DOWL was selected by the Matanuska-Susitna Borough to design fish passage improvements at the Meadow Creek crossing at Big Beaver Lake Road. Meadow Creek provides important spawning and rearing habitat for Coho, chinook, and sockeye salmon. DOWL provided the full suite of design and support services, including a geotechnical investigation, topographic survey, and geomorphic analysis. DOWL completed a cost-benefit analysis of prefabricated bridges and corrugated structures (buried bridges), ultimately finding that a 32-foot wide, bottomless, steel-plate box culvert on precast concrete footers provided the most efficient design solution. Realigning the channel allowed the existing culverts to be used for the stream diversion and facilitated speedy construction, minimizing traffic control concerns. DOWL obtained all necessary permits, assisted in easement acquisition, and provided engineering assistance during construction. Minimal questions were received during bidding and the cost estimate was between the lowest and second-lowest bid. The final stream simulation design was passing salmon upstream within days of completion.
Matanuska-Susitna Borough, Alaska
Drainage and River Systems