Open Space District's Road and Trail Management Plan

8 Documents in Project


SCH Number
Lead Agency
Marin County
Document Title
Open Space District's Road and Trail Management Plan
Document Type
FIN - Final Document

Document Description
MCOSD proposes to implement trail and drainage improvements to the Bob Middagh and Gas Line Trails in the Alto Bowl Open Space Preserve. The proposed realignments, drain dips, new culverts, change of use, and other actions to protect the environment and improve the user experience would increase the sustainability of the trail consistent with the Road and Trail Management Plan (RTMP) policies, best management practices (BMPs), and trail design standards. These measures would substantially reduce, over the existing trails, impacts from erosion and runoff into nearby drainages, thereby reducing sedimentation into the Richardson Bay watershed. Modifications to the Bob Middagh Trail include realignment of 1,952 feet of new trail, decommissioning of 938 feet of existing trail, installation of four sloped climbing turns, installation of three rock retention walls, construction of one rock armor swale 20 feet wide by ten feet long, replacement of two failing culverts, and changing the use designation to allow bicycles. Improvements to the Gas Line Trail include constructing 1,610 feet of new contoured trail at an average seven percent grade, installing appropriate dewatering measures for a more sustainable design and reduce potential sediment loading to streams, realigning 480 feet of the existing Horse Hill Trail, decommissioning 1,554.2 feet of existing social trails, and incorporating other actions to protect the environment and improve the user experience. MCOSD would build the new trail using the RTMP's policies, design standards, and BMPs.

Contact Information
James Raives
Marin County Open Space District
3501 Civic Center Drive, Room 260
San Rafael, CA 94903



San Rafael
Cross Streets
County Wide
Total Acres
State Highways
Hwy 101, 1, I-580
Marin County & San Rafaels
Novato, Miller, Corte Madera, San Geronimo Creeks

Notice of Completion

Development Type
Recreational (Open Space areas available for outdoor rec.)
Local Action
Master Plan
Project Issues
Other Issues Cumulative Effects Landuse Wetland/Riparian Water Supply Water Quality Vegetation Traffic/Circulation Toxic/Hazardous Soil Erosion/Compaction/Grading Recreation/Parks Public Services Population/Housing Balance Noise Minerals Geologic/Seismic Forest Land/Fire Hazard Flood Plain/Flooding Drainage/Absorption Other Issues: Utilities & service
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