Environmental Engineering Reference
In-Depth Information
box culverts. Wetland mitigation was also integrated into the plans. Stormwater guide-
lines were based on regional standards and included appropriate Best Management
Practices. And water quality and fish habitat were improved through daylighting
buried waterways in both rural and urban areas. Detailed concepts were developed
for each wildlife crossing which included restoration plans to restore native veg-
etation, improve hydrologic functioning, facilitate wildlife migration, and enhance
habitat structure. Also, the cultural uses of these sites were taken into consideration;
i.e., the major creeks and rivers were and still are networks for traveling, harvesting,
hunting, and camping.
Wildlife Crossings
Simply improving hydrology and connectivity of waterways is not enough.
Throughout the highway corridor, there was a need to provide wildlife habitat for
cover, forage, and movement. Forty-two wildlife crossings were incorporated into
the 56-mile highway stretch, strategically located in response to known patterns
of wildlife migration such as along drainage paths. Tribal wildlife data on animal
behavior and mortality rates were instrumental in determining proper structure type
and placement. Wildlife crossing structures ranged from a large overpass near the
town of Evaro to bridges to large box culverts to smaller 1.2 × 2 m undercrossings
(Figures 17.21 and 17.22). Throughout the agriculture-dominated corridor, there
was a need to provide wildlife habitat for cover, forage, and movement. Native veg-
etation typifying one of the sixteen distinct plant communities along the highway
was specified by the design team to be planted along the roadside, and clustered
FIGURE 17.21
New Jocko River bridge.
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