Development and implementation of water resource development projects that will restore historically lost lake and floodplain storage to aid in reestablishing minimum

flows to rivers and enhance recharge. The District is focusing on a number of ways to increase wet-weather storage in the upper Peace River watershed. These include raising structures on lakes, restoring old mined lands and wetland systems that have been drained, and storing excess wet season river flow in abandoned waste clay settling ponds. Water stored could be released to augment flow of the river and its tributaries during low-flow periods. The District has estimated that currently identified restoration projects could provide as much as 50 mgd (about 75 cfs) of additional flow to the upper Peace River during a 90-day low-flow period.

6. Resource monitoring, reporting and cumulative impact analysis. As the major

elements of the Recovery Strategy described above are implemented, the District will continuously monitor trends in resource conditions and permitted and actual water use. Elements of this monitoring program will include aquifer levels, lake levels and streamflows, permitted quantities and actual water use, changes in use types and relocations, and surface and groundwater quality. Recovery Strategy elements may be modified in the future in response to these resource trends. The monitoring will specifically include the movement of saltwater intrusion in the upper Floridan aquifer. The District will make available its various preventative and remedial programs to permittees potentially at risk of saltwater intrusion, including well backplugging, alternative supplies development and conservation and best management practices implementation, including the FARMS program.

The Recovery Strategy will be reevaluated at a minimum of once every five years as the Regional Water Supply Plan and District Water Management Plan are updated. The District will conduct an annual assessment of water resource criteria and cumulative impacts and review the Recovery Strategy at least every five years prior to 2025. Based on the annual assessment or five-year review, the District may revise the Recovery Strategy as appropriate. If the annual assessments or five-year reviews do not indicate sufficient progress to meet the Recovery Strategy goal of achieving the minimum levels for the Ridge lakes by 2025, the minimum flow for the upper Peace River by 2025, and the saltwater intrusion minimum aquifer level (SWIMAL) by 2025, the Governing Board will revise the Recovery Strategy, as

appropriate, to achieve these goals. This adaptive management approach will ensure that the recovery elements are tailored to achieve the principles established by the Governing Board.

Cumulative Impact Analysis

A major component of the resource monitoring and reporting process will involve the cumulative impact analysis. The purpose of the proposed cumulative impact analysis is to integrate the District’s comprehensive monitoring program into future Governing Board decision-making regarding recovery in the SWUCA. The cumulative impact analysis will evaluate all changes in permitted and used groundwater quantities and water resource

development projects benefiting the upper Floridan aquifer in and around the MIA that have taken place since January 1, 2000. The cumulative impact analysis will take into account the positive effects of reduced groundwater withdrawals and the reduced impacts associated with these withdrawals, the positive effects of water resource development projects that benefit groundwater levels in and around the MIA, as well as the negative effects of new groundwater withdrawals.

As stated in Section 5, in order to achieve the SWIMAL, it is estimated that groundwater pumpage must be reduced by up to 50 mgd. This has been expressed as “up to 50 mgd” because if groundwater withdrawals were optimally distributed throughout the SWUCA, withdrawals could be reduced by less than this amount to achieve the minimum aquifer level. However, for purposes of the cumulative impact analysis, this 50 mgd reduction (e.g., a worst-case scenario) will be used. This 50 mgd reduction is associated with a 0.7-foot decrease in impacts from withdrawals on the aquifer levels in the MIA. The 0.7-foot decrease in impacts also represents the worst-case difference between actual levels and the proposed minimum aquifer level when expressed as the 10-year moving average of levels in the aquifer that existed in the period between 1990 and 1999.

The reduction in impacts from groundwater withdrawals on the minimum aquifer level can also be expressed as an annual amount of recovery. To achieve a reduction in impacts of 0.7-foot by the year 2025, an annual reduction of 0.028-foot (0.7 divided by 25) in impacts must be achieved. Given the volatility of the actual aquifer level, a long-term moving average provides a more practical measure of progress in the field. This can also be

expressed as a 2 mgd annual reduction in withdrawals impacting the minimum level (50 mgd divided by 25). Figure 4-1 shows this reduction in withdrawals over the 25-year recovery period.

However, to achieve a net reduction of 50 mgd in groundwater withdrawals by 2025, the challenge is even greater. There are certain water use types in the SWUCA that have

permitted groundwater quantities greater than the actual use. Recent trends and projections for these use types indicate that actual use will eventually grow into these permitted amounts. These use types primarily include public supply and power generation. There are other use types, particularly agriculture, where permitted groundwater quantities are also greater than actual use. However, trends indicate that actual use is not growing into the permitted quantities. In fact, just the opposite is true, whereby actual and permitted quantities are decreasing.

In order to achieve a net reduction of 50 mgd in groundwater withdrawals by 2025, this anticipated growth into permitted but unused groundwater quantities must also be offset by reductions in other uses. It is estimated that this growth into permitted but unused

quantities represents an additional groundwater amount of 25 mgd. So, the total reduction necessary, in order to achieve a net reduction of 50 mgd in groundwater withdrawals, is 75 mgd, or 3 mgd per year. This required reduction in groundwater withdrawals is depicted in Figure 4-2.

Under the cumulative impact analysis, these reductions in groundwater withdrawals and the associated reductions in impacts on the SWIMAL required to achieve recovery by 2025 will be compared to the actual reductions that have been achieved. The District will monitor reductions in withdrawals associated with such activities as reuse project offsets, savings achieved through reductions in irrigated citrus acreage, savings achieved through the District’s FARMS program, and savings attributable to reductions in phosphate mining activities. Actual savings in each of these categories have been estimated through the year 2002 and are depicted in Figure 4-3. The cumulative impact analysis would also take into account improvements in groundwater levels attributable to any water resource development projects that benefit actual groundwater levels, such as aquifer recharge projects. Under cumulative impact analysis, as long as the actual savings achieved are equal to or greater than those necessary for recovery and to offset growth into permitted but unused quantities, it is anticipated the SWIMAL will be achieved and the Governing Board may rely on these existing mechanisms.

Cumulative Impact Analysis – An Example

Figure 4-4 illustrates cumulative impact analysis for a hypothetical situation involving reductions in withdrawals and a water resource development project, both lessening impacts on the minimum aquifer level, and a request for a new groundwater withdrawal increasing impacts on the MIA. In this example, subsequent to January 1, 2000 a 5 mgd reduction in withdrawals in southwestern Polk County is attributable to conservation implemented by the permittee and results in an improvement in the minimum aquifer level of 0.20-foot. In addition, an aquifer recharge project is implemented in western Hardee County, resulting in an improvement in groundwater levels of 0.10-foot. Finally, there is a reduction in

groundwater withdrawals in western Manatee County caused by a land-use transition, resulting in an improvement in groundwater levels of 0.10-foot. This results in a total improvement in groundwater levels of 0.40-foot (0.20 + 0.10 + 0.10 = 0.40).

Assuming we are in the fifth year (2004) of the recovery period, we know that the 0.7-foot reduction in impacts by the year 2025 represents an annualized reduction of 0.028-foot in impacts, for a total reduction of 0.14-foot in impacts by 2005 (5 x 0.028). In addition, we know that growth into permitted but unused groundwater quantities also represents an additional withdrawal of 5 mgd, and in this example the evaluation of these increased withdrawals indicates an additional impact on the aquifer of 0.10-foot. The amount of positive benefit associated with reductions in withdrawals (0.40-foot) exceeds that which is required for both recovery and growth into unused quantities (0.14 + 0.10 = 0.24-foot required). In this example, recovery is being achieved consistent with this Recovery Strategy and the staff would recommend to the Board no modifications to the strategy are necessary. If the cumulative impact analysis indicates that actual reductions in withdrawals (as measured through modeling and in the field) are not sufficient for recovery, growth into permitted groundwater quantities, and to accommodate a request for new groundwater withdrawals, then the District would need to revisit the strategy, resulting in additional rule making, projects or financial incentives, or some combination thereof, designed to achieve recovery.

The above example is a very simplified scenario, but serves to demonstrate how the

cumulative impact analysis will be implemented. The example also makes it abundantly clear that a comprehensive monitoring program is essential to the cumulative impact analysis. The District is continuously enhancing its monitoring capabilities. A recent significant improvement is referred to as the Water Use Tracking system, designed specifically to support the SWUCA cumulative impact analysis. The Water Use Tracking system was substantially completed in 2005, but refinements will continue over time, including making much of the information available to interested parties on an as-needed basis for their decision-making.

Figure 4-1.

Reductions in

withdrawals required for recovery.

Figure 4-2.

Reductions in

withdrawals required for recovery and growth into permitted quantities.

Figure 4-3.

Reductions in

withdrawals required for recovery and growth into permitted quantities; reduced quantities associated with reuse and conservation.

¯

0 10 Miles

ETB MAL Wells MIA

Conservation 5 mgd Land Use Change

2 mgd Aquifer Recharge 2 mgd MFL Recovery = 0.7 ft at 2025 MFL Recovery = 0.028 ft/yr Conservation = 0.20 ft Recharge = 0.10 ft Land Change = 0.10 ft Total Increase = 0.40 ft

Growth into Permits = 0.10 ft Year 5 Recovery = 0.14 ft Polk Hardee DeSoto Manatee Sarasota Charlotte Highlands Hillsborough Figure 4-4. Cumulative impact analysis – a hypothetical example.