Lobitos Creek Culvert- Emergency Debris Management

Lobitos Creek Culvert- Emergency Debris Management

At the Project site, the County owns and maintains a double box culvert that passes Lobitos Creek below Verde Road. Due to the recent rains, two logs and smaller woody debris accumulated al the double box culvert Inlet. The debris was completely obstructing one box and the other box was at half capacity. This debris was obstructing and deflecting streamflow, causing erosion and scouring at the culvert wingwall. The purpose of this emergency work was to protect the culvert wingwalls from further scour. Also, if immediate work was not performed prior to the additional forecasted heavy rainfall and high streamflow, additional debris accumulation could create additional flooding concerns and cause further scour at the culvert inlet. Project activities occurred in the following sequence: biological survey, best management practice (BMP) Implementation, equipment staging, and small woody debris removal. Standard sediment and erosion control BMPs were on-hand to control any unanticipated Increases In turbidity. Turbidity was actively monitored during construction. For the duration of the Project, materials and equipment were positioned on the paved roadway and shoulder. Operation of heavy equipment and vehicles was limited to the roadway, Equipment used to complete the debris management Included a Bobtail. Equipment access lo the creek channel was not required. A wench was attached to the equipment and was used to clean pluck accumulated debris from the culvert inlet. The accumulated debris was not of significant size or diameter to be beneficial as large wood debris and habitat structures. A biologist was on site to monitor all work. Dewatering was not performed. The work took 1 day lo complete,

Half Moon Bay

San Mateo

Unincorporated

San Mateo