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Conclusion of Preliminary Engineering Report This report provides an estimate of the potential maximum demand for reuse water from all communities on the North barrier island, from Old Winter Beach Road north to Windsor. This estimate approaches 4.2 MGD. However, the likely demand will be lower. Considering that of the 4.2 MGD estimated demand, at least 2.25 MGD of this estimated demand comes from developments / communities within the COVB utility service area. Currently the COVB provides limited amounts of reuse water to several developments (including John's Island). Some existing developments, especially those lying in the city's service area who may be able to refuse service, may not want to connect to IRCDUS reuse water. Reasons vary, but one may be the significant costs that would be realized by any development to modify its irrigation system to take reuse water. Another obstacle may be the actual cost to purchase the reuse water from IRCDUS when the perception is that groundwater and/ or surface water is free. This report also models and estimates the reuse infrastructure capacity and has found that the reuse transmission system / pipe network could potentially deliver 4.34 MGD of reuse water (if available). However, actual capacity of the IRCDUS reuse system (the entire system) to deliver reuse water is likely lower. It will be many years before the ,equisite quantity of reuse water is available from the county's three WWTP's. In addition, the a acity of the Hobart reuse storage tank and pumping facility may be a limitation. The facili , was esigned to deliver 1.6 MGD with a 3.0 MG storage tank. Consider that if total barrier islarl' deman .eached 4.2 MGD, and existing mainland demand is 0.79 MGD (Redstick and JI Well ;the total de ; and from the Hobart facility could approach 5.0 MGD, or over 3 times its orig' 1 d si n. Further, the transmission mains (double 12" parallel mains) that cross (and ang fro the Wabasso Bridge are older system components, and IRCDUS may not want theseli s co star,tly running at peak capacity. Recommendation: It is SBS recommendation that RG-DIan to construct facilities that will provide for the future demand of at least 3.116 M D o e se a er to the North Barrier Island. This flow allocation is depicted and listed in Scerati.o C in th Hydraulic modeling and is summarized as follows: -1.964 MGD - flow to north1barrier island communities within IRCDUS service area -1.0 MGD - to JI -0.153 MGD - to COVB service area - the Shores and River Club 3.116 MGD total Two system models (C-2 and C-3) that were proposed with this flow allocation are favorable 1. With storage and pumps: These flow allocations have been modeled and results indicate that the allocated flows are provided with consistently high pressures with the storage tank and pump capabilities (system model C-2). 2. Without storage and pumps: While pressures drop up to 30+- psi at the furthest demand nodes, the same flows can be provided without the tank and pump (system model C-3). This may not be a desirable Tong -term solution. The burden will be on the Hobart tank and pumping facilities to provide pressurized reuse water to the developments/ communities on the barrier island without a backup or fail safe that the proposed Sea Oaks 3.0 MG Reuse water storage tank provides. 163 13