Inventory of Dams Report for Selected Washington Counties and Selected Dam Hazard Categories Report data current to: 6/11/2019 Revised Edition June 2018 Publication #94-16 DEPARTMENT OF ECOLOGY State of Washington Department of Ecology - Water Resources Program - Dam Safety Office Report Run: 2019-06-11 13:37 i Document Information Copies of this document may be obtained from: Publications Distribution Department of Ecology P.O Box 47600 Olympia, WA 98504-7600 (360) 407-6624 Cover Photos: Top - Sylvia Lake Dam in Grays Harbor County in the Sylvia Creek drainage basin about 1 mile North of Montesano. The property is owned by Washington State Parks and Recreation Commission (State Parks) and was built for recreational purposes. This timber and concrete structure has dam buttresses or piers with concrete infills between each buttress. This dam has a concrete cut-off wall with a downstream grouted rock buttress on the right side of the dam. The principal spillway is located in the center concrete portion of the dam and is made up of five bays. It was originally constructed in 1901 with the most recent modifications occurring in 1995. Bottom - Tumwater Falls Dam on the Deschutes River at flood stage. Located in Tumwater, Washington and built in 1900, the Tumwater Falls Dam is very picturesque seen from either side of the river. The Department of Ecology is an Equal Opportunity and Affirmative Action employer and shall not discriminate on the basis of race, creed, color, national origin, sex, marital status, sexual orientation, age, religion, or disability as defined by applicable state and/or federal regulations or statutes. Report Run: 2019-06-11 13:37 ii Dam Inventory Report Table of Contents Section: Page: Inventory Selection Criteria 4 Introduction and Background 5 Dam Safety Office Background 6 Water Resources Background 6 Characteristics of Dams in WA 7 Characteristic Charts of Dams 8 Terminology Definitions 12 The Inventory by County 16 Dam Classification and Code Tables * Index by Dam Name * Index by Water Resource Inventory Area (WRIA) * WRIA Map by WRIA Number * * Due to the dynamic nature of this report, it is not possible to pre-calculate the page numbers for these sections of the report Report Run: 2019-06-11 13:37 iii This Inventory is Based on the Following Selected Counties and Dam Hazard Categories: County: Hazard Categories: Dam Count: Adams (all) 28 dams Asotin (all) 2 dams All 39 counties are listed. The results from your selection are highlighted in gray. Benton (all) 37 dams Chelan (all) 45 dams Clallam (all) 19 dams You have selected 39 of 39 Counties and 7 of 7 Hazard Categories. Applying Clark (all) 31 dams these two filters, this inventory now contains 1233 dams from 39 counties out of Columbia (all) 10 dams Cowlitz (all) 17 dams 1233 regulated dams in Washington State. Douglas (all) 23 dams Ferry (all) 11 dams Some counties may show a dam count of zero depending on the hazard category Franklin (all) 33 dams Garfield (all) 1 dams filters chosen. If this is the case, those counties will be highlighted in dark gray in Grant (all) 75 dams the list to the right and their statistics will be excluded from the text and charts Grays Harbor (all) 18 dams found in this report. Island (all) 13 dams Jefferson (all) 6 dams King (all) 127 dams (See Figure 1 on page 7 for a sorted distribution.) Kitsap (all) 25 dams Kittitas (all) 20 dams Klickitat (all) 15 dams Lewis (all) 53 dams Lincoln (all) 19 dams Mason (all) 23 dams Okanogan (all) 45 dams Pacific (all) 11 dams Pend Oreille (all) 42 dams Pierce (all) 58 dams San Juan (all) 55 dams Skagit (all) 30 dams Skamania (all) 10 dams Snohomish (all) 66 dams Spokane (all) 38 dams Stevens (all) 42 dams Thurston (all) 39 dams Wahkiakum (all) 1 dams Walla Walla (all) 17 dams Whatcom (all) 45 dams Whitman (all) 12 dams Yakima (all) 71 dams Report Run: 2019-06-11 13:37 1 Counties: 39/39, Hazard Categories: all, Dams: 1233/1233 Dam Inventory - Introduction and Background Introduction Background This Inventory of Dams is now an electronic report based on a series of In 1972, the U.S. Congress passed Public Law 92-367 which authorized the publications describing the physical characteristics of regulated dams in development of a National Inventory of Dams. Subsequently in 1975, the Washington State. It represents a compilation of information that was first Department of Ecology assembled the first dam inventory. This initial inventory assembled in 1975 and has been maintained and updated since that time. was published May 1976 in WRIS Information Bulletin No. 28. The full inventory contains 1233 regulated dams. These dams are defined as In the following years, this original inventory was updated with the assistance structures that can impound 10 acre-feet or more of watery material at the dam from the Seattle District office of the U.S. Army Corps of Engineers. In December crest elevation. Past publications had also listed dams that had been removed or 1981, the second Inventory of Dams in Washington State was published in a joint breached. This report only lists existing dams that are being operated that match effort by the Department of Ecology and the State Energy Office. your selection criteria. Figure 1 represents the number of inventoried dams by In 1986, the U.S. Congress passed the Water Resources Development Act of 1986, county. Public Law 99-662, which reauthorized the fiscal support for the National As with any database, this inventory represents current conditions to the best of Inventory of Dams. Monies provided by this source and administered by the our knowledge. No warranty for the correctness, accuracy, or usefulness of this Association of State Dam Safety Officials (ASDSO) have augmented ongoing data is expressed or implied. If errors or inaccuracies are discovered, or if you efforts to maintain and update the Washington inventory. have special accommodation needs, please contact the Dam Safety Office of This inventory is now available electronically. The Dam Inventory Report can be Ecology at (360) 407-7122 (voice) or (360) 407-6006 (TDD). requested from Gus Ordonez, Dam Safety Lead Engineer at [email protected]. Report Run: 2019-06-11 13:37 2 Ecology - Water Resources - Dam Safety Background Counties: 39/39, Hazard Categories: all, Dams: 1233/1233 Water Resources Program - Dam Safety Office Water Resources Historical Background Under state law, the Department of Ecology (Ecology) is responsible for In Washington State, dam safety concerns were part of the normal water-rights regulating dams that capture and store at least 10 acre-feet (about 3.2 million duties in the state departments of Conservation and Development and Water gallons) of water or watery materials such as mine tailings, sewage and manure Resources. In 1970, dam safety regulations were transferred to the newly created waste. Ecology's Dam Safety Office currently oversees 1088 of 1233 dams across Department of Ecology. In the early 1980s, a separate Dam Safety Office was the state. Through plan reviews and construction inspections, the agency helps formed to concentrate on dam issues, primarily in response to the National Dam ensure these facilities are properly designed and constructed. To reasonably Safety Act in 1977. In 1990, Ecology's Dam Safety Office was reorganized and secure the safety of human life and property, Ecology also conducts inspections initiated its first long-range planning for improving dam safety in Washington. of existing dams to assure proper operation and maintenance. The 145 Federal dams not overseen by Ecology are exempted by Washington State regulation WAC 173-175-020, but they will be included in this report if they meet your search criteria. Report Run: 2019-06-11 13:37 3 Characteristics of Dams in Washington Counties: 39/39, Hazard Categories: all, Dams: 1233/1233 Reservoir Purposes Dam Ownership Dams and reservoirs in Washington are constructed for a variety of purposes. As there are a wide variety of dam and reservoir purposes, there is a From the Washington counties and hazard categories selected for this report, correspondingly wide category of dam owners. To help delineate the types of about 6% of the dams are constructed for domestic water supply, 24% for owners, they have been separated into five categories: private, local government, irrigation, and another 23% of the dams are built for recreation. The remaining public utilities, federal, and state. From the Washington counties and hazard 47% of the dams provide a wide variety of functions including: water quality, categories selected for this report, 58% of the dams are privately owned and hydropower, flood control, and mine tailings storage. In addition, the larger many of these are for recreational purposes. Another 29% are owned by local reservoirs are commonly multi-purpose and serve a number of functions. See Bar governments and public utilities or irrigation districts for water supply, flood Chart 3 in the Characteristic Charts of Dams in Washington section for more control, or hydropower purposes. See Bar Chart 4 in the Characteristic Charts of details. Dams in Washington section for more details. Dam Height Downstream Hazard Classification The height of the dams also varies widely. Dams in Washington are categorized The Downstream Hazard Classification system used in Washington (Table 1.) is as small, intermediate, or large for purposes of setting design criteria, identifying similar to the types of classification systems used throughout the United States. acceptable construction methods and scheduling periodic inspections. From the The purpose of the system is to provide a simple characterization of the setting Washington counties and hazard categories selected for this report, 588 dams are downstream of a dam to reflect the general nature of consequences if the dam classified as Small, 530 are classified as Intermediate, and 111 are classified as were to fail and release the reservoir into the downstream valley.