sources
Assessment, are described as follows.

SALT WATER INTRUSION

Comments Generally Agreed Upon by Consultant Group

Terminology

1. The terminology used to express the evaluation factors should
more closely adhere to that included in Section 17-40.501 Florida
Administrative Code. This should clarify the purpose for which
the proposed evaluation factors are being developed as planning
rather than regulatory.

Planning Horizons

2. SJRWMD should establish a clear planning horizon or horizons for
assessment of projected changes in salinity in ground water.
This planning horizon or horizons should be more than the 20
years specified in Chapter 17-14.501 Florida Administrative Code;
because the movement of saline ground water in response to
lowered potentiometric pressures occurs considerably more slowly
than the pressure changes, probably on the order of tens to
hundreds of years. Minimum planning horizons of 20 and 50 years
are reasonable particularly in light of SJRWMD plans to repeat
the model evaluations every five years.

Reversal of Direction of Ground Water Flow

3. Reversal of the vertical or horizontal direction of regional
ground water flow does not necessarily mean that a critical water
quality problem will occur as a result of the reversal. Further,
deterioration of ground water quality can occur without gradient
reversals. Therefore, areas which have experienced or are
projected to experience a reversal in the direction of ground
water flow should be highlighted as areas which need to be
investigated and monitored, but should not be identified as
critical problem areas without further supporting information.

Movement of the Fresh/Salt Water Interface

4. Vertical or horizontal movement of the fresh/salt water interface
virtually always occurs in response to ground water withdrawals.
However, the magnitude of this movement is often immeasurable and
the response time is very slow, probably on the order of tens to
hundreds of years. Areas which have experienced or are projected
to experience notable vertical or horizontal movement of the
fresh/salt water interface should be highlighted as areas which


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need to be investigated and monitored, but should not be
identified as critical problem areas without further supporting
information.

Potentiometric Surface Evaluation at or Below Mean Sea Level

5. Potentiometric surface elevations which exist at or below mean
sea level do' not necessarily result in significant salt water
intrusion. Areas which experience or are projected to experience
potentiometric surface elevations which are at or below mean
level should be highlighted as areas which need to be
investigated and monitored, but should not be identified as
critical problem areas without -further supporting information.

Ground Water Quality Models

6. The numerical ground water quality models currently available are
not able to predict chloride concentration changes precisely
enough to detect exactly when the proposed revised evaluation
factors are met or exceeded. Rather, they are able to provide an
indication that the factors may be exceeded in some areas but not
in others.

7. The numerical ground water quality models developed for the
purpose of projecting salinity of ground water in the future
should not be relied upon as the only means of assessing
potential impacts of ground water withdrawals on ground water
salinity. These models may represent the best tools available
for such analyses, but they need to be improved upon with
additional water use, aquifer characteristic, ground water level,
and ground water quality data.

Trend Analysis

8. SJRWMD should supplement its numerical ground water quality model
analyses with analyses of trends in concentrations of parameters
such as chloride, sulfate, and total dissolved solids. Water
quality sampling to support such trend analyses should be from
production wells and strategically located monitoring wells.

Water Quality Parameters

9. The revised proposed evaluation factors provide for managed
degradation of water quality within zones of the aquifer while
protecting drinking water, agricultural irrigation water, and
water for reverse osmosis. The approach is reasonable; however,
the concentrations of key water quality parameters which are the
basis of delineation of these zones should be carefully reviewed
to be sure they represent the best values for this delineation.

10. The revised proposed evaluation factors are more restrictive than
necessary to protect future water supplies. Additional managed
degradation particularly at the base of the Upper Floridan
aquifer should be considered.






Other significant comments


11. Serious consideration should be given to DEP's ground water
classification system when deciding on the water quality
parameter concentrations used to describe aquifer zones. (This
comment was made by Steven Walker, Esq., from the Law Firm of
Messer, Vickers, Caparello, Madsen, Lewis, Goldman, and Metz,
P.A.)

12. An alternative approach to numerical modeling for delineating
critical water supply problem areas should be considered because
in most areas inadequate data is available for the development of
numerical ground water quality models that can predict water
quality changes precisely enough to meet SJRWMD's needs. This
alternative approach should be based on an evaluation of the
factors which influence changes in the salinity of ground water.
The final product of this approach would be a map of SJRWMD with
areas of relative potential for salt water intrusion delineated
on it. (This comment was made by Peter Anderson, P.E., GeoTrans,
Inc.).

EXISTING LEGAL USER IMPACTS

1. The terminology used to express the evaluation factors should
more closely adhere to that included in Section 17-40.501 Florida
Administrative Code. This should clarify the purpose for which
the proposed evaluation factors are being developed as planning
rather than regulatory.

2. The proposed evaluation factors should describe the period over
which a decline in water level would constitute a problem.

3. The proposed evaluation factors related to free flowing wells and
centrifugal pumps seems to provide a higher level of protection
to areas which are not realizing their full development
potential.

4. The proposed evaluation factor for free flowing wells could allow
for substantial impacts to existing legal users before the impact
is considered to be a problem.




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