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United States Department of Agriculture

Agricultural Research Service

Title: Integrated watershed economic model for non-point source pollution management in Upper Big Walnut Creek Watershed, OH

item Nair, Sujithkumar
item Sohngen, Brent
item King, Kevin
item Fausey, Norman - Norm
item Witter, Jonathan
item Southgate, Douglas

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/27/2010
Publication Date: 7/25/2010
Citation: Nair, S.S., Sohngen, B.L., King, K.W., Fausey, N.R., Witter, J.D., Southgate, D. 2010. Integrated watershed economic model for non-point source pollution management in Upper Big Walnut Creek Watershed, OH [abstract]. Agricultural & Applied Economics Association Joint Annual Meeting.

Interpretive Summary:

Technical Abstract: Today, non-point source pollution (NPS) is one of the major sources of water quality impairments globally (UNEP, 2007). In the US, nutrient pollution is the leading cause of water quality issues in lakes and estuaries (USEPA, 2002). The maximum concentration of nutrients in streams is found to be in agricultural basins, and it is correlated with nutrient inputs from fertilizers and manures. This clearly shows the role of agricultural practices in water quality degradation (USGS, 1999). To improve the quality of water bodies, the United States Environmental Protection Agency (USEPA) mandates individual states to implement the Total Maximum Daily Load (TDML) (USEPA, 2002). The state and federal governments are working with several conservation programs to reduce the NPS load from agriculture (Mausbach and Dedrick, 2004). However, the ever-increasing water quality impairment by agricultural NPS in US clearly shows that the task of formulating and implementing the cost-effective policies for controlling the NPS impact on water resources is challenging. An integrated watershed-economic modeling (IWEM) offers a holistic approach, where compounding effect of biophysical and anthropogenic variables can be identified and their impact on NPS can be partitioned by linking the biophysical process and the economic behavior models. Such an IWEM would have three components, a biophysical process model component, an economic behavior component and a tool to integrate both the biophysical and economic components. In this research IWEM methodology is applied to the Upper Big Walnut Creek (UBWC) watershed of central Ohio to derive socially benefiting choices of conservation practices to reduce nutrient nitrogen (N) load from agriculture. The UBWC watershed was identified by Ohio EPA as an impaired watershed due to nutrient enrichment from agricultural (Ohio EPA, 2005). Additionally, the watershed encompasses perennial and intermittent streams that drain into Hoover Reservoir, and serves as a primary source of drinking water supply and a favorite local recreational site for residents in the neighboring communities. Soil and Water Assessment Tool (SWAT), a widely used basin scale biophysical process model was used as biophysical component of IWEM. The baseline nutrient production function, watershed level N production function for corn and wheat, and phosphorous production function for soybean were estimated by using SWAT model for the UBWC watershed. A quadratic relationship between applied nutrients and the yield were established by regressing applied nutrient against simulated yields of for different crops for the watershed. In addition, SWAT model was also used to derive the baseline soil N balance equation. The conservation management options, such as split application of N fertilizer, conservation tillage, cover cropping and vegetative buffer were simulated using the SWAT model for deriving crop and technology specific quadratic nutrient production functions and N loading function. The predominant crop rotations in the watershed, corn-corn (C-C), corn-soybean (C-S) and corn- soybean-wheat (C-S-W) were considered for SWAT simulations. The economic component of IWEM consists of social cost of N load, cost of production of crops and technology cost of conservation practices. The benefits of water quality improvements were derived from two different studies, 1) The recreational value of water quality improvement were estimated based from a combined stated and revealed preference method applied to UBWC and 2) A conjoint analysis of the use (excluding recreation) and non-use value of water quality improvement in UBWC reported by Tennity (2005). The value of complete marginal benefit of per hectare N loading reduction by half from a farm was estimated as $328.77 for streams and $387.86 for Hoover reservoir, which was used to parameterize social damag

Last Modified: 10/16/2017
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