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Water System


Water System Plan Update The Future — The Second Supply Project
It Starts at the Green River Watershed Howard Hanson Dam Additional Storage
Groundwater Helps Meet Growing Needs Habitat Conservation Plan
Storing Water To Meet Peak Demands Water Conservation Plan
Green River Watershed Management Plan Tacoma Water’s Service Area and Water Use

2006 Tacoma Water Comprehensive Water System Plan Update

Green River Diversion DamTacoma Water’s planning activities center on the need to meet increasing demands in an expanding service area, to address local, state and federal government planning policies and regulations, to satisfy Department of Health planning guidelines and to satisfactorily address customer expectations. As a municipal water supplier, Tacoma Water is required by the Washington State Department of Health to update its water system plan every six years.  The 2006 Tacoma Water Comprehensive Water System Plan Update assists Tacoma Water in making the best use of available resources in order to provide quality water services and protect the health of its customers.  The Plan accomplishes the following objectives:

  • Provides Tacoma Water with a guide to evaluate the impacts of future proposed development and land use changes on the water system
  • Identifies existing and potential water resources available to Tacoma Water.
  • Provides a review of existing water quality data for Tacoma Water’s system and discusses existing and forthcoming regulatory requirements as they apply to the water system.
  • Conducts a water system inventory, including a description of supply, storage and distribution facilities operation.
  • Establishes water system policies that will help Tacoma Water make decisions and manage the water system, incorporating the requirements discussed in the water resource, water quality, water supply and water distribution sections of the Plan.
  • Documents Tacoma Water’s Satellite System Management program.
  • Documents planning and design criteria used by Tacoma Water.
  • Identifies existing and potential future water system deficiencies by conducting storage and transmission/distribution system analyses.
  • Develops a program of capital improvements, including priorities for construction and provides a financial evaluation to support the identified water system improvements.
  • Documents Tacoma Water’s commitment to implementing an effective conservation plan as an element of the overall Tacoma Water resource mix.
  • Documents Tacoma Water’s Green River Watershed Control Program.
  • Responds to new water system planning requirements resulting from the 2003 Municipal Water Law (HB 1338).
  • Incorporates Tacoma Water’s ten- year Business Plan Strategic Initiatives into the water system plan.

The Planning Process

The multi-year process of updating the Tacoma Water Comprehensive Water System Plan included agency, stakeholder and public outreach activities.  The Department of Health and Tacoma Public Utility Board have approved the 2006 Tacoma Water Comprehensive Water System Plan Update.  The 2006 Tacoma Water Comprehensive Water System Plan Update consists of Volume I and Volume II (titled Green River Watershed Management Plan).   Questions on the 2006 Tacoma Water Comprehensive Water System Plan can be directed to Susan Clark at 253-502-8204 or sclark@cityoftacoma.org

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Green River Watershed Management Plan (Volume II, August 2006 )

Mt. RainierVolume II of the 2006 Comprehensive Water System Plan Update (Green River Watershed Management Plan) serves as documentation of the watershed control program implemented by Tacoma Water for the Green River Watershed. Washington Administrative Code 246-290-690 mandates that public water supply systems using unfiltered surface water develop and implement a Department of Health approved watershed control program to avoid degradation of the physical, chemical, microbiological, and radiological quality of the source of the supply. The Green River Watershed Management Plan characterizes the watershed hydrology, geography and critical areas; details landowners and written agreements with landowners; identifies watershed characteristics and activities that may have an adverse effect on source water quality; summarizes monitoring and control of watershed activities; and discusses potential future improvements in watershed control.

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Tacoma Water Conservation Plan

As required by the Washington State Department of Health, Tacoma Water has been developing a water conservation plan to be included as an element of the Tacoma Water Comprehensive Water Plan 2006 Update.

Since the 1980s, Tacoma Water has been committed to implementing an effective conservation program as an element of the overall water resources plan. The focus has been on developing long-term sustained conservation activities in a balanced program including both supply management and demand management measures. The conservation measures have been designed to increase customer awareness of conservation issues, to provide incentives for reduced consumption and to reduce water losses within the system.

Low flow shower headThe general goal of Tacoma Water’s conservation program is to protect and preserve present and future water resources and to maintain or reduce present per capita water usage levels in all customer classes.  Tacoma Water’s specific conservation goal is to reduce per capita water use by 10 percent over the ten year time period 2000 to 2010.

In 2006, Tacoma Water undertook a conservation program assessment to evaluate the existing water conservation program – which is based upon a 1997 conservation program assessment – and to recommend elements to strengthen the program. The objectives of the 2006 Conservation Program Assessment include:

  • To instill a long-term conservation ethic among customers (retail, wholesale and in regional supply area).
  • To establish a 2000 base year on water use.  This will enable the utility to measure the effectiveness of the conservation program in accordance with State guidelines.
  • To establish criteria to assess the effectiveness of the conservation program including methods to establish savings, effectiveness of public information programs and measurements of economic benefits received.
  • To identify conservation program activities which, if implemented by Tacoma Water, will result in water savings necessary to meet Tacoma Water’s 10 percent reduction goal.

The results of the conservation program assessment were used to develop the Tacoma Water Conservation Plan.

Over the next four years – through 2010 – Tacoma Water will select for implementation the conservation program packages that are cost effective for customers. The water conservation program packages that may be implemented include:

  • Faucet Aerators & Low Flow Showerheads for Residential Customers
  • High-Efficiency Toilets for Residential Customers
  • Pre-Rinse Spray Valves for Commercial Customers
  • High-Efficiency Clotheswashers for Residential Customers
  • High-Efficiency Urinals for Commercial Customers
  • High-Efficiency Commercial Kitchen Equipment
  • Public Education
  • Water Efficient Product and Service Promotion
  • Intergovernmental & Regional Cooperation

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Tacoma Water’s Service Area and Water Use

Tacoma Water provides water service to residences, businesses and industries located in the cities of Tacoma, University Place and Ruston; in portions of the cities of Puyallup and Federal Way; and, in portions of Pierce and southern King county. Tacoma Water also provides wholesale water supplies to 14 independent water systems operating in Pierce and King counties and provides management services to the Tacoma Narrows Airport located on the Gig Harbor Peninsula. Tacoma Water is a participant in, and operator of, the Second Supply Project: a new regional water partnership between Tacoma Water, the Lakehaven Utility District, the City of Kent and the Covington Water District. To view a map of Tacoma Water's service are click here.

As of year-end 2006, Tacoma Water provides retail water service to approximately 94,000 connections or an estimated population of 302,392. While single-family residential connections account for the majority (89 percent) of Tacoma Water’s customer base, water use by the single-family customer class accounts for 36 percent of total water consumption. On the other hand, one industrial connection (the Simpson Tacoma Kraft Mill) accounts for 27 percent of total water consumption. The multi-family customer class makes up 5 percent of Tacoma Water’s customer base and 12 percent of total consumption, with commercial connections accounting for 6 percent of the customer base and 15 percent of consumption. 

Chart of water consumption by customer class

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The Water Supply Starts at the Green River Watershed

The Green River begins in the Cascade Mountains near Stampede Pass and serves as Tacoma Water’s primary water supply. For more than 80 years, Tacoma Water has managed the Green River watershed. This forested land serves as a collecting point for melting snow and seasonal rainfall. The watershed covers 148,884 acres on the west flank of the Cascade Mountains between Chinook and Snoqualmie passes. Tacoma Water owns only 10 percent of the watershed, but has agreements with other landowners to limit activities in order to keep the Green River water supply pure and fresh. 

Tacoma Water’s First Diversion water right is for up to 73 million gallons of water each day (MGD). Tacoma Water can substitute this Green River supply with water from seven wells located along the North Fork of the Green River. The well field can normally meet the same 73 MGD production as the Green River in the winter and spring months. The North Fork wells are used only when the water in the river is too turbid (or cloudy), usually in the fall and winter, or in the event of other unusual or unacceptable water quality in the Green River.

Headworks Diversion Dam, Intake and Fish FacilityIn addition to Tacoma Water’s First Diversion water right, the Green River is also the source of supply for a regional partnership formed by the City of Kent, the Covington Water District, the Lakehaven Utility District and Tacoma Water. The Second Supply Project, named after the fact that this is the second supply coming from the Green River, supplies up to 65 MGD to Tacoma Water and its Second Supply Project Partners. The Partners participate in the Second Supply Project under the terms of the Second Supply Agreement. Tacoma Water has a 15/36 Participant Share and the City of Kent, the Covington Water District and the Lakehaven Utility District each have a 7/36 Participant Share. Generally, a Participant Share represents a participant’s proportional right to receive, and obligation to pay for, water delivered by the Second Supply Project.   

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Groundwater Helps Meet Growing Needs

In addition to surface and groundwater sources from the Green River watershed, Tacoma Water owns 24 wells located in and around the city. These wells pump water from aquifers, which are underground layers of water saturated sand and gravel. This water comes from local rainfall, which has percolated deep into the soil. Tacoma Water’s wells have a short-term combined pumping capacity of about 60 million gallons per day. Approximately 15 percent of total annual water requirements are met through the use of the Tacoma Water groundwater sources. Current plans call for the development of additional well capacity, consistent with existing water rights, to meet projected future water requirements.

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Storing Water to Meet Peak Demands

Alaska Street ReservoirTacoma Water has built a storage system consisting of the 210-million-gallon McMillin Reservoir located near Puyallup, plus 16 other reservoirs, standpipes and tanks that can store up to 78 million gallons of additional water. This system, operated mostly by gravity, assures that water can be supplied economically to customers throughout the Tacoma Water service area. Planning is underway to convert the currently uncovered McMillin Reservoir to a covered facility with reduced capacity. Design work is to occur in 2008 with the first of three 30 to35-million-gallon tanks to be constructed in 2009.
 Alaska Street Reservoir

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The Future — The Second Supply Project

To meet its own future water supply requirements, as well as to increase regional supply, Tacoma Water has been developing the Second Supply Project since 1968.  In 1970, a plan was developed for another transmission main, Pipeline No. 5 (now also known as the Second Supply Project Pipeline) to convey additional water supply to the City and to blend water from the North Fork Well field with Green River water during high turbidity events. Phase I of the project, development of the well field, connecting pipe and reservoirs was completed in 1975.

Construction sign for Second Supply ProjectPhase II, design and construction of the transmission main, was hindered by politics and evolving environmental laws in the early 1980s. The Second Diversion water right on the Green River was finally awarded in 1986. In 1995, an agreement with the Muckleshoot Indian Tribe (MIT) regarding the Green River was reached. All major permits and permissions for the construction of the Second Supply Project Pipeline were acquired by 1997. By 2001, a Partnership Agreement between Tacoma Water, the City of Kent, the Lakehaven Utility District and the Covington Water District was enacted which covers each participants’ rights and obligations regarding the use of the Second Supply Project. Although the Second Supply Project was developed as a joint venture known as the Regional Water Supply System (RWSS) and operation and maintenance of the RWSS is jointly funded by the Partners, the operation and maintenance of the RWSS is carried out entirely by Tacoma Water, in a manner as described in the 2002 Second Supply Project Partnership Agreement.

In total, the Second Supply Project consists of the following components:

  • Green River water as allowed under Tacoma Water Green River Second Diversion water right;
  • The 34-mile-long Second Supply Project Pipeline;
  • Improvements made at the Tacoma Water Headworks diversion dam and intake;
  • Second Supply Project fisheries and environmental enhancements, including a new fish trap-and-haul facility at the Headworks diversion dam;
  • The right to store water as a result of the Howard Hanson Dam Additional Storage Project; and
  • New Treatment Facilities (disinfection, pH adjustment, fluoridation and ozone).

After many years of preparation, major construction of the Second Supply Project began in 1999. In 2000, the Tacoma to Federal Way portion of the Second Supply Project Pipeline was completed and Lakehaven Utility District began receiving water from another portion of the Tacoma Water system. In 2002, the upper ten miles of the Second Supply Project Pipeline was completed and placed in service, delivering water to the City of Kent and to the Covington Water District. Changes to the Headworks diversion facilities, including the addition of a new fish trap-and-haul facility, were completed in 2006.  The new Phase I water treatment facilities (chlorination, fluoridation and pH adjustment) were finished and placed in service in August 2005. Ozone treatment and an integrated operations center are anticipated to be completed by 2007. On October 20, 2005, Second Supply Project water began flowing through the entire 34-mile-long Second Supply Project Pipeline. On May 16, 2006 Tacoma Water made use of the Second Diversion water right to meet demands for the first time.

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Howard Hanson Dam Additional Storage Project

Howard Hanson Dam spans the Green River approximately three miles upstream from Tacoma Water’s Headworks diversion dam, where water from the Green River is diverted by Tacoma Water. The Howard Hanson Dam was built in 1961. The U.S. Army Corps of Engineers (USACE) operates the dam, controls water levels in the reservoir, and regulates flow in the Green River for flood control in the winter and flow-augmentation during low-flow periods (typically late summer through fall). The primary authorized use of the project is to provide flood control for the Green River Valley during the winter. Secondary authorized uses include augmentation of low summer flows downstream of the dam, irrigation, and water supply. The dam impounds the Green River, forming the Eagle Gorge Reservoir.

Eagle Gorge ReservoirTacoma Water and the USACE are working in cooperation on the Howard Hanson Additional Water Storage Project. This project – a component of the Second Supply Project - will increase the amount of water stored behind Howard Hanson Dam for use as municipal supply by increasing the surface elevation from 1147 feet (above sea level) to 1167 feet. This will increase the stored volume of water by approximately 75 percent. Concurrent with this increased storage volume, a new downstream Fish Passage Facility is being constructed to enhance survival and passage of out-migrating juvenile fish. This facility will predominantly take water off the top water elevations from the reservoir, rather than the deep elevations, as is currently the design. Storage plus downstream migration is expected to be in service by 2009, with some storage capability available in 2007.

Under the Howard Hanson Dam Additional Storage Project, Tacoma and its Second Supply Project Partners will have the ability to store up to 20,000 acre-feet (AF) of water behind Howard Hanson Dam during the spring. Tacoma Water’s share of the stored water is 15/36, or up to 8,333 AF, which equates to 30 MGD (million gallons per day) if used at a uniform rate over a 90-day period.

If water is diverted to storage during the spring, it will not be available for consumption during the spring. Each year Tacoma Water, the Lakehaven Utility District, the City of Kent and the Covington Water District will each need to decide if they want to divert water to storage during the spring and meet spring demands using other sources of water, or consume Second Supply Project water during the spring and rely more heavily on other sources during the summer. In either case, the Additional Storage Project will provide flexibility in how sources are used and will allow for the movement of less valuable spring-time water into the summer where it is more valuable given increased summer demand.

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Updated: September 23, 2008