Expert Commentary

Sustainable water management in the U.S. Southwest

2010 study by Nature Conservancy Center for Science and Public Policy on depletion across 18 Arizona watersheds and possible mitigation strategies.

Sustainable water management refers to managing resources in a way that the water needs of present and future generations as well as the broader ecology are met. While the concept of sustainability has received considerable attention, actual efforts have been limited as population growth has continued.

A 2010 study from the Nature Conservancy Center for Science and Public Policy, “Sustainable Water Management in the Southwestern United States: Reality or Rhetoric?” uses Arizona as a test case to analyze the pattern of stream-flow depletion across 18 watersheds. The study takes stock of the current water depletion rate and projects how conservation strategies could reduce the current pace of depletion. The study was published in PLoS ONE, a peer-reviewed, open-access online publication.

Using four scenarios, the authors modeled population growth and water use through 2050 to explore the potential effects of growth and water management strategies. Some of the study’s key findings include:

  • In 2000, municipal water demand has already exceeded the full base flow capacity in two watersheds. During the same time, seven watersheds registered low current and projected demand.
  • Under the base population projection, seven of the 18 rivers studied could be dewatered due to municipal demand.
  • Implementing conservation scenarios that reduce water demand by 30% could mitigate the risk of the intermediate watersheds being dewatered.
  • Water demand and river flows have key impact on the broader ecology. Unless conservation efforts are intensified, the number of threatened or endangered species would continue to grow.

The authors conclude by stating that because impacts from groundwater extraction are cumulative and cannot be immediately reversed, proactive water management strategies should be implemented where groundwater will be used to support new municipal demand.

Tags: water, conservation, biodiversity

About The Author