Balancing Conflicting Goals: The Water Budget for the C-44 Reservoir/STA Project

The C-44 Reservoir/Stormwater Treatment Area (STA) Project is one component of the Comprehensive Everglades Restoration Plan (CERP) designed to improve the overall viability of the St. Lucie Estuary. The C-44 Reservoir/STA Project design is largely dependent on the inflows and nutrient concentrations from the C-44 Canal and those potentially diverted from the C-23 Canal in the future. The goals of maximizing the quantity of water treated and attenuating large flows to the estuary are somewhat contradictory and will require operational flexibility. The water quality goal requires large amounts of water to be passed through the Reservoir and STA system while the flow attenuation goal requires the retention of even larger amounts of water. The purpose of this paper is to discuss the water budget and nutrient load reduction modeling used to simulate the C-44 Reservoir/STA system to demonstrate that both goals can be met. This includes the analysis of the expected inflows to the facility, an assessment of the expected operational conditions, and the verification of Reservoir/STA sizing. The operational rules applied to the water budget attempt to develop a beneficial balance between the volume of water stored in the Reservoir and the water treated in the STA.