Reprinted with permission from the Introduction to the Issaquah Creek Valley Ground Water Management Plan:
Draft December 1994; March 1996.
The Issaquah Creek Valley Ground Water Management Area's Ground Water Management Plan was developed by the Issaquah Ground Water Advisory Committee to meet the ground water protection needs of the area. The goal of this plan is (1) to protect the quality and quantity of ground water within the area for present and future use, and (2) to provide for effective and coordinated management of this essential resource. A comprehensive ground water plan tailored to the specific needs of the region is necessary to protect the ground water supply, especially considering expected population increases.
Reliance on Ground Water
In the Issaquah Creek Valley Ground Water Management Area, ground water provides 100 percent of the water used for private, municipal, industrial and agricultural needs. Ensuring that ground water is available for the uses noted is crucial. The natural hydrologic system can be interrupted by development, by paving over recharge areas, and by aquifer overuse. Promoting development techniques to ensure that continued recharge to the aquifer occurs can prevent water losses to the system; however, wise use and management of the resource can only occur after the extent of the resource is determined.
Threats to Ground Water
Generally, the quality of ground water meets potability (drinking water) standards throughout the Issaquah Creek Valley Ground Water Management Area. However, ground water is susceptible to contamination and depletion. As population increases, the threats of ground water contamination and depletion also increase. King County's population is expected to increase by 325,000 by the year 2014, with the Issaquah area's population (excluding the Sammamish Plateau area) increasing to 13,967. New urban and residential development, and expanding industrial uses are introducing potential sources of ground water contamination-and the possibility of decreasing the natural recharge. Geologic conditions in the Issaquah Creek Valley Ground Water Management Area may make the ground water extremely vulnerable to contamination from residential, commercial, and other sources.
A ground water management plan for the Issaquah Creek Valley Ground Water Management Area is intended to address these specific concerns.
Legislative History Surrounding the Ground Water Management Program
The following introduction to the Ground Water Management Program has been reprinted with permission from the State of Washington Department of Ecology April 1986 Booklet: Guidelines for Development of Ground Water Management Areas and Programs (Chapter 173-100 WAC)
In response to growing concern about Washington State's ground water resources, the 1985 legislature passed landmark legislation to assist state and local governments in effectively managing the public's ground water. Substitute House Bill 232 directed the Department of Ecology to establish a process for the identification and designation of ground water management areas and for the development of comprehensive ground water management programs. This process is described in Chapter 173-100 WAC of the state administrative code, entitled "Ground Water Management Areas and Programs which became effective on January 17, 1986.
What is a "ground water management area"?
A ground water management area is a specific geographic area which encloses one or more aquifers and in which there exists a justifiable concern for the quality and/or quantity of the ground water. The purposes of designating a ground water management area are to:
The regulation states that an area must first be designated by Ecology as a ground water management area before an advisory committee can be established to develop a ground water program.
Reference: WAC 173-100-050
What does Ecology consider a "justifiable concern?"
A list of concerns to help guide in the identification of probable ground water management areas is included in WAC 173-100-050 of the regulations. The following is a summary of that list:
Aquifers where an approved coordinated water system plan has identified a need for a ground water management program.
What is a "ground water management program"?
A ground water management program is a comprehensive program designed to protect ground water quality and assure ground water quantity for current and future uses.
The Issaquah Creek Valley was designated a Ground Water Management Area by the Department of Ecology in December, 1987.
Water Use in the Ground Water Management Area
City of Issaquah: The city of Issaquah operates a Group A water system, which is defined as a public water system with 15 or more connections. The City has five wells ranging in depth from 97 to 412 feet. Water rights allow water to be pumped at rates of 250 gpm to 1,200 gpm depending on which well is being pumped.
Sammamish Plateau Water and Sewer District: The Sammamish Plateau Water and Sewer District draws all of its water from wells, with only wells No. 7, 8 and 9 operating in the study area. Located between Interstate 90 and East Lake Sammamish Parkway, wells 7 and 8 have an actual depth of 150 feet and carry a potential capacity of 2,000 and 3,500 gpms, respectively. Well 9 is located north of Interstate 90 and east of East Lake Sammamish. It is completed to a depth of 200 feet and has a potential capacity of 3,500 gpm.
King County Water District #90: Water District #90 operates a Group A water system serving the King County community of Newcastle. Only a small portion of this district exists within the boundaries of the Issaquah Ground Water Management Area. The Lake MacDonald residential area represents the largest area served by District #90 in the Issaquah Ground Water Management Area. No Group A source wells for this district are located in the Issaquah study area.
King County Water District #123: District #123 operates a Group A water system serving Preston. Only a small portion of this district falls within the boundaries of the Issaquah Ground Water Management Area.
Other Purveyors: The largest private Group A water system in the study area serves the Mirrormont area. Water provision in the Mirrormont area is from five Group A wells that range in depth from 209 feet to 325 feet and have a combined potential capacity of 1,000 gpm. .Other Group A providers in the area include Overdale Water, Four Lakes, First City Development Corp., Consolidated Dairy, WA State Parks. In addition to these purveyors, there are numerous Group B water systems and individual wells in the Issaquah Ground Water Management Area.
Questions or comments can be directed to:
Issaquah GWAC Education Chair