5.9 Using Known Fluxes

   For the contaminated vadose zone case, the known flux capabilities of the module can be applied to leaching, water erosion, wind suspension, and volatilization. Known flux capabilities can be used in two ways for each pathway. The first way to use known fluxes for leaching would be to pass known leaching flux rates to the groundwater transport code. The second way would be to "turn leaching off", by inputting a known leaching flux of 0. The same is true for the water erosion, wind suspension pathway, and the volatilization pathway. The volatilization pathway offers an additional method for adjusting flux. An adjustment factor (called the volatization ratio) is multiplied by [dM_i/dt]_vol to reduce the volatization flux. The overall treatment of mass loss in the source-term module does not change. The known leach rate replaces the calculated value for [dM_i/dt]_leach, the known water erosion rate replaces the calculated [dM_i/dt]_eros, the known wind suspension rate replaces the calculated [dM_i/dt]_susp, and the known volatilization rate replaces the calculated [dM_i/dt]_vol in Equation 5.56. All other calculations are done identically to the calculated flux cases.