New Jersey Water Science Center
Great Falls of the Passaic River at Paterson, N.J.
USGS IN YOUR STATE
USGS Water Science Centers are located in each state.
Salem river Flow and Water Quality Model
Project Title: Salem river Flow and Water Quality Model
The objectives of the project are to develop flow and water quality models of the Salem River Basin that will provide the NJDEP with a tool to evaluate nutrient loading processes in the basin, develop a TMDL for the watershed, and identify the significant sources. A question to be answered by the TMDL is what is the nutrient loading that limits algal growth during the growing season (Jun 15 - Aug 31) to an average chlorophyll (a) concentration of 20 ug/l.
Statement of Problem
NJDEP has determined that water quality modeling of the Salem River is necessary for a nutrient (phosphorus) TMDL. However, little background data is available for the basin. Intensive field monitoring was commenced by the U.S. Geological Survey (USGS) for the NJDEP in 2007 to support understanding of the nutrient loading processes in basin as well as to provide the input data to the flow and water quality models. This data, while valuable, may still not provide all the data necessary for modeling. The monitoring work is documented in a separate proposal. The current proposal documents the proposed USGS work on flow and water quality models for the development of a nutrient TMDL for the Salem River.
Strategy and Approach
The eutrophication module of the WASP model will be used for determining the TMDL. The initial approach would be to use the kinematic wave option that is built into WASP. Experts at EPA suggest this hydrodynamic approach may be adequate for the for the follow-on water quality modeling. However that assessment canít be confirmed until the modeling process has begun. For example, the model must be able to handle low velocity conditions due to the flat slope and dam at the downstream end. If the kinematic wave approach is not sufficient for the water quality model, then a proposal addendum will have to be scoped out and additional funding provided to develop a more complex hydrodynamic model. Such a change might involve developing an EPA EFDC model, which already has a linkage with WASP.