The University of Arizona

A Colorado River Shortage Declaration: Planning, Responses, and Consequences | CLIMAS

A Colorado River Shortage Declaration: Planning, Responses, and Consequences

A Colorado River Shortage Declaration: Planning, Responses, and Consequences

CLIMAS Lead:  

Based on interstate and international agreements, a Colorado River shortage declaration would reduce surface water deliveries to primarily to Central Arizona, with nearly all the cuts applied to agriculture, representing a 25%—40% reduction in surface water to the region’s farms. The U.S. Bureau of Reclamation provides forecasts of the probability of a shortage declaration based on Lake Mead water levels. Little is known about whether early warning systems are meeting farmers’ needs and what a shortage would mean for income, jobs, and groundwater use in rural economies. The study will assess how stakeholder groups currently use Colorado River supply forecasts in decision-making and what contingencies they are making in the event of a shortage declaration, the economic consequences of a shortage declaration on agriculture and the local economies in central Arizona, and potential impacts of a shortage declaration on groundwater pumping and water levels in central Arizona Active Management Areas.

According to the 2007 Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated Operations for Lakes Powell and Mead a near-term shortage declaration would result in more than $20 million in lost personal income (employee compensation + proprietor’s income). These losses are likely to be concentrated in rural communities. One adaptation that farmers can make is to switch to exhaustible groundwater supplies. While this may reduce short-term adjustment costs, it may reduce the sustainability of agricultural production in Central Arizona.

This project estimated the economic impacts of changes in wheat, alfalfa, and cotton acreage resulting from a hypothetical reduction of 300,000 acre-feet of irrigation water for Pinal County agriculture. This was meant to capture approximate potential effects of water cutbacks under the state Drought Contingency Plan. Changes in acreage, agricultural production, and broader impacts to the Pinal County economy were estimated under different fallowing scenarios.