CHARLOTTE COUNTY v. SOUTHWEST FLORIDA WATER MANAGEMENT DISTRICT

PREVIOUS SECTION

IV. Existing Rules, Proposed Rules, and Agency Statements Concerning Minimum Water Levels and Flow Rates

320. Section 373.042, F.S., directs the water management districts to set minimum flows and levels for streams, lakes and aquifers. See, Section III A.5.

A. Existing Rules Concerning Minimum Water Levels and Flow Rates - Rule 40D-8.041

321. ECOSWF has challenged the District's existing rules regarding minimum flows and levels, Rules 40D-8.041(2), 40D-8.041(3), and 40D-8.041(4), F.A.C., alleging that the rules exceed the statutory authority of the District, contravene, enlarge or modify the rules' enabling statutes and are arbitrary and capricious.

322. Rules 40D-8.041(2) and (3) purport to establish a methodology for calculating minimum flows and levels for streams and the water table aquifer. It does not appear that the District utilizes the existing methodology rules, and the District was not able to provide any scientific basis for them. A minimum flow or level established by the existing rule methodologies would not necessarily protect the water resources from further harm.

323. The District conceded that Rule 40D-8.041(4) was premised on the "water crop" methodology and has no current viability for regulating the consumptive use of water resources in the District. See, Section III A.2.

B. Proposed Rules Establishing the SWUCA and the Minimum Aquifer Level - Proposed Rules 40D-2.801(3)(b)1., 40D-8.628 and BOR Section 4.3

1. Water Use in the SWUCA

324. As discussed in Section III, withdrawals of groundwater in the Southern Basin have caused reductions of the potentiometric surface in the Floridan Aquifer and a consequent reduction of the seaward gradient of groundwater flow.⁶² When the seaward gradient is reduced, coastal discharge of freshwater is reduced and saltwater can move upward and inland in the aquifer.

325. Underground flow migrates toward areas of low potentiometric pressure. Saltwater intrusion will occur much more rapidly in an area where potentiometric levels fall below sea level, particularly if there is no barrier or buffer having a positive seaward gradient to the coast.

326. Under predevelopment conditions, potentiometric levels near the Gulf Coasts of Hillsborough and Manatee Counties were 20-to-30 feet above sea level. In more recent years, however, potentiometric surface levels of the UFAS in southern Hillsborough and central Manatee Counties have been near or below sea level under average annual conditions.

327. During certain periods, declines in the potentiometric surface of the UFAS measured up to 50 feet in central Manatee, portions of east-central Hillsborough, and central Polk Counties. For example, due to very high pumping in 1989, an area developed in northern Manatee and southern Hillsborough Counties where the potentiometric surface was below sea level.⁶³ This condition was not present in 1991, and a positive flow-gradient to the coast was re-established.

328. Both the ETB WRAP and SWUCA Management Plan concluded that groundwater pumping needed to be capped in the SWUCA. At the time these studies were concluded, total permitted quantities of groundwater in the SWUCA were more than 1300 MGD. That number has since risen to almost 1500 MGD. These figures greatly exceed the "safe yield" estimates of the ETB WRAP and SWUCA Management Plan.

329. The District projects that the imposition of the conservation measures in the SWUCA Rules would ultimately decrease permitted quantities to approximately 1000 MGD. It also predicts that the permitted quantities would never be fully utilized at any given time.

330. In the SWUCA, more than 90 percent of non-public-supply water withdrawals are derived from groundwater sources. Public supply utilizes surface water reservoirs for some of its use but also depends on groundwater.

331. According to District estimates, 1989 was the year of highest groundwater use in the SWUCA. In that year, the lowest potentiometric levels on record for most areas of the SWUCA were recorded. In 1989, permitted withdrawals for all groundwater users in the SWUCA totaled approximately 1,268 MGD. Actual groundwater use in the SWUCA for 1989 was estimated at 832 MGD with agriculture accounting for 531 MGD (64 percent), mining and industrial uses approximately 166 MGD (20 percent),⁶⁴ and public supply 114 MGD (14 percent).⁶⁵

332. In 1991, actual groundwater usage in the SWUCA was estimated at approximately 688 MGD or about 20 percent less than the estimated water use in 1989. Although it has been suggested by some Petitioners that post-1991 figures showing declines in actual water usage in the SWUCA resulted from better estimating procedures and more accurate metering, no persuasive evidence was presented to support that contention.

333. The District's Needs and Sources Report projects that total water demand in the SWUCA could increase to approximately 1,300 MGD by the year 2020. Such an increase in water use would add significant additional stress to the water resources in the SWUCA.

334. The District has estimated that there is from 203-336 MGD total water available from sources in the SWUCA other than confined aquifers that have not yet been developed. Potential alternative water sources include rivers (100-143 MGD), lakes (up to 31 MGD), reclaimed water by the year 2015 (0-160 MGD) and surficial aquifers (2 MGD).

2. The Need for Regulation

335. Faced with ever increasing demand in upcoming years, the District has concluded that it is necessary to put in place regulatory tools to address the cumulative impacts of regional groundwater withdrawals. The District is faced with a task of enormous complexity as it attempts to address the significant water resource issues within its jurisdiction. A vast number of difficult choices must be made, and it is not possible to resolve the issues in a manner acceptable to all affected interests. The proposed rules were developed by the District after many years of study and extensive public input.

336. Because of the extensive water use already existing when the Water Resources Act was enacted in 1972, the District was not able to initially assess availability of the resource and determine an appropriate minimum aquifer level. Without question, a regulatory program would have been easier to implement if it had been possible to establish minimum levels before water use began.

337. The District notes that district-wide water use from all sources has not changed significantly since the inception of the water use permitting program in 1975.⁶⁶ Likewise, the District claims that total use in the SWUCA have not increased significantly since 1975. While the District has suggested that the over-permitting in the SWUCA can largely be attributed to the continuation of water uses that pre-dated the District's consumptive use permitting program, all existing uses should have been subject to at least one renewal process in the intervening years. Moreover, there have been changes in the nature and location of water uses in the SWUCA. For example, during the 20-year period that the District's permitting program has been in place, there has been a decline in water use by the phosphate industry, which is primarily located in the northern inland portions of the SWUCA. During the same period, there has been increased usage by agriculture (principally citrus and tomatoes) and public supply, much of which has been located in the coastal counties of Hillsborough and Manatee.

3. Saltwater Intrusion in the SWUCA

338. Some of the parties argue that the District does not have adequate evidence to indicate that saltwater intrusion is occurring in the SWUCA. However, the more persuasive evidence supports the District's conclusion to the contrary.

339. In the late 1970s, the District started the Regional Observation and Monitoring Program ("ROMP") which included drilling monitor wells along the coast to locate and monitor movement of the saltwater transition zone over time. Although sometimes drilled as deep as the evaporites to gain data for a water quality profile, the wells were plugged slightly above the level where the 1,000 mg/liter chloride concentration occurs, close to freshwater portions of the aquifer. Because the monitor wells were specifically selected, drilled and operated according to reliable standards, they have been an important and reliable source of data.

340. The District confirmed the regional movement of the saltwater interface by monitoring chloride levels at the ROMP wells over time. As expected, wells along the coast have shown increasing trends in chlorides. In addition, in some areas of southern Hillsborough and Sarasota Counties, sulfates have also increased. Overall, the ROMP wells have shown an increase in both sulfates and chlorides in the SWUCA in patterns consistent with the District's conclusions regarding movement of the interface.

341. The District has performed statistical analysis of data from individual wells to confirm that the trends demonstrated have not been the result of random error. In reaching its conclusions, the District has taken into account site-specific information regarding the influences on each well. The District's approach has been reviewed and approved by a number of statisticians, and no persuasive evidence was presented to refute the conclusions that the data demonstrated statistically significant trends.

342. The District has also examined data from hundreds of WUP wells that have been monitored by permittees as a condition of the permits. While the data is not as reliable as the ROMP well data, it is largely consistent with and confirms the trends evidenced by the ROMP wells.⁶⁷ The consistency of the WUP and ROMP wells' data is particularly notable in the lower production zone, where the proportion of increasing chloride trends has increased significantly in the last five years.

343. Not only are there a growing number of wells showing increased chloride trends, but median chloride values have also increased over time. In the upper production zone, the median chloride values have increased from 17 mg/liter (between 1977-1982) to 51 mg/liter (during 1989-1993). Median sulfate values in the upper production zone have increased from 73 mg/liter to 360 mg/liter over the same time periods.

344. Although saltwater intrusion is often considered a coastal phenomenon caused by coastal water withdrawals, in actuality the entire aquifer is underlain by water that is high in chlorides and sulfates. Therefore, the entire aquifer is potentially susceptible to saltwater intrusion with resulting adverse impacts upon potable water supplies due to a loss of pressure within the potentiometric surface. Wells along the coast generally show the first signs of adverse impact because of the increasing slope of the interface toward the coast. Whether a particular well is affected by saltwater intrusion is a function of its location and depth. It is not surprising that some wells have not yet been affected.

345. Inland wells are more likely to show increased saltwater intrusion the deeper they are drilled.

346. The District relies primarily upon its monitor well network and actual WUP data well to reach its conclusions on the vertical rate of saltwater interface migration. The District has also conducted solute transport modeling of saltwater interface movement calibrating the models with the best available data.

347. Solute transport modeling is very complicated, and the resulting predictions of future interface movement are based on assumptions regarding numerous interrelated variables. The District's modeling runs attempt to project the anticipated movement of the saltwater interface (1000 mg/1 isochlor line). The original runs were included in the ETB WRAP and were completed in March 1993. Although the modeling efforts confirmed the District's conclusions regarding the continuing movement of the saltwater interface, they are not the sole or primary evidence upon which the District relies to conclude that saltwater intrusion is occurring.

348. In sum, the District has sufficient data to document that saltwater intrusion is occurring in the SWUCA. The District continues to install water quality and water level monitoring wells and to perform additional modeling and surface water studies to augment its data base. Some of the District's efforts are reflected in the Supplemental Investigations Report.

349. Saltwater intrusion is a gradual process that ebbs and flows with pressure differentials. The best computer model simulations indicate that along the coast of the SWUCA, there has been one-to-two miles of saltwater intrusion into the UFAS from predevelopment times to the present.

350. Saltwater intrusion progressively reduces an aquifer's freshwater storage and supply capabilities. While at least one expert in this case suggested that saltwater intrusion permanently destroys fresh groundwater resources of the UFAS by causing irreversible degradation of water quality, the greater weight of the evidence indicates that if the head differentials are great enough, saltwater intrusion can be reversed and freshwater can replace saltwater in the aquifer. In that situation, there may be minimal loss of storativity and water quality in certain areas where water quality may not be as high as prior to intrusion because small pockets of saltwater may remain but the aquifer is not permanently lost.

351. Thus, if the potentiometric surface in the SWUCA returned to predevelopment levels, movement of the saltwater interface would reverse and progress toward the coast at approximately the same rate at which it has progressed inland. With a reverse interface movement, freshwater would gradually flush the aquifer and, given enough time, would return to the same quality that existed prior to seawater inundation. Of course, the hypothetical reversal assumes a total halt to groundwater pumping.

352. As long as groundwater is withdrawn from the region, the location of the saltwater transition zone will necessarily be landward of its pre-development location. The key question, then, becomes how much landward movement is acceptable. The decision is complicated by the diverse hydrogeology, the uncertainty of projecting future events which are influenced by numerous variables, and the socio-economic consequences of the decision.

4. Unified Basin Regulation

353. A fundamental premise of the District's entire SWUCA regulatory strategy is that the designated area should be regulated as a unified groundwater basin. Although several petitioners challenge the concept, the more persuasive evidence establishes that the Southern Basin of the UFAS essentially acts as a single hydrologic unit, especially with regard to saltwater intrusion, which is heavily influenced by cumulative stresses throughout the basin.

354. Within the Southern Basin, the UFAS is well-confined, highly transmissive, and has a relatively low storage coefficient, which means that a cone of depression caused by groundwater pumping generally propagates over a large area. While transmissivity values vary throughout the Southern Basin, the differences are not significant from a hydrogeological perspective.⁶⁸ Consequently, the Southern Basin tends to equilibrate from groundwater withdrawals within a matter of months. An analysis of well hydrographs in the SWUCA indicates that peaks and valleys generally occur during the same period. While an individual well may vary because of local conditions and/or local pumping, persuasive evidence was presented to support the District's view that there is a regional pattern.

355. While a particle of water moves very slowly throughout the Floridan Aquifer, pressure changes are translated much more quickly. In a confined aquifer like the Floridan, pressure changes significantly affect available water supplies and the direction of groundwater flow.

356. The flow of the UFAS in the Southern Basin is derived principally from rainfall recharge that occurs in the Green Swamp and Lake Wales Ridge area, located along the northern and eastern edges of the basin, respectively. Down-gradient of the recharge areas, groundwater gradually flows west and southwest toward and into the Gulf of Mexico, except in southern Hillsborough and western Manatee Counties, where groundwater pumping has modified the natural flow pattern.

357. The persistent flow lines currently found in the Southern Basin are fairly consistent with those in predevelopment times. Because the flow lines that formed the basis of the District's Southern Basin delineation have been persistent over the period for which maps are available, it is not anticipated that they will change by any significant degree.

358. Even though the flow lines may shift slightly due to climatic conditions and/or withdrawals, and there may be withdrawals outside the flow lines that affect the basin, the persistence of the flow lines indicates that in terms of potentiometric pressure, a more dominant impact results from withdrawals within the Southern Basin as opposed to without. While there are no absolute physical divides between the basins, there is no significant interrelationship between hydrological events occurring on the north and south sides of the basin boundaries.

359. The adverse impacts associated with saltwater intrusion along the ETB coast and lowered lake levels in the HR area are functions of the pressure within the aquifer system. The lowering of water levels in the Southern Basin can lead to a deterioration of water quality in vulnerable areas because of regional lowering of hydraulic heads throughout the interconnected aquifer system. Water level reductions ultimately lead to decreased pressure along coastal areas, which enables the upward movement of the saline waters that underlie the aquifer system. Similarly, when the potentiometric pressure decreases beneath lakes that are hydraulically well-connected to the UFAS, the downward movement of water accelerates, causing lake levels to drop. Monitor well hydrographs throughout the Southern Basin reflect short-term similarities between seasonal rainfall and water use patterns, which are characterized by depression in the spring and recovery in the fall. The amplitude of swings from season to season increases or decreases with the availability of rainfall.

360. Cumulative pumping stresses in the Southern Basin have caused many wells in the basin to show similar hydrograph patterns in terms of annual highs and lows. While all wells in the SWUCA do not reflect identical patterns, there is clear evidence that the entire system is interconnected. For example, the District's flow model study conducted within the ETB WRAP concluded that up to 40 percent of the declines in the potentiometric surface within ETB resulted from pumping in Polk, Hardee and DeSoto Counties.

361. The more persuasive evidence supports the District's decision to regulate the Southern Basin as one unified basin.

5. Boundaries of the SWUCA

362. Defining a boundary for an underground aquifer system such as the Southern Basin, where there are few geological impediments to lateral groundwater flow, is a somewhat amorphous proposition. In defining the SWUCA boundary, the District relied upon available data regarding persistent flow lines reflected by the potentiometric surface. This method is commonly employed by hydrogeologists when establishing a boundary for an underground aquifer system. While persistent flow lines are influenced by physical or geological characteristics, the pattern of groundwater withdrawals can affect the potentiometric surface and the direction of groundwater flow. Thus, it is inevitable that some uncertainty exists in the definition of a hydrologic boundary based upon persistent flow lines, especially when changes in use patterns can influence the location of groundwater divides. Although such unavoidable factors inject some imprecision into any attempt to regulate groundwater, the lack of precision is not a basis for abandoning all attempts at regulation.

363. While the District's delineation of the SWUCA as a separate regulatory area is premised upon its conclusion that the area operates as an identifiable groundwater basin, the District cannot realistically rely upon invisible, fluctuating hydrologic divides for regulatory purposes. Accordingly, in establishing the boundaries of the SWUCA, the District has relied upon natural and man-made surface features that approximate the location of the groundwater divide. In addition, the District continued and/or incorporated within the SWUCA previously identified regulatory boundaries. By using the boundaries established for the ETB and HR, the District hoped to circumscribe the areas of concern while utilizing boundaries that were already familiar to regulated users, District staff and the general public. The SWUCA boundaries are set forth in proposed Rule 40D-2.801(3)(b)1, F.A.C.

364. Several challenges were brought regarding the accuracy and appropriateness of the boundaries selected by the District for the SWUCA. Some Petitioners complained that the SWUCA boundaries were not sufficiently inclusive, while others claimed that the District's SWUCA delineation was too extensive and encompassed areas that do not contribute to the problems the District seeks to address. Among the SWUCA boundary issues raised are the following:⁶⁹

a. Areas Outside the Delineated SWUCA Boundary

365. The District's failure to include the entire Southern Basin within the SWUCA boundary has not been shown to be arbitrary or capricious or to otherwise render the rules invalid. With the exception of a relatively small area lying north of the SWUCA's northern boundary, the SWUCA boundary delineation includes virtually all of the Southern Basin that lies within the District's jurisdiction.

366. Some portions of the Southern Basin lie outside the jurisdiction of the District. Part of the northeast section of the Southern Basin lies within the regulatory jurisdiction of the St. John River Water Management District. Similarly, the South Florida Water Management District has permitting jurisdiction over portions of the southern and southeastern sections of the Southern Basin.

367. Ideally, the entire Southern Basin should be included in the SWUCA, but the District has no authority to regulate permitting outside its jurisdiction. Groundwater withdrawals in the areas outside the District's jurisdiction can affect the potentiometric surface of the UFAS in the SWUCA. Water management district's boundaries are largely based upon surface water rather than groundwater divides. Chapter 373 does not provide guidance for solving jurisdictional obstacles to the comprehensive regulation of groundwater. No agreement has been reached with regard to water use permitting in the areas of the Southern Basin that lie outside the District's authority. The District has communicated the results of its studies to the South Florida Water Management District.

368. The proposed SWUCA Rules contain no mechanism by which the District could adjust for effects of new or increased withdrawals from areas outside the SWUCA boundaries that are not subject to the same regulatory sanctions or stringent conservation measures as areas within the SWUCA. Considerable development activity has occurred in areas immediately adjacent to certain portions in the SWUCA. Petitioners have expressed concern that the proximity of some of these "external" development projects increases the possibility that water withdrawals from outside the SWUCA could adversely impact the SWUCA's potentiometric levels and thereby preclude the issuance of new permits in the SWUCA.⁷⁰ It is not clear from the record in this proceeding whether any external project realistically poses a threat to the water resources of the SWUCA. Because the flow lines of the Southern Basin have persisted over an extended period of time, it is highly unlikely that the effects of withdrawals outside the SWUCA could preclude the issuance of new permits within the designated area.

369. The foregoing issues highlight the need for comprehensive water use regulation that is coordinated among all permitting agencies. However, the limitations of the existing statutory framework do not invalidate the District's attempt to regulate the use of water within the area subject to its jurisdiction.

b. Northern Boundary of the SWUCA

370. For the northern boundary of the SWUCA, the District has chosen State Road 60 in Hillsborough County, eastbound to its intersection with Countyline Road along the divide between Hillsborough and Polk Counties. The boundary then continues north along Countyline Road until it intersects Interstate Highway No. 4 ("I-4"). Because the actual hydrologic boundary of the Southern Basin more closely approximates the I-4 corridor that extends through Hillsborough County in a southwesterly direction, there is a triangular area north of State Road 60 in Hillsborough County - referred to during the hearing as the "Hillsborough Triangle" - that is located within the Southern Basin but not within the SWUCA. The area's exclusion from the SWUCA has been challenged by several parties.

371. State Road 60 was also one of the boundaries established for the ETB WUCA.⁷¹ During the rulemaking process, the District considered using the I-4 corridor as the northern boundary for the SWUCA. After considering objections from user groups in the area, the District decided to use State Road 60 as the northern boundary of the SWUCA.

372. The northern boundary of the Southern Basin is located in a transition area from the well-confined UFAS to the south to a poorly or semi-confined aquifer system to the north. Along the transition area, the Intermediate Aquifer narrows significantly and flow lines shift seasonally. While there are hydrologic justifications to support using I-4 as the northern boundary of the SWUCA, the District's determination to use State Road 60 has not been shown to be arbitrary or capricious.

373. Most of the Hillsborough Triangle is currently regulated under the District's NTB WUCA rules, which the District asserts will provide protections similar to those contained in the proposed SWUCA Rules. There is extensive groundwater use by strawberry growers in the Hillsborough Triangle. By utilizing State Road 60 as the SWUCA's northern boundary (and thereby excluding the Hillsborough Triangle), the District ensures that this principal user group will be regulated consistently under one set of rules. The District claims that it expended considerable effort to educate the strawberry growers during the NTB WUCA rule development process and that the area can be further addressed (if necessary) in conjunction with the District's upcoming review of the NTB WUCA. The District does not believe that the Hillsborough Triangle will be a future growth area in terms of new uses.

374. In sum, regulatory considerations rather than hydrologic factors led the District to select State Road 60 rather than I-4 for the northern boundary of the SWUCA. While it makes sense from a hydrological standpoint to include the Hillsborough Triangle in the SWUCA -- as recommended by some District staff personnel -- the District Governing Board ultimately concluded that it was more important to consistently regulate a major user group under the same rules, especially since it theoretically has additional statutory authority to prohibit or restrict new or existing uses on a case-by-case basis. See e.g., Sections 373.119, .175, .223 and .246, F.S. This decision was not without thought or reason and has not been shown to be arbitrary, capricious or otherwise invalid.

375. Some Petitioners suggested that the District's exclusion of the Hillsborough Triangle from the SWUCA was intended to and/or will result in facilitating the development of a wellfield on the Cone Ranch -- a 12,600-acre tract of land purchased by West Coast for purposes of developing a major regional wellfield. Lying in the northeast corner of Hillsborough County, just west of the Polk-Hillsborough line and north of State Road 60, the Cone Ranch is not a part of the SWUCA, nor is it within any other water use caution area at this time. The Cone Ranch has been considered a potential major new source of water for West Coast. The District's January 1992 Needs and Sources Report recognized Cone Ranch as part of a projected regional wellfield system to meet water demands in that area of the District.⁷² No persuasive evidence supports Petitioners' claim that the District's decision to exclude the Hillsborough Triangle from the SWUCA was related to the Cone Ranch. The development of any new major wellfield will have to comply with District rules in existence at the time of application.

c. Inclusion of Areas Outside the Basin

376. Along the eastern boundary of the SWUCA, the District has included some areas that lie outside the Southern Basin. Because withdrawals in the subject areas could affect the stressed lakes nearby, the District's decision to include them within the SWUCA is reasonable.

377. There is an area in northern Polk County, however, that also lies outside the Southern Basin, but is not in the vicinity of any stressed lakes. Referred to during the hearing as the "Polk County Nub," the area is included in the SWUCA because it is not currently subject to the rules of any water use caution area. The District contends that withdrawals in the Polk County Nub could extend beyond the boundaries of the groundwater divide and affect the SWUCA. There is no evidence, however, that withdrawals in the area have contributed to any of the existing SWUCA problems and, absent an extremely large withdrawal or a change in existing conditions, future withdrawals from the area will have a negligible impact on the SWUCA. While the District should monitor future withdrawal requests from the Polk County Nub, there is no reasonable basis for precluding future withdrawals in the area until the minimum aquifer levels in the SWUCA have been achieved. Accordingly, the District's decision to include the Polk County Nub in the SWUCA was arbitrary.

d. Eastern Tampa Bay and Highlands Ridge

378. The SWUCA Rules utilize the boundaries of the ETB and HR WUCAs but only for purposes of implementing and monitoring the SWUCA minimum aquifer level. (The District's methodology that uses the ETB and HR areas for purposes of assessing the status of the minimum aquifer level in the SWUCA is discussed in more detail below.) In all other respects, the areas will be regulated in a manner consistent with the remainder of the SWUCA.

379. The existing ETB Rules -- which preclude any withdrawals that would cause a drawdown of more than two tenths of a foot in an area designated as the "most impacted area" (the "MIA"), where the impacts of saltwater intrusion have been most heavily felt -- will be withdrawn. It has been suggested that the withdrawal of this protection, which extends to withdrawals outside the SWUCA, could actually exacerbate saltwater intrusion. The District claims that any withdrawals outside of the SWUCA which would have a measurable impact upon the MIA can be regulated under the District's existing rules. See, Rule 40-2.301(1)(h). The District's decision in this regard has not been shown to be arbitrary, capricious or otherwise invalid.

6. Minimum Aquifer Level for the SWUCA

380. The SWUCA Rules represent the District's first attempt to establish a minimum level for a groundwater aquifer on a regional basis. The effort is embodied in proposed Rule 40D-8.628(1) which provides: