Lavon Lake Water Quality Modeling – TPDES Permitting Support

Plummer developed a CE-QUAL-W2 model of Lavon Lake to evaluate impacts on dissolved oxygen, nutrients and chlorophyll-a levels in the lake. The model was converted from the WASP platform originally used in the late 1990s to allow for more flexibility and provide a more robust hydrodynamic calculation engine.

To support the October 2017 TPDES permit renewal for the Wilson Creek Regional Wastewater Treatment Plant, Plummer revised the CE-QUAL-W2 water quality model of Lavon Lake to model the 2002-2004 and 2011-2014 time periods. Plummer adjusted heat transfer and wind coefficients to produce water surface elevations and temperature profiles consistent with observed data, then calibrated the model by adjusting kinetic coefficients and settling rates to produce nitrogen, phosphorus, and chlorophyll-a profiles consistent with observed data. Plummer modified the calibrated model to perform projections of Lavon Lake water quality at different treated effluent flowrates and performed sensitivity analyses on sediment nutrient loading and watershed nutrient loading. Plummer assisted the District in answering TCEQ questions about the model and the modeling results during the permit renewal application review process.