
SURFACE WATER
RIVERS, LAKES & COASTAL ENVIRONMENTS

Eugene Delta Ponds
Eugene, OR
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.