June 19, 2007
Contact: Dave Mansfield, Water Resources GM, (480) 312-5681
Scottsdale Water Achieves Safe Yield in 2006
Residents and City Play Key Roles in the Accomplishment
Scottsdale achieved a major milestone in 2006 -- as much water was recharged into its groundwater aquifer as was pumped out from wells. This balance is known as “safe yield” and it ensures long-term sustainability of the city’s groundwater resources.
Arizona’s landmark 1980 Groundwater Management Act set safe yield as the goal for cities in the Valley and in other areas of the state. Scottsdale’s Water Resources Department accomplished safe yield through balancing natural recharge from rainfall runoff and artificial recharge -- primarily at the Water Campus -- with decreased groundwater pumping. Groundwater is needed for peak demand, particularly during the summer and for drought protection.
Scottsdale has come a long way to achieving safe yield. In the 1980’s, the city was using 100 percent groundwater. In 2006, that number was reduced to 25 percent. Several factors contributed to the decrease, including strategic planning and the construction of the Water Campus. Residents also played a role by continuing to conserve water and reducing demand.
Even though safe yield has been achieved, residents are still asked to conserve water and to take advantage of tips and tools available to them from the city’s Water Conservation Office. To learn more about how you can conserve water, please call the office at (480) 312-5650.
Scottsdale is a leader in the Valley and the nation in using artificial groundwater recharge to enhance the sustainability of the city’s water supply. This is an important part of Scottsdale’s overall water supply management strategy. Maintaining the city’s safe yield balance is the city’s next goal. For more information on groundwater recharge and safe yield call (480) 312-5009.
KEY POINTS REGARDING SCOTTSDALE’S SAFE-YIELD MILESTONE:
Safe yield was achieved by increasing recharge and decreasing groundwater pumping. Reaching the goal has long-term benefits.
Increasing recharge
- Recharging water means to replace or renew the groundwater supply.
- In addition to natural recharge from rainfall runoff, Scottsdale artificially recharges water at the Scottsdale Water Campus in three ways:
- Surface water from the Central Arizona Project (CAP) is put into shallow dry wells (tubes filled with sand and gravel).
- Reclaimed wastewater is treated to drinking water standards and is then recharged.
- Treated drinking water is injected directly into the groundwater aquifer at specially designed wells. These wells put water into the ground during the winter low-water-use demand periods and take water out to supplement the supply during the high-demand summer months.
- Groundwater recharge in 2006 added 2.75 billion gallons of water to the city’s groundwater supply.
- That’s enough water for more than 8,000 families for one year.
- Or, if you had a football field sized tank, it would be enough water to fill the tank more than a mile and a quarter deep.
Decreasing groundwater pumping
· In the 1980’s, the City of Scottsdale received 100% of its drinking water supply from groundwater sources. By 1990, the city was down to 63%, and in 2000 that number was reduced to 50%.
· In 2006, due to our increased use of available CAP and Salt River Project (SRP) water, the amount was reduced to approximately 25%.
Long-term benefits
- Safe yield allows the city to conserve the water supply for future drought conditions.
- Increasing recharge and decreasing pumping allows the city to enhance the water levels in groundwater aquifers. Higher water levels make it more efficient to pump water from the ground, resulting in decreased energy usage and lower pumping costs.
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