Modeling Lake Clarity

Dynamic Lake Model with Water Quality (DLM-WQ) includes a physical process based one-dimensional hydrodynamic model and newly developed sub-modules to simulate turbulent diffusion transfer, fine particle dynamics, dissolved oxygen, phytoplankton, zooplankton, nutrients (species of nitrogen and phosphorus) and  Secchi depth.   Although the hydrodynamic model is one-dimensional, lake outflows and turbulent mixing due to stream inflows are treated two-dimensionally. The model parameterizations are derived from the extensive field and laboratory experimental data.

DLM-WQ simulates the temporal changes in the temperature and water quality distributions in lakes/reservoirs and the lake water level. Because boundary forcing inputs to the DLM-WQ include time series weather variables; inflow volumes (stream and intervening zones) and associated physical, chemical and biological characteristic of the water; lake outflows; groundwater fluxes; atmospheric deposition; and shoreline erosion; it is used for development of TMDL, monitoring TMDL, operation and management of the lake, and assessments of climate change impacts.

This work was partially supported by an EPA/NSF sponsored Water and Watersheds grant through the National Center of  Environmental Research and Quality Assurance (R826282), the U.S. EPA–sponsored (R819658 and R825433) Center for Ecological Health Research at U.C. Davis, and grants 01‐174‐160‐0 and 01‐175‐160‐0 from the Lahontan Regional Water Quality Control Board.

Schematic of Dynamic Lake Model with Water Quality (DLM-WQ). The double lines box includes all in-lake processes and a hydrodynamic model. The four broken line boxes from left to right represent for fine inorganic particle, light, phytoplankton and zooplankton sub-model, respectively. Shown are external sources (streams, intervening zones, atmosphere, groundwater, and shoreline erosion (thick line boxes on the top of double line box)) and internal source (sediment fluxes (thick line box inside the double line box)) of the pollutant loads. CDOM represents colored dissolved organic matters.