Water Resources Research Act Program

Details for Project ID 2018NC220B

Adding Additional Model Years and Other Model Refinements to the Updated Neuse Estuary Eutrophication Model

Institute: North Carolina
Year Established: 2018 Start Date: 2018-03-01 End Date: 2019-02-28
Total Federal Funds: $15,000 Total Non-Federal Funds: $45,000

Principal Investigators: James Bowen

Abstract: We propose to continue for a second year a project to develop a mechanistic eutrophication model of the Neuse River Estuary. That original one-year project (WRRI Project No. 16-02-W, “Comparing the Impact of Organic vs. Inorganic Nitrogen Loading to the Neuse Estuary with a Mechanistic Eutrophication Model”) was narrowly focused and designed to leverage our earlier model development work in the estuary. We now have successfully updated the model and used it to investigate the system’s sensitivity to nitrogen load reduction (Harrigan and Bowen 2016, Bowen 2017). An additional year of funding would enable us to make significant additional contributions and improvements to the model and would allow us to work with stakeholders and potential users of the model such as the NC Division of Water Resources (DWR) who are interested in running it for basin planning and water quality assessment. We plan model development in three areas. First, after May 2009 our data set lacks water surface elevation at the downstream boundary. Adding this single time history would enable us to extend the model period by more than five years. We plan to use the ADCIRC (Luettich Jr, Westerink et al. 1992) model to simulate elevations. Second, we will develop a simple second-order sediment diagenesis sub-model to predict denitrification and sediment related oxygen demand to replace the approximate approaches that we currently use. Third we have leveraged our earlier work on pathogen modeling (Froelich, Bowen et al. 2013) to develop an automated calibration system that can run the model in parallel over 2-50 processors. This system allows us to test thousands of candidate parameter vectors during calibration and then run the calibrated model with many suitable parameter vectors. Because of time restrictions we have the system sparingly, but in the coming year we would use it to systematically test and calibrate alternate approaches to modeling the algal constituents. We plan also to have several briefings during the coming year with DWR staff to update them on our progress and to query them on how best to tailor the model and create the front and back end systems needed for their use of the model.