Scottsdale’s Water Security Began Decades Ago

By Thyra Ryden-Diaz, PE, MPA – Scottsdale Water Interim Senior Director

Interim Senior Director of Water Resources

Recent discussion surrounding Scottsdale’s purchase of additional Long-Term Storage Credits prompted understandable questions about the City’s long-term water strategy. Water is one of our most valuable resources, and Scottsdale has planned for decades to assure the supply.

The most important thing residents should know is this: the City Council did not approve new groundwater pumping, new wells, pipelines or construction. Instead, it approved the purchase of water that already exists underground in the Harquahala Valley for future use.

This was not the start of a new project. It was another step in a strategy Scottsdale and some of its golf course partners started more than two decades ago.

In 2002, Scottsdale partnered with golf courses served by the city’s Irrigation Water Distribution System to create an innovative public-private water partnership. Together, they purchased land and groundwater rights in the Harquahala Valley, securing access to approximately 3,460 acre-feet of groundwater annually for the next 100 years.

What made the agreement truly visionary was not just the water rights it secured, but the structure of the deal. The participating golf courses agreed to fund the future infrastructure needed to recover and transport the groundwater to Scottsdale if it was ever the water was ever needed. The costs of developing the wells, treatment facilities, if required, and conveyance infrastructure would be borne by the golf course partners, not the Scottsdale taxpayers. More than two decades later, that long-term plan remains in place, with the infrastructure currently in the design phase.

As opportunities arose, the city continued improving the strategy. In 2012, Scottsdale sold the original property and purchased replacement land closer to the Central Arizona Project canal, reducing future transportation costs. The participating golf courses later expanded the property, further strengthening the City’s long-term position.

Last week’s Council action continues that same strategy by purchasing 15,000 additional Long-Term Storage Credits. These credits represent water that already exists in the aquifer. Buying them is much like adding to an existing savings account and increased the amount of water available to Scottsdale in the future without needing any new pumping or infrastructure.

Recovering that water remains part of the long-term plan established years ago, and the infrastructure needed to do so is now in the design phase and progressing through agency approvals for the delivery of water via the Central Arizona Canal.

Scottsdale’s approach to water security has never relied on a single solution. Instead, the City has adopted a five spoke strategy to reduce dependence on the Colorado River: investing in conservation and demand management to reduce water use; advancing Pure Water; expanding long-term groundwater supplies through the Harquahala partnership; supporting regional water storage projects such as the proposed Bartlett Dam expansion; and pursuing emerging water solutions as new technologies and opportunities develop. Harquahala is one critical piece of this larger strategy—a forward-thinking investment that complements, rather than replaces, Scottsdale’s diversified approach to securing a reliable water future.

As the Southwest faces increasing uncertainty on the Colorado River, communities throughout the region are looking decades ahead to secure reliable water supplies. Scottsdale has been doing exactly that in Harquahala for nearly 24 years.

Scottsdale made thoughtful investments with forethought decades before they were needed. This week’s Council action reflects that philosophy: not a new project, but another prudent step in a long-term commitment to protecting Scottsdale’s water future.

Thyra Ryden-Diaz is Scottsdale’s interim senior director of Water Resources and has spent more than two decades helping deliver critical water infrastructure projects for the Scottsdale community.