Lapwai Basin

Lapwai Basin

Despite its relatively small size, and perhaps because of it, the Lapwai Basin serves as a meeting place for nearly all of the contentious and complicated water resource issues that western watersheds can expect to face in the upcoming decades.

Physical obstacles to fisheries/water quality restoration include: reduction of viable aquatic habitat due to channelization; water quality degradation from septic systems and timber harvest and agricultural runoff; riparian habitat viability; diminished stream flow.

Management obstacles include multiple political jurisdictions and management agencies and "checkerboard" ownership pattern of tribal and private land. Legal obstacles include ongoing litigation concerning an out-of-watershed diversion by the U.S. Bureau of Reclamation.

Political and social obstacles include: application of management goals across jurisdictional/demographic divides; poverty and access to resources; and local movements to diminish tribal sovereignty.

It is the hope of the Waters of the West program that information on these pages will assist in collaborative efforts towards solutions to these problems.

Basin Description

The Lapwai Creek watershed is a 70,700 hectare (174,700 acre) watershed located almost entirely within the Nez Perce Reservation of northern Idaho in the Lewis and Nez Perce counties. The elevation of the watershed ranges from 335 to 1,371 meters (1,100 to 4,500 feet). The watershed is comprised of Columbia River basalt group as the predominant rock type. The upland headwaters are separated from a lower valley by a basalt escarpment where Lapwai Creek flows through steep canyons and receives the tributaries of Mission, Sweetwater, Webb, and Tom Beall Creek. Lapwai Creek is approximately 45 km in length and flows south to north. It is a tributary to the Clearwater River, just upstream of the confluence with the Snake River, a major tributary of the Columbia River.


The average annual precipitation ranges from 45 centimeters (18 inches) near the town of Lapwai to more than 66 centimeters (26 inches) at some of the higher elevations. Snowmelt from the headwaters on Craig Mountain drive a seasonally variable hydrograph. In recent years, the precipitation patterns in the watershed have caused a shift from snow-dominated to rain-dominated hydrology.

Land Cover / Land Use

Allotment of reservation land and opening of surplus land to homesteading in 1893 resulted in a checkerboard mixture of trust, individual trust, and private land. Only 17% of the land within the Lapwai Creek watershed remains in trust status. The Lapwai Creek watershed is a rural landscape consisting of approximately 70% agricultural and the remaining 30% timber land. Water is diverted from the watershed to serve a small Bureau of Reclamation Project, the Lewiston Orchards Irrigation District.

Historically, the upland areas were characterized by forests of conifer and ponderosa pine and herbaceous communities mixed with shrubs. The wetlands were populated by camas, forbs, and grasses; the riparian areas were characterized by willows, quaking aspen, black cottonwood, and red alder. Today, 94% of native grassland and 97% of wetlands have been converted to crop, hay, or pasture. Between 1940 and 1989, 61% of the riparian zones were destroyed.

Fish Habitat

The Lapwai Creek watershed provides spawning and rearing habitat for juvenile steelhead (Oncorhynchus mykiss). Despite its relatively small size, the Lapwai Creek watershed may have disproportionately contributed to the historic Clearwater-Lower main stem population of the Snake River distinct population segment, listed under the Endangered Species Act. Pursuant to the Act, Lapwai Creek and its tributaries Sweetwater Creek and Webb Creek were designated "critical habitat" for steelhead by the National Marine Fisheries Service (now NOAA Fisheries) on February 16, 2000. The disproportionate contribution may, in part, be related to the emergence of cold clear springs in parts of the upper tributaries.

The Lapwai Creek watershed lies almost entirely within Nez Perce Reservation, an area carved out of the much larger territory that served as home to the Nez Perce people since time immemorial. The steelhead that live and spawn in Lapwai Creek and the salmonid species in the rest of the Columbia River basin are sacred foods for the Nez Perce, embodying both physical sustenance and spiritual connection. The Nez Perce Treaty of 1855 guaranteed the Tribe [t]he exclusive right of taking fish in all the streams where running through or bordering said reservation is further secured to said Indians; as also the right of taking fish at all usual and accustomed places in common with citizens of the Territory.