Open Area (OA, Marin County)/Public Open Space (OS, Marin County)
The purpose of the proposed project is to implement the MCOSD Road
and Trail Management Plan (RTMP) to provide the public with a safe multi-use trail system to enhance the visitor experience, reduce the environmental impacts on sensitive resources by reducing sedimentation and erosion, and establish a sustainable system of roads and trails that meet design and management standards and would provide year-round access along the trail alignment. The project includes the following elements, which are summarized below and fully described in the Project Description section of the IS/MND:
Ecological and Hydrologic Restoration: Reestablish a multi-threaded Stage Zero wetland-channel complex to reconnect Upper Larsen Creek to its surrounding floodplain, reduce erosion, restore hydrologic functions, increase infiltration and raise the groundwater table, rehabilitate approximately 77,170 square feet of heavy visitor use areas throughout the valley floor to reduce soil compaction and increase conditions for natural regeneration of vegetation, halt development and persistence of incised channel reaches of Upper Larsen Creek through the valley floor using large and small wood structures, and re-orient existing fallen trees and downed branches and obtain and place additional logs, where needed, through the floodplain to improve natural hydrologic function by slowing and spreading water throughout
the floodplain to allow flows to infiltrate into the soil.
Trail Improvements: Upgrade and realign approximately 5,670 feet if existing trails to improve drainage, prevent future erosion and sedimentation, meet RTMP trail design standards and upgrade approximately 1,900 feet of existing trails to meet Marin County Parks Inclusive Access Plan standards for an Access and Discovery Trail.
Parking and Entryway Improvements: Develop two new designated entryways and improve the existing entryway adjacent to Nicasio Valley Road, relocate the existing porta-toilet out of the floodplain and closer to the existing entryway, install one inclusive access parking spot on the shoulder of Nicasio Valley Road, and reinstall
fencing along the Nicasio Valley Road shoulder.
Social Trail Decommissioning: Decommission approximately 6,465 feet of existing social trails located in sensitive areas using passive trail closure methods and active methods that involve heavy equipment and hand tools.
Visitor Education: Install new fencing and visitor information signage to notify visitors of closed trails and discourage development of new social trails, construct a Nature Exploration Area and Scramble, and provide visitor interpretive services and wayfinding signage.
San Geronimo Preschool, West Marin Montessori preschool
Larsen Creek, San Geronimo Creek, Nicaso Creek
Notice of Completion
State Review Period Start
State Review Period End
State Reviewing Agencies
California Air Resources Board (ARB), California Department of Forestry and Fire Protection (CAL FIRE), California Department of Parks and Recreation, California Department of Transportation, District 4 (DOT), California Department of Water Resources (DWR), California Native American Heritage Commission (NAHC), California Natural Resources Agency, California Regional Water Quality Control Board, San Francisco Bay Region 2 (RWQCB), California State Lands Commission (SLC), Office of Historic Preservation, State Water Resources Control Board, Division of Drinking Water, State Water Resources Control Board, Division of Water Quality, California Department of Fish and Wildlife, Bay Delta Region 3 (CDFW)
State Reviewing Agency Comments
California Department of Fish and Wildlife, Bay Delta Region 3 (CDFW)
Recreational (Park/Preserve Restoration and Access)
Park/Preserve Restoration and Access
Aesthetics, Agriculture and Forestry Resources, Air Quality, Biological Resources, Cultural Resources, Cumulative Effects, Drainage/Absorption, Energy, Flood Plain/Flooding, Geology/Soils, Greenhouse Gas Emissions, Hazards & Hazardous Materials, Hydrology/Water Quality, Land Use/Planning, Mandatory Findings of Significance, Mineral Resources, Noise, Population/Housing, Public Services, Recreation, Solid Waste, Transportation, Tribal Cultural Resources, Utilities/Service Systems, Vegetation, Wetland/Riparian, Wildfire
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