Habitat Restoration & Enhancement
  Eugene Delta Ponds | Tres Rios Ecosystem | Ponca State Park

Occupying 180 acres of abandoned gravel quarries, the Eugene Delta Ponds are remnants of floodplain alluvial deposits from the Willamette River’s meandering. Both terrestrial and aquatic habitats associated with the ponds are in poor condition as a result of extensive disturbance and development. This project will provide off-channel rearing and refuge habitat and improve water quality within the Delta Ponds by reestablishing a frequent hydrologic connection to the Willamette River. Tetra Tech conducted baseline habitat surveys, wetland delineations, developed conceptual alternatives for restoration, and also prepared all environmental documents. Tetra Tech helped develop and screen preliminary alternatives, quantified environmental outputs, and assisted with cost-effectiveness and incremental-cost analyses that resulted in the development of a recommended alternative. Continued work has included hydraulic analyses for the design of a gated culvert inlet and proposed operation of the project to maximize fish access while preventing flooding; landscape plans; and permit support including a FEMA Letter of Map Revision. The project will be constructed in several phases. Current work has included the removal of noxious weeds and revegetation. Approximately 40 acres of the site was reconnected to the Willamette River in 2005 and final designs and construction to reconnect the entire site are currently in process for construction in 2007.