Chehalis River Basin Nonpoint Action Plan -WISHKAH RIVER

WISHKAH RIVER

WISHKAH RIVER

The Wishkah River, which drains approximately 102 square miles, includes the mainstem, West and East Forks, all of which originate near the southern edge of the Olympic National Forest. Like the Hoquiam to the west, and the upper reach of tidewater on the Chehalis mainstem, the soils along the streams are of the poorly drained, Ocosta clay series. Here, Sitka spruce thrives right up to the high tide line. In recent geologic times these Ocosta soils were submerged alluvium of eroded upstream sediments. Effective agriculture often requires drainage of these soils. Despite proximity to water and population centers, little agricultural development has taken place other than pasturage and haying. Some of the first agriculture in the region was the introduction of cattle, to these natural tidewater meadows.

Upland soils are of the Hoquaim-LeBar glacial upland series, with the headwaters of the West and main branches underlain by Bunker-Knappton soils (Franklin, 1981). This is very productive timber growing land, with favorable soils and slopes, abundant rain, and a mild maritime climate. The Wishkah joins the Chehalis at Aberdeen, where much of its timber over the last century has been milled. For the first half of this period, much of the timber was floated as sawlogs down the Wishkah, using splash dams and log booms to move the wood to the mills.

The minimum recorded discharge was 33 cfs in October 1942, and the maximum recorded discharge was 7,400 cfs ten days later (USGS, 1992).

Climate

Climate information for this subbasin is presented in the basin overview section of the Watershed Characterization report.

Existing Population

Using 1990 U.S. Bureau of Census data and maps for the area, and relating census block numbers to the watershed boundary of the Wishkah Basin, the subbasin population appears to be 12,000.

Based upon an average for the entire Chehalis River Basin of 2.29 people per household, there are close to 5,300 households in this subbasin.

Beneficial Uses of Water

The City of Aberdeen diverts up to ten cfs for municipal water supply. The Aberdeen Reservoir is located at RM 32.3 on the mainstem. ITT Rayonier holds water rights to 15 cfs of the Wishkah.

A total of 179 acres have surface water irrigation rights. An estimated one-third of these rights are used (Ecology, 1980).

Existing Land Use Patterns

The land is used predominantly for commercial forest, with some pasture land. Ownership is about equal between private and corporate interests with small municipal and county holdings.

Some farming, fishing, and recreational homesites appear on the upper Wishkah. In the lower reaches, fishing vessels use the banks for storage and repairs.

Anticipated Population and Land Use

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 Wishkah Basin:

   1990          Pop. in 2000      Units in 2000
Pop. Units   low    hi   avg  low    hi   avg
12000  5300 12324 15120 13320  5443  6678  5883

By the year 2010, the growth rate could be 6.1% (low), 53% (high), or 23% (average).

   1990         Pop. in 2010     Units in 2010
Pop. Units   low    hi   avg  low    hi   avg
12000  5300 12732 18360 14760  5623  8109  6519

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.

Biological Resources

This river, and its tributary streams provide good spawning and rearing habitat for salmon. Industrial and municipal pollution in the lower Wishkah and Grays Harbor negatively affect juvenile salmon.

Historical Uses Impacting Watershed

Between 1880 and 1920, logging splash dams were prevalent in the watershed. There were more than 100 splash dams in the Chehalis Basin. As logging operations worked from the river mouths upstream, transport became more difficult. Relying solely on seasonal freshets to transport logs, cost jobs and slowed production. With the splash dams, artificial freshets were created. Large amounts of water were needed to flush the logs downstream, so many of the dams were huge. Almost all of the splash dams were large enough to completely block fish passage, and very few included fish passage structures. Salmon species extinctions and near extinctions resulted from these dams (Van Syckle, 1981).

When the flood gates were lifted, the man-made freshets scoured the river bottoms, ripping away spawning beds, channelizing the river bed and removing pool/riffle characteristics. The freshets also removed thousands of salmon eggs and left the fish flopping on gravel bars as the waters receded.

One of the most effective methods for diving logs was the use of multiple dams on one river. The idea was to clear the entire length of the river by timing the release of water from a series of splash dams beginning with the highest in the watershed.

While much of the early study on the effects of splashing focused on the blockage of upstream migration, later studies concluded that the most devastating effects came from stream bed preparation. Preparing a river or stream involved: blocking off of sloughs, swamps. low meadows, mouth of streams, and side channels by log cribbing, to keep the logs and water in the main channel. removal of boulders, large rocks, leaning trees, sunken logs, or debris accumulation such as floating logs. Obstructions of any kind in the main bed had to be blasted out or removed during periods of low flows (Van Syckle, 1981).

Water Quality Plans

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.

Revised and corrected, April 2000 -