Economic and environmental trade-offs of irrigation best management practices in the Lower Arkansas River Valley
Date
2017
Authors
Orlando, Anthony, author
Hoag, Dana, advisor
Goemans, Christopher, committee member
Gates, Timothy K., committee member
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Abstract
The flows of the Arkansas River cascade through the Rocky Mountains and spill into Colorado's eastern plains. In the Lower Arkansas River Valley (LARV), these flows serve irrigators on over 250,000 acres, and are critical to the production of everything from corn to cantaloupes. Concurrent to the "goods" produced with this irrigation, are a series of "bads" occurring in the form of pollution. Elevated selenium, nitrate, and salinity concentrations have been related to high volumes of irrigation return flows, and threaten compliance with the Arkansas River Compact. Implementing a series of regional land and water Best Management Practices (BMPs) is thought to reduce the negative impacts ("bads") of irrigated agriculture in the region and in some cases, increase the productivity of land and water ("goods"). A deeper understanding of impacts of proposed BMPs is required. The specific question I hope to answer with this thesis is "What are the economic and environmental trade-offs face by Lower Arkansas River Valley producers when implementing a series a land and water best management practices?" To answer this question, an economic linear programming (LP) model is written to maximize regional net returns for a representative area within the LARV, using the General Algebraic Modeling System (GAMS). The LP is calibrated to match the physical characteristics of the region, historic water application volumes, and the historic crop mix. BMPs are tested by constraining various equations in the model, resulting in a series of economic measures. These economic measures are then compared to the output of a water flow, and reactive solute transport model to quantify the trade-offs that exist between regional net returns, in-stream selenium concentrations, in-stream nitrate concentrations, and yield losses to soil salinity. The results of this analysis suggest the existence of win-win scenarios, which increase net returns, and reduce pollution concentrations. No single BMP outperforms all others, supporting the notion that LARV producers and water policy makers face trade-offs in their efforts to control irrigation-induced pollution.
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Subject
linear programming
optimization
economics
water management
non-point source pollution