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ARS Home » Southeast Area » Oxford, Mississippi » National Sedimentation Laboratory » Watershed Physical Processes Research » Research » Publications at this Location » Publication #186218
Title: WATER QUALITY SIMULATION OF RICE/CRAWFISH WITHIN ANNUALIZED AGNPS

Author
item YUAN, YONGPING - UNIVERSITY OF MISSISSIPPI
item Bingner, Ronald - Ron
item THEURER, FRED - NRCS
item Kolian, Steve

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2007
Publication Date: 10/1/2007
Citation: Yuan, Y., Bingner, R.L., Theurer, F.D., Kolian, S.R. 2007. Water Quality Simulation of Rice/Crawfish Within Annualized AGNPS. Applied Engineering in Agriculture, Vol. 23(5): 585-595.

Interpretive Summary: The development of management practices used to reduce pollutants produced from agricultural fields entering stream systems is critical in improving overall watershed water quality. The evaluation of the effectiveness of conservation management practices is difficult because of the long-term data collection effort needed throughout a watershed system. In order to better assess conservation practices, computer simulation modeling tools have been developed to evaluate how much pollutants are produced and where they come from within watersheds. In addition, these tools serve as an aid in determining the most effective conservation practices that can be applied to minimize any downstream impacts on water quality. This study introduces and evaluates an aquaculture pond feature developed within the USDA AnnAGNPS non-point source pollution watershed model. The aquaculture pond feature allows the AnnAGNPS simulate rice/crawfish production practices and the resulting impact on the water quality of receiving water bodies. This feature is critical in Louisiana, where rice/crawfish farming is common, for watershed evaluation and in the development of TMDL watershed implementation plans for water quality improvement.

Technical Abstract: Rice and crawfish farming are important agricultural management practices in Louisiana. The effluent from rice/crawfish ponds is an environmental concern because of high sediment and nutrient concentrations. However, current available models used for TMDL development such as BASIN, SWAT and AnnAGNPS do not have the capability of simulating rice/crawfish farming and their impact on water quality. The objective of this study is to develop a rice/crawfish feature which can be integrated into Annualized Agricultural Non-point Source Pollution model (AnnAGNPS) to simulate rice/crawfish farming and its impact on water quality. The AnnAGNPS has been developed to aid in the evaluation of watershed response to agricultural management practices. Both hydrologic and pollutant mass balances are maintained for the rice/crawfish field ponds in AnnAGNPS. Inflows, outflows, precipitation, infiltration (or seepage), and evaporation (or evapotranspiration) are considered for hydrologic mass balance. Outflow from the pond is assumed to be added to the AnnAGNPS cell's receiving reach. Pollutant mass balance is maintained based on the inflows and outflows and their water quality. Water quality constituents considered in the model are total suspended sediment, total nitrogen, total phosphorus, dissolved nitrogen and phosphorus. When this feature is applied, it is recommended that water samples should be taken during water releasing processes so that the pollutant load from rice/crawfish ponds can be quantified. However, detailed rice/crawfish management practices and their impact on water quality have been thoroughly reviewed and a water quality database was built into AnnAGNPS. This water quality database provides an estimate of water quality in the pond effluent. Application of the model in the Bayou Plaquemine Brule watershed in Louisiana shows that the model simulated annual average sediment concentration is close to the monitored annual average sediment concentration.