Lake Hancock Lake Level Modification and Outfall Treatment Projects

Lake Hancock Outfall Treatment Project

The Lake Hancock Outfall Treatment Project involves constructing a treatment system to improve water quality leaving the lake. Discharge from the lake has been documented as a major source of poor water quality in the upper Peace River. This poor water quality from the lake affects the entire river all the way to Charlotte Harbor, an “estuary of national significance,” and a State Surface Water Improvement and Management (SWIM) priority water body. A study conducted by the District in the late 1990s investigated the cost and benefits of improving water quality in the lake versus improving the water quality of the water leaving the lake. The in-lake option would benefit the lake, river and estuary, while treating the water leaving the lake benefits only the river and estuary. The results of the study showed little benefit for in-lake water quality treatment in regard to the high cost of treatment. Based on the findings of the study the option to treat waters leaving the lake was chosen.

The first step in the process is to investigate the feasibility of various water treatment methods, including constructed wetlands, chemical treatment followed by settling, aquatic plant-based water treatment technology and other physical treatment processes. The evaluation was completed in February 2006 and involved quantitative criteria such as cost effectiveness and treatment efficiency, and qualitative criteria such as performance track record, operational considerations, wildlife habitat potential, water storage capacity and recreational opportunities. In addition, costs associated with each technology were estimated at two treatment efficiencies: 27 percent and 45 percent. Both are predicted to improve water quality in the upper Peace River from “poor” to “fair.” A 27 percent load reduction goal is expected to offset the load increases from the Peace River to Charlotte Harbor projected to occur over the next 19 years. Based on benefits to the resource combined with cost considerations, the most feasible project goal is a wetland treatment system designed to reduce nitrogen loads by approximately 27 percent. This recommendation was approved by the District’s Governing Board and Peace River Basin Board at the February 2006 and April 2006 meetings, respectively.

The current step involves the engineering testing, design, environmental permitting, and preparation of construction documents for a wetland treatment system. Construction of the treatment system could commence after the permits are issued. The treatment system is to be constructed on the Old Florida Plantation property purchased by the District in 2003.