Carli Beisel Thesis Proposal

Title: Water Balance in Urbanizing Agricultural Systems

Abstract: States across the western US are facing a water crisis in which demand is exceeding the available water supply. Climate change is exacerbating this through rising temperatures changing annual precipitation and increased extreme weather events, like droughts. The Treasure Valley (TV), located in southwestern Idaho, is projected to exceed available water supply due to population growth, urbanization, and climate change. Rising temperatures in Idaho are causing more precipitation to fall as rain rather than snow, diminishing the snowpack and resulting snowmelt that is the predominant supply of agricultural water. Urbanization of agricultural land decreases the surface permeability, alters the rate of evapotranspiration (ET), and changes water demand. Understanding how much water is currently used in the TV and how demand may shift with climate change and urbanization is necessary for water supply planning. A complex network of canals supply water to the valley and drains remove surplus irrigation water from the landscape which is often used downstream. The Mason drain is an example of a complex irrigation system that is undergoing rapid urbanization which is decreasing drain flows. Assessing when Mason Drain return flows will drop to zero will be important for water management and planning in the TV. The goal of this project is to estimate when Mason Drain will have no return flows back to the Boise River to give watermasters and farmers time to change irrigation practices or find new water sources. To accomplish this we will 1) create a water budget for Mason Drainage, and 2) compare remote sensing derived ET products across the TV to assess validity and uncertainty in these products. We will work with watermasters to install instrumentation along Mason Drain canals and quantify water inflows and outflows from the data collected during the 2024 irrigation season (April 1 to October 1). The conclusions from this study will be directly implemented by the water masters of TV to inform farmers when to expect no flow in Mason Drainage, and the results from this study benefit other urbanizing landscapes through application of this water budget blueprint process.

Advisor: Kendra Kaiser

Committee Members: James McNamera, David Ketchum