Future growth and water supply management sparks Arizona town to pursue a water allocation policy

Water is a precious resource, especially in the arid southwest. The Town of Gilbert, Arizona understands the value of its water, and is committed to actively managing its precious resource by making regular updates to its master plans and infrastructure improvement plans. Like its water supply, land resources are limited too. As population continues to rise, the town is seeing an increase in vertical development, where multi-story residential and non-residential buildings are more commonplace. This shift in development has caused the town to reconsider its historical approach to water management; and as part of its most recent Integrated Water Resources Master Plan update, Gilbert adopted a new approach to develop unit demands. Historically, unit demands have been developed on a per acre basis (i.e. gallons per day per acre) and later applied to estimate demand at build out in undeveloped areas or those planned for redevelopment.

However, with more vertical development occurring, Gilbert realized the “per acre” approach may not accurately capture a community’s demand profile across customer classes. These discrepancies can pose a problem when it comes to making accurate demand projections as new communities/infrastructure are built. By transitioning unit demand development from “per acre” to “per unit” for residential customers and “per 1,000 square feet of building area” for non-residential customers, municipalities can more accurately project demands, while inherently accounting for multi-story development.

In concert with Gilbert’s water conservation efforts, the town is also seeking to adopt a water allocation policy for future non-residential customers. To provide a basis on which to develop an allocation policy framework, Gilbert’s current and projected water supply portfolio has been quantified as part of its most recent master plan update. Currently, new customers are connected on a first-come, first-served basis. This new policy may include a base amount of water allocated to future non-residential customers with options to increase. This would help Gilbert continue its forward-looking strategy to consciously and proactively manage its water portfolio to build out, which will likely include redevelopment and “build-up” development.

Although in its early stages of development, the water allocation policy may include characteristics such as customer class and minimum meter size to trigger use of any supplies reserved for economic development. Complementing the policy, Gilbert is also documenting current business processes to accept new water customers and development agreements, which includes potential modification of current processes to support the future implementation of the water allocation policy.

Interested in learning more about the Town of Gilbert’s approach to managing its water resources in a sustainable manner? Join Jacobs’ water experts in Tucson, Arizona, where they will be discussing sustainable water management best practices during the Sustainable Water Management Conference, March 31-April 3.

• Tyler Jantzen, Laurens Van der Tak, John Phillips and Brent Robinson will present “Climate Changed Precipitation Time Series for Use in Collection System Modeling” on April 1.
• Fair Yeager and Doug Toy, along with Eric Braun, Water Resources Manager for the Town of Gilbert, will present “Water Supply: Are You Good to the Last Drop?” on April 2.
• Jim Lozier will present “Membrane Process Energy Optimization Opportunities” on April 2.