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Watershed management

The sustainable management of the three watersheds that cover a 13,000-square-mile area in northern and eastern Arizona are vital to the Valley's water supply.

What is a watershed?

A watershed includes a healthy forest, undergrowth, creeks, streams and rivers that all drain toward a large body of water — in this case, the Salt and Verde rivers . These components work together to store and filter water as it moves through the watershed, flows into the reservoirs downstream and eventually comes out of your tap.

A healthy forest is key to maintaining a watershed. Each component of a forest, from the canopy to the vegetation, serves a function in the storage and filtration of the water that passes through it.

  • The forest canopy’s shade prevents snowpack from melting too fast, thereby "storing" the water for when it is most needed — spring and early summer.
  • The vegetation, streams and rivers filter the water, removing debris and sediment.

This natural system results in a steady and sustainable supply of water flowing into the reservoirs on the Salt and Verde rivers downstream.

Arizona’s forests today

Arizona's forests are unhealthy and overgrown, and without action, catastrophic fires are almost a certainty — putting the state's physical beauty, economic vitality and water supplies at risk.

Since 2002, more than 2.5 million acres of forests in or around the Salt, Verde and East Clear Creek watersheds has been burned by wildfires, including mega-fires such as the Rodeo-Chediski and Wallow fires.

Historically, small fires were a natural part of the ecosystem in Arizona's forests, removing excess vegetation and improving soil conditions. As forest management policies changed to suppress fires, vegetation built up, creating more fuel for catastrophic fires. This practice led to overgrown forests. For example, in the Cragin Watershed, the number of trees grew from an average of 100 per acre to today’s ranges that can be up to 6,000 trees per acre .

The aftermath is scorched landscapes that cause a breakdown in the natural storage and filtration the forest once provided.

  • Snowpack is exposed to excessive sunlight causing it to melt more quickly.
  • Runoff from fire-scarred areas brings ash and debris with it.
  • The waste settles at the base of the dams, reducing reservoir capacity and affecting water quality, placing a strain on water treatment facilities.

Working toward healthy forests

Forest thinning is the process of removing the excess trees and brush.

The problem is now so large that millions of acres of Arizona forest are at risk of high-severity fire. With this increased threat, we are increasing our focus on helping efforts to strategically thin our forests to prevent catastrophic wildfires.

A cross-departmental team of SRP employees has been working on solutions that focus on prevention through strategic forest thinning. As part of this effort, SRP has worked tirelessly to forge partnerships with organizations across the state.

Restoration partnerships and projects

It is only through partnerships that we have begun the process of restoring Arizona forests.

From 2010 when our customers began contributing to help restore Arizona forests through the Trees for Change program to the Four Forest Restoration Initiative that began in 2011, these valuable partnerships continue to be key to the process.

Four Forest Restoration Initiative

Map showing areas burned on the SRP watershed since 2002. This includes the Rodeo-Chedeski Fire on the Apache-Sitgreaves National Forest in 2002, the Warm Fire in 2006 in Kaibab National Forest, the Schultz Fire in 2010 in the Coconino National Forest and Wallow Fire in 2011 in the Apache-Sitgreaves National Forest.

The Four Forest Restoration Initiative is a U.S. Forest Service-endorsed plan to thin 50,000 acres of forest annually for 20 years across the Tonto, Coconino, Apache-Sitgreaves and Kaibab national forests that began in 2011.

In 2019, the U.S. Forest Service, in partnership with SRP, the Arizona Commerce Authority, the Arizona Department of Forestry and Fire Management, and the U.S. Bureau of Reclamation, developed a request for proposals (RFP) for the next long-term, large-scale contract(s) to promote a sustainable forest product industry and accelerate forest restoration in northern and eastern Arizona. By jointly developing the RFP, the partners' unique perspectives and interests in restoring national forest system lands are represented.

Key partnerships

Forest thinning work has been slow to take root, and the problem isn't contained to the national forests that are the focus of the Four Forest Restoration Initiative. Private, state, tribal and U.S. Bureau of Land Management lands are also affected.

To address this, SRP is working with other groups, including the U.S. Forest Service, the U.S. Bureau of Reclamation, the Ecological Restoration Institute at Northern Arizona University, the Nature Conservancy, the Arizona Department of Forestry and Fire Management, White Mountain Apache Tribe and private industry, to seek joint solution.

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