The Spokane Valley-Rathdrum Prairie Aquifer Atlas
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The Spokane Valley-Rathdrum Prairie Aquifer Atlas 2009 Update Contents Welcome! A Bi-State Aquifer Study Navigating the Atlas he Spokane Valley-Rathdrum Prairie Aquifer Atlas In response to concerns about continued growth, water The pages are organized into four (4) theme Tpresents a comprehensive summary of the region’s management issues, and water availability, a bi-state categories with a unique color for each . most precious groundwater resource and is a basic aquifer study was initiated in 2004 by the Idaho Department reference of the geographic, geologic and hydrologic of Water Resources, the Washington Department of characteristics of this Aquifer . It is intended for broad Ecology, and the U .S . Geological Survey . The study was Shaded Relief Map . Front Cover community use in education, planning, and general funded by: Congressional appropriations through the Contents . 1 technical information . The preparation and publication U .S . Environmental Protection Agency, state funding from of the original Atlas were partially funded by a United both the Washington and Idaho legislatures and staff Introduction . 2 States Environmental Protection Agency aquifer support from both state agencies . The total study cost was The wellhead protection grant . approximately $3 .5 million . Aquifer Historic Aquifer . 3 The Spokane Valley-Rathdrum Prairie Aquifer spans Building upon previous studies and new data from Aquifer Timeline . 4 two states (Washington and Idaho) and lies within four a coordinated ground and surface water monitoring counties (Kootenai, Bonner, Stevens and Spokane) . program conducted in 2004-2005, the study reassessed Aquifer from Space . 5 the hydrogeology and water budget of the Spokane Valley- Natural resources, such as the Aquifer, that cross Geography . 6 political boundaries are often subject to different, and Rathdrum Prairie Aquifer (Aquifer) . The Aquifer boundary sometimes conflicting standards, protection and uses . has been redrawn to reflect recently available geologic Glacial Lake Missoula . 7 This Atlas is a joint effort by agencies in both states to information (see below), and the result is a new, detailed create a holistic representation of the Aquifer as both estimate of the shape of the basin . A key objective of the Aquifer Ice Age Floods . 8 a geologic feature and a natural resource used daily by study was to develop a ground-water flow model to serve as Formation more than 500,000 people . a tool for estimating Aquifer dynamics, and the model was Geology . 9 completed in 2007 . Results of this study were incorporated Political boundaries are absent on the front cover map . into this Atlas update . Geologic Map . 10 The authors intend the reader to first view the Aquifer Water Cycle . 11 as a continuous natural feature, then investigate the various aquifer elements presented in this Atlas . The Water Budget . 12 authors believe that factual information about the Aquifer will generate greater public understanding of the Aquifer Recharge . 13 region’s groundwater and lead to continued protection and wise use of this precious and finite resource . Aquifer-River Interchange . 14 Water The original Aquifer Atlas was published in 2000, Aquifer Extent Used Budget Aquifer Discharge . 15 and an Update was issued in 2004 . This document in 2000 & 2004 Atlases is an update of the 2004 publication that includes Human Uses . 16 information from the 2007 USGS Bi-State Aquifer Aquifer Model Maps . 17-18 Study . Aquifer Monitoring Sites . 19 Aquifer Study Results . 20 Water Quality . 21 Aquifer Extent Aquifer Issues . 22 The Aquifer extent designations differ somewhat between Aquifer Tour Map . 23 investigators and over time . The 2000 and 2004 Aquifer Aquifer Tour . 24 Atlases used a modified version of the original Sole Aquifer Extent Used General Source Aquifer boundary designated by the USEPA in in 2009 Atlas Regional Trends . 25 1978, as shown at upper right . The extent used in this Reference document is the same defined in 2005 by the USGS Glossary & Definitions . 26-27 in their Scientific Investigations Report 2005-5227, as shown at right and on page 19 . The Aquifer extent used Acknowledgements . 28 in the 2007 groundwater modeling (see page 17) is a modified version of the 2005 USGS extent . Ice Age Map . Back Cover 1 Spokane Valley-Rathdram Prairie Aquifer Atlas 2009 Update, see Page 28 for a list of contributors and authors, printed December 31, 2009, ©2009 - may be freely reproduced and copied with appropriate credit given. Introduction Groundwater Recharge per Capita SPOKANE’S WATER PUREST IN WORLD City Bacteriologist Frank Rose Reports Results No Colon Bacilli Found Showing the Spokane water supply purer than the average of American cities, Frank Rose, city bacteriologist, has made a report of tests from the city well made monthly since last October. The tests are simply counts of the number of bacteria found in a cu- bic centimeter of water. The average count shows only Groundwater Recharge seven or eight germs in that in cubic meter per person annually 0 250 500 1,000 1,500 3,000 10,000 amount of water. The test was made from water taken from the drinking fountain at Howard Earth’s Water street and Riverside avenue or from water from a faucet in the Of all the Earth’s water, only about 3% is fresh water . The majority of fresh water Rookery building. Speaking of is found in icecaps and glaciers (68 .7%) and groundwater (30 .1%) . A global view his tests, Dr. Rose said: of groundwater is provided in the map above . The remaining 1 .2% of freshwater is “It can be said that there is no The Aquifer contained in lakes, rivers, swamps, the atmosphere and the soil . Our Aquifer with its city in the world that has a bet- ample quantity of fresh, potable groundwater is a rare feature in the world . ter water supply than Spokane. The sole source of water for most people of gravels, cobbles, and boulders . Water Water which shows 100 germs in in Spokane County, Washington and from adjacent lakes, mountain streams, a cubic centimeter is considered Kootenai County, Idaho, is a large the Spokane River, and precipitation flows comparatively pure and drink- underground rocky formation containing through these flood deposits supplying the able. I made from four to eight high-quality water called the Spokane Aquifer . counts monthly since last Octo- Climate Change ber, and the counts in any one Valley-Rathdrum Prairie Aquifer (Aquifer), month was 17 bacteria, while the In the 1970s area residents recognized and it is also commonly known as the The Climate Impacts Group (CIG) located at the tests last month showed 15 bac- that their unconfined aquifer could “Rathdrum-Spokane Aquifer .” Discovered University of Washington (Seattle) is studying the teria in eight tests, less than two easily become contaminated . The highly in 1895, this Aquifer has become one of the impacts of natural climate variability and global each. most important resources in the region, permeable flood deposits, together with climate change on the U .S . Pacific Northwest . “In April, 1908, I made tests of very thin topsoil layers in many locations, the river water from which Spo- supplying drinking water to more than The CIG used climate computer models to assess 500,000 people . The Aquifer has been make the Aquifer highly susceptible to probable impacts associated with projected 21st kane got its drinking supply at that time. I took water from the studied in considerable detail since 1977, pollution . The Environmental Protection century changes in climate that indicate three place where the Coeur d’Alene and the results of these investigations Agency (EPA) took the first important step major changes for the Inland Northwest . sewer emptied into it and anoth- have produced programs and regulations to protect the Aquifer by designating the Spokane Valley-Rathdrum Prairie a “Sole First, winter snow pack will be lower than normal . er sample from a place about 500 designed to ensure this aquifer will remain feet below the outlet of the sewer. Second, while total annual precipitation will a valued and protected resource for future Source Aquifer” in 1978 . It was the second In both cases the number of bac- generations . aquifer in the nation to receive this special remain about the same, extreme high precipitation teria was so great as to be practi- designation . The sole source designation events will increase . Third, temperatures are cally uncountable. The Spokane Valley and Rathdrum Prairie increased public awareness for Aquifer projected to increase across all seasons with the “In contrast to this is the practi- are ancient geologic features that have, protection and supported the development largest temperature increases cal purity of the water since last over millions of years, been formed by of special management practices (such as in summer . October. Special care was taken water flowing from the western slopes of eliminating septic tanks and pre-treating Aquifer Facts to make tests for colon bacilli, As these changes occur, the the Rocky Mountains to the Pacific Ocean . stormwater over the Aquifer) by local Our Aquifer underlies about 370 square miles which show the presence of sew- Inland Northwest will likely age, and in no case was there a During the last Glacial Age (18,000 to agencies . Presently, Aquifer protection in two states . It has one of the fastest flow rates experience peak stream flows single trace.” 12,000 years ago), and possibly in multiple efforts are managed cooperatively by in the United States, flowing as much as 60 feet earlier in the spring and with previous Ice Ages, cataclysmic floods Spokane County, local cities, agencies per day in some areas . In comparison, a typical greater variability . How the inundated North Idaho and Washington as and utilities in Washington and by the aquifer has a flow rate between 1/4-inch and five feet per day .