Effective In-Structure Bridge Night Roost Habitat – Oakville Cross Road Bridge, Napa

The Oakville Crossroad Bridge over the Napa River was built in 1922, and was constructed with materials and a design that made the bridge a highly-visited bat night roost. Greg Tatarian conducted a bat habitat assessment and survey of the bridge under subcontract to Horizon Water & Environment, and provided initial take avoidance and minimization measures, along with mitigation measures for replacement roost habitat.

Planning and engineering was almost complete when the bridge was closed May 22, 2015 as a result of damage from the Napa Earthquake. The emergency nature of the bridge replacement project after the earthquake resulted in a fast-track project that was  completed in about half the time originally planned, but which still incorporated replacement night roost habitat, which Greg designed for bridge engineers and the contractor to implement.

Within a few months of the new (and beautiful) bridge being completed, bats had already begun to return, where they can safely roost at night to rest between foraging bouts.


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Beneath the 1922 Oakville Cross Road Bridge. Bats had been night-roosting near abutments.

 

Newly-constructed bridge with night roost habitat incorporated into bridge deck.

Newly-constructed bridge with night roost habitat incorporated into bridge deck.

 

The new Oakville Cross Road Bridge with bat night roost habitat beneath deck.

The new Oakville Cross Road Bridge with bat night roost habitat beneath deck.

 

Evidence of bats night roosting just a few months after bridge completion.

Evidence of bats night roosting just a few months after bridge completion.