Grass integrated synthetic sediment routing model (GISSRM)

For most watersheds, extensive rainfall, streamflow, and sediment discharge data are not available. Without such data, it is difficult to accurately calibrate and verify watershed hydrologic models for the purpose of predicting sediment yield. However, land use, topographic, edaphic, and meteorological information are generally available. Spatial and physical attributes of a watershed that affect water quality and sediment yield can be assembled into a geographic information system (GIS) data base. This information can then be used to generate synthetic water quality data or estimate sediment yield by a simplistic approach. An important problem, particularly in the watersheds located in North-Central Mississippi that are part of the Demonstration Erosion Control (DEC) Project, is how to estimate the reduction in sediment yield from the watershed due to the construction of grade control drop structures. This paper focuses on the development and testing of a synthetic watershed sediment routing model that can be integrated with the GRASS GIS. It is anticipated that this model can also be used to assess the effectiveness of the drop structures