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Cottonwood Creek Watershed (Nez Perce County)

Physical and Biological Characteristics

The Cottonwood Creek Watershed (42,080 acres) is located in Nez Perce County and is entirely within the Nez Perce Reservation. The creek flows predominantly north for 16 miles before discharging into the Clearwater River near the town of Myrtle. Two perennial tributaries, Magpie Creek and Coyote Creek are located in the lower reaches. The mainstem of Cottonwood Creek flows sub-surface at stream mile 4.8, but maintain small stretches of surface water and isolated pools in the canyon area upstream. The watershed is composed of upland plateau and steep canyon habitat, with elevations ranging from 853 feet at the confluence with the Clearwater River to 3,642 feet in the uplands.

Evidence of frequent high flows and flooding are evident from river mile 6 to river mile 9.
The dominant land use in Cottonwood Creek watershed is agriculture (69% cropland), with areas of meadow/pastureland (20%) and coniferous forest lands (5%). The community of Gifford is located in the upper watershed.The watershed contains steelhead/rainbow trout, speckled dace, piute sculpin, bridgelip sucker, Northern pike minnow, and chiselmouth. Kucera (1983) found substantial numbers of steelhead/rainbow trout and sufficient quantities of spawning gravels. In addition, Fuller (1984) noted presence of cutthroat trout, redside shiner, and numerous crayfish.

Early studies indicate that Cottonwood Creek water quality is limited by extreme annual stream flow variation, low summer flow, and high in stream temperatures (Kucera 1983). Temperature data collected in 2000 with continuous temperature recorders was compared to Idaho State Standards (WRD 2001). One thermograph was placed at the mouth of Cottonwood Creek. The watershed was evaluated for cold water biota (CWB) (22ºC) for the entire record, June – October and salmonid spawning (13º C) for the interval monitored between January 15 – July 15. Temperatures at the mouth exceeded the salmonid spawning criteria (13 C) 100% of the time. The cold water biota instantaneous criteria (22º C) were exceeded 36% of the time monitored.

Past Cottonwood Creek stream survey data (NPT 2004) for 3 reaches-total of 359 meters, indicate suboptimal conditions for: width/depth ratio, cobble embeddedness, large woody debris, and pool frequency (see Appendix C). Nonpoint sources of pollutants are predominantly agriculture and grazing. Numerous residences are present in the lower 4 km of the stream where very little overhead canopy is present and grazing is generally heavy. Logging has taken place in the drainage and several old logging roads remain (Kucera 1986).

Cottonwood Land Use Map

Studies, Plans and Reports

Carter Ward Watershed Treatment Plan (1981)
Nez Perce Soil and Water Conservation District

The Carter-Ward hydrologic watershed area is located in Nez Perce County, Idaho and enters
Cottonwood Creek. It is 1.5 miles southwest of the town of Gifford

Cottonwood Creek Initial Assesment (July 1995)
Nez Perce Soil and Water Conservation District

The objectives of completing an Initial Assessment (IA) are:
* To determine if the problems and local objectives are within the realm and scope of the Natural
Resources Conservation Service’s mission and technical expertise.
* To determine if a detailed evaluation such as a Preliminary Investigation (PI) is warranted.

Preliminary Investigation Report Cottonwood Creek Watershed (July 2001)
Nez Perce Soil and Water Conservation District

The philosophy of a preliminary investigation (PI) is to identify and assess a specific watershed’s
problems, develop potential solutions, and evaluate their relative impacts in a cost efficient
manner.

Physical Characterization of Riparian Area through Photography (March 2002)
Idaho Soil Conservation Commission- Boise Idaho

Photographs were taken on March 18, 2002 along Cottonwood Creek in
Nez Perce County Idaho. These photos that follow provide a limited visual
baseline of the physical characteristics of the channel and riparian
vegetation.

Cottonwood Creek and Tributaries Water Quality Monitoring Report, 2015