The Alameda Creek Bridge project was a seismic retrofit of the existing Decoto Road Bridge over Alameda Creek in Union City. The work included installing cast-in-steel-shell piles, concrete footings, pier wall extensions, widened abutment seats, constructing new shear keys, and enlarging the existing pier caps. The work required excavation to the bottom of the existing footings, which were located approximately 6 ft. below the creek bed. Retrofit of the pier wall footings included driving 140 20-inch diameter steel pipe piles to a depth of 60 feet with tight overhead limitations due to the existing bridge deck. All bridge deck expansion joints and the median were also replaced during the retrofit. Most of the retrofit work was performed from within the creek bed and, to accomplish this, DMZ temporarily diverted the creek low flow channel and restored the creek to pre-construction conditions when work was complete. DMZ collaborated successfully with the California Department of Fish & Game, East Bay Regional Parks District and Alameda County Flood Control & Water Conservation District to mitigate any negative impacts to the environmentally sensitive area.