Development of Nutrient Sub-Modules (NSM) for Integration with USACE Hydraulic and Hydrologic Modeling Systems

The control of nutrients arising form Non-Point Source Pollution (NPSP) is difficult because the source areas can be hard to identify and typical treatment methods are infeasible due to the distributed nature. While restoration attempts may provide significant returns, they can be costly to implement and often are met with resistance. In order to quantify potential benefits, detailed hydrologic/water quality modeling of watersheds and the effects of Best Management Practices (BMP) is required. Extending model results beyond the range of calibration to model future conditions requires the use of physically based models that include the important processes that generate stream flow, material transport, uptake, loss, transformation, and recycling. In addition, given the complex nature of surface water and groundwater interaction, as well as the spatial nature of nutrient distribution, a distributed source transport model is needed to accurately account for the movement of water and nutrients through the various landscape media where more simplistic models are not applicable, or are homogeneous which is not appropriate for the heterogeneous nature of distributed sources. This paper will discuss the current research efforts and demonstrations taking place at the Engineer Research and Development Center (ERDC) as it relates to the nutrient sub-modules.