The need for detailed plans describing the restoration of impaired waters is widely recognized in developed countries.
TMDL studies demand technically defensible models that translate pollutant loads into receiving water quality outcomes and support allocation across multiple source types. EFDC+ is widely recognized across North America as the go-to model for this work.
EFDC+ has supported dozens of TMDL studies across North America. EEMS streamlines the entire workflow — linking watershed model outputs, running load reduction scenarios, applying statistical tools, and producing clear visuals for regulatory audiences — all within a single integrated platform.
DSI developed a linked watershed and 3D water quality model for Stevenson Creek, a tidally influenced, nutrient-impaired segment on Florida’s Gulf Coast. The models established TMDLs for dissolved oxygen and nutrients, providing FDEP with a scientifically sound basis for restoration targets.
As part of the EPA’s TMDL process, DSI built a linked watershed and water quality model for Tenkiller Ferry Lake. HSPF supplied 20 years of flow and nutrient loads that fed the EFDC+ water quality model, which was then calibrated and used to evaluate load reduction scenarios across the full allocation process. See also the EPA Water Oklahoma program.
DSI built a 3D model of Perdido Bay — a shallow Gulf Coast estuary impacted by agricultural and industrial discharges — to support FDEP’s TMDL development for dissolved oxygen and nutrients. The model gave regulators a clear picture of the load reductions needed to restore water quality.
DSI developed a 3D EFDC+ model of Klosterman Bayou, linked to an HSPF watershed model, to simulate nitrogen, phosphorus, and oxygen dynamics in this tidally influenced coastal system. The model supported FDEP’s TMDL development for dissolved oxygen and nutrients.
DSI applied EFDC+ to model the fate and transport of pollutants in Cook Inlet as part of a biological evaluation for an NPDES permit renewal. With the Cook Inlet beluga whale listed under the Endangered Species Act, the model delivered the ecological risk assessment needed to support the permit reauthorization decision. See also the free grid.
