The headwaters of the Walla Walla River lie in the Blue Mountains of northeastern Oregon. The river originates as the North and South Forks of the Walla Walla River. The surrounding forested land holds a network of hiking and mountain-biking trails.
The confluence of the North and South Forks lies east of Milton–Freewater, Oregon. The river flows eastward to reach Milton–Freewater, which is built along its banks, and then flows northward through Milton–Freewater. Irrigation water is drawn from the river here and at numerous locations along the river.
The Walla Walla River flows southwest of the city of Walla Walla in the Walla Walla valley. Mill Creek, which flows through the city of Walla Walla, joins the Walla Walla River at the Whitman Mission west of the city of Walla Walla.
The Touchet River joins the Walla Walla at the town of Touchet, Washington. The annual mean discharge of the Walla Walla River just below the Touchet River confluence is 589 cu ft/s (16.7 m3/s). The maximum recorded discharge was 33,400 cu ft/s (950 m3/s) in 1964.[3][4]
The river enters the Columbia a mile south of the town of Wallula just north of Wallula Gap. The section of the Columbia River is called Wallula Lake, the reservoir impoundment created by McNary Dam.
History
Wind turbines over the lower Walla Walla. River depleted by irrigation water withdrawal.
The Walla Walla tribe occupied the region around the Walla Walla river prior to white settlers entry to the region.
The Lewis and Clark Expedition (1804–1806) was the first United States overland expedition to the Pacific coast and back—the return expedition stopped at the mouth of the Walla Walla and stayed with the Walla Walla tribe for a portion of the journey, proceeding from there overland to the Snake River. British explorer David Thompson was the first European to navigate the entire length of the Columbia River, to the Pacific Ocean, in 1811.
Work done by Oregon and Washington State governments, federal and state environmental agencies and local watershed councils and groups on the Walla Walla River & the overall catchment area has produced a wide range of studies. The Walla Walla Basin Watershed Council (WWBWC www.wwbwc.org) has both electronic and paper copies of many of these reports that date back to the 1930s. Considerable work has gone into the assessment of water quantity and quality for the purpose of salmon recovery and sustainable irrigation supply. A highly-connected alluvial groundwater system and its over-abstraction through over-allocated irrigation usage have also acted to influence flows and quality in the Walla Walla River.
The promise of the Walla Walla River lies in its integrated water-management strategy using Managed Aquifer Recharge (Or Shallow Aquifer Recharge) to utilise available non-irrigation season water to replenish groundwater supplies and the over-allocation of groundwater resources by both state governments. The Walla Walla partnership along with the WWBWC set a national example with this innovative and low-cost alternative to surface storage using dams.
Photos
The South Fork of the Walla Walla River at Harris Park, 13 miles (21 km) above Milton-Freewater, Oregon
The North Fork of the Walla Walla River above Milton-Freewater
The Wallula Gap, where the Walla Walla enters the Columbia, as seen from near Fort Nez Percés, looking to the south
South Fork of Walla Walla River at Harris Park, Umatilla County, Oregon
Walla Walla River in the Blue Mountains of northeastern Oregon
