The Phoenix Water Services Department meets the needs of a service area that currently covers over 500 miles. Major features of the current potable water system include the surface water treatment plants and approximately 30 wells. The initial water system acquired by Phoenix in 1907 utilized groundwater obtained from shallow wells. The relatively brackish and poor-tasting condition of this water led to the tapping and delivery of the higher quality water from the Verde River, about 30 miles east of town. The water was delivered through a redwood pipeline which was replaced by a larger capacity concrete pipe in 1931. In the 1940's, deeper wells were drilled about 12 miles east of town.
In 1947, the city's first surface water treatment plant was completed on the Verde River to utilize surface water. As the system grew with the acquisition of several private water companies, it became clear that additional surface water treatment plants were needed. Thus, the city entered into the 1952 Water Delivery and Use Agreement with SRP which provided for deliveries of water (that formerly went to farm land within the city) to treatment plants. As a result, three additional surface water treatment plants were built between 1952 and 1975, all on the SRP canal system. The 24th Street, Deer Valley and Val Vista Plants treat and deliver water primarily to urbanized lands with rights to SRP supplies. The agreement, which was revised and updated in 2002, also allows the city to access untreated canal water for irrigation of city parks and golf courses.
In 1986, the city completed the Union Hills Water Treatment Plant on the newly constructed CAP canal. The city is in the process of constructing an additional CAP plant at Lake Pleasant for service to the northern portion of the system. Another plant on SRP's Western Canal (to the south) is proposed for construction in the next 10 years. This plant will predominantly serve "on-project" areas (those within the SRP boundaries).
In 1990, an interconnect facility was built at the Granite Reef Diversion Dam where the CAP and SRP canal systems intersect. This facility allows CAP water to be sent to Phoenix's water treatment plants on the SRP system (through SRP's canals) under both normal and drought conditions. This feature significantly increases the reliability of Phoenix water supplies.
The city has developed or acquired more than 200 groundwater production wells through the years. However, a majority of these wells have been removed from service due to age, reduced efficiency and/or degraded water quality due to groundwater contamination. Currently available wells can generate up to 67 million gallons of water per day (mgd). Five of these wells were drilled and equipped since 1998. Planning for the expansion of the well network is currently underway to assist in meeting future peak demand needs to provide operational flexibility and redundancy and to accommodate surface water shortfalls during anticipated drought conditions.
The five treatment plants and well network combined have a production capacity of 697 mgd. The plants, wells, and more than 6,000 miles of water mains are designed to meet the maximum day water demands that occur during the summer months. Other facilities, such as reservoirs, booster stations, and pressure reducing valves are designed in synergy to meet "maximum day peak hour demands" and to provide emergency capacity when treatment plants or distribution components are restricted. Large transmission mains provide substantial ability to move water throughout the interconnected system, thus providing a high degree of redundancy under foreseeable conditions.
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Last modified on
12/19/2007 09:30:09
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