Land Management Strategies for Watershed Restoration: An Integration of Spatial Modeling with Dynamic Programming

Land Management Strategies for Watershed Restoration: An Integration of Spatial Modeling with Dynamic Programming

Summary

The project is an attempt to develop a framework for ex-ante evaluation of land management strategies to test the efficacy and cost efficiency for controlling the nutrient load by using stochastic dynamic programming based economic model in conjunction with Arc-SWAT based spatially explicit water quality model. A conservation technology preference survey conducted among Ohio farmers indicated that conservation tillage and grass waterways are the most preferred conservation technology measures by the farmers of Ohio. Arc-SWAT modeling of the watershed is completed by using daily flow data from United States Geological Survey (USGS) gage, which is located within the watershed and nutrient load data collected by USDA research team stationed at Ohio State University (OSU). The stochastic dynamic program is developed based on the baseline data from the ArcGIS-ArcView extension and a graphical user input interface for the Soil and Water Assessment Tool (Arc-SWAT) simulation. The simulation of different conservation options for the watershed is in progress.

Objectives/Performance Targets

The overall goal of the project is to understand the farmer’s production practices, perception and knowledge about non-point source pollution from agriculture, and need for watershed restoration. The overall goal was addressed with the following specific objectives.

Objective 1: To identify, evaluate and prioritize the site-specific on-farm and off-farm Land Management Strategies (LMS) to reduce nitrogen loading.

Objective 2: To evaluate the farmer’s perception about the selected on-farm and off-farm strategies for nutrient export from agriculture.

Accomplishments/Milestones

Accomplishment by objectives

Objective 1
A survey was proposed to understand existing farmer’s practices and farmer’s preference over conservation technologies. As we have direct access to data from a survey conducted among Ohio farmers about conservation decisions, which exactly matches with our objective 1, we decided to use the data from the above-mentioned survey to support the analysis of objective 1. The survey results revealed that the conservation tillage and grass waterways were the most preferred conservation practices among the farmers of Ohio.

Objective 2
Arc-SWAT modeling of the watershed was proposed to simulate different on-farm and off-farm LMS to derive estimates of off-site nutrient loading. The calibration and validation of Arc-SWAT model was completed using the data from USGS gage at Sunbury, Columbus, Ohio and the nitrate loading data collected by USDA research unit stationed at OSU. The uncertainty analysis of the models was also completed. The simulation of different conservation scenarios for the watershed is progressing and will be completed within a month.

A stochastic dynamic program (SDP) for the watershed was already developed with the baseline simulation of Arc-SWAT. After simulating different conservation options using Arc-SWAT, SDP will be recalibrated with the new Arc-SWAT results and analyzed for societal value of the specific conservation technology.

Pending work: Simulation of conservation strategies and evaluation of its benefit-cost analysis using SDP.

The results from the second objective will be compared with the outcome of the first objective.

Impacts and Contributions/Outcomes

The project is not yet completed to report the impact or outcome.

Collaborators: