Geo-economic Analysis of Alternative Uses of Woody Draws in Agricultural Landscapes

Background

A draw is a small natural drainage area formed by cumulative overland flow. In a storm event, surface runoff first accumulates in draws and then moves into stream channels. Woody draws are draws covered by trees and shrubs. Since woody draws accumulate storm flow and then pass it through the landscape, they are critical areas for achieving uniform runoff flow and lowering overland flow velocities. Woody draws also could be the most active variable source areas in a watershed. Management of woody draws is an effective way to control nonpoint source pollution. However, many woody draws have been converted into agricultural uses. In recent years, the total area in woody draws has decreased substantially in Missouri. Agricultural use of woody draws is not justified from an environmental standpoint. Unfortunately, effective management and protection of woody draws is hindered by the lack of information regarding the costs and benefits of alternative uses of woody draws.

Objectives

The overall objective of the proposed research is to develop a computer tool that would allow a resource manager or resource management agency to evaluate the merits of alternative policies for managing woody draws and farmers and agency personnel to evaluate the costs and benefits of alternative uses of woody draws. 

The specific objectives are:

1. To develop a Geographic Information System (GIS)-based procedure for identifying woody draws in agricultural watersheds
2. To evaluate the costs and benefits of alternative uses of woody draws in different agricultural landscapes
3. To develop a PC-based tool and web-based prototype model for evaluating the economic and environmental costs and benefits of alternative uses of woody draws

Methods

Long Branch watershed  is selected as the study site for the project. The watershed represents a diverse agricultural landscape with several nonpoint source pollution problems. Comprehensive digital geophysical and socioeconomic database has been developed for this watershed in connection with the Missouri Watershed Initiative. This watershed is the site for complementary research on contribution of variable source areas to nonpoint source water pollution, which is important because woody draws can be considered as active variable source areas in a watershed.

1. Draws are small natural drainage areas formed in landscape by cumulative overland flow. The polygon coverage of draw areas will be developed from digital geographic data. Specifically, a 1-meter resolution digital elevation model (DEM) will be developed from a digital topography layer. Flow accumulation will then be determined based on the flow directions in the DEM. A scheme will then be developed to delineate draw areas by interactively manipulating the flow accumulation and digital hydrologic layers. The polygon coverage of draw areas will then be overlaid with the 1-meter resolution digital orthophoto quadrangles (DOQs) to identify the current uses of draws, such as cropland, grassland or woody areas. Classification accuracy will be evaluated by ground-truth checking.
2. The costs and benefits of alternative uses of woody draws will be evaluated by treating the woody draws and their contribution areas as an integrated system. The net benefit of an alternative use of a woody draw is the incremental benefits minus incremental costs. Costs can be production costs, construction and maintenance costs. Costs of agricultural production can be evaluated using biophysical simulation and enterprise budget models. APEX (Agricultural Policy/Environmental eXtender) will be used to evaluate the interaction between the area in a woody draw and the contributing upland area and simulate the environmental impacts of alternative uses of woody draws. Construction and maintenance costs and cost sharing information will be obtained from NRCS personnel. The current agricultural operations will be identified using a representative farm approach. Benefits of alternative uses of woody draws will be evaluated in terms of market and non-market values of their alternative uses. The market value will be used when the woody draws are used for agricultural production. Non-market valuation will be used when the woody draws are used for non-agricultural, environmental purposes. The procedure developed by Qiu and Prato (1998) will be used to determine non-market values. Their procedure estimates the value of a woody draw or its alternative non-agricultural use by the net return for the woody draw and its contribution area when it is used for agriculture minus the net return when it is used for non-agricultural use. The most valuable use of woody draws will then be determined using the traditional cost-benefit ratio.
3. Cost-benefit analysis of alternative uses of woody draws requires the integration of knowledge and techniques from several disciplines. Development of a decision support system is a reasonable way to integrate diverse knowledge and techniques. The decision support tool will be developed for non-technical users. The proposed PC-based tool will use ArcView GIS. The Avenue program embodied in ArcView will be used to create graphical user interfaces that will streamline the evaluation procedures and interface the simulation and economic models. After implementing the cost-benefit analysis of woody draws on a PC using ArcView, this procedure will be converted to an interactive web-based system using ArcView Internet Map Server. By integrating JavaScript and HTML programming, the ArcView Internet Map Server allows users to access and implement the whole functionality of ArcView through the Internet.

Major Findings and Products

• Click here to run the woody draw management model (WDMM), the decision support tool for evaluating alternative uses of woody draws in the study area.
• Draws and Their Alternative Uses. Photos taken during a field trip to the Long Branch Watershed.
• Qiu, Zeyuan and Tony Prato. “Cost Effectiveness of Reducing Agricultural Nonpoint Source Pollution with Conservation Buffers in Variable Source Areas.” The Selected Paper presented at the Annual Meeting of the American Agricultural Economics Association, Tampa, Florida, July 30 - August 2, 2000.
• Qiu, Zeyuan and Tony Prato. “A Precision Landscape Planning Approach for Controlling Agricultural Nonpoint Source Pollution.” The Proceedings of the 5th International Conference on Precision Agriculture and Other Precision Resources Management, Bloomington, MN July 16-19, 2000.
• Qiu, Zeyuan and Tony Prato. “A Precision Landscape Planning Approach for Environmental Quality.” Poster presentation. The 2001 Missouri Natural Resources Conference, Osage Beach, Missouri, January 31 - February 2, 2001.
• Qiu, Zeyuan, Larry Godsey, Verel Benson and Tony Prato. “Economic and Environmental Assessment of Alternative Uses of Woody Draws in Agricultural Landscapes.” The selected presentation in the 2001 Missouri Natural Resources Conference, Osage Beach, Missouri, January 31 - February 2, 2001.
• Qiu, Zeyuan. “Geo-economic Analysis of Alternative Uses of Woody Draws in Agricultural Landscape.” The selected presentation in the 2001 Missouri Environmental Quality Conference, Columbia, MO, April 26, 2001.
• Qiu, Zeyuan. “Integrated Assessment of Alternative Uses of Woody Draws in Agricultural Landscapes.” Poster presentation. The 2001 Soil and Water Conservation Society Annual Conference, Myrtle Beach, South Carolina, August 4-8, 2001.
• Qiu, Zeyuan, Tony Prato, Larry Godsey and Verel Benson. “Integrated Assessment of Uses of Woody Draws in Agricultural Landscapes.” The paper revised and resubmitted to the Journal of American Water Resources Association.

Principal Investigators: Tony Prato, Zeyuan Qiu, Chris Fulcher and Chris Barnett

Project Manager: Zeyuan Qiu

Project Staff: Jim Meyer

Collaborators: Gray Henderson and Missouri NRCS State Office

Funding Source: the Missouri Cooperative Agricultural Research Grants (MOCARG) program administered by the Missouri Soil and Water Districts Commission and the Missouri Department of Conservation

Funding Amount: $59,748

Project Duration: July 1, 1999 - June 30, 2001.