Environmental Review 00-03: Seasonal Low-Water Crossing

Environmental Review 00-03: Seasonal Low-Water Crossing

The project involves the annual construction and removal of a seasonal, low-water crossing of Tres Pinos Creek at the entrance to the San Benito County Historical Park. The project has been undertaken yearly since the loss of a permanent structure in 1995, and the County seeks to continue the practice until a permanent crossing can be constructed. The low water crossing is the only entrance to the Historical Park. At the end of the seasonal heavy rainfall period (normally around April 15), County work forces construct an earthen roadbed, with base rock surface and metal culverts, within the San Benito River channel. Later, before the start of heavy winter rains (around December 15th), the roadbed and culverts are removed, and the stream channel is restored to its previous condition. Equipment is used to move the earthen material into and out of the stream channel during construction and removal activities. No concrete is involved in the roadbed construction and no roadway material is taken from areas covered by flowing or standing water. No trees or aquatic vegetation are removed. The seasonal roadbed measures approximately 350 feet long and five (5) feet high. The width of the temporary roadway structure varies from 25 feet at the top to approximately 50 feet at the bottom, with a side slope ratio of 2 to 1. Approximately 1000 cubic yards of material are used to construct the roadway. Two 3-foot diameter steel culverts, approximately 55 feet in length, are installed to allow low-flow water levels to pass under the roadbed. During the rainy season, the earthen material and associated culverts are pushed up out of the channel and piled for storage on an upper terrace, above floodstage. Silt fences are installed to prevent fines from washing into the river.

Hollister

San Benito

California Department of Conservation (DOC), California Department of Parks and Recreation, California Department of Transportation, District 5 (DOT), California Highway Patrol, California Native American Heritage Commission (NAHC), California Regional Water Quality Control Board, Central Coast Region 3 (RWQCB), California State Lands Commission (SLC), Department of Water Resources, Office of Historic Preservation, Resources Agency, California Department of Fish and Wildlife, Bay Delta Region 3 (CDFW)

California Department of Fish and Wildlife, Bay Delta Region 3 (CDFW)

Transportation:Other (Seasonal stream crossing)

Other

Air Quality, Drainage/Absorption, Flood Plain/Flooding, Transportation