Bell Design Company was contracted by the City of Hood River to oversee and manage the redesign of the City’s 60-inch combined sewer and sanitary outfall from the municipal wastewater treatment plant.
The project involved evaluating several alternative outfall locations, performing a mixing zone analysis, and analyzing the WWTP’s hydraulics.
BDC designed the modifications of the existing chlorine contact chamber to accommodate the new outfall pipe, the 1,950 feet of 36-inch HDPE butt-fused pipe along the Port of Hood River’s Hook area, and the 300 feet of in-water buried diffuser pipe.
Bell Design Company has served as the prime consultant for the Outfall Redesign, but also is contracted with Vigil-Agrimis to perform the in-water construction design and to acquire the required in-water work permits.
The objective of this project is to develop a new confluence zone for the municipal wastewater treatment plant to flush out treated effluent into the Columbia River, by extending the current sewage pipe under the Hook road and farther into the active river currents on the Wells Island side of the plant.
This redesign is meant to address the undesirable accumulation of wastewater near the shoreline and nearby recreational use areas due to the formation of a reverse-current eddy which resulted from a newly-created landmass know as the "Spit".
This landmass developed in the Columbia River after a glacier broke free of nearby Mount Hood and washed down Hood River into the Columbia in 2006.
BDC expects the project will require approximately 2,000 feet of land piping with a few hundred feet of underwater pipe needed as well.
A custom manifold will be engineered for this project, and this will be installed by specialized barges in a very unique implementation process.
Upon completion of the project, the City of Hood River plans to partner with the Port to build a pedestrian and bike walkway which will connect the Hook Boat Launch to the Waterfront Park trail.
For more information, and for projected close times for the Hood River Hook recreational area, read more about this project in The Hood River News.