St. Lucie and Indian River Counties Water Resources Study Final Summary Report November 2009 Prepared for: South Florida Water Management District St. Johns River Water Management District St Lucie and Indian River Counties Water Resource Study St Lucie and Indian River Counties Water Resources Study Executive Summary Study Purpose The purpose of this study was to evaluate the potential for capturing excess water that is currently being discharged to the Indian River Lagoon in northern St. Lucie County and southern Indian River County and making it available for beneficial uses. The study also evaluated the reconnection of the C-25 Basin in the South Florida Water Management District (SFWMD) and C-52 in the St. Johns River Water Management District (SJRWMD) so that available water supplies could be conveyed to meet demands across jurisdictional boundaries. The study objectives were to: Identify the quantity and timing of water available for diversion and storage; Identify water quality information needed to size water quality improvement facilities; Identify and provide cost estimates for the improvements and modifications to the existing conveyance systems necessary for excess runoff diversion and storage; Identify, develop cost estimates, and evaluate conceptual alternatives for storing excess runoff, and Provide conceptual designs and cost estimates for the highest ranked alternative in support of feasibility analysis and a future Basis of Design Report. Study Process The study process consisted of the following activities: Data compilation and analysis, Identification of alternative plans, Evaluation of alternative plans, Identification of the preferred plan, and Development of an implementation strategy. St Lucie and Indian River Counties Water Resource Study Formal stakeholder meetings were conducted throughout the study. Stakeholder input was also obtained through smaller informal meetings, site visits, phone calls. Data Compilation and Analysis Through a literature review, thirteen projects and studies that are related to the issues addressed in this study were identified and evaluated. Three of the projects were found to have substantial impacts on the assumptions used for this study. Key findings are summarized below: The Indian River Lagoon – South (IRL-S) Project is a component of the Comprehensive Everglades Restoration Plan (CERP). The plan includes storage reservoirs and stormwater treatment areas (STAs) in the C-23, C-24, and C-25 Basins designed to attenuate stormwater discharges that disrupt natural salinity regimes in the St. Lucie Estuary and Indian River Lagoon. Land acquisition has been completed and design is underway for the IRL-S Project features in the C-23 and C-24 Basins. For analysis of certain alternatives in this study, it was assumed that the C-23/24 North and South Reservoirs and STA included in the IRL-S Project will be in place. There has been no land acquisition or detailed design work initiated for the C-25 reservoir and STA component of the IRL-S Project. The North Fork of the St. Lucie River Water Reservation was required by the federal Water Resources Development Act (WRDA) of 2000 as a condition for signing an agreement to receive federal CERP funding for the Indian River Lagoon – South Project. The water reservation is a legal mechanism to set aside water for the protection of fish and wildlife or public health and safety. When a water reservation is in place, volumes and timing of water at specific locations are protected for the natural system ahead of consumptive uses such as new development. Water withdrawals evaluated for this study were limited to avoid violation of the water reservation. The Upper St. Johns River Basin (USJRB) Project is located in the northern portion of the study area. With the development of an inter-district hydraulic connection, flows from the SFWMD to the SJRWMD would have to pass through C-52 and Blue Cypress Water Management Area (BCWMA), components of the USJRB Project. A number of constraints on flows to and from the BCWMA are necessary to maintain flood control and protect natural resources, including listed species. Drainage basins were delineated and the physical and operational characteristics of the water management systems in the study area were identified. The schematic shown in Figure 8 represents the four independent water management systems in the study area: Upper St. Johns River Basin Project, Indian River Farms Water Control District, Ft. Pierce Farms Water Control District, and the C-23, C-24, and ii Summary Report C-25 Basins. Except for the USJRB Project, all other water management systems discharge excess stormwater runoff to Indian River Lagoon. Large volumes of water are discharged to the Indian River Lagoon from the study area. The median annual discharges to IRL from the C-23, C-24, and C-25 Basin are each about 130,000 acre-ft. The Indian River Farms Water Control District’s Main, South, and North Canals collectively discharge a median annual volume of just over 100,000 acre-ft. These flows are relatively flashy – there are extended periods with little or no flow with short periods of very high flows. The Florida Department of Environmental Protection has listed numerous water bodies in the study area as impaired under Section 303(d) of the Clean Water Act. This indicates that the water quality does not meet applicable standards. Impairments are based on the following parameters: dissolved oxygen, fecal coliforms, nutrients, and mercury. The study guideline with respect to water quality was to avoid inter-basin transfers of water that would degrade the quality of the receiving water or cause a violation of a water quality standard. Total phosphorus was used to assess the need for water quality treatment to meet this guidline. The following table shows the median total phosphorus concentrations for the main water bodies in the study area: Median Total Phosphorus concentration (mg/l) Basin 1 (Ft. Pierce Farms 0.178 Water Control District C-23 0.338 C-24 0.261 C-25 0.158 Total phosphorus data for the Indian River Farms Water Control District was only available for 2006. For that period, total phosphorus concentrations ranged between 0.064 and 0.120 mg/l. The SJRWMD standard for total phosphorus concentrations in the Upper St. Johns River Basin Project is 0.080 mg/l. As a result, any discharges from the SFWMD northward into the Upper St. Johns River Basin Project would require treatment to avoid degradation. Identification of Alternative Plans Preliminary alternatives were identified through a series of meetings with stakeholders and individuals that are knowledgeable of the water resources issues in the study and input from the project team. The goal was to identify a large number of alternatives that represent a variety of concepts in terms of their scale and types St Lucie and Indian River Counties Water Resource Study of approaches. No attempt was made to evaluate the alternatives at this point – all alternatives were retained. Preliminary alternatives fell into two categories: Inter-District transfer alternatives and other alternatives. The Inter-District transfer alternatives enable the exchange of water between SFWMD and SJRWMD. This concept could be applied at a number of scales with and without storage being included. The other alternatives are generally intended to impact more localized areas. A total of 16 preliminary alternatives were identified and subjected to a screening process. Three of the preliminary alternatives were eliminated during the initial screening because they were being undertaken by others or did not directly address the objectives of this study. The remaining preliminary alternatives were then evaluated based on qualitative measures of cost, potential availability of water, and water quality. Cost was assessed in terms of the extent of new infrastructure that would be required for each alternative. Availability of water was based on the average annual discharge of water to IRL from the drainage area that would be included in each alternative. Water quality was assessed in terms of whether treatment would be required to prevent increases in total phosphorus concentrations of the receiving water body. It was assumed that since the IRL-S Project features in the C-23 and C-24 Basins include an STA, no additional treatment would be required to discharge water to the C-25 Basin. Screening of the preliminary alternatives resulted in identification of the following four alternatives to be carried forward for more detailed evaluation. C-25 Central Reservoir (ICS-01) - This alternative would enable the capture and storage of excess flows from the western C-25 Basin and C-25 Extension Basin in a central above-ground storage reservoir with a pumped inflow. An inter-district connection would be established to enable discharges between SJRWMD and SFWMD. This connection would involve removal of an existing plug in the Turnpike Canal, construction of a water control structure, and construction of a pump station adjacent to S-253 to discharge water northward into the Upper St. Johns River Basin Project. A stormwater treatment area would be required to reduce total phosphorus concentrations to 0.080 mg/l for discharges from the C-25 Basin to the Upper St. Johns River Basin Project. C-23, 24, and 25 Central Reservoir (ICS-02) - This alternative would contain all of the components of the C-25 Central Reservoir Alternative in addition to canal improvements to the north/south section of C-25 from its junction with the east/west section of C-25 to G-81. The canal improvements would provide conveyance capacity to move water from the C-23/24 Basins up C-25 to the storage reservoir. It was assumed that the C-23 and C-24 reservoirs and STA components of the IRL-S Project will be in place. Only excess water that would be available when the IRL-S reservoirs and STA in the C-23 and C-24 Basins are iv Summary Report in place would be available for storage in the reservoir.