Project Number: 6413-13000-009-02
Project Type: Specific Cooperative Agreement

Start Date: Sep 28, 2006
End Date: Sep 30, 2009

Objective:
Using modeling and simulation techniques with the AnnAGNPS model, evaluate and compare on a sub-watershed scale the effectiveness of different on-farm and in-stream management practices to reduce stream nitrate loading caused by nitrate loss in drainage flow from agricultural cropland. The following management practices are to be evaluated for the Cabin-Teele Sub-Watershed in Northeast Louisiana: (1) Drainage Water Management in Open Field-Ditches of cropland to reduce nitrate load carried in ditch drainage flow to a main stream outlet. (2) Diversion of Stream Flow through Wetland Resources Areas to reduce nitrate load prior to routing the flow back to the main stream channel. (3) In-Stream Reduction of Nitrate Loading through natural chemical processes and interactions. The above management practices are to be evaluated individually and in various combinations. As time, staff, equipment, and funding permit, some stream-flow volume measurements will be made and flow water samples taken for chemical analysis to provide some quantification background data to assist in calibration the AnnAGNPS model for simulations in the Cabin-Teele Sub-Watershed.

Approach:
Conduct a series of simulations for the Cabin-Teele sub-watershed using the AnnAGNPS model and the GIS data-base and weather data previously assembled by the Soil & Water Research Unit (SWRU) for modeling the drainage hydrology, management practices, and agrochemical transport in the sub-watershed. Current SWRU scientists will assist in the establishment of various scenarios for conducting simulation runs, some of which would include different options for Open-Ditch Drainage Water Management in the previously identified areas within the sub-watershed. The simulations would also include scenarios for Diversion of Stream-Flow Through Wetland Resource Areas previously identified within the sub-watershed to evaluate potential reduction in N-loading prior to allowing the flow to re-enter the main stream. There are about three identified sites within the sub-watershed where this practice could be easily implemented for simulation studies and actual physical structures for future field testing.