U.S. Route 7 Bypass

Wildlife Passage Structure

 

         Beginning in 2006 a six year study was initiated to evaluate the impact of the then proposed U.S. Route 7 Bypass in Brookfield, Connecticut and success of the proposed mitigation package on a population of Eastern Box Turtles.  In order to evaluate the highway impacts and success of the mitigation initiatives this project was conducted in three Phases:

 

• Phase One monitoring was conducted from 2006 to 2008 prior to construction activities.

• Phase Two monitoring was conducted in 2009, during construction activities.

• Phase Three monitoring was conducted from 2009 to 2010 after construction of the U.S. Route 7 Bypass was completed.

 

          As part of the mitigation package a wildlife passage structure was installed to maintain connectivity between habitats on the east and west side of U.S. Route 7. The dimensions of the wildlife passage structure are  24’ wide by 6’ height (clearance) by 108’ length.  It has a natural bottom fill with full spectrum lighting controlled by a photoreceptor turning the lights on and off daily to mimic natural sunlight patterns.  Moisture levels in the passage  structure are  maintained through a modified riprap drainage swale within the structure. Scattered brush was placed within the passage structure to provide wildlife protective cover and help facilitate movement through the crossing.  To monitor activity within the passage structure a motion detecting camera was installed to photograph all wildlife utilizing the passage tunnel.

         A total of six box turtles, representing 16.6% of the total adult turtle population used the passage structure during the study period.  In addition to box turtles a variety of mammals were photographically documented crossing through the tunnel including whitetail deer (Odocoileus virginianus), bobcat (Lynx rufus), coyote (Canis latrans), raccoon (Procyon lotor), woodchuck (Marmota monax), gray squirrel (Sciurus carolinensis), opossum (Didelphis virginianus), eastern striped skunk (Mephitis mephitis), chipmunk (Tamias striatus), shorttail shrew (Blarina brevicauda) and mice (Peromyscus spp)., many of which used the passage tunnel on a regular basis.  In addition to the species photographically documented, sporadic activity of green frog (Rana clamitans melanota), American toad (Bufo a. americanus), pickerel frog (Rana palustris), red-spotted newt (Notophthalmus v. viridescens) and northern ringneck snake (Diadophis punctatus edwardsii) were observed within the tunnel.