The Tualatin Project, authorized by Congress in 1966, was the last Bureau of Reclamation project authorized in the Pacific Northwest. (Note: There have been later re-authorizations for Projects in the region.) It is the only Reclamation Project in the Willamette Valley.

Known as the "Twality Plains" in the pioneer era, the area was one of the earliest farming settlements in Oregon. Agriculture developed quickly. From a small beginning in the 1930's, irrigation increased substantially. By the late 1950s, only about 6,000 acres of the Tualatin Basin were inadequately irrigated.

However, flooding and draining problems had been a source of concern since the early settlement days. Reclamation began studies in the area in 1948 and, followed by locally-held meetings to formulate the type of irrigation development best suited to the area. A report in 1956 analyzed storage at the site of present-day Scoggins Reservoir, but following review of this report, it became apparent there was a greater need for municipal and industrial water than originally anticipated. A feasibility report issued in 1963 identified irrigation water for 17,000 acres of land, 14,000 acre-feet of municipal and industrial water, and water for fish and wildlife, recreation, quality control, and flood control benefits. On the basis of this plan, the project was authorized in 1966.

The principal features of the Tualatin Project include Scoggins Dam, Henry Hagg Lake, Patton Valley Pumping Plant, Spring Hill Pumping Plant, and more than 120 miles of a piped distribution system.

Scoggins Dam, Henry Hagg Lake, and related recreation facilities were initially operated and maintained by the Reclamation. However, the Tualatin Valley Irrigation District is now responsible for the operation and maintenance of Scoggins Dam and Patton Valley and Spring Hill pumping plants. The recreation facilities are operated and maintained by Washington County.

The Patton Valley Plant is located on Scoggins Creek and provides water for the Patton Valley area and upper Tualatin River. The Springhill Pump Plant has four 350 HP pumps and five 1500 HP pumps which withdraw water from the Tualatin River for distribution through the North, East and West pipelines. Water is delivered via the Tualatin River for irrigators who pump directly from the river. TVID personnel routinely inspect and maintain miles of pipeline checking for damage or leaks. Field technicians also routinely inspect flow meters to assure accurate measurement of water use is recorded.

Currently, TVID and other local partners are working with Reclamation to address the seismic risks at Scoggins Dam due to its proximity to the Cascadia subduction zone. Reclamation's Safety of Dams program is in the process of evaluating modifications to the dam to reinforce and strengthen the structure.