Colorado River Basin

Colorado River water is delivered to the Town of Gilbert through the Central Arizona Project (CAP) canal and is treated and delivered through Gilbert’s water treatment facilities.

For information on the current shortage on the Colorado River, visit gilbertaz.gov/WaterShortage.

The CAP canal starts at Lake Havasu and ends south of Tucson for a total of 336-miles. Colorado River supplies originate from snow up in the mountains of Wyoming, Utah, and Colorado. The runoff flows into Lake Powell, Lake Mead, and eventually to Lake Havasu where it is pumped into the CAP canal for delivery to central Arizona.

The CAP water supply is managed and delivered by the Central Arizona Water Conservation District (CAWCD). The CAP is designed to deliver approximately 1.5 million acre-feet of Colorado river water each year to the Arizona counties of Maricopa, Pinal, and Pima.

Gilbert receives Salt and Verde river water supplies from both the Salt River Project (SRP) and the Roosevelt Water Conservation District (RWCD). The Salt and Verde water comes from the forests of northern and eastern Arizona traveling 150 miles from the forest to the valley. The watershed encompasses 8.3 million acres.

SRP Watershed and Water Service Area (Source: Salt River Project)

Salt and Verde supplies delivered by SRP are treated and then delivered to SRP “On-Project” customers. SRP supplies are available for use only on lands that were originally committed to the construction of Roosevelt Dam which are referred to as “On-Project” lands. The On-Project lands are situated in the western portion of the Gilbert service area between the Eastern Canal and the western boundary of Gilbert Limits.

RWCD supply can only be delivered to land situated east of the Eastern Canal and west of the Roosevelt Conservation District Canal.

Gilbert has developed a strong portfolio of long-term renewable supplies complemented by the strategic use of groundwater. Today, Gilbert meets most of its customers' water demands with surface water. However, Gilbert still must utilize groundwater for operational performance, to meet peak demand, and as backup for surface water supply during shortage conditions or other surface water supply interruptions. Gilbert currently operates 20 groundwater wells throughout its service area.

Gilbert can use approximately five percent of groundwater each year that is considered Safe Yield groundwater. When withdrawn, Safe Yield groundwater does not contribute to loss of groundwater supplies. It is an amount of water that is recharged to the aquifer as a result of Gilbert’s routine production and distribution of supply to their end users.

Reclaimed water is an important component of Gilbert’s water supply. Gilbert has implemented strategic efforts to maximize its capability to locally reuse and recharge reclaimed water. Groundwater recharge efforts can result in the accumulation of credits that can contribute to Gilbert’s plans for meeting its long-term Assured Water Supply.

Gilbert delivers reclaimed water to HOAs, golf courses, schools, parks, and other community facilities for landscape irrigation. Available reclaimed water above what is delivered for direct use is recharged to replenish the aquifer. The reclaimed water percolates several hundred feet into the aquifer where it is capable of being used again as a future water source. The act of recharging helps maintain groundwater levels and provides a reserve supply that can be used during shortages. Gilbert conducts the banking of surplus reclaimed water at the following local recharge sites:

• Neely Ranch Recharge Facility
• Riparian Preserve
• South Recharge Site (SRS)
• Municipal Injection Well Facility

Gilbert has prepared for any type of shortage to our water supply, whether that is from long-term drought, which is the current driver of the Colorado River shortage, or an acute interruption. While the diversity of the water supply portfolio reduces the vulnerability of the supplies to potential shortages, shortages can still occur and require an action plan to protect public health and safety. Gilbert has adopted its Water Supply Reduction Management Plan to guide water demand management during these periods of reduced supply. This plan provides a timely, appropriate, and effective response in proportion to the seriousness of the event.