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.