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Design Construction Impacts
· Additional rock blasting may be necessary based on recent geotechnical investigations in stage 2.
· A recently identified stream in stage 2 will be relocated and will require additional mitigation.
· A new temporary alignment was designed around a sensitive area to reduce impacts and enable two lanes of traffic to remain open through the area during construction. The new design will reduce the amount of right of way purchase. This design will require more wall and roadway construction.
· The estimate for Stage 1 has increased due to increased bridge costs, increased materials costs, and the use of ecology embankment to treat highway runoff.
· There are existing utility easements on State right of way. A portion of the utility relocation costs will be the responsibility of the WSDOT.
· The estimate for Stage 2 has increased due to results obtained from the latest geotechnical investigations, increases in materials costs, roadway redesign to avoid recently discovered utility easements and sensitive areas, and the need to construct a temporary roadway due to the lack of an adequate detour route.
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