Agua Fria, Toroges and Agua Caliente Creek Improvements (Fremont, CA) & Alum Rock Fish Passage Project

Key features of the project included:

• Toroges Creek construction included replacement of an old bridge with a precast UPRR railroad bridge requiring steel piling across the existing concrete u-channel, and construction of a 65 ft. long 6’ x 8’ cast in place box culvert.
• Work at Agua Fria Creek required a dual precast concrete box culvert be placed in a weekend closure under active UPRR tracks, as well as construction of a 168 ft. log 10’ x 5.5’ and a 626 ft. long 5’ x 5.5’ cast in place box culverts.
• Agua Caliente Creek work involved micro tunneling of a 78-inch reinforced concrete pipe approximately 1,800 linear feet under active UPRR are tracks as an additional creek conveyance facility and connecting to the existing 81-inch reinforced concrete pipe, as well as extension of the inlet structure at the upstream headwall.

The $1 Million Alum Rock Fish Passage project included the construction of two creek restoration areas to fully mitigate biological impacts of the above channel works. Directly relevant project elements include:

• Work in sensitive red legged frog, steelhead, roosting bat and archeologically sensitive areas in Upper Penitencia Creek at Alum Rock Park with tight regulatory creek work windows of June 15 – October 15.
• Creek diversion (gravity flow and pumped) as well as groundwater dewatering discharge back to channel, which required regulatory negotiations to adjust turbidity levels higher.
• Repair of a rill in the City Park wall near the Youth Science Institute with an in-kind new mortared rock wall, connecting walls upstream and downstream of the weir with the bottom of grouted sack wall keyed into the channel and backfilled with compacted engineered fill.
• Construction of a new 250 ft. long roughened channel downstream of the existing 5 ft. high weir which blocked steelhead passage, including placement of new rock bands and engineered streambed material.
• Removal of approximately 120 LF of existing Park rock wall along the channel downstream of Bridge L, to create a new floodplain along the eastern bank of the channel.
• Construction of a new wall on the south side of the east footing of Bridge L conforming to the existing wall under the bridge.
• Y.S.I. Bridge Site Abutment/Bank Repair required installation of a reinforced, concrete, curved retaining wall, piles, and stone veneer, installation of permeable backfill and drainage system, repair of buckled concrete asphalt path.
• Removal of nonnative and invasive plant species, earthwork, irrigation, and native plantings at both locations to create riparian and floodplain habitats.

Both projects were completed successfully and on schedule to mitigate biological impacts.