The largest municipal water supplies (water sources) serving the Forum's planning area are described in the links below. Click on the utility name for additional information on the supply
Seattle Public Utilities (SPU)
Tacoma Public Utilities (TPU)
City of Everett
City of Kent
Lakehaven Utility District
Lakewood Water District
City of Auburn
City of Renton
Covington Water District
City of Puyallup
Sammamish Plateau Water and Sewer District
City of Marysville
Parkland Light & Water Company
Additional links to regional water supply, resource management and conservation are available through the Water Information Resource Center.
Seattle Public Utilities (SPU)
Seattle has two surface water sources and a small groundwater source (well fields): the Cedar River system, the South Fork Tolt Reservoir, and the Seattle Well Fields. Deliveries from each supply source vary from year to year depending on the hydrologic conditions affecting each supply source. Additionally, the configuration of the transmission system allows flexibility in the use of the different sources thereby strengthening overall system reliability. On average, the Cedar River system provides two-thirds of SPU's total supply, and the South Fork Tolt system delivers the remaining one-third. The well fields are used, if and when needed, during emergencies or peak summer water use periods.
Water from the Cedar River is treated at the 180-mgd Cedar Treatment Facility, which is located at Lake Youngs and was completed in 2004. A maximum of 200 mgd can be delivered from the treatment facility to the regional system. Operation of the Cedar River system is managed under the provisions of the 50-year Cedar River Watershed Habitat Conservation Plan (HCP) adopted in 2000, including the Instream Flow Agreement. In 2006, SPU and the Muckleshoot Indian Tribe reached an agreement that commits SPU to the HCP instream flows and related research in perpetuity, limits SPU's diversions from the Cedar River, and addresses other issues of mutual interest. The limitations of these agreements are considered in determining the system-wide firm yield.
Deliveries from the South Fork Tolt system are treated at the Tolt Treatment Facility completed in 2001. Treatment capacity is 120 mgd, and the hydraulic capacity of the transmission system is 135 mgd. The 1988 South Fork Tolt River Hydroelectric Project Settlement Agreement, which was negotiated and committed to as part of the Federal Energy Regulatory Commission (FERC) licensing process for the Seattle City Light South Fork Tolt hydroelectric facility, established the instream flow requirements that must be met when operating the system.
SPU's well fields consist of the Riverton well field, which has two wells, and the Boulevard Park well field, which has one well. In total, the three wells can supply up to 10 mgd for approximately four months. The well fields are naturally recharged, but the wells can also be artificially recharged using a method known as aquifer storage and recovery (ASR), if needed. When used, ASR injects treated water from the Cedar River into the production wells to supplement natural recharge into the aquifer. Operation of the well fields has been through temporary water rights permits; SPU applied for a reservoir permit in 2005 for the ASR project to replace these temporary permits.
Sustainable use of SPU's water supplies is constrained by the firm yield of the system. Calculation of the firm yield is based on historic hydrology, the average pattern of seasonal demand, instream flow requirements and other system capacity constraints. Because of the tremendous variability in stream flows (and thus water availability) from year to year, firm yield is determined using a 98 percent reliability standard. Under this definition, the firm yield is the amount of water that could be delivered using all sources in 98 years out of 100, on average, based on historic records of stream-flows, while maintaining minimum instream flows and without lowering reservoirs below minimum levels. Using this method, the annual firm yield for SPU is estimated to be 171 mgd. In most years, more water can be delivered.
City of Everett
The City of Everett's main source of supply is its treated surface water supply from the Sultan River. This source is retained in the Spada and Chaplain reservoirs. Other sources include surface water diversions from Chaplain Watershed. The City relies on 4 transmission lines from the Spada/Chaplain System to feed their service area. This transmission network is a gravity system, so pumping costs are little to none and there is a high reliability to most of their customers during periods of extended power outages. One of these transmission lines is an unfiltered/untreated line that supplies their largest industrial water user, Kimberly-Clark, which currently uses about 30 mgd.
Water Rights for the Sultan, Lower Snohomish1 and groundwater sources total an instantaneous (Qi) availability of 426.1 cfs and an annual quantity (Qa) of 168,244 acre-ft. This is equivalent to a maximum production rate of 275 mgd and an annual average production volume of 150 mgd.
Everett's Lower Snohomish water right, equivalent to 10mgd annual average and 15mgd maximum day, comes from the Snohomish River Regional Water Authority water right of 23.7mgd (Qa) and 36 mgd (Qi), which is shared with Woodinville Water District and Northshore Utility District. This right is presently being analyzed for future use.
Tacoma Public Utilities (TPU)
Tacoma Public Utilities' existing sources of supply include the Green River and twenty-four wells located within the City's service area. The City's surface water supply from the Green River consists of two diversion water rights. The first diversion water right is senior to State established instream flow requirements; however, TPU limits diversion to protect instream flows under an agreement with the Muckleshoot Indian Tribe. The second diversion is shared with regional supply partners the City of Kent, Covington Water District, and Lakehaven Utility District. Although Tacoma owns the water right and supply facilities, the three supply partners have an ownership interest in the water supply coming from the second diversion. The second diversion is also subject to instream flow requirements that make the water available only from storage during drier periods of the year. TPU has developed additional reservoir storage to make this seasonal diversion available in the summer and fall.
Tacoma's annual water right for these sources is 123.9 mgd and the total maximum instantaneous water right is 188 mgd. City's total yield from surface diversions equals 83.3 mgd while the city's wells, which currently meet about 17 percent of the total annual water requirements, yield about 22.3 mgd on an average day annual basis.
City of Kent
The City of Kent receives its water from multiple ground, surface and partnership water sources. Three springs supply groundwater from the area near Kent and are piped to the city; Kent Springs, Clark Springs and Armstrong Springs. Groundwater is also obtained from various wells located throughout the area. The springs and well sources provide the majority of the city's water needs presently. The remaining water supply is acquired through a partnership with the Second Supply Pipeline project, managed by TPU, which obtains water from the Green River, as it is available.
The total annual right (Qa), which includes the surface water portion, is 25.3 mgd, while the total instantaneous amount (Qi) is 33.8 mgd.
Lakehaven Utility District
Lakehaven Utility District's (LUD) main source of water supply is groundwater that comes from a network of 24 production wells completed in 4 deep aquifer systems located beneath the Federal Way area. These production wells are all within the central area of their distribution system. LUD augments this groundwater supply with treated surface water from the Green River as a partner in the Tacoma Second Supply Project. This surface water, managed by TPU is delivered to the District via a 34-mile pipeline that was built by a partnership between LUD, the TPU, City of Kent, and Covington Water District.
The combined annual water rights (Qa) for LUD's water sources including their portion of the second supply surface water totals 31.8 mgd, while their total instantaneous (Qi) rights equal 59.2 mgd.
Lakewood Water District
The Lakewood Water District (Lakewood) is a major water purveyor in Pierce County. The supply is developed from four separate aquifers found at successive depths. Each aquifer is comprised of permeable glacial sediments and tapped by their network of 29 active wells. Lakewood is the lead wholesaler for the Pierce County Co-op (Co-op) members, many of who augment Lakewood's source water with their own groundwater sources.
Lakewood's existing annual water rights (Qa) total 22.23 mgd, while their instantaneous water rights (Qi) currently equal 69.65 mgd.
City of Auburn
The City of Auburn's water comes from a combination of 10 wells and 2 springs. The total annual water right (Qa) of the groundwater sources is equal to 21 mgd, while the total instantaneous quantity (Qi) is equal to 27.4 mgd. Coal Creek Springs and West Hill Springs are located south of the White River and on the West Hill respectively. The City's wells are located in the Auburn valley and in the Lakeland Hills area in the southeast portion of the City.
City of Renton
The City of Renton obtains most of its water from groundwater sources. One spring source is located at the south end of the City. In addition, there are 9 production wells regularly used and one emergency well. The City also has 3 drilled, but unused, wells that currently do not have water rights. The combined annual water right (Qa) of the City's production wells and spring sources is equal to 13.2 mgd, while their total instantaneous water right (Qi) is equal to 20.3 mgd. Approximately 1% of the water supply is augmented with treated surface water purchased from SPU annually to supply water to the Boeing Plant.
Covington Water District
Covington Water District's (CWD) water supply consists of groundwater from 12 production wells and water from Second Supply Project (SSP) on the Green River Watershed, managed by TPU. In addition, CWD purchases water from the City of Auburn. CWD is a member of the Cascade Water Alliance and will eventually purchase water from the new regional entity.
The combined annual water rights (Qa) for CWD's water sources including their portion of the second supply surface water totals 18.11 mgd, however they are currently limited by the number of connections of the SSP to draw the full amount of water. Covington Water District's total instantaneous (Qi) rights are equal 25.6 mgd.
City of Puyallup
The City of Puyallup obtains its groundwater water supply from 7 sources, 5 wells and 2 springs. The largest source is Maplewood Springs. The combined annual groundwater rights (Qa) for the City's wells and springs total 10.2 mgd while their instantaneous (Qi) rights are equal to 14.4 mgd.
Sammamish Plateau Water and Sewer District
The primary source for the Sammamish Plateau Water and Sewer District is groundwater that is pumped from 11 wells. Eight of the groundwater wells are completed in 3 aquifers located under the Sammamish Plateau and 3 are completed within the Lower Issaquah Valley. Sammamish Plateau Sewer and Water District is a member of Cascade Water Alliance and supplements its groundwater supply through purchases from Cascade. The purchased surface water is supplement in the winter and early spring seasons (November through April) to provide water supply for consumption and their ongoing aquifer storage and recovery program.
The total annual quantity (Qa) of their groundwater rights is equal to 6.7 mgd, while the instantaneous quantity (Qi) is equal to 15.2 mgd.
City of Marysville
The City of Marysville obtains its water through surface and groundwater sources and supplements its own supplies with purchased the City of Everett. Surface water is obtained primarily from the Stillaguamish River, which provides approximately 16% of the total water for the City. Water purchased from Everett provides approximately 57% of the water supplied to the City. The remaining water is collected from other groundwater sources.
The total annual water right quantity (Qa) for the City's surface and groundwater sources is equal to 6.0 mgd and the instantaneous water right (Qi) is also equal to 6.0 mgd.
Parkland Light & Water Company
Water supply sources for the Parkland Light & Water Company are 12 groundwater wells. The wells tap aquifers within the Clover/Chambers Creek Basin. The combined annual water rights (Qa) from their production wells equal 5.2 mgd and their total instantaneous (Qi) water right is equal to 25.4 mgd.