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This document is provided to help you answer any questions you may have about the Agua Fria Linear Recharge Project. If you have any additional questions please contact us. What is SROG?SROG is short for 'Sub-Regional Operating Group'. It is comprised of the cities of Glendale, Mesa, Phoenix, Scottsdale and Tempe. This group of cities is looking for ways to reuse reclaimed water so that a greater amount of the water from the Central Arizona Project, Salt River Project and local groundwater wells can be used for drinking water. What is groundwater? Groundwater is water stored in the ground resulting from hundreds or even thousands of years of rain and flows from snowmelt. What is an aquifer? An aquifer is typically a regional basin where large amounts of groundwater are stored. It is like an underground reservoir, except we didn’t have to spend billions of dollars to build it. Storage capacity can run into the billions of gallons. What is recharge? Recharge is the process of proactively adding water back into the aquifer. It amounts to managing the aquifer similar to a reservoir. Recharge is a common practice in the United States and other countries. Some municipalities in California have been practicing recharge for over 40 years. Several communities in the Phoenix area have been recharging water, including reclaimed water since the 1980s. Sometimes groundwater recharge is referred to as groundwater replenishment. Why is groundwater so valuable? Groundwater is an extremely valuable resource for several reasons. First, it is water stored underground which means there are no losses caused by evaporation. Second, it is completely reliable, and can be used to supplement the overall water supply during droughts. Stored water is the key to water supply reliability. Third, groundwater is typically pumped at the location it is needed, which reduces infrastructure and pumping costs. Why is recharge important for the Phoenix area? Proactive recharge in the Phoenix area is important because natural replenishment is very slow due to low precipitation. Recharge water will replace water that has been pumped out of the aquifer over many years. Continued pumping of water from the aquifer combined with inadequate replenishment can result in declining water tables, increased pumping costs, land subsidence and potentially loss of storage capacity in the aquifer. What is reclaimed water? Reclaimed water is wastewater that has flowed through the sewers to a wastewater treatment plant and has been cleaned and treated to a level such that the water quality is appropriate for a variety of different uses. In general, reclaimed water is treated to different quality levels depending on the requirements of the application. How much treatment has reclaimed water received? The reclaimed water from the 91st Avenue Wastewater Treatment Plant (WWTP) meets all applicable water quality standards. SROG’s reclaimed water systems provides several contaminant barriers. The Cities operate an extensive industrial pre-treatment program to remove toxics and metals before raw industrial sewage is discharged to the sewer. The sewage, which is a combination of pre-treated industrial wastewater and commercial/residential wastewater, undergoes a significant amount of treatment at the WWTP. The WWTP is equipped with state-of-the-art treatment processes that remove the organic and nitrogenous compounds that are the main components of raw sewage. The City of Phoenix, as the operator of the 91st Avenue WWTP monitors the water quality from the WWTP on a daily and weekly basis for nearly 200 chemicals. The water is essentially safe for non-potable reuse. Can we use reclaimed water? In general, the answer is yes. Reclaimed water is already being used throughout the Phoenix area. Some reclaimed water is directly used to irrigate golf courses and crops. Some reclaimed water is used to replenish groundwater in the Phoenix basin and water supplies are being replenished in many locations around the country. SROG and the Bureau of Reclamation have begun studying the use of reclaimed water as an alternative for recharging groundwater at the Agua Fria location. Are we currently using any reclaimed water? Yes, several years ago, SROG built a state-of-the-art wastewater treatment plant at 91st Avenue. A majority of the reclaimed water produced by this plant is used by the Palo Verde Nuclear Generating Station, Tres Rios Ecosystem Restoration Project and the Buckeye Valley Irrigation District. However, there is still a significant amount of reclaimed water that goes unused for these purposes. Approximately 13 to 20 billion gallons per year of reclaimed water is available for groundwater recharge. How is reclaimed water used? Reclaimed water is used for many different applications including the following:
Reclaimed water from the 91st Avenue Wastewater Treatment Plant is currently used by the Buckeye Irrigation Company, the Tres Rios Wetlands Demonstration Project and the Palo Verde Nuclear Generation Station. The City of Scottsdale intercepts water from the sewers before it goes to the 91st Avenue Plant, treats it to high standards, and uses it for irrigation and recharging the groundwater. Why use reclaimed water for recharge? Reclaimed water is an available, drought tolerant, renewable water resource. As long as residents live in the Valley, they will be generating wastewater that can be treated and polished into water that is safe and acceptable for many uses. Failure to use this valuable resource fails to take advantage of the significant investment already made to clean it. Why do we want to put this water in the aquifer? Reclaimed water will replace water that has been pumped out of the aquifer over the years for use by the community and farmers. Aquifers hold water and if too much water is taken out, they collapse (subsidence) and once damaged, an aquifer cannot be restored Will the discharge of reclaimed water be ongoing? There will be no recharge of reclaimed water into the Agua Fria riverbed during three months of the year because current users will need the entire supply. The water is likely to be unavailable during the summer months. Do all communities use reclaimed water? Reusing or recharging reclaimed water is a common practice in the United States and other countries. Some municipalities in California have been practicing recharge for over 40 years. What is a recharge facility? A recharge facility is where water is collected for dispersal into the aquifer. Sometimes it is a pond or series of ponds where water is held while it is infiltrating into the aquifer. A recharge facility may also use a pump to inject water directly into the aquifer. Neither of these methods will be used in the Agua Fria project. Ponds attract birds that are hazardous to aircraft and mosquitoes that are hazardous to the human population. The Agua Fria Project will use either an in-channel surface infiltration with berms, L-bars and T-bars in the river channel. What is the appropriate quality of "recharge water?" To define the appropriate recharge water quality we must consider two important factors. First, recharge water goes through a natural treatment process as it percolates into the aquifer. Second, groundwater is treated by water utilities prior to it reaching homes, businesses and industry. In general, recharge water meets all applicable water quality standards. How does the city produce the appropriate water quality? The SROG wastewater and reclaimed water management systems provides several contaminant barriers which include the following:
Will the recharge activities occur year round? In general, little or no recharge will occur during the summer months because the water can be used to meet immediate customer needs for irrigation water. |
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Sponsored by the Sub-Regional Operating Group (SROG) - Member Cities:
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In partnership with:
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