No abstract

No abstract

Real-time salinity management increases annual average salt export from the agriculture-dominated and salt-impacted San Joaquin Basin. This strategy also reduces the likelihood of potential fines associated with exceedences of monthly and annual salt load allocations which could exceed $1 million per year based on average year hydrology and State-mandated, TMDL-based salt load export limits. The essential components of this program include the establishment of telemetered sensor networks, a web-based information system for sharing data, a basin-scale salt load assimilative capacity forecasting model and institutional entities tasked with performing weekly forecasts of River salt assimilative capacity and coordinating westside drainage return flows. San Joaquin River (SJRRTM) Online (SJRO) is a new web portal that combines WARMF-Online a dedicated web portal for sharing model input data and salt assimilative capacity forecasts with an informational website for increasing stakeholder awareness of the unique characteristics and opportunities for enhanced water and water quality resource management in the River Basin.

The Cheat River of West Virginia is impaired by acid mine drainage (AMD). Fifty‐five of its river segments were placed on the 303(d) list, which required calculations of total maximum daily load (TMDL) to meet the water quality criteria for pH, total iron, aluminum, manganese, and zinc. An existing watershed model was enhanced to simulate AMD as nonpoint source load. The model divided a watershed into a network of catchments and river segments. Each catchment was divided into soil layers, which could contain pyrite, calcite and other minerals. A kinetic expression was used to simulate pyrite oxidation as a function of oxygen in the soil voids. Oxygen in the soil voids was consumed by pyrite oxidation and replenished by earth breathing. The by‐products of pyrite oxidation were calculated according to its mass action equations. Chemical equilibrium was used to account for the speciation of ferrous and ferric irons and precipitation of metal hydroxides. Simulated hydrology and water quality were compared to available data. The USEPA used the calibrated model to calculate the TMDLs in the Cheat River Watershed.