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Chehalis River and Grays Harbor Watershed| Waterbody Name | Chehalis River and Tributaries |
| WRIA(s) | 22 and 23 |
| County(ies) | Grays Harbor Lewis Mason Pacific Thurston |
| Parameter(s) | Fecal Coliform Bacteria Dissolved Oxygen Temperature |
| Current Status | Implementation plans completed for:
|
| TMDL Approval Date (if applicable) | Dissolved Oxygen:
Fecal coliform bacteria:
Temperature:
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| # of TMDLs (if approved) | Dissolved Oxygen: 32 Black River:
Grays Harbor/Chehalis: 28 Upper Chehalis:
|
| TMDL Lead(s) | Dave Rountry, Water Quality Program - SWRO Greg Pelletier, Environmental Assessment Program Anise Ahmed, Environmental Assessment Program Paul Pickett, Environmental Assessment Program |
The Chehalis River Basin (Basin) lies between the Deschutes River Basin on the east and the Cowlitz River Basin on the south, the Willapa Hills on the west, and the Olympic Range on the north. The Basin includes parts of Lewis; Thurston; Cowlitz; Pacific; Grays Harbor; Mason; Jefferson; and Wahkiakum counties.
The Chehalis River Basin is the second largest river basin in the state of Washington. (The largest is the Columbia River Basin.) The total drainage area of the Chehalis River Basin is 2,660 square miles, of which approximately 85 percent is forestlands. Approximately 257 square miles (164,000 acres) or 9.7 percent of the Basin is agricultural land. The Chehalis River system is largely rain-fed, with precipitation levels ranging from 45 inches per year in the Eastern Chehalis River valley to over 200 inches in the Olympic Mountains. Estimated average annual discharge of the entire basin is 11,208 cubic feet per second (cfs).
The four major population centers: Chehalis, Centralia, Aberdeen, and Hoquiam, depend on surface waters of the basin for the largest portion of their municipal and industrial supplies. The principal industrial use of water is to manufacture wood, pulp, and paper products. Aberdeen’s industrial water system supplies most of this water from the Wynoochee River, with the remainder from Lake Aberdeen.
Land within the Basin is mostly forest cover with interspersed agricultural and residential areas. Forestlands, which constitute approximately 77 percent of the Upper Chehalis Basin (upstream of Porter) and 91 percent of the lower basin (downstream of Porter), are generally located on the upland areas with scattered amounts on bottomlands. Most forested acres are corporation-owned, with the remainder being privately or government-owned (Capitol State Forest, Mt. Baker-Snoqualmie National Forest and Olympic National Forest). Intensive agriculture and irrigation occur mostly in the low-lying valleys along the Chehalis River and its tributaries. Commercial farms in the basin are following national trends of increased acreage and reduced numbers. Primary use of agricultural land is crop production (133,000 acres). Pasture comprises 1.8 percent, or 31,000 acres, of the Basin.
Although the Chehalis Basin has a high proportion of forestlands, development is concentrated in areas close to important Basin streams and rivers. This can have adverse impacts on water quantity and water quality. Although only 11 percent of the basin, as a whole, is in agriculture, urban, or industrial uses, this figure climbs to 42 percent in those areas within one mile of the major Chehalis Basin Rivers. These streams are the Chehalis main stem; South Fork Chehalis; Newaukum; North Fork Newaukum; South Fork Newaukum; Skookumchuck;Black; and Satsop main stem. The developed segments of these water bodies account for almost half the length of the major rivers in the Basin.
The resident and anadromous fish resources are of national, local, and international economic significance. Sport, tribal, and commercial fishing are important to the economy of the Chehalis Basin. The Chehalis River headwaters begins at Elk creek in East Pacific County, Washington State, in Water Resource Inventory Area (WRIA) 24. It flows eastward towards Centralia/Chehalis in Lewis County where it migrates north and crosses into the south part of Thurston County. At that point the Chehalis River turns westward and flows into Grays Harbor County. The river continues westward where it enters Grays Harbor near the town of Cosmopolis.
The Chehalis River and its tributaries cover more than 3300 surface miles. The watershed has been the subject of several water quality studies since 1990. The studies include 303(d) listings for dissolved oxygen (DO), fecal coliform bacteria (BacT), and temperature (T) conditions. For study and cleanup planning purposes the watershed was split into upper and lower river segments. A “line” dividing WRIAs 22 and 23 at Porter separates the upstream and downstream parts of the basin.
Pollution concerns were documented in several Willapa studies by various organizations with interests beyond total maximum daily loads (TMDL). Low DO and higher temperatures were determined to be limiting factors affecting the aquatic habitat and fish in the Willapa system. BacT levels are high enough during certain periods to violate standards set for protection of shellfish harvest outside the river mouth at Grays Harbor. During certain periods BacT levels are high enough at several other places to violate standards set for protecting people during swimming or other recreation in the river.
To address the fishery resource concerns various organizations are helping to protect and enhance the riparian corridor. Landowners, the local conservation districts, the Confederated Tribes of the Chehalis Indian Reservation, cities, volunteer groups including students and local fishery support groups provide labor and plant materials for stabilizing the stream banks and to increase plant cover and shade. Increased shade is the most important feature to lower temperatures in the river. Landowners install fencing to keep livestock from eroding the banks and plant more trees to increase shade. The fence and vegetative “barriers” help block animal waste or other sheet erosion to keep it out of the river. Because the shoreline protections prevent or reduce transport of nutrient and biological oxygen demand (BOD) materials into the river, they help improve DO conditions too.
A wide section of the river near the cities of Centralia and Chehalis is considered the critical segment for temperature and DO conditions. Natural conditions were found to be a major cause of higher temperatures and lower dissolved oxygen in that segment known as the “Centralia reach”. To ensure that the cities' wastewater treatment plants do not compound the natural pollution, the plants stop discharging to the river during low-flow river conditions (i.e., when flows are less that 1,000 cubic feet per second.) During the critical low river flow period, the treated effluent is instead utilized as reclaimed water and applied as agricultural irrigation.
A local discussion and water resource planning group called the Chehalis Basin Partnership (CBP) helped develop the plans for water quality improvement. They expect to continue serving as a focal point for coordinating implementation of local elements of the implementation plans. A water quality committee of the CBP advises about priorities for conducting a comprehensive water quality monitoring plan throughout the basin. To track changes in water quality conditions since the TMDL studies were done about 10 years ago, about 100 sites are sampled at least once per month. This sampling is conducted primarily by the Confederated Tribes of the Chehalis Indian Reservation, with administrative support from Grays Harbor Community College, and financial support from Ecology.
A comprehensive water quality implementation plan (WQIP) was completed in 2004 to address all of the approved TMDL project elements. The partners’ implementation work was reviewed in early 2008. Results of the comprehensive monitoring program were also summarized by Grays Harbor Community College in an “Annual State-Of-the-River Report (2006-2007) for the Chehalis Basin”.
Following are examples of some water quality improvement actions reported in the 2008 progress review for the Chehalis TMDLs.
Agricultural BMP improvements:
General actions to protect shorelines/ buffers include contributions from the Confederated Tribes of the Chehalis Indian Nation of fencing and riparian planting throughout the upper Basin. They often partner with the City of Centralia, Port of Centralia, Chehalis Land Trust, local classrooms to plant and protect riparian zones.
Land Acquisition for Perpetual Conservation:
The Chehalis TMDL partners, including Ecology, are certain that the actions help reduce fecal coliform, bacteria, BOD, ammonia, and nutrient loadings.
Water Quality Improvements Noted in 2007
Between 79 and 86 percent of samples (parameter dependent) covered in the 2007 State-of-the-River report met Washington State water quality standards. pH, followed by dissolved oxygen and temperature accounted for the majority of water quality violations; however this was highly variable depending on location and season. In general, November had the most water quality violations (across all parameters) and March had the fewest. The frequency and magnitude of water quality violations was greater in the upper Basin (WRIA 23); however, within any given subbasin (including the mainstem of the Chehalis), water quality was generally better in headwater reaches and decreased downstream. These results support the findings of previous studies, further suggesting that although there are general trends in water quality throughout the Chehalis Basin, specific needs for restoration and preservation of water quality are likely to be site-specific. Fecal coliform bacteria standards were attained (most restrictive 90th percentile criteria) in 93 percent of all samples. Only six of the 83 sites failed the 90th percentile criteria. This suggests that the Bacteria TMDLs are succeeding.
Chehalis River/Grays Harbor Watershed Project Studies and Cleanup Plan Reports
Dissolved Oxygen:
Revised -- Upper Chehalis River Basin Dissolved Oxygen Total Maximum Daily Load Submittal Report
www.ecy.wa.gov/biblio/0010018.html
Fecal Coliform Bacteria:
Temperature:
Upper Chehalis River Basin Temperature Total Maximum Daily Load Submittal
www.ecy.wa.gov/biblio/9952.html
Multi-parameter Water Quality Implementation Plan:
Chehalis Basin Partnership -Lower Chehalis/Upper Chehalis Watershed Planning
(WRIAs 22/23)
www.co.grays-harbor.wa.us/info/pub_svcs/ChehalisBasin/Index.html
Ecology publications pertaining to WRIA 22 (Ecology publication)
www.ecy.wa.gov/biblio/wria22.html
Ecology publications pertaining to WRIA 23 (Ecology publication)
www.ecy.wa.gov/biblio/wria23.html
WRIA 22 and WRIA 23: Chehalis Basin and Nearby Drainages: Salmon
Habitat Limiting Factors (WA State Conservation Commission)
www.scc.wa.gov/index.php/Download-document/277-WRIA-22-and-WRIA-23-Chehalis-Basin-and-Nearby-Drainages.html
WRIA 22 Watershed Information (Environmental Assessment
Program website)
www.ecy.wa.gov/apps/watersheds/wriapages/22.html
WRIA 23 Watershed Information (Environmental Assessment
Program website)
www.ecy.wa.gov/apps/watersheds/wriapages/23.html
Dave Rountry
Water Quality Coordinator
Water Quality Program - SWRO
WA Department of Ecology
Phone: 360-407-6276
Email: drou461@ecy.wa.gov
Copyright © Washington State Department of Ecology. See http://www.ecy.wa.gov/copyright.html.
