|
|
CHARLOTTE COUNTY v. SOUTHWEST FLORIDA WATER MANAGEMENT DISTRICT
B. Environmental Impacts - Rules 40D-2.301(1)(b)and (c) 626. Rule 40D-2.301(1)(b) requires WUP applicants to provide reasonable assurances on an "individual and cumulative basis" that the proposed water use "will not cause quantity or quality changes which adversely impact the water resources, including both surface and ground waters." This Rule does not have a corresponding section in the BOR explaining how the District will interpret and apply this criteria. 627. Rule 40D-2.301(1)(c) requires a permit applicant to provide reasonable assurances that its proposed water use "will not cause adverse environmental impacts to wetlands, lakes, streams, estuaries, fish and wildlife, or other natural resources." 628. BOR Section 4.2 corresponds to Rule 40D-2.301(1)(c). The introductory language of Section 4.2 of the Basis of Review states: The withdrawal of water must not cause unacceptable adverse impacts to environmental features. Where appropriate, District staff will review the Applicant's submittal and identify the environmental features that are directly related to the water resources of the District and evaluate the impact of the Applicant's withdrawal, combined with other withdrawals, on those environmental features.
District staff may inspect the site to delineate environmental features and evaluate the effects of withdrawals. For certain permits, the applicant may be required to supply additional information regarding the existing status and condition of associated environmental features. This information may consist of aerial photographs, topographic maps, hydrologic data, environmental assessments or other relevant information. Base-line hydrologic and/or environmental data collected prior to permit application shall be provided if available and requested by the District. The need for additional information may be established through pre-application meetings with the District.
Environmental features that will be evaluated by District staff when determining withdrawal impacts include:
1. Surface water bodies such as lakes, ponds, impoundments, sinks, springs, streams, canals, estuaries, or other watercourses;
2. Wetland habitats;
3. On-site environmental features and their relationship to local and regional landscape patterns;
4. Habitat for threatened or endangered species; and
5. Other environmental features which are dependent upon the water resources of the District.
Potential environmental impacts will be evaluated by comparing the existing natural system to the predicted post-withdrawal conditions. Previous physical alterations to environmental features, such as drainage systems or water control structures will be considered. The District's objective is to achieve a reasonable degree of protection for environmental features consistent with the overall protection of the water resources of the District.
Listed below are the performance standards District staff will use to ensure that unacceptable adverse impacts to environmental features do not occur. Additionally, presumptions are described that the District will use as guidelines to predict whether withdrawals will cause unacceptable impacts. Impacts to canals, springs, and estuaries are considered under the streams criteria. Impacts to ponds, sinks, and impoundments are considered under the lakes criteria. 629. The District's regulatory staff interprets and applies the terms "adverse environmental impact" in Rule 40D-2.301(c) as synonymous with "unacceptable environmental impact" in BOR Section 4.2. In assessing whether an impact to an environmental feature is unacceptable, the District says it will look at the normal biotic component of a natural system and attempt to preserve the status quo for that component. Adverse impacts that would be solely restricted to non-native species would not be considered unacceptable. It is not clear whether the District will compare the projected impact with the condition of the natural system as it exists at the time of the application or as it existed at the time the use first began. 630. There are no commonly accepted definitions in the fields of biology, ecology or hydrology for the terms "adverse environmental impact" or "significant adverse impact". Equally competent biologists and/or ecologists can differ as to the interpretation of what is an unacceptable environmental impact. The environmental managers at the four District field offices are trained in the application of these terms. While the District claims the terms are consistently applied, there is constant discussion and even disagreement among District environmental scientists as to what changes in natural systems constitute unacceptable adverse impacts. 631. Without a consistent definition of an adverse, significant, or unacceptable environmental impact to a natural system, it can be very difficult to require WUP modifications and/or mitigation. In addition, the lack of a clearly articulated definition of acceptable or unacceptable environmental impacts limits the effectiveness of the District's environmental data-gathering process. 632. Representatives from DEP and five of the water management districts formed a Groundwater Availability Conventions Committee to develop and define methods and criteria for assessing the ability of groundwater supply sources to meet demands. The final report of this Committee was a consensus report and proposed methods and criteria for assessing groundwater availability for planning and regulatory purposes including water use permitting. The Committee proposed interim guidelines (but not final conclusions) for developing thresholds for various criteria above which unacceptable impacts are likely to occur to natural systems, such as lakes and wetlands. The committee considered the use of hydrologic presumptions as guidelines, but did not adopt this approach. The District has not adopted the recommendations of the Groundwater Availability Conventions Committee regarding impacts to natural systems and has continued to rely upon the presumptions in its Basis of Review. 633. The Impacts to Natural Systems Subcommittee of the Groundwater Availability Conventions Committee consisted of agency environmental scientists who attempted to establish a biologically sound definition of an unacceptable environmental impact to natural systems, such as wetlands, lakes and streams. This subcommittee was chaired by Dr. Ed Lowe, of the St. Johns River Water Management District, who prepared a report (the "Lowe Report") in 1994 after the subcommittee's deliberations. The Lowe Report, which was not a consensus report, includes a proposed definition of "unacceptable harm to natural systems" that is more specific and covers more areas than the District's performance standards. So far, the District has not adopted the approach set forth in the Lowe Report. 634. The subcommittee could not come to a consensus regarding the use of presumptive hydrologic criteria for purposes of evaluating water use permit applications. The Lowe Report expressed concern as to whether such an approach would succeed in the long run in protecting natural systems. 2. Environmental Presumptions - Generally 635. BOR Section 4.2 has three major categories: section A relating to wetlands; section B relating to lakes; and section C relating to streams. Under each of these sections, the District has created performance standards and presumptions. 636. Absent site specific information to the contrary, if a water use permit applicant demonstrates compliance with the applicable presumptions, the use is deemed to meet the performance standards and comply with Rule 40D-2.301(1)(c). 637. The numerical presumptions in BOR Section 4.2 are used as a screening tool to distinguish between acceptable and unacceptable environmental impacts. The District claims that the qualitative terms in the rules such as "significantly" and "adverse" and "unacceptable" should not preclude the use of quantitative tools such as the presumptions to evaluate environmental impacts. 638. The District staff has discretion when to apply the presumptions. As explained in Section III above, as part of the permit review process, a computer model simulation or some other technique that allows for simulations and calculations would be utilized to apply the presumptions. 639. Based upon the evidence presented, it is clear that hydrologic presumptions should not be used as conclusive pass/fail tests District-wide for diverse natural systems with different ecological requirements. The nature and extent of impacts resulting from groundwater withdrawals vary for areas with differing hydrogeologic characteristics. Thus, it is virtually impossible to develop hydrologic criteria that can be expected to consistently provide the desired protection of natural systems. 640. The manner in which the presumptions are utilized by the District has been the source of great controversy in these proceedings. The District denies that the presumptions are used as a pass/fail mechanism. In this regard, it is necessary to look at the specific language of each of the presumptions. In addition, because the scientific underpinnings for certain presumptions have been challenged, it is necessary to review the analysis relied upon by the District in developing the presumptions. 3. Wetlands Presumption - BOR Section 4.2.A.5 641. There is a undeniable relationship between groundwater withdrawals and adverse impacts to wetlands. Generally, the closer a wetland is to the withdrawal point and the larger the drawdown of the water table, the larger the adverse impact. This relationship can be observed despite the heterogeneous nature of the aquifer and it is both spatial and temporal.93 Other factors such as drought and surface drainage can also impact wetlands and can interact with and/or exacerbate the effects of groundwater withdrawals. 642. The adverse impacts that can occur to wetlands because of a change or loss of hydroperiod as a result of groundwater withdrawals include: (1) rapid succession, which is a shift in the vegetative composition from wetland to upland species; (2) soil subsidence and resulting loss of overstory, which occurs when trees fall because the soils no longer provide structural support for the roots; (3) more frequent and severe burning of the organic soil during naturally occurring fires, including severe peat fires that would not occur if the soil were inundated; and (4) wildlife changes when wetland species and upland species that are dependent upon the wetland are unable to find food and habitat.643. Pond cypress depressional wetlands in the vicinity of extensive groundwater withdrawals have shown evidence of surface and subsurface subsidence and observable ecological responses which start with a proliferation of pollen and seed cones and progress to the point where there can be attacks by fungal pathogens and opportunistic insects attracted to vegetation under stress. Subsidence can also lead to rotting of the base of the trees resulting in severe leaning or even toppling of the trees. 644. The wetlands presumption found in BOR Section 4.2 subsection A.5 was developed by the District's Rule Revision Committee and adopted by the District in 1989. Under BOR Section 4.2.A.5, the District presumes that no adverse environmental impact will occur to a wetland if the water table drawdown at the wetland is less than one foot. In other words, if a WUP applicant demonstrates that its proposed withdrawal of water, in combination with other withdrawals, will not lower the water table by more than one foot at a wetland, then the applicant is presumed to have complied with the performance standards for wetlands and the criteria in Rule 40D-2.301(1)(c). 645. Although BOR Section 4.2.A.5 refers to "actual" water table drawdowns, the District has always intended and applied this provision using a simulated drawdown, usually through the use of a groundwater flow model, rather than applying the presumption to actual measured water table reductions. 646. The District applies the wetlands presumption to all WUP applications irrespective of whether the application is for a new use or renewal of a long-standing use. 647. The District says it utilizes the one foot water table drawdown presumption as a threshold mechanism to screen out those water use applications that are not likely to cause unacceptable environmental impacts to wetlands. Neither the District nor any third party has ever successfully rebutted the presumption that unacceptable impacts do not occur when the water table drawdown at a wetland is less than one foot. 648. The District suggested at the hearing that if a proposed WUP is challenged by a third party, the presumption no longer applies. This interpretation is not evident from the language of the District's presumption. Moreover, the evidence indicates there is some confusion or uncertainty as to how the presumptions should apply in such a case. 649. As written, the District's wetland presumption applies to all wetlands throughout the District's jurisdiction regardless of type or location. 650. The District applies the inverse of this presumption, i.e., if the modeled water table drawdown at a wetland is more than one-foot, the District presumes there is an unacceptable impact. If the water table drawdown at a wetland is projected to be more than one foot, the applicant can still obtain a permit if it proposes a mitigation or monitoring program satisfactory to the District. There are no guidelines or standards set forth in the rules for determining an appropriate mitigation program nor is there any delineation of the factors that will be balanced in determining whether to issue the permit. b. District Monitoring of Wetlands Impacts 651. The District's field staff has been involved in continuous efforts to evaluate the ecological conditions of wetlands. The District has been monitoring wetlands surrounding public supply wellfields in the Northern Tampa Bay area since the 1970s. Although these sites were not optimally designed for the purpose of establishing a point of demarcation between acceptable and unacceptable environmental impacts, the information developed from these sites was the best data available in 1989 as to the impacts of groundwater withdrawals on wetlands. 652. At the time of the 1989 rule revisions, the District was convinced that there was a relationship between groundwater withdrawals and adverse wetland impacts. This conclusion was based upon the District's observations and experience, including field information supplied by permittees. 653. The District has relied upon sites in the Green Swamp, Hillsborough River Park, upper Hillsborough area and Starkey Wellfield as a control network for environmental monitoring sites. Aerial photography has also been used to establish baseline conditions. 654. Most of the District's monitoring experience has been with moderate to deep water cypress dome depressional wetlands and marshes, which are very common in the District. There are other types of wetlands in the District that are affected by drawdowns. For example, wet prairies and meadows can be particularly vulnerable because they are typically shallower than cypress dome systems and more sensitive to a lowering of the water table. Because many of the studied wetlands are surrounded by wet prairies, monitoring transects often run through some of the wet meadows and prairies. Thus, the District has developed some information and data regarding these systems. In addition, riverine systems have been monitored in the Cypress Creek area since the 1980s. 655. Saltwater or marine wetlands, which are subject to tidal action, have not been extensively monitored by the District. Those wetlands are usually more under the influence of riverine flow and tidal influences than water table drawdowns. 656. While different wetlands types respond differently to water table drawdowns, information gained by the District from the study of the wetland impacts of wellfield withdrawals in the Northern Tampa Bay region is useful for formulating some general principles. 657. The District says it is actively expanding its data base to include other wetland types. In the meantime, the District says it is obligated to process permit applications with currently available information. 658. To accurately ascertain impacts associated with groundwater withdrawals requires long-term environmental monitoring of wetland conditions. Many practical difficulties are involved. For example, gaining access to wetland sites beyond the property boundary of a permittee for monitoring purposes can present a problem. It may take one or two decades for the full effect of withdrawals to be realized. 659. The District utilizes both "quantitative" and "qualitative" environmental monitoring sites.94 660. Quantitative methodologies are complex to design, costly to implement and require accurate baseline data and/or long study periods. Even then, the results can be imprecise and difficult to interpret. A rigorous quantitative monitoring program, while desirable from an academic standpoint, is not always practical. In some instances, the District has imposed the significant burdens associated with such a program on permittees. 661. Qualitative evaluations refer to assessments of condition based on subjective judgments. Qualitative evaluations by a competent environmental scientist can be useful in evaluating wetland impacts, but the inherent subjective nature of this approach must be kept in mind. 662. The District has assisted West Coast in the development of an "Environmental Monitoring Plan" which is designed to integrate various wellfield monitoring programs into a single regional approach that incorporates a greater number of wetland sites and types, and would key in with more emphasis on hydroperiods and reduction in hydroperiods as the parameter of greatest concern. The results of these efforts when they become available should increase the reliability of the data and conclusions about the relationship between groundwater withdrawals and wetlands impacts. c. Development of the Wetlands Presumption 663. Theodore Rochow has been employed by the District as an environmental scientist in the Environmental Section of the Resource Projects Department since 1974. Dr. Rochow has monitored the impact of wellfield withdrawals on wetlands in the Northern Tampa Bay area for 20 years. His qualitative methodology involves the assessment of six parameters: water levels, soil conditions, canopy conditions, fire effect, plant and animal life, and human effects. The first five parameters can reflect adverse effects associated with loss of hydroperiod. Ratings on a five-point scale are utilized, comparing the rated wetland with the rater's experience as to what a healthy wetland should look like. 664. As part of the rule development process in 1989, the District's Rule Revision Committee asked Dr. Rochow to develop a water table drawdown threshold for unacceptable environmental impacts to wetlands. The one-foot water table drawdown presumption appearing in BOR Section 4.2.A.5. was developed based principally upon Dr. Rochow's recommendation. Dr. Rochow prepared a Technical Report dated February 9, 1989, to the Rule Revision Committee setting forth his rationale for the wetlands presumption found in BOR Section 4.2.A.5. 665. In developing the one-foot water table drawdown presumption for wetlands, Dr. Rochow compared his environmental monitoring data with computer modeled water table drawdowns from five separate public supply wellfields located within the Northern Tampa Bay area. The modeled water table drawdowns were produced by site-specific computer models utilized by the District in evaluating the WUP applications for the wellfields. From the various permit application reports, Dr. Rochow took the maps showing the simulated drawdowns from various pumping scenarios and correlated the drawdown information for specific wellfields with his environmental assessments in order to draw conclusions about whether or not impact occurred to wetlands at certain drawdown contours. Generally, the more impacted areas were within the higher drawdown contours. 666. Because there is no universally accepted definition of what constitutes an unacceptable environmental impact, Dr. Rochow relied upon his own personal definition of the term in developing the one-foot water table drawdown presumption for wetlands. There was some variation in the ratings of the wetland sites within the modeled drawdown contour lines irrespective of the modeling used to generate the drawdown contours. 667. Dr. Rochow did not perform any statistical analysis in correlating the one foot modeled water table drawdown to adverse impacts to wetland monitoring sites, and Dr. Rochow did not attempt to correlate actual water table drawdowns with wetland impacts.95 668. There are limitations on the ability of any model to accurately and comprehensively predict water table drawdowns. The site-specific models relied upon by Dr. Rochow to develop the one-foot water table drawdown presumption utilized simplistic aquifer parameters and the computer modeling runs were usually for short-term periods of from 90 to 120 days. 669. Different time scenarios and different pumpage levels were used in the models for the various wellfields. Those differences limit the comparability of the water table drawdowns. 670. None of the District's environmental monitoring programs were optimally designed or established to correlate water table drawdowns with impacts to wetlands. 671. When the District's environmental monitoring sites and programs were established, the modeled water table drawdown contours for the northern Tampa Bay area wellfields were not available to provide assistance in locating the sites. An optimal design would have a series of monitoring sites radiating out from the center of a wellfield or withdrawal source travelling outward so there is sufficient coverage in each of the drawdown contours generated by the model. There are, of course, practical and fiscal limitations on implementing such an optimal monitoring program. 672. In sum, the studies relied upon by Dr. Rochow were not located or distributed in the environment so as to provide a scientific basis to reasonably derive a relationship between unacceptable impacts to wetlands and modeled water table drawdowns. Moreover, the inherent limitations of the models that produced the drawdown contours used in the analysis preclude specific correlations with the environmental monitoring data.96 Wetlands react to the cumulative impact of all groundwater withdrawals and not just the impact of a single withdrawal. The site-specific stress models relied upon by Dr. Rochow did not simulate cumulative withdrawals. 97 673. From a geological and biological perspective, the District's monitoring data in the northern Tampa Bay area has been relatively short term. Longer term monitoring could reveal wetland impacts in areas where the water table is currently drawn down to a relatively small extent. In fact, there is some evidence that significant adverse impacts to wetlands can occur within the 0.5 foot modeled water table drawdown contour. 674. In developing the one-foot water table drawdown presumption, Dr. Rochow looked only at wetland systems located in the NTB area. The District has not studied the applicability of a modeled one-foot water table drawdown threshold for protection of the health of wetlands located north of Pasco County or south of Hillsborough County. Wetlands in other parts of the District may have different water table requirements. For example, there are significant differences from a hydrogeologic standpoint between the Northern Tampa Bay area and the southern part of the District. Dr. Rochow's work should not automatically be extrapolated to other areas. 675. In February 1994, Dr. Rochow updated his February 1989 report. He looked at the five wellfields previously considered in 1989 as well as an additional wellfield in the NTB area. In his February 1994 memorandum, Dr. Rochow again utilized drawdown contours generated by site-specific stress drawdown models. 676. Dr. Rochow's 1994 update memorandum contains several qualifications regarding the use of a one-foot modeled water table drawdown as a threshold between acceptable and unacceptable environmental impacts to wetlands. One qualification was that the one-foot water table drawdown presumption should be applied only to freshwater cypress and marsh wetlands in the Northern Tampa Bay area. As noted above, the District's monitoring experience has been focused on cypress dome and marsh wetlands. At the hearing, Dr. Rochow testified that, while he believes the one-foot water table drawdown presumption offers some protection for wet prairies and meadows, it is probably not as protective as he would like. 677. Dr. Rochow's 1989 and 1994 reports do not include any discussion of brackish water or saltwater, tidal wetland systems. The District performed no studies to determine the appropriateness of applying a modeled one-foot water table drawdown presumption to these saltwater and marine wetlands. 678. Drawdowns of equal amounts can have different impacts depending on timing. 679. Dr. Rochow's 1989 and 1994 studies focused basically on public supply or municipal water withdrawals. Some other types of groundwater withdrawals, such as agricultural use, are more seasonal in nature and can have a very different impact on wetlands, even when the withdrawal is the same quantity as from a public supply wellfield. Dr. Rochow's 1989 and 1994 studies do not address this factor. 680. Other limitations of the environmental monitoring programs and analyses relied upon by Dr. Rochow in developing the one-foot water table drawdown presumption for wetlands include: changes in the location of groundwater pumpage during the time of Dr. Rochow's observation without adjustment in his studies; variations in the number and duration of visits to wetland sites; the lack of baseline information and data about the wetland sites for the period before pumping from the wellfields began; variations in monitoring at different sites; and a lack of intermediate sites between the alleged impacted sites and control sites. 681. All of these issues should not obscure the important conclusion that the District has developed sufficient evidence to establish that there is a correlation between impacts to wetlands and drawdowns from a withdrawal. There are practical reasons, including fiscal and time constraints, that preclude a perfect scientific study of the precise relationship. Moreover, site-specific factors make universal conclusions difficult if not impossible. While it may be possible to develop a screening guideline to assist in the WUP process, the presumption in BOR Section 4.2.A.5 as currently written does not fit the bill. The information developed by the District fails to support the general conclusion set forth in the presumption that no unacceptable impacts will occur if the modeled water table drawdown is less than one-foot. d. Use of Models in Applying the Presumption 682. In the WUP review process, the District utilizes different models and/or different modeling assumptions depending upon the circumstances and the use involved. The District's use of the "limited cumulative" analysis (Level 2 of the Design Aids) provides for the consideration of some cumulative impacts, but applications under the Level 2 threshold do not receive any cumulative scrutiny. The modeling for the Level 2 Analysis is more sophisticated than the modeling utilized by Dr. Rochow. Dr. Rochow's correlation between unacceptable impacts to wetlands and modeled water table drawdowns should not be automatically extended to drawdowns generated by these more sophisticated models. 683. In connection with the NTB WRAP study, the District has developed the NTB Regional Groundwater Flow Model to simulate cumulative impacts of groundwater withdrawals from all users in the Northern Tampa Bay area. This regional model is much more complex than the site-specific stress models relied upon by Dr. Rochow. The regional model includes recharge and is calibrated.98 684. In most instances, the site-specific stress models relied upon by Dr. Rochow utilized flat starting surfaces in order to produce drawdown contours, while the regional model uses historical water levels as the basis for the model runs. Depending on the assumptions utilized, there can be a significant difference between drawdown contours generated with a cumulative simulation run on the regional model and drawdown contours from a non-cumulative simulation using the site-specific models relied upon by Dr. Rochow.99 Because of the inherent differences between the models, including how the models are run, the amount of pumpage inputted (permitted versus actual pumpage), and the period of time of the model run, it is not surprising that the modeling results are not identical. Generally, the District says it has found that the one-foot drawdown contour of the regional model incorporates within its boundary the 0.5 foot individually modeled drawdown contours for most withdrawals and circumscribes many of the areas where significant environmental impacts occur in the NTB. 685. The District contends that the variations from the different models do not diminish the usefulness of the site-specific models and do not invalidate Dr. Rochow's conclusions. At the time of the development of the presumptions in 1989, the District did not have regional calibrated models available. Ultimately, calibrated regional models may provide a basis for regulating all water use, but these models are still being refined, and they cannot currently be implemented on a localized basis. Most calibrated models have an error range of two feet or greater for simulated water drawdowns and it is usually not possible to utilize such a model to predict drawdown contours of one-foot or less. Thus, site-specific stress model predictions of drawdowns are still the best information available in most cases. However, these models are not accurate enough to reach anything other than general conclusions about the correlation between water table drawdowns and wetlands impacts. 686. In sum, it is clear there are more sophisticated modeling tools and better evidence available today than in 1989 when the presumption was developed. Dr. Rochow acknowledges that, in light of more recent studies by the District including the NTB WRAP, the one-foot water table drawdown contour generated by a site-specific stress model may not be an appropriate threshold for acceptable and unacceptable environmental impacts to wetlands. In many instances, wetlands respond to less than an individual stress modeled one-foot drawdown contour. If actual water table drawdowns are analyzed, wetlands may be impacted by drawdowns of even a few tenths of a foot. Thus, the presumption as it is currently written is not supported by the current scientific data. 687. There is no hydrological basis for concluding that a one-foot water table drawdown at a wetland is the appropriate threshold or demarcation between acceptable or unacceptable environmental impacts for all wetlands in the District. The need for additional study of issues such as the impact of seasonal withdrawals on wetlands and the limited ability to accurately analyze cumulative impact preclude such a conclusion. Moreover, it is doubtful that any single water table drawdown presumption could be applied on a District-wide basis because of the variability within the District and the limitations on the ability of the current models to evaluate site-specific conditions that are not in the immediate vicinity of a given withdrawal. 688. The District concedes that the one-foot water table drawdown presumption is not an absolute dividing line between acceptable and unacceptable impacts for all wetland systems. The District claims, however, that these issues can be handled through site-specific information. The District says further study is not necessary to provide scientific support for the wetlands presumption because the presumption is not used as a pass/fail test. According to the District, the wetlands presumption is used only to identify projected drawdowns that deserve more scrutiny. However, the one-foot wetlands presumption is not written in such terms. Instead, the presumption is written so that applications that could potentially cause unacceptable adverse impacts can be approved without further scrutiny. 689. The regulation of the environmental impact associated with groundwater withdrawals is an extremely important yet complex and uncertain task. The District contends that vital resources could be irretrievably lost if scientific certainty were a prerequisite to regulation. Those concerns are not an adequate basis for the wetlands presumption as currently written. The District can and should regulate impacts to wetlands without the presumption in BOR Section 4.2.A.5. While there is a relationship between the distance from a withdrawal point and the severity of hydroperiod reduction and associated adverse impacts to wetlands, the studies relied upon by the District do not support application of the one-foot water table drawdown presumption as written. Moreover, an application with a modeled water table drawdown that exceeds the presumption is held to account for the impacts from all withdrawals in the area while applications below the threshold are not subject to any cumulative scrutiny. 690. There are roughly 1800 lakes over 10 acres in size within the District. Like wetlands, a large percentage of the lakes in the District are depressional. In general, Florida lakes are defined as shallow. 691. The level of a lake is often closely associated with the level of the surficial aquifer. Lake levels fluctuate naturally in response to rainfall, evapotranspiration, and surface and groundwater inflow and outflow. While lakes may show extreme short-term fluctuations due to seasonal rainfall, the fluctuations generally occur around a prevailing water level, which responds slower to long-term changes in hydrologic conditions. 692. Maintaining water level fluctuations within the normal range is an important factor in preserving the ecological characteristics of lakes. Important physical features, such as natural beaches, littoral shelves, bars, and contiguous wetlands, are influenced by prevailing water levels and the fluctuating range. 693. Much of the biological productivity for lakes occurs in the shallow littoral areas, which are habitat to a wide variety of attached algae, zooplankton, macroinvertebrates, and fish, including fish bedding areas where eggs are deposited. Significant reductions in lake levels can have deleterious effects upon submerged vegetation, which is generally found in the shallow waters along the littoral shelf, and neighboring wetlands which are dependent upon periodic or continued inundation. Lowering of a lake level for long periods can cause desiccation of the valuable littoral shelf vegetation and a corresponding loss of habitat and productivity which adversely affects fish and wildlife. 694. The District began efforts to establish management levels for lakes in the late 1970s and early 1980s. In 1989, the District began a formal effort to assess the lakes in the Highlands Ridge area. In 1991, the District extended this effort to begin establishing management levels district-wide. 695. The District's methodology for establishing lake levels involves the establishment of four management levels for each lake: a ten-year flood warning level, which is a level that a lake can be expected to rise every ten years or statistically having a 10 percent chance of reaching in any given year; a minimum flood level, which is roughly equivalent to the normal seasonal high; a low management level, which is roughly equivalent to the normal seasonal low; and an extreme low management level, which is the low to be expected every four to six years during drought conditions. Under these definitions, the District deems it desirable for a lake to reach its minimum flood level at least twice during a five-year period. In determining whether a lake is "stressed", the District reviews records regarding the lake's level during the proceeding five years and, if the lake is below the low management level two-thirds of the time, it is deemed "stressed". 696. In establishing management levels, the District utilizes an integrated methodology that takes into account historical maps, ecological indicators, site assessments and personal observations of neighboring residents. See, Rule 40D-8.603, F.A.C. The District looks as far back historically as the data permits. There is a wide range in the quality of the historical records regarding lake levels. 697. Once management levels are established, a standard monitoring program is implemented to record the lakes levels. 698. At the time of the hearing, the District had adopted management levels for more than 370 lakes District-wide. See, Rule 40D-8.624, F.A.C. This represents a significant percentage of the lakes in the District that are greater than 20 acres in size. There are still a number lakes, many of them small and unnamed, for which the District has not adopted management levels. In establishing management levels, the District has prioritized lakes based upon size, the number of water use permits for withdrawals from the lake, whether there were artificial structures under the control of someone other than the District that could influence the lake level and the degree to which the surrounding area was populated. 699. The District began publishing an annual list of "stressed" lakes in 1991. All of the District's annual reports on stressed lakes indicate a significant number of lakes along the Highlands Ridge in southern Polk County and northern Hillsborough County are stressed. b. Regulating Lake Withdrawals 700. Lakes vary widely in the degree to which they are interconnected with other surface water bodies and/or groundwater aquifers. Because of the various hydrologic factors which can influence lake levels, it is difficult to establish a proportionate relationship between direct surface water withdrawals from lakes and a lowering of lake levels. Nonetheless, because surface water withdrawals from lakes have a direct effect on lake levels, the District concluded it was essential to develop guidelines to manage such withdrawals. The District sought to provide both the regulatory staff and the regulated public with guidance as to whether or not a particular activity or magnitude of an activity could be permitted. 701. Prior to the 1989 rule revisions, the withdrawal of surface water from lakes and impoundments was not regulated by the District on a cumulative basis. The rules were applied so that each permittee was entitled to withdraw from a lake a volume of water equal to one-foot of the total surface area of the lake. The District was concerned that too much water was being permitted on a cumulative basis thereby raising the prospects of serious ecological harm to some lakes. 702. In preparation for the 1989 rule revisions, District Environmental Scientist Sid Flannery analyzed existing information to determine whether a relationship existed between permitted quantities and low water level conditions within lakes. He particularly focused on those lakes where permitted quantities exceeded more than one-foot of the entire lake area. Mr. Flannery concluded that there were a number of lakes that appeared to have excessive quantities permitted for withdrawal on a cumulative basis. 703. As part of Mr. Flannery's analysis, actual conditions were reviewed for many of the lakes and lake stage data and adopted management levels were considered when available. A large proportion of the studied lakes were found to be fluctuating below their normal range with varying degrees of severity of water level reduction. Based on these studies, the District decided to modify its then existing rules. One of the primary goals was to insure that the one-foot lake volume presumptive guideline would be applied cumulatively. c. Development of the Lakes Presumptions 704. Adopted lake management levels can be a useful tool in managing lake withdrawals. However, the District states that adopted lake levels cannot be used alone to manage lake withdrawals because of the variability in lake hydrologic budgets. The District does not have sufficient data to calculate accurate hydrologic budgets for most lakes. In many cases, extensive further data collection would be necessary and, even then, hydrologic budgets cannot always be calculated accurately. From a scientific standpoint, a bad budget can be worse than no budget. 705. It is simply impracticable and cost prohibitive to do a water budget for all lakes within the District to determine how much water can be permitted. To implement a cumulative approach for regulating surface water withdrawals from lakes and to address certain other issues, the 1989 Rules Revision Committee developed and the District adopted Section 4.2.B.2. of the Basis of Review which sets forth presumptions relating to potential lake impacts caused by surface and groundwater withdrawals. This section provides as follows: a. The District presumes that a surface water withdrawal will not cause unacceptable environmental impacts if the total annual withdrawal, combined with other surface withdrawals, does not exceed the volume contained within the top foot of water at average lake area.
For lakes with adopted levels, average lake area is the average of the area at maximum desirable stage and the area at low management level. (See Part C of this Manual.) For lakes without adopted levels, average lake area will be determined by District staff.
b. The District presumes that a surface water withdrawal will not cause unacceptable environmental impacts if the withdrawal of water, combined with other surface withdrawals, does not exceed a rate of one-quarter inch per day over a 30-day period. A quarter inch lowering shall be equivalent to the volume contained in the top quarter inch of water at average lake area.
c. The District presumes that a groundwater withdrawal will not cause unacceptable environmental impacts if the withdrawal of water, combined with other groundwater withdrawals, does not lower the water table at the lake by more than 1 foot. 706. According to the District, the three presumptions are aimed at addressing the total impact of surrounding surface and groundwater withdrawals on the health of a lake. While there was some testimony that an applicant must meet all three lake presumptions conjunctively, subsections a. and b. on their face only apply to direct surface water withdrawals from lakes and subsection c. applies only to groundwater withdrawals that impact a lake. The language of BOR Section 4.2 does not delineate or explain how the presumptions are applied conjunctively. Currently, there is limited understanding of the impacts of groundwater withdrawals on lakes. It is not clear when or how the District could apply the three presumptions in conjunction. More particularly, it is not clear how or what information the District will use to assess the impacts to lakes from groundwater withdrawals. 707. As written, the presumptions provide that surface water users need only be concerned with the cumulative affect of other surface water users and, likewise, groundwater users need only be concerned with the cumulative affect of other groundwater users. Thus, the lakes presumptions currently do not provide a basis for analyzing the cumulative impacts on a lake of all water uses. 708. The presumptions in BOR Section 4.2.B.2 were based on the analysis conducted by Mr. Flannery, with the assistance of other District staff. Mr. Flannery prepared a technical memoranda dated February 28, 1989 to the District's Rules Revision Committee setting forth his rationale for the surface water presumptions in BOR Section 4.2.B.2.a and BOR Section 4.2.B.2.b. He prepared a subsequent memorandum dated March 7, 1989, which updated his February 28, 1989 memorandum. 709. The District claims that the three presumptions in BOR Section 4.2.B.2 are used as thresholds or guidelines to screen out those water use applications which are not likely to cause unacceptable environmental impacts to lakes from those impacts that are likely to cause unacceptable impacts. The District believes that, because of the time frames required for regulatory review and the data needed to calculate accurate hydrologic budgets, some initial screening guidelines are necessary for regulatory purposes. The District views the presumptions as safety checks, providing some measure as to the impact of cumulative water use in the absence of a detailed hydrologic budget for each lake. 710. The District applies the three lakes presumptions to all lakes regardless of type or location. 711. Unless the District has information available to the contrary, a water use applicant who satisfies the presumptions does not have to present any further evidence to the District in order to show compliance with BOR Section 4.2.B. and is deemed to meet the condition in Rule 40D-2.301(1)(c) insofar as lakes are concerned. 712. Although the District claims the presumptions can be rebutted by site specific information, neither the District nor any third party has ever successfully rebutted any of the lakes presumptions in BOR Section 4.2.B.2. 713. Application of the lake presumptions can lead to some anomalous results. For example, an applicant who proposes a surface water withdrawal that is projected to result in a one and half foot drawdown of the lake level would be deemed to cause unacceptable environmental impacts. However, if an applicant proposed a surface water withdrawal and a separate groundwater withdrawal each of which was projected to cause a drawdown of three quarters of one foot, the language of the surface water and the groundwater lake presumptions dictate that they be applied separately so the applicant would be deemed to not cause unacceptable environmental impacts. The District suggests that this hypothetical result is unlikely because the site-specific information would make it clear that the presumptions should not be applied. Thus, the District claims that if a lake was lowered by one foot due to surface water withdrawals, then a groundwater applicant would not be able to meet the performance standard for the lake and the presumption would not apply because there would be site-specific information which indicated to the contrary of the presumption. However, the performance standards address fluctuations outside normal ranges which lead to impacts to water quality, wildlife, and other biota. The presumptions as written would effectively shift the burden of proof from the applicant to the District and/or a third party challenger to prove such adverse impacts. d. BOR Section 4.2.B.2.a. - One Foot Maximum Cumulative Drawdown 714. In the 1989 rules revision process, the District decided that, because the fluctuation of lake stages within normal historic ranges was so important to lake ecology, water withdrawals should be regulated so as to not greatly reduce this range of fluctuations. As noted above, the District did not believe that an accurate hydrologic budget could be adopted for every lake. The District believed its prior regulatory methodology for issuing permits based on area was worth using on a cumulative basis because it was relatively simple and used consistently available information to relate the amount of the withdrawal to the size of the lake. Unlike information on bathymetry and volume which are generally unavailable, lake area can be easily determined. 715. Mr. Flannery's March 7, 1989 memorandum reviewed water level variations in a number of lakes in the District for two separate years. Mr. Flannery calculated the average water level for each of these years and then calculated the average of these two averages. He found an average fluctuation of 2.5 feet in the water levels in those lakes. Mr. Flannery's analysis noted that the presumptive threshold of one-foot for the total annual surface withdrawals from a lake was approximately equivalent to 40 percent of this 2.5 feet of natural fluctuation. In other words, a cumulative one-foot lowering represented about 40 percent of the typical yearly range of stage fluctuation based upon Mr. Flannery's analysis of the hydrologic records of twenty-one lakes in the District for the years 1983 (a normal to wet year) and 1985, (which incorporated a severe drought followed by heavy summer rains.)100 716. Mr. Flannery's 1989 report delineates four reasons in support of the presumptive threshold in BOR Section 4.2.B.2a which would limit total annual surface water withdrawals from a lake to an amount equal to the volume of the top one foot of water of the lake: (a) one foot of water per year represents a high proportion of the normal variability of lake levels in the District and withdrawals larger than the threshold could significantly alter the normal fluctuations of lake stages; (b) lakes are shallow in Florida and more than a one foot withdrawal could be a fairly large fraction of the volume of a given lake; (c) more than one foot of decrease in the water elevation in a lake could expose a fair amount of littoral zone area; and (d) because of the surface water and groundwater interactions in lakes, some of the one foot presumed withdrawal from a lake could be dampened or ameliorated by movement of water into the lake. 717. The choice of 40 percent of the average annual seasonal variance was not based on any specific principal in the field of limnology. The District relied upon the professional judgment of Mr. Flannery and Donald Richters, who had managed the District's lake levels management levels program since its inception. 718. Pinellas contends that the District's justification for the one-foot cumulative drawdown threshold is not scientifically valid. Pinellas points out that the District used data from only twenty-one lakes over two years to support its choice. Pinellas also contends that Mr. Flannery's analysis is flawed because he did not evaluate the long term and/or year to year fluctuations that occur in lake levels, including those due to the annual variability in rainfall. Pinellas' contentions are not persuasive. 719. There is no overriding hydrological standard for regulating withdrawals from a lake. The District looked at typical conditions and selected a standard that would be conservative in favor of the resource. No persuasive evidence was presented that the District's decisions in this regard were unreasonable. Similarly, the District's decision not to utilize long-term variations in lake levels because of the flood-drought cycle was sound. The District did not consider year to year variations in lake levels to be relevant to its analysis. The District was concerned with comparing its presumptive threshold with natural fluctuations within a lake. Looking at the seasonal fluctuations of a typical lake was appropriate. 720. The presumptions in BOR Section 4.2.B.2.a are applied using an analytical procedure known as the "closed basin analysis." This closed basin analysis is not described in the rules but is set forth in the Water Use Design Aids, Part C of the Water Use Permit Information Manual. 721. Pinellas claims that the District's analysis is flawed because the one-foot presumption is calculated under the assumption that all lakes are closed-basin lakes even though a large number of lakes in the District are actually flow-through. 722. Flow-through lakes behave differently than seepage or closed basin lakes when water is removed. The amount of flow into and out of a flow-through lake can be two to three times the amount of annual rainfall in the area of the lake. Closed basin or seepage lakes do not have this type of additional inflow and outflow. 723. The extraction of the equivalent of one foot of water from a flow-through lake may be a small portion of the quantity of water flowing into or through the lake in a year. Indeed, a flow-through lake might not experience any physical decline at all given the inflow of water. Because the actual drawdown for flow-through lakes would be less than the predicted drawdown based upon the closed basin analysis, the one-foot guideline is actually conservative in favor of protecting the flow-through lakes. The District's choice of a regulatory strategy that maximizes protection of lakes with long residence times is reasonable since these lakes are particularly sensitive to withdrawals. 724. The District has not established a separate guideline for flow-through lakes because of the variability in the characteristics of these lakes. The District felt these variations could be considered in the permitting process as additional site-specific information. The rules do not preclude the use of surface water inflow and outflow as part of the analysis. 725. Pinellas contends that Mr. Flannery's analysis does not adequately consider the variability in lake dimensions and lake shapes. The withdrawal of an amount of water equal to the volume of the top one foot of the lake at average lake area will have varying impacts depending on the lake morphometry.101 726. The District recognizes the uniqueness of each lake mandates that flexibility be built into the rules for site-specific information. The desirability of utilizing site-specific information in the review process was acknowledged in Mr. Flannery's technical analysis. A fundamental goal of [the] rules should be to keep total withdrawals in proportion to the size or water yield of the lake....
The presumptions...for the evaluation of lake withdrawals are to be used as guidelines which can be superseded if adequate site specific information if [sic] available....The evaluation of site-specific information may indicate that the allowable water yield of a standing water body is higher or lower than the quantity indicated by the presumption....
Lake stage data is the most important site specific information for evaluating withdrawals from lakes. Stage data are absolutely necessary to determine if a lake is fluctuating within normal management levels which represent healthy ecological conditions. It should be standard practice that each lake that supports direct lake withdrawals also have stage data collected at least as frequently as every two weeks. 727. The amount of surface water withdrawals from a lake that will cause unacceptable impacts to the lake will vary depending on numerous site-specific factors such as precipitation, evapotranspiration, runoff, hydrogeology, the nature of the water withdrawals and the type of vegetation. Nonetheless, a rebuttable, upper threshold screening guideline may be a useful regulatory tool if it is adequately described and properly applied. The more persuasive evidence established that the District's approach is reasonable and, if properly applied, can effectively serve as a cap on withdrawals from any lake. 728. In the August 19, 1994 report by the Surface Water Availability Conventions Committee the usefulness of a stage-volume threshold, like the District's one-foot presumption, as an initial screening guideline for assessing surface water availability from lakes was recognized. The Surface Water Availability Conventions Report recommended that the districts develop separate thresholds for different types of lakes based on physical or ecological characteristics, such as average depth, shore line morphometry or the abundance of surrounding wetland community. It does not appear that any district has yet adopted separate thresholds for different types of lakes. As noted above, the District's use of a closed-basin analysis insures that its threshold will be conservative in favor of the resource. 729. In sum, the evidence in this case established that a properly worded and applied stage-volume threshold can serve as a useful cap and/or screening tool for regulating withdrawals that impact lakes. The analysis performed by the District does not, however, support the presumption as currently written. 730. There is no scientific basis for concluding that total surface water withdrawals of less than one-foot of the total area of a lake will not have an adverse impact, especially since groundwater withdrawals can be affecting the lake in ways that are difficult to determine. 731. The District's rules also lack an adequate explanation of how the presumption applies to lakes that do not have adopted management levels. The stage-volume threshold in BOR Section 4.2.B.2a is based on "average lake area." Under the pre-1989 rule, there were some problems in calculating area because most lakes have sloped sides, which reduces the actual quantity within the top one foot, and some estimates of lake surface area were derived when the lakes were at higher stages. As part of the 1989 rules revisions, a new criterion was included in BOR Section 4.2.B.2a to clarify and standardize lake area measurements. For lakes with adopted management levels, an average of the lake area derived from the maximum desirable stage and the low management level is to be used. However, there is still a great deal of uncertainty as to how to determine the area for lakes without adopted levels. The presumption as currently written leaves the determination of average lake area in such cases completely to the District with no delineation of the factors that will be considered. Unless some standards or criteria are provided for making this determination, the rule vests unbridled discretion in the District. 732. Finally, it is not clear how the District applies this presumption to lakes with permitted withdrawals that already exceed the presumption. This issue was not fully developed at the hearing, but it appears the presumption (and perhaps the performance standards) are not applied in many instances. The conditions and factors that will be considered in this regard are not set forth in the rules. e. BOR Section 4.2.B.2b - 30 day maximum withdrawal 733. As part of its analysis for the 1989 rule revisions, the District looked at total permitted quantities from a maximum daily perspective. The District was concerned that a rapid lowering of a lake could expose littoral shelf areas without allowing time for biological communities to adjust and relocate. Such impacts can be exacerbated when the maximum withdrawals occur during the dry season when lakes are at their lowest level. Prior to the 1989 rule revisions, there was no limit in the District's rules on the amount of water that could be taken from a lake on a short-term basis. Some permits had maximum daily withdrawal limits which allowed lakes to be drawn down from five to ten inches a day. 734. The District felt it needed to have some measure to try to keep cumulative water withdrawals within scale within a lake. The 1989 rule revisions added a one-quarter inch per day cumulative maximum daily withdrawal averaged over a thirty-day period (which is equal to 7.5 inches per month) to address these concerns about rapid short-term withdrawals. 735. The District wanted its regulatory scheme to be consistent with the naturally occurring hydrologic processes for a lake. Mr. Flannery's March 7, 1989 memorandum sets forth his analysis in support of the maximum 7.5 inches per month presumption in BOR Section 4.2.B.2b. In his memorandum, Mr. Flannery sought to compare the presumption to natural lake evaporation. He noted that the maximum pan evaporation rate102 calculated at the Lake Alfred Experimental Station over a 24 year period for the month of May (when evaporation losses are highest) was 8.5 inches.103 736. The 7.5 inch presumptive limit was felt to roughly correspond with the worst case scenario for water level declines due to natural influences. Since lake level declines from withdrawals typically stabilize to some degree because of rainfall and groundwater inflows, the District believed that a limitation of 7.5 inches over a thirty day period would provide a safe upper limit for lakes. 737. Pinellas claims that the District's analysis in developing this presumption was flawed because the District did not use a pan coefficient in comparing the presumption with the Lake Alfred data.104 738. The District's decision to not apply a specific pan evaporation coefficient to the Lake Alfred data was not unreasonable since the District was not seeking a precise scientific measurement, but rather was looking for a general idea of the high range of natural water loss. 739. Pinellas notes that the District has not conducted any specific scientific studies that examine the environmental characteristics of lakes to confirm that an increase to the maximum monthly evaporation rate would not cause unacceptable environmental impacts to a lake. Pinellas contends that, absent a specific study which directly links the reduction of water in a lake with adverse environmental impacts to the lake, the presumption is not scientifically valid. 740. The more persuasive evidence established that the District has an adequate basis for concluding that rapid drawdowns in a lake can increase the severity of the impacts. Thus, there is a basis for regulatory steps to minimize the possibility of rapid drawdowns. To the extent the District's chosen threshold is used only as a preliminary screening guideline or upper limit on withdrawals, there is support in the District's studies. The presumption should not be used or viewed as a demarcation between acceptable and unacceptable impacts for all lakes. Moreover, as currently written, the District's presumption assumes no adverse impact if a withdrawal, combined with other withdrawals, is below the threshold. There is no persuasive evidence that withdrawals under the presumptive level will not cause adverse impacts. It should be noted that, under this presumption, an applicant could, within a 30 day period, remove over 60 percent of the one foot volume of the lake which is allowed for the entire year under the BOR Section 4.2.B.2a presumption. f. BOR Section 4.2.B.2.c. - Lake-fringing Wetlands - Water Table Presumption 741. No specific technical report or memoranda was prepared to support the one foot water table drawdown presumption for lakes found in BOR Section 4.2.B.2c. This presumption was based, in part, on the technical work conducted by Dr. Rochow for the wetlands presumption in BOR Section 4.2.A.5. Dr. Rochow was not directly involved in developing the lakes presumptions nor has he performed any studies attempting to determine a relationship between water table drawdowns and unacceptable environmental impacts to lakes. 742. Mr. Flannery concluded that, since many Florida lakes are surrounded by fringing wetlands and Dr. Rochow had purportedly found that wetland impacts were associated with a modeled one foot water table drawdown, a similar one foot water table drawdown standard could be used as a threshold for unacceptable impacts on lakes from groundwater withdrawals. The District's 1989 Rules Revision Committee accepted this analysis. The Rules Revision Committee was not aware of any research which specifically addressed the impacts of groundwater withdrawals upon wetlands around lakes and considered Dr. Rochow's research to be the best available information. 743. There is no clear scientific demarcation between wetlands and lakes. Limnologists have not developed a uniform definition of what constitutes a lake. Similarly, ecologists cannot generally agree upon the boundary between a wetland and a lake or an upland. Whether a wetland that fringes a lake should be classified as part of the littoral zone of the lake or a separate wetland system that is contiguous with the lake is a decision that is most accurately made on a site-specific or system-specific basis, but such information is often unavailable. 744. The predominant ecological differences between lakes and wetlands include the following: (a) water depth - lakes are typically deeper than wetlands; (b) permanence of inundation - lakes are typically inundated or contain water throughout the year and from year to year, while wetlands will commonly experience a dry period with very little water or dry conditions; (c) thermal structure - lakes will often have a thermal structure with layers of temperature zones with some zones higher in certain chemical constituents, nutrients, and salts, wetlands are typically not deep enough to experience a thermal structure; (d) hydrodynamics - the hydrodynamics of lakes can include currents that behave and form in different ways, while wetlands are not typically able to form currents because of their shallow nature and their emergent vegetation; and (e) primary production/vegetation -- the primary production or growth of plant material occurs mostly underneath the water in lakes in the form of either submerged vegetation or phytoplankton or attached algae that may be on the bottom or growing on surfaces of things underwater, while in wetlands the majority of vegetation is emergent and most of the growth and green area of plants is above the surface of the water. 745. Despite these differences, wetlands and lakes have many common physical features and they both have ponded water which communicates with the surficial aquifer system. The District felt that the hydrologic similarities warranted a consistent regulatory approach. 746. Most lakes in Florida have a surrounding ring of marshes or hardwood wetlands. The District says the purpose of BOR Section 4.2.B.2c was to capture those withdrawals which might affect lake-infringing wetlands in cases where there might be doubt or confusion as to whether a particular area should be considered wetlands or part of a lake. The District wanted to cover these areas with the same level of protection, regardless of whether they are considered as wetlands or a portion of a lake. 747. A water table drawdown in a marsh can lead to changes that impact the health of various types of emergent and submergent vegetation and the habitat space available for fish and invertebrates. It can also lead to foraging changes in wading birds and can cause substantial impacts on vegetation in the vicinity. The District concluded that a similar groundwater withdrawal impact analysis could be used for wetlands whether they were isolated or fringing lakes. No persuasive evidence was presented to refute this conclusion. 748. Lakes often have different hydroperiod conditions and sources of water than isolated wetlands. Pinellas contends that Dr. Rochow's work relating to wetlands reflected in his 1989 and 1994 reports does not extrapolate scientifically to lakes and, consequently, is not a scientifically valid basis for adopting a one foot water table drawdown presumption for lakes. While Dr. Rochow's work relating to wetlands primarily focused on isolated cypress wetlands, it did include some marshes as well as hardwood wetlands. 749. The District's conclusion that Dr. Rochow's analysis of the impact of water table drawdowns on wetlands is useful in looking at fringe wetlands along lakes is reasonable so long as the limitations of that study are recognized. 750. Like the District's wetlands presumption, the lakes presumption provides that no unacceptable impacts will result from withdrawals that fall below the threshold. Thus, as written, the presumption is not just a cap or screening guideline. The scientific evidence is insufficient to conclude that a modeled water table drawdown of less than one foot will not cause an unacceptable impact at any lake. 751. To determine compliance with the presumption in BOR Section 4.2.B.2c, the District does not use actual water table drawdowns. Instead, drawdowns simulated by a groundwater flow model are utilized. As noted in the discussion above regarding the wetlands presumption, site-specific models have inherent limitations, including the lack of cumulative impact analysis, that hinder the ability of such models to accurately predict actual drawdowns. 752. It should also be noted that the District's rules do not provide any guidelines or criteria that will be considered in determining whether and how an applicant can mitigate the presumed adverse environmental impacts if the modeled water table drawdown contour is greater than one foot at a lake. 753. Because of the large variability within the surficial aquifer and how it communicates with lakes, it is not possible to develop a single annual withdrawal threshold or a single daily withdrawal threshold that can account for all the various factors that affect water levels in lakes, such as recharge, runoff, and the inflow and outflow of the lakes. 754. Moreover, Mr. Flannery's 1989 studies do not establish a link between specific water level reductions in a lake and impacts to any particular biota. He assumes a linkage between changes in lake level fluctuations and adverse impacts to the various biotic components of lakes. The actual impacts to a lake will depend on many factors including the health of the lake and the unique ecosystem. 755. The inverse of the presumptions within BOR Section 4.2.B.2 may be appropriate initial screening guidelines to determine where there is a greater likelihood of impact. However, there are no specific studies to determine conclusively at what level withdrawals will not have an impact. Thus, the scientific evidence does not support the presumptions as written. 756. Because the presumptions conclude that an applicant will not have an unacceptable impact if the withdrawal is under the threshold, they effectively shift the burden of proof from the applicant for permits below the presumptive thresholds. Furthermore, it is not clear how the presumptions are applied to the renewal of existing permits and/or what factors would be considered in determining whether to allow a proposed withdrawal to exceed the presumptive threshold and/or what factors would be considered in the development of a mitigation plan.
|