Overview of Water Issues
In the early 1900s, the Salt River Project (SRP) was founded to impound surface water from the Salt and Verde Rivers for irrigation in the Salt River Valley (where the Phoenix Metropolitan area is located today). The US Bureau of Reclamation grew out of the SRP. By the 1920s, well-pumping technology had improved, and groundwater became a major source of water as irrigated agriculture expanded in the state. The Central Arizona Project (CAP) is the second major water project in Arizona. Completed in 1992, the CAP annually delivers approximately 1.5 million acre-feet of water from the Colorado River to Central Arizona.
As a condition of its financial support for the CAP, the Federal Government required that Arizona address its groundwater overdraft problem. After careful negotiation, state leaders adopted The Groundwater Management Act of 1980 (GMA). The GMA provides a framework for managing groundwater use across agricultural, industrial, municipal, and mining interests. It established five Active Management Areas (AMA) around major urban centers, and three Irrigation Non-Expansion Areas (INAs), designed to regulate groundwater extraction and achieve safe yield of groundwater. Within these areas, only land that was under irrigation between 1975 and 1980 can be irrigated going forward. When farmland in the AMAs and INAs is converted to urban use, no new agricultural land can be placed under irrigation.
Arizona has a strong water rights regime governed by the principle of first in time, first in right. Farmers in the state largely have secure water rights, however, the effects of groundwater extraction on surface flows have become more apparent, and with increasing competition for water resources, a number of lawsuits have been filed throughout the state to adjudicate water rights. This and factors affecting the cost of irrigation have put pressure on farmers to reduce their water consumption through efficiency measures, and/or crop choices that require less water.
Today Arizona has an active, and growing agricultural and ranching sector, with strong cattle, dairy, cotton, wheat, and leafy green production, among many other activities and products.
The overarching issue related to water in Arizona today is scarcity. Historically, the sector that consumed the most water was agriculture. This is changing, however, as the population has grown and urbanized starting in the 1940s. Today there is increasing competition for water across sectors (agriculture, urban, environmental, industry), with growing municipal demand. There are very few uninterrupted free-flowing rivers in the state. The primary water quality issue is salinity, due to high evapotranspiration of surface water, and high salt concentrations in groundwater.