Topography and Geology
This portion of the Chehalis Basin runs from river mile (RM) 29, where Mox-Chehalis Creek enters, to RM 0.0 at the mouth of the Wishkah River, and includes the land base surrounding Grays Harbor. Grays Harbor is approximately 15 miles long and 13 miles wide and can be described as boot-shaped with the toe being the mouth of the Chehalis River.
The total drainage area of the Lower Chehalis subbasin is 349 square miles (Ecology, 1980). This figure includes the Grays Harbor, Westport, and Grayland areas. The two largest creeks that merge with the Chehalis River the Lower Chehalis subbasin (below Porter, but above the mouth) are Mox Chehalis Creek, which drains 27 square miles, and Newman Creek, with a drainage area of 23 square miles. The two largest rivers within this subbasin that empty directly into Grays Harbor are Johns River, draining a 32 square mile area and the Elk River, which has an 18 square mile drainage. These rivers drain forested areas.
Hydrology
The mean annual discharge from the river and all its tributaries is estimated at 14,000 cfs (Ecology, 1980).
In the Lower Chehalis Subbasin, the surrounding land is characterized by a broad and flat valley floor, with the river flowing near its southern edge. Steep hills rise from the river on the southern side. On the northern side the valley blends with tributary valleys or rises in gentle to steep hills.
Soils
Soils in the subbasin range from deep to very deep. On the hillsides and in the upstream portions of the lower Chehalis subbasin soils are well-drained. In the downstream portions and in the estuary they range from well drained to poorly drained. During periods of high water in the winter much of the floodplain is covered with water . Most of the soils classified as poorly drained occur along the river downstream from Montesano and in large areas around the periphery of Grays Harbor. Soils lying within the floodplain receive nutrients from periodic flooding (USDA, 1975).
The Chehalis River has changed course over time leaving behind many oxbows and sloughs. These are connected to the mainstem during parts of the winter, and in some cases all year. These features provide areas for the storage of flood water, and provide valuable fish and wildlife habitat.
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The climate is mild and wet throughout the subbasin; foggy, and/or overcast days are common. Temperatures near the ocean are slightly warmer in winter and cooler in summer than inland areas and receive fewer days of sunshine. The sun shines 45% of possible hours during the summer, and 20% of possible hours during the winter. Rainfall averages 68" at Elma, and 84" at Aberdeen and Grays Harbor. Rainfall increases north and south of Grays Harbor because of the effects of coastal mountain ranges. Despite its generally mild climate, some extremes in conditions have been recorded. A one month rainfall of 49.16 inches occurred at Aberdeen. Montesano received a one day rainfall of 9.47 inches. Elma reached a high temperature of 105øF on one day in 1956.
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The major population center in the lower Chehalis subbasin is the Cosmopolis-Aberdeen-Hoquiam area, which is home to 33,000 people. These residents are part of several subbasins, and the total population is divided among them. Other population clusters in this subbasin are located at Westport, pop. 1,950; Montesano, pop. 3,270; and Elma, pop. 2,420. Other residences are scattered in the valleys; few people reside in the uplands.
Using 1990 U.S. Bureau of Census data and maps for the area, and relating census block numbers to the watershed boundary of the Lower Chehalis basin, the population appears to be 18,000.
Based upon an average for the entire Chehalis River Basin of 2.29 people per household, there are close to 7,900 households in this subbasin.
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Little information is available on water use within this basin, but it is probably very limited. There are surface water rights for irrigation of 231 acres from Mox Chehalis Creek (Ecology, 1980).
Studies are now underway for a firm water supply of 80 cfs for the Satsop thermonuclear power plant (Envirosphere, 1982). The proposed location of this plant is south of the Chehalis River near the mouth of the Satsop River. Both ground and surface water sources are being considered.
Ground water is the source for most individual and domestic use, and is also the source for municipal water supplies for the towns of McCleary and Elma. Water resources for the city of Montesano come from a surface water intake on the middle fork of Sylvia Creek, and the city has also drilled a well for use in emergencies such as fires. The safe yield from these sources is 2,000 gpm. Water samples from Sylvia Creek have indicated color and turbidity readings above U.S. Public Health Service standards. Aberdeen diverts up to 10 cfs from the Wishkah River for municipal use. Hoquiam derives its water supply from Davis Creek, the West Fork Hoquiam and the Little Hoquiam River.
Water-related recreation and tourism activities center around fishing, clamming, canoeing, kayaking, swimming, birding, hunting, and sailing. Land-based recreation activities include hiking, biking, horseback riding, motorbike riding and ORV riding, and photography. Serving this area are three state parks near Westport, one near Ocean Shores, and one just outside of Montesano at Lake Sylvia. There are two county parks; one south of Elma on Vance Creek, and one east of McCleary, (the Thurston County ORV Park). The Capitol State Forest lies southeast of Mox-Chehalis Creek. Also in this subbasin are the wildlife areas of Bowerman Basin, Oyhut State Wildlife Recreation Area (SWRA), Johns River SWRA, and the wildlife area south of Elma. An abandoned railroad right-of-way stretching from Cosmopolis to Chehalis, mostly along the south bank of the Chehalis River, has the potential for becoming a hiking/biking trail linking these two cities, and travelling through remote and diverse sections of this subbasin.
Aberdeen is developing the Morrison Riverfront Park, close to the Seaport, home of the Tall Ships Project. Hoquiam has a newly developed river access at 8th Street. Lakes in this subbasin include Lake Sylvia and Lake Aberdeen.
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Forestry is the principle commercial land use, although the valleys are extensively farmed. Grays Harbor County has ranked at the top of Washington counties in volume of logs harvested since 1982 (GHRPC, 1988). Many of these logs came from other sections of the county, and it was not possible to ascertain exact statistics for this subbasin. While production from forest lands has remained high, employment has decreased due to mill closures and modernization efforts. In the future, employment is expected to decline further because of changes in harvest practices and set asides for the Northern spotted owl.
Agriculture is diverse in the Chehalis valley, ranging from dairy and beef cattle to hay, potatoes, peas, bulbs, flowers, and ornamental plants. Cranberries are raised in the bogs near Grayland along the south shore of Grays Harbor. A large cranberry processing plant, also located on the south shore of Grays Harbor, handles most of the regional cranberry harvest. The market value of all crops sold in Grays Harbor County in 1987 was $16.9 million (GHRPC, 1988).
There is a history of gravel mining along the Chehalis River near Elma. A few of the abandoned pits have been reclaimed for wildlife habitat, and swimming ponds for a county park.
Aberdeen/Hoquiam is the commercial center for much of Grays Harbor and part of Pacific County. It contains two malls and many businesses in the downtown area. Industries are numerous around the harbor. They include a port and large log storage yard, two pulp and paper mills, a veneer plant, a shake plant, a plywood plant, a pulp mill equipment plant, and a strapping plant.
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Based upon projections from the Washington State Office of Financial Management, Forecasting Division (OFM, 1992), the entire Chehalis River Basin is experiencing growth. Using data from the three major counties (Thurston, Lewis, and Grays Harbor) this growth rate between now and the year 2000 could be 2.7% (low), 26% (high), or 11% (average).
Applying these figures to today's population and housing units results in the following estimates for the Lower Chehalis Basin:
By the year 2010, the growth rate could be 6.1% (low), 53% (high), or 23% (average).
While this subbasin has not experienced high or even average growth rates, high rates of growth in nearby population centers are encouraging residential development in rural areas. This spillover effect could cause growth to exceed traditional norms.
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Fisheries
Fisheries resources at present represent a fraction of their former diversity and richness, according to the Lower Chehalis River Basin Water Quality Plan (GHRPC, 1991). Several theories have been presented to account for this decline. Among the major ones are: extensive filling of eelgrass beds in the inner Grays Harbor (eelgrass beds serve as rearing places for young salmonids): industrial pollution from pulp mills; overharvesting; pollution from municipal sewage; and increased nonpoint source pollution. Some of the problems have been vigorously addressed in recent years by both industry and municipalities, and still the problems remain. A state grant recently enabled research to continue on the cause of the low escapement of salmonids from the Chehalis River (Fisheries, 1992). Despite problems, the salmonid and some sturgeon fisheries are important resources. Much commercial fishing in saltwater has shifted from salmon to bottom fish because of the generally declining salmonid stocks. There is a movement towards aquaculture. Grays Harbor College conducts an aquaculture research station. Fish processing is done at three plants in Westport and two in Hoquiam.
The sport fishing industry is the lifeblood of the town of Westport. The movement of commercial fishing boats toward the charter business is one result of the decline of ocean fish populations.
Shellfish, mainly oysters, are raised in shellfish beds in Grays Harbor. Oyster production has increased by 95% since 1984 (GHRPC, 1988). There is an oyster processing plant on the south shore. Razor clams occur along the ocean beaches, but have been decimated in recent years by a virus that is deadly to the clams. The harvest seasons have reopened since 1990, but the debate continues on how best to manage the species.
Wildlife
Wildlife habitat remains intact in tidal wetlands at the mouth of the Chehalis River. This 4,000 acre spruce and shrub community, flooded daily by the tides, is home to bald eagles, black bears, otters, ospreys, and many other species. Its intricate system of sloughs and smaller connecting waterways and quantities of woody material in the water provide excellent cover for fish. This area is being considered for Natural Area Preserve status by the Sate of Washington, and work has been done toward the purchase of portions of it. One million dollars, in Federal money, has been earmarked for wetlands purchases totalling up to 3,000 acres in Grays Harbor near the Chehalis and Elk rivers. Amazingly, these wetlands are located adjacent to heavily industrialized sites as well as to the major population center of Grays Harbor County. Another piece of land, Bowerman Basin, is so rich in small tidal organisms that millions of birds stop during migration to rest and feed each season. It is the last large feeding area south of Alaska, and one of the few such productive areas left along the Northwest coast. Bowerman Basin has been designated a National Wildlife Refuge.
Other wildlife habitat remains along the streams and rivers, remaining wetlands, and fringes of agricultural fields of the Lower Chehalis subbasin. One recent acquisition by the Washington Deptartment of Wildlife and Ducks Unlimited preserves a 300 acre reserve of wetlands, meadows, and ponds. The former farm, just south of Elma, is open to the public for wildlife observation year round and waterfowl hunting during designated seasons.
The forested hillsides along the south bank of the lower Chehalis provide upland habitat. Near Elma, Washington Public Power Supply System (WPPSS) owned land is being selectively logged, rather than clear-cut. The Washington Department of Wildlife has advised WPPSS on harvesting techniques which will retain favorable wildlife habitat.
Many wetlands, and some oxbows have been filled or otherwise altered for agricultural purposes. Some low-lying fields have also been drained. These types of activities have changed the original species composition and numbers of local wildlife, favoring more upland species such as deer.
Vegetation in the uplands consists of Douglas fir, Red alder, western hemlock forests and clear-cuts in various stages of regrowth. Valley plant species show greater variety. Cottonwoods and big-leaf maples exist in areas along the rivers and sloughs. A large solid expanse of Sitka Spruce forest remains in the tidal wetlands area mentioned previously, but most of the bottom-land forest has been converted to agriculture. Few forested areas remain around Grays Harbor, except for areas along the south shore and along the farthest reaches of the northern shore. These remaining forested areas are virtually all under commercial forest company ownership.
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Water quality plans for this subbasin are reviewed in the basin-wide overview section of the Chehalis River Basin Characterization and the Water Quality Assessment.
Back to top or back to Action Plan home page or back to Action Plan Vol II Index Revised and corrected, April 2000 -
1990 Pop. in 2000 Units in 2000
Pop. Units low hi avg low hi avg
18000 7900 18486 22680 19980 8113 9954 8769
1990 Pop. in 2010 Units in 2010
Pop. Units low hi avg low hi avg
18000 7900 19098 27540 22140 8382 12087 9717