Two-DIMENSIONAL SIMULATIONS OF CONTAMINANT CURRENTS IN STRATIFIED RESERVOIR

~BSTRACT: A~ unsteady ~wo-dimens~onal (20) reservoir hydrodynamics and transport model is employed to slm~late contammate~ denSity cu~ents m the Shasta Reservoir after a chemical spill into the Sacramento River, Cahf. Three flow regimes (plungmg flow, underflow, and interflow) and their occurrence are captured by the laterally ~verag~d model. Transp~~ and mixing processes in the temperature-stratified reservoir are analyzed through simulatIOns of flow velOCities, water temperature, and contaminant concentration. Flow behavior of the contaminan.t p~ume is desc?bed b~ plun~e distance, separation depth, intruding thickness, and the spatial and tempor~l dtlutlon of chemicals. Simulation results are compared with field data for water temperature and contammant concentration collected in the reservoir during the emergency response to the spill. Relatively good ag~eement between fiel~ measurements and predicted reservoir stratification and chemical dilution is obtained. It IS show~ that the aeration system installed in the reservoir contributed to the downstream reduction of chemical conc~ntration to a. n~ndetectable level shortly after the spill. The 2D simulations and analyses improve understandmg and predictions of the movement of a conservative contaminant plume in a stratified reservoir. The res~lts can a~sist in cont~mi~ation c~ntrol and remediation after a toxic chemical spill, guide field sampling dunng the spill, and provide mformation useful for water quality management.