Upstream of the SR 3 culvertsChico Creek was historically channelized (probably in the early 1960s during construction of SR 3 crossing) into a straight alignment along the west side of the valley and confined by a 4-ft high levee that disconnected the channel from the floodplain. Gravel was extracted from the east half of the valley to fill an embankment as part of SR 3 construction. Gravel pits were left as ponded areas in the disconnected floodplain. A metal debris rack was installed in the channelized segment approximately 800 ft upstream of the culverts to prevent debris from blocking the double box culvert at SR 3. The debris rack was a barrier to fish passage when blocked with wood transported from upstream and required frequent maintenance by WSDOT to remove material accumulated during storm events. A channel avulsion in the early 2000s resulted in split flow with a majority of the streamflow being redirected into the gravel pit areas and bypassing the debris rack channel (Figure 47). Sediment has since accumulated in the pond area as the channel rebuilds a floodplain within the former gravel pit.

This project is identified in the Chico Creek Assessment for the Identification of Protection and Restoration Actions.