SCH Number 2023030371

Project Info

Title

Flint Canyon Wash Trail Restoration Project

Description

The Proposed Project would improve a 1,000-foot section of the 2.4-mile-long Flint Canyon Wash Trail. Improvements include the installation of gabions, which are steel wire mesh cages filled with rip-rap (large rock aggregate). The Proposed Project would install 3-foot by 3-foot gabions on the downslope of the unprotected bank. The purpose of the gabion wall is to stabilize the slope and to inhibit stream flows from eroding and undercutting the slope supporting the Flint Canyon Trail. In addition to the gabions, soil nails would be used to stabilize the embankment. The soil nails would be placed in a grid-like pattern along the length and height of the wall, inserted laterally into the slope. The gabions would be placed in front of the soil nails, facing the wash, for erosion protection. The Proposed Project would also include the installation of five erosion monitoring stations at key points along the stream where high velocity flows occur. These stations would help the City identify future problem areas that could affect the stability and safety of the Flint Canyon Trail. These stations would require rebar to bedriven horizontally into the slope. The City would measure over time the length of exposed rebar, which would help gauge the extent of erosion that is occurring. In addition to stabilizing and protecting the slope supporting the Flint Canyon Trail, the Proposed Project would enhance natural habitat adjacent to the trail. A biological restoration plan is being prepared for the Proposed Project and will be included with the final engineering plans, specifications, and estimates (PS&E) submittal. Habitat enhancement would include removal of non-native vegetation and may include planting of native vegetation. The biological restoration plan will include a maintenance, monitoring, and reporting component for a 120-day Plant Establishment Period (PEP) and for five years following the end of the 120-day PEP. Temporary staging for construction would be along the trail just south of the proposed improvements. Two other potential temporary staging areas also include a portion of the parking lot of the La Cañada United Methodist Church and an adjacent dirt lot located south of Berkshire Place and east of the westbound Interstate-210 off-ramp at Berkshire Place.

2 documents in project