56 Sea Grant Law and Policy Journal, Vol. 2, No. 1 (June 2009) Managing Water Resources for Sustainability on Vashon-Maury Island, King County, Washington Laurence Stockton, Eric Ferguson 1 “Whiskey is for drinking; water is for fighting over.” Mark Twain “When the well is dry, we know the worth of water.” Benjamin Franklin I. Introduction…………………………………………………………………………………….57 A. Geology…………………………………………………………………………………57 B. Precipitation and Climate Change…………………………………………………58 C. Population and Land Use/Cover……………………………………………………58 II. Vashon-Maury Island Water Resources…………………………………………………...60 A. Vashon-Maury Island Water Resources Report………………………………….61 B. Groundwater Management Plan…………………………………………………...64 C. Water Resources Evaluation………………………………………………………..66 III. Legal Framework for Management of Water on VMI……………………………………67 A. Water Code of 1917…………………………………………………………………..68 B. Groundwater Code of 1945………………………………………………………….68 C. Water Rights Claims Act of 1967…………………………………………………..69 D. Water Well Construction Act of 1971……………………………………………...69 E. Water Resources Act of 1971………………………………………………………..69 F. Public Water System Coordination Act…………………………………………...71 G. Growth Management Act……………………………………………………………72 H. Watershed Planning Act…………………………………………………………….72 I. Municipal Water Law………………………………………………………………..73 IV. Water Rights on Vashan-Maury Island……………………………………………………74 V. Managing VMI’s Water Resources for Sustainability……………………………………77 A. King County Groundwater Protection Plan………………………………………77 B. Vashon-Maury Island Groundwater Protection Committee…………………...77 C. Vashon-Maury Island Watershed Plan……………………………………………78 D. King County Comprehensive Plan…………………………………………………79 E. Sustainable Water Resource Management Strategy……………………………81 VI. Water Management Challenges…………………………………………………………….83 A. Models and Data……………………………………………………………………...83 B. Water Rights and Exceptions……………………………………………………….83 C. Laws, Plans, and Institutions………………………………………………………86 D. State and Local Authority…………………………………………………………..87 VII. Sustainable Water Resource Management Options……………………………………..87 A. Sustainability Report Card………………………………………………………….87 B. Conservation…………………………………………………………………………..88 1 Laurence Stockton is the Groundwater Protection Program Manager for King County (Washington) Department of Natural Resources and Parks. Eric Ferguson is a Water Quality Planner for the Groundwater Protection Program, King County Department of Natural Resources and Parks. Sea Grant Law and Policy Journal, Vol. 2, No. 1 (June 2009) 57 C. Exempt Wells………………………………………………………………………….90 D. Exempt Wells Legislation…………………………………………………………...90 E. State Rulemaking Authority to Protect Surface and Groundwater…..………92 F. Growth Management Strategies……………………………………………………93 G. Low Impact Development……………………………………………………………94 H. Rainwater Harvesting……………………………………………………………….95 I. Adjudication…………………………………………………………………………...96 VIII. Desired Outcomes……………………………………………………………………………..96 I. Introduction The Vashon-Maury Island (VMI or Island) watershed is an EPA-designated sole source island aquifer located in the Puget Sound. All drinking water sources on the island (springs, surface water, and groundwater) are supplied by precipitation. Understanding the water budget for VMI, and changes that are occurring in response to human activities and climate, is critical to determining the amount of water that can be consumed on a sustained basis. On VMI, there is broad local recognition of the shared responsibility for water resources and recognition that each water user can affect the quantity and quality of the water supply of others. Vashon-Maury Island is located in the Puget Lowland within the boundaries of King County, Washington situated southwest of Seattle and north of Tacoma.2 The Island encompasses approximately 37 square miles of which 29.7 square miles are on Vashon Island and 7.0 square miles on are Maury Island (see Figure 1). The topography of the Island varies from sea level to elevations in excess of 460 feet based on U.S. Geological Survey topographic maps. The shoreline extent of Vashon-Maury Island is just over 58 miles, most of which lies beneath steep, slide-prone slopes. The Island has more than 70 stream basins.3 Two of these, Judd Creek (3,149 acres) and Shinglemill Creek (1,996 acres), are large with separate sub-basins. All of the stream basins drain into Puget Sound. A. Geology A recently updated geologic map of VMI provides a comprehensive description of its geology. In 2004, GeoMap NW completed a detailed analysis of field data and data compiled from well logs for King County as part of the Water Resources Evaluation (WRE) Project (discussed in detail below). The analysis concluded that the Island is composed of glacial derived sediments deposited during several glacial episodes. The predominant geology on Vashon-Maury Island is glacial till. This unit (as well as other till-like units) covers 2 The two islands are linked by a narrow isthmus and are not, therefore, truly independent islands. Vashon-Maury Island is bordered on the west by Colvos Passage from the Kitsap Peninsula, on the south by Dalco Passage from Tacoma, on the east by Puget Sound and King County, and on the north by Puget Sound. Vashon Island is about 13 miles long (north to south) and 4 miles across (east to west) in the widest areas. Maury Island is about 5 miles long (northeast to southwest) and about 1 mile across (northwest to southeast). 3 KING COUNTY, DEPARTMENT OF NATURAL RESOURCES AND PARKS, VASHON-MAURY ISLAND RAPID RURAL RECONNAISSANCE REPORT S-2 (2004) available at http://www.kingcounty.gov/environment/watersheds/central-puget-sound/vashon-maury- island/recon-report.aspx (last visited June 15, 2009). 58 Sea Grant Law and Policy Journal, Vol. 2, No. 1 (June 2009) approximately 68% of the Island and helps define the topography. The remaining 32% of the Island is composed of glacial outwash and alluvial deposits generally occurring on stream corridors and shoreline areas where erosion has removed the till overburden. In addition, GeoMap NW updated the aquifer contamination susceptibility mapping on Vashon-Maury Island by compiling a new geologic map and newly gathered depth to water information. The updated aquifer contamination susceptibility mapping is the foundation for the Critical Aquifer Recharge Area (CARA) map showing critical water supply aquifer recharge sites on Vashon-Maury Island. B. Precipitation and Climate Change Precipitation is the main source of recharge and can vary greatly across Vashon-Maury Island. According to the National Oceanic and Atmospheric Administration’s average precipitation zone maps for the Puget Sound area, Vashon-Maury Island has three zones (at 5-inch intervals) across the Island, with rainfall ranging from 45 inches to 35 inches per year. The measured variation was 18 inches from the east to west side of the Island.4 In 2004, additional precipitation gauges were installed as part of the WRE Project to help determine the variation in precipitation across the Island.5 New rainfall contours (zones) were generated from this new data showing a variation of about 13 inches (48 to 35 inches/year) across the island. The new precipitation data is being used to model a more representative distribution of recharge for the Island. Recently, the University of Washington Climate Impacts Group predicted a warming trend in temperature for this region.6 The Group predicts that by 2075 the average temperature will increase by 4 to 9 ºF in the summer and by 2 to 8 ºF in the winter. The predictions for the total amount of precipitation are variable depending on the model, but there is agreement that precipitation is likely to fall with higher intensity over shorter time periods. Despite unknown changes in the amount of precipitation, changes in recharge will occur on VMI due to elevated temperatures resulting in more evapotranspiration and less groundwater inflow. C. Population and Land Use/Cover The population of Vashon-Maury Island is growing. The Island population has grown steadily from 6,516 in 1970, to 7,377 in 1980, to 9,309 in 1990, to 10,100 in 2000.7 The fastest growth since 1970 occurred between 1980 and 1990 when the population increased 4 J.R. CARR, CARR & ASSOCIATES, VASHON-MAURY ISLAND WATER RESOURCES STUDY (1983). 5 ERIC FERGUSON, KING COUNTY DEPARTMENT OF NATURAL RESOURCES AND PARKS, VASHON-MAURY ISLAND 2005 DATA REPORT (2006), available at http://your.kingcounty.gov/dnrp/library/2006/kcr1941.pdf (last visited June 15, 2009). 6 King County, Climate Change Technical Subcommittee Regional Water Supply Planning Process, Climate Change Building Blocks (2006). 7 U.S. CENSUS BUREAU, WASHINGTON: 2000 SUMMARY POPULATION AND HOUSING CHARACTERISTICS, PHC-1-49 (2002) available at http://www.census.gov/prod/cen2000/phc-1-49.pdf (last visited June 15, 2009). Sea Grant Law and Policy Journal, Vol. 2, No. 1 (June 2009) 59 26%. Between 1990 and 2000 the rate of growth had slowed to 9%. According to the Puget Sound Regional Council (PSRC), the population of VMI will continue to grow.8 Fig. 1. Map of Vashon-Maury Island, courtesy of King County. 8 The PSRC estimates that the population of the Island will increase by 1,000 people by 2040, or 10% per decade. PUGET SOUND REGIONAL COUNCIL, VISION 2040: THE GROWTH MANAGEMENT, ENVIRONMENTAL, ECONOMIC, AND TRANSPORTATION STRATEGY FOR THE CENTRAL PUGET SOUND REGION (2008), available at http://psrc.org/projects/vision/index.htm (last visited June 15, 2009). 60 Sea Grant Law and Policy Journal, Vol. 2, No. 1 (June 2009)