Introduction
Regional water supply planning is critical to ensuring effective water management. This is especially true when significant resource and supply concerns exist. In such cases, Florida law (F.S. 373.0421) requires a recovery or prevention strategy to be expeditiously developed as part of the regional water supply planning process if the existing flow or level in a water body is below, or is projected to fall within 20 years below, the applicable minimum flow or level established. The recovery or prevention strategy must include the development of additional water supplies and other actions, consistent with the authority granted by this chapter to: (a) achieve recovery to the established minimum flow or level as soon as practicable; or (b) prevent the existing flow or level from falling below the established minimum flow or level. The recovery strategy must also include phasing or a timetable which will allow for the provision of sufficient water supplies for all existing and projected reasonable- beneficial uses, including development of additional water supplies and implementation of conservation and other efficiency measures concurrent with, to the extent practical, and to offset, reductions in permitted withdrawals, consistent with the provisions of this chapter.
Existing flows and levels are below nearly all the minimum flows and levels currently being proposed in the SWUCA. Appropriately, the Governing Board has directed staff to develop this recovery strategy, the foundation of which is a regional water supply planning effort that demonstrates that minimum flows and levels will be restored as soon as practicable and that adequate water supplies will be available for all existing and projected reasonable and
beneficial uses for a planning horizon of at least 20 years. This planning effort is described below and estimates additional water use needs, including reductions in groundwater withdrawals needed for environmental restoration. The recovery strategy also identifies potential water sources and demand management measures needed to ensure sufficient supplies through 2025.
Regional Water Supply Planning Component of the SWUCA Recovery Strategy
There are two major elements of a regional water supply plan. The first is the identification of future water needs and includes any reduction in withdrawals needed for environmental restoration. The second is identifying sufficient traditional and alternative sources, as well as additional savings through conservation efforts, to meet all existing and projected reasonable and beneficial water uses. Other actions such as plugging wells that waste ground water by allowing it to flow away freely at land surface, artificially recharging an aquifer, or retiring water use permits associated with acquired preservation lands can contribute to addressing water needs of a region.
For several decades, the District has conducted long-term water supply planning. Several of the most prominent efforts include the Four River Basins Study published March 1977, the Water Supply Needs and Sources 1990–2020 published January 1992, and the Regional Water Supply Plan published August 2001, which is currently being updated. These reports have been instrumental in advancing the use of alternative supplies and demand
Much of the information included in this recovery strategy is derived from the District’s unpublished internal review draft of the 2006 Regional Water Supply Plan. The recovery strategy includes projections for both average annual conditions and drought conditions that are expected to occur 1 out of every 10 years.
Reductions Needed to Achieve the Proposed Saltwater Intrusion Minimum Aquifer Levels — Over the past 20 years, the long-term average annual ground-water withdrawals in the SWUCA have been about 650 mgd, of which nearly 90 percent are from the Floridan aquifer. Based on the existing distribution of withdrawals, it is estimated that long-term average annual withdrawals from the Floridan aquifer need to be reduced by 50 mgd to ensure the saltwater intrusion minimum aquifer level is met. If withdrawals were more optimally distributed (i.e., declines in the most impacted areas and increases in the least impacted areas) a reduction of significantly less than 50 mgd would be required. As
previously discussed, minimum flows for the upper Peace River and minimum levels for the Ridge area lakes will be primarily achieved through water resource restoration projects. However, a reduction of up to 50 mgd in withdrawals from the Floridan aquifer will enhance restoration efforts for the upper Peace River and the eight minimum level Ridge area priority lakes.
Public Supply – Changes in Water Use 2000 to 2025 — Public supply water use is
anticipated to account for the majority of increases in water use through 2025. Table 5-1 summarizes public supply demand projections for each of the counties in the SWUCA. Projections are that an additional 105.2 and 111.8 mgd will be required during average annual and drought conditions, respectively (note, public supply includes domestic self- supply and individual irrigation wells in Table 5-1). The largest increases are expected in Polk, Sarasota, Hillsborough, Manatee and Charlotte counties where increases during drought conditions are anticipated to increase by 22.1, 22.7, 23.1, 20.0 and 10.3 mgd,
respectively. As further evidence of the growth trends in public supply demands, Figure 5-1 illustrates the growth in urban land use from 1990 to 2004, a period when over 128,000 acres were converted to urban land uses.
Agriculture – Changes in Water Use 2000 to 2025 — Agricultural water use is expected
to decline in many areas of the SWUCA over the next several decades, as shown in Table 5- 2. During the past half century, agricultural water use has substantially increased and has become the dominant water use, particularly in the SWUCA. In 2000, a period of record drought, estimated ground water withdrawn in the SWUCA was 836 mgd, of which 581 mgd, or 69 percent, was for agricultural irrigation. In recent years, however, there have been several developments that have adversely impacted or displaced agricultural operations in the area. These include expansion of urban areas; full implementation of the North American Free Trade Agreement (NAFTA) and other global competition issues, more stringent regulations, and destructive insect and disease outbreaks.
Figure 5-2a displays the change in agricultural land use in the SWUCA between 1990 and 1999 and shows that agricultural acreage is declining in areas where urban expansion is occurring. Although there are increases in the more rural areas, examples of land use transitions from agriculture to residential/urban abound, such as in two specific areas in Manatee and Polk counties that were more closely examined. In the 1991–2002 time period, 41,063 acres of agricultural lands were rezoned for residential/commercial development in Manatee County. This is over 9 percent of the county’s total land area. The estimated water
historically permitted for the rezoned agricultural land is nearly the same as the estimated demand for the projected new development on this land. Another example is in the Polk County Northeast Regional Utilities Service Area. From 1995 to present, 4,616 acres of citrus are in transition to residential/urban. This citrus acreage represents nearly 5 mgd of water use. These reductions are also evident in industry reports. For example, in their 1996–97 Citrus Summary Report, the Florida Agricultural Statistics Service (FASS) reported that at the end of 1995 the total citrus acreage in Charlotte, DeSoto, Hardee, Highlands, Hillsborough, Manatee, Polk and Sarasota counties was 375,263 acres. In 2002, FASS reported total acreage had declined to 371,250 acres, a reduction of 4,013 acres.
Additionally, in April 2000, FASS published its most recent Vegetable Summary Report that showed that tomato acreage in the Palmetto-Ruskin growing area, where most of the tomatoes are grown in the SWUCA, decreased from 15,150 acres in the fall of 1994 and spring of 1995 to 13,125 acres in the fall of 1998 and spring of 1999. As further evidence of the declining trends in agricultural activities and associated water use, Figure 5-2b displays the change in agricultural land use in the SWUCA between 1990 and 1999 with proposed land acquisitions and conservation lands.
Phosphate Mining and Processing, Other Industrial and Power Generation Use –
Changes in Water Use 2000 to 2025 — Groundwater use for mining and processing of
phosphate ore in the SWUCA is expected to remain stable, if not decline over the next several decades, then eventually cease as economically extractable ore deposits are depleted. Groundwater use for phosphate mining and production peaked in the 1970s, but has since dramatically declined as the industry began to recycle water. Average daily use of ground water associated with mining and processing of phosphate ore in the SWUCA has declined from over 300 mgd in the mid-1970s to less than 75 mgd in recent years. Figure 5-3 displays the change in mined areas in the SWUCA between 1990 and 1999 and shows that mining is moving south at a rate of about 5,000 acres per year. Overall water use for other industrial uses and power generation is projected to remain stable or increase in the SWUCA through 2025. Projections indicate that there will be combined effect of a 6.7 mgd increase through the planning period (mostly for power generation), with other components of this use sector experiencing a decrease of 7.0 mgd (mostly in the mining sector).
Recreational and Aesthetic Use – Changes in Water Use 2000 to 2025 — Water use for
recreational and aesthetic uses is projected to increase in the SWUCA through 2025. An anticipated increase of 19.6 and 25.3 mgd is projected during average and drought conditions. Much of this increase is for golf course irrigation and should be able to be supplied by reclaimed water, captured stormwater and other alternatives to Floridan aquifer withdrawals.
Table 5-2 is a summary of projected water use changes for all categories in the SWUCA from 2000 through 2025 during average and drought conditions experienced once every 10 years. The table indicates both increases and decreases that are projected to occur in each major use type. Both increases and decreases are shown in this table because these changes in water use may occur at different points in time throughout the planning period and in different locations, such that it would be inappropriate to assume decreases or increases in one area at one point in time will be equally offset by changes in other areas at other times. The total additional need for water is estimated to be 181.7 and 193.7 mgd during average and drought conditions, respectively. Over half of this need is for public supply (average annual of 98.0 mgd and drought of 103.9 mgd). Environmental restoration accounts for
over half of the remaining increase (up to 50 mgd). The following is a discussion on how these projected increases can be met.
Potential Sources of Supply for Anticipated Water Needs for the Period 2000 through 2025 — As stated above, most of the projected water use increases in the SWUCA are for public supply. Fortunately, alternative supplies and additional demand management can meet most of these increases. In areas where utilities have limited opportunities to develop alternative supplies, significant quantities needed for growth are anticipated to be met as urban areas expand and use some of the ground water permitted to the land use they have displaced. Potential sources to meet growth in public supply water use are best evaluated by examining individual counties or water supply authority areas. The following is a discussion of the projected public supply water needs and potential supplies for the four counties that comprise the Peace River/Manasota Regional Water Supply Authority. Hardee, Highlands, Hillsborough and Polk counties are presented separately. Table 5-3 is a summary of additional public supply water needs and potential sources from 2000 to 2025 during both average and drought conditions for Charlotte, DeSoto, Manatee and Sarasota counties (the counties that comprise the Peace River/Manasota Regional Water Supply Authority). As listed, 55.0 and 58.3 mgd of additional demands are anticipated by 2025 under average and drought conditions. Potential supplies to meet additional demands include the use of permitted but unused surface water and non-Floridan aquifer supplies not currently being used in the amount of 32.4 and 1.6 mgd, respectively, during average
conditions. Details of how these quantities were derived are included in Appendix 4. These sources total 34 and 35 mgd under average and drought conditions, respectively. This leaves a remaining deficit (projected needs exceeding these sources) of 21 and 23.3 mgd. Reducing water use through conservation efforts could reduce projected demands by an estimated 22.3 mgd. Currently, average per capita rates for the four-county region in an average year are estimated to be about 125 gallons per day. Per capita rates are calculated generally by dividing pumpage by the population served. Per capita rates vary throughout the SWUCA due to variations in the characteristics of utility customer bases and differences in the conservation and reclaimed water programs implemented by utilities.
Other potential supplies include the use of additional reclaimed water. It is estimated reclaimed water could offset additional needs in the amount of 23.7 mgd. The four-county region’s increase in public supply demands through 2025 under both average and drought hydrologic conditions are more than offset through the combination of increased surface water, non-Floridan ground water, enhanced conservation and use of reclaimed water. Table 5-4 is a summary of additional public supply water needs and potential sources from 2000 to 2025 during average and drought conditions for the portion of Hillsborough County in the SWUCA. As listed, 23.1 and 24.5 mgd of additional demands are anticipated by 2025 under average and drought conditions, respectively. Potential supplies to meet these needs include the use of permitted but unused surface water and Floridan aquifer groundwater supplies not currently being used (Appendix 4). This includes approximately 4.3 mgd of the 17 mgd set aside for growth that is part of the 85 mgd of alternative supplies developed as part of the Partnership Agreement. These sources total 5.3 and 5.5 mgd under average and drought conditions, respectively. This leaves a deficit (projected needs exceeding these sources) of 17.8 and 19 mgd. Water demand projections could be reduced by about 5.6 mgd through enhanced conservation efforts. Currently, countywide per capita rates in an average
year are estimated to be about 138 gallons per day. Reclaimed water could also offset an additional 4.2 mgd. The additional estimated 8.0 and 9.2 mgd needed under average and drought conditions could be provided by development of additional alternative supplies, more aggressive conservation efforts, the transition of agricultural lands and water uses to public supply or any of the Net Benefit options discussed in Section 8.
Table 5-5 is a summary of additional public supply water needs and potential sources from 2000 to 2025 for the portion of Polk County in the SWUCA. As listed, 22.1 and 23.5 mgd of additional demands are anticipated by 2025 under average and drought conditions, respectively. Potential supplies include the use of Floridan aquifer water that is currently permitted but not being used (Appendix 4). This leaves a deficit (projected needs exceeding sources) of 2.6 mgd under average conditions and a surplus of 0.2 mgd under drought conditions. Water demand projections could be reduced by about 11.8 mgd through
enhanced conservation efforts. Currently, countywide per capita rates in an average year are estimated to be about 147 gallons per day. Reclaimed water could offset an additional 5.9 mgd. Cumulatively, the growing public supply needs in Polk County can be more than offset by these various sources of water. In addition, the transition of agricultural land uses to residential and other forms of development will allow for the conversion of ground water historically used for agriculture to help meet needs where the sources in those specific situations where the sources listed above are not adequate.
Table 5-6 is a summary of additional public supply water needs and potential sources from 2000 to 2025 for the portion of Highlands County in the SWUCA. As listed, 4.6 and 4.9 mgd of additional demands are anticipated by 2025 under average and drought conditions, respectively. Potential supplies include the use of Floridan aquifer water that is currently permitted but not being used (Appendix 4). This leaves a deficit (projected needs exceeding sources) of 1.3 and 1.0 mgd. Water demand projections could be reduced by about 2.1 mgd through enhanced conservation efforts. Currently, countywide per capita rates in an average year are estimated to be about 142 gallons per day. Reclaimed water could offset an
additional 1.7 mgd. Cumulatively, the growing public supply needs in Highlands County can be more than offset by these various sources of water. In addition, the transition of
agricultural land uses to residential and other forms of development will allow for the conversion of ground water historically used for agriculture to help meet needs where the sources in those specific situations where the sources listed above are not adequate.
Table 5-7 is a summary of additional public supply water needs and potential sources from 2000 to 2025 for Hardee County. As listed, approximately 0.6 mgd of additional demand is anticipated by 2025 under both average and drought conditions. Potential supplies include the use of Floridan aquifer water that is currently permitted but not being used (Appendix 4). This leaves a deficit (projected needs exceeding sources) of 0.4 and 0.3 mgd. Water demand projections could be reduced by about 0.2 mgd under both average and drought conditions through enhanced conservation efforts. Reclaimed water could offset an
additional 0.7 mgd. Cumulatively, the growing public supply needs in Hardee County can be more than offset by these various sources of water. In addition, the transition of agricultural land uses to residential and other forms of development will allow for the conversion of ground water historically used for agriculture to help meet needs where the sources in those specific situations where the sources listed above are not adequate.
In addition to potential supplies and demand management measures discussed above, there are a broad array of other potential conservation initiatives, alternative supplies, water resource development projects, Net Benefit efforts and resource restoration options available to meet future environmental and growth needs. Table 5-8 summarizes these options, as well as future projected needs and potential options described above.
As shown in Table 5-8, for the time period 2000 to 2025, up to 181.7 mgd under average conditions and 193.7 mgd under drought conditions of additional supply and aquifer reductions are needed to ensure the saltwater intrusion minimum aquifer level is met and sufficient supplies are available for projected increases in water use. As discussed above, potential options to meet these needs include existing permitted but not fully used public supply surface water, Floridan aquifer ground water and other groundwater sources, savings from public supply conservation efforts, and reclaimed water offsets. Other potential supplies include conservation efforts by water users other than public supply, including all future projects to implement best management practices for agriculture, other alternative potable supplies under construction or design, turnover in water use as changes in land use occur, availability of groundwater quantities to meet needs when lands are acquired for conservation purposes, and further use of shallow aquifers. Each of these potential supplies is discussed further below, and together can provide between 325.6 to 353.2 mgd to more than offset the 181.7 to 193.7 mgd of future demands under average and drought conditions, respectively. Additional potential sources, demand management and resource restoration,