COMPREHENSIVE WATERSHED MANAGEMENT PLAN FOR A SUSTAINABLE DEVELOPMENT OF LEHIGH ACRES, LEE COUNTY, FL

A.D.A. Engineering Inc (ADA) is currently working with AIM Engineering, Inc. in watershed planning for the East County Water Control District (ECWCD) in Lehigh Acres, Lee County, FL., to develop the comprehensive water resources plan. ECWCD is responsible for maintaining the canals of 100 square mile area of Lehigh Acres, which was created in the 1960's when canals were dug to drain an extensive wetland system in South Florida. Roads were constructed, and 90% of the area was platted with 1/4-acre lots served by individual wells and septic systems. Recent assessments have shown that peak runoff rates will double at full build-out, water quality conditions will deteriorate, and ground water levels will drop by 40 feet due to well pumpage. The system, as originally designed, is not sustainable for planned levels of development. The objectives of the comprehensive plan are to have a sustainable water management plan by implementing the following actions:Reduce the extent, magnitude, and duration of flooding in the Orange River downstream of ECWCDIdentify and implement a regional water and wastewater treatment system that will provide reliable service in both wet and dry conditions,Increase groundwater recharge within the ECWCD to increase Orange River baseflows, andImprove water quality for waters leaving ECWCDThe Comprehensive Plan will result in re-design of a number of existing structures on canals in the areas covered by the ECWCD jurisdiction. As part of this project, a number of flow diversions and water storage options are being considered. This paper will summarize the alternatives considered and the management actions that are being implemented.The modeling is being conducted with the integrated surface/ground water modeling system MIKE SHE/MIKE 11. The model has detailed representation of ECWCD canals, Amil Gates, weirs, underflow gates, overflow gates, and pump stations. Detailed evaluations are being conducted of the impact of alternatives on reducing the extent of flooding in downstream areas while improving baseflow in the Orange River, improving hydroperiods in ECWCD wetlands and increasing ground water recharge.