Swamped With Drought - Expedited Reclaimed Water Implementation in King County, Washington

摘要

On March 14, 2001, under recommendation from the Department of Ecology and the Executive Water Emergency Committee, Washington State Governor, Gary Locke, declared drought status in Washington State. The National Weather Service reported the winter of 2000-2001 as the driest winter for Washington since 1976-77. It was also one of the five driest in the past 100 years. Snow pack measurements indicated that there would be less than seventy five percent of normal runoff this year. Runoff from the snow pack is a major source of water to streams. This affected reservoir levels as well as groundwater recharge. Washington instituted conservation measures to maintain instream flows required for salmonids and other aquatic life as well as for providing the hydropower generating capacity to meet energy needs. At the time of the drought declaration, King County Department of Natural Resources was already in the process of developing a comprehensive reclaimed water program to defer the need to develop new potable water supplies. The County was also in the process of implementing its own drought response plan. The county's two wastewater treatment plants currently have the capacity to produce up to two million gallons of Class A reclaimed water per day, some of which was already in use irrigating parks, ball fields and for landscaping. Portions of the distribution system were also in place. The county has the capability to use treated secondary effluent for non-contact cooling and similar industrial uses. King County recently also completed a water reuse task force report identifying potential satellite facility locations for non-potable use. The county is currently implementing a comprehensive nine-month pilot-scale study to evaluate potential technology treatment trains for satellite facility use. King County executive, Ron Sims, responded to the drought by asking county staff to rapidly accelerate the development of the reclaimed water program to aid in reducing the potential effects of the water shortage. This paper will discuss the challenges, innovative solutions, successes and lessons learned from those efforts.