Pacific Northwest Research Station

Entiat Experimental Forest

Introduction

The Entiat Experimental Forest was established in 1957 to study the effects of road building and timber harvesting on the quantity, quality, and timing of water discharge from small watersheds in the mountains of north-central Washington. Instrumentation was installed in three similar, adjacent watersheds (4.74 to 5.65 km2 each) to monitor weather and streamflows. Scientists from the Pacific Northwest (PNW) Research Station’s Wenatchee Forestry Sciences laboratory collected baseline data for almost 12 years before a lightning-caused wildfire burned all three watersheds in 1970. This unplanned “treatment” shifted the research focus from road and timber harvesting effects on hydrology to wildfire and post-fire recovery effects on hydrology. Over the following decade, research within the Entiat produced numerous publications related to fire effects on streamflow characteristics, water temperature, water quality, and sediment production. Additional studies investigated the efficacy of various post-fire forest rehabilitation treatments. Work continued on the Entiat until 1977 when a change in research priorities at PNW halted research efforts. Elevation ranges from 610 to 2,164 m, and mean aspect in the three watersheds ranges from 205 to 237 °.

Climate

At the Entiat, winters are cold and moderately wet, and summers are warm and dry. Average annual precipitation from 1961 to 1971 was about 580 mm, about 70 percent of which was snow. Monthly mean temperatures (at 915 m elevation) range from -4 °C in January to about 18 °C in July and August.

Soils

Soils are well-drained Entisols of the Choral and Rampart series. Surface soils have are classified as sandy loams. Soils were derived primarily from volcanic ash and pumice deposits that overlay the granitic bedrock of the Chelan Batholith.

Vegetation

Prior to the 1970 fire, forests at low elevations were dominated by ponderosa pine and Douglas-fir. Stands of lodgepole pine and whitebark pine were also present. About 15 percent of the Entiat was classified as bare rock.

Long-Term Data Bases

High quality streamflow data measured at 120° V-notch weirs were recorded on Burns, Fox, and McCree Creeks for the period 1959 to 1971. High sediment flows in 1972 destroyed the weirs on Fox and McCree Creeks, and the weirs were replaced by Parshall flumes. The weir on Burns Creek continued to function and produce high-quality flow data through 1977, with only occasional interruptions caused by sediment accumulations.

Stream temperature data were collected hourly at the three weir sites during 1968 to 1971. Additional stream temperature data were collected on Burns (1972 to 73) and McCree (1974 to 77). Precipitation, air temperature, and humidity were recorded at the Burns Creek weir site. Some stream chemistry and coarse sediment production data are also available.

Research, Past and Present

Most research to date has focused on effects of disturbances (especially fire) and vegetation recovery on watershed hydrology, with additional work on the effects of post-fire harvesting systems and rehabilitation efforts on soils and vegetation. After 32 years of post-fire vegetation recovery, work on the Entiat is being revived. In 1999, work began to compile, organize, and archive historical hydrologic and vegetation data.

Plans are in place to resume studies of streamflow generation, water quantity and quality, surface-subsurface water routing, and fire and road effects in the three watersheds beginning in 2003 in collaboration with Oregon State University’s Department of Forest Engineering. This work is intended to form the basis for a nested watershed monitoring and modeling approach for scaling up findings to the larger Entiat watershed and other watersheds in the mid-Columbia region. The Entiat watershed contains a USDA Natural Resources Conservation Service, SNOTEL station, and the existing stream-gauging network is being expanded. Personnel from the National Forest System, Washington State, and Chelan County are actively cooperating in this joint effort.

Additional research is also under consideration, including studies of stream productivity and material and invertebrate transport and their subsequent effects on downstream fish habitats.

Major Research Accomplishments and Effects On Management

Approximately 20 primary publications were developed from studies at Entiat. These have contributed significantly to our knowledge of fire effects on waterflow and quality, microclimate, and soil-water relationships, as well as watershed rehabilitation, post-fire salvage effects, and vegetation recovery.

Collaborators

Collaborators at Entiat include Oregon State University, Washington State University, and the University of Washington.

Research Opportunities

The reestablishment of stream gauging and collection of climate data will form a basis from which other studies could benefit.

Facilities

There are no on-site facilities; the Entiat is located about 30 miles north of Wenatchee and 12 miles northwest of Entiat in the eastern Cascade Mountains of Washington.
Lat. 47° 57' N, long. 120° 28' W

Contact Information

Entiat Experimental Forest
USDA Forest Service
Pacific Northwest Research Station
1133 N Western Avenue
Wenatchee, WA 98801
Tel: (509) 662-4315
http://www.fs.fed.us/pnw/exforests/entiat/index.shtml

¹Information has been updated since original publication.

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