RES 03027 - Laserfiche WebLink

ENGEO E. BiotechnicaI Recommendations for Prevention and Mititation of Existing or Potential Erosion Hazards iNCORPORATED Biotechnical slope protection involves the use of mechanical elements or structures in combination with biological elements (plants) to provide erosion control and help prevent small-scale slope failures. Locally, crib walls, welded-wire walls, gabion walls, rock walls, riprap, and reinfomed earth walls used in combination with carefully-selected and planted vegetation can provide high quality slope protection. Vegetation provides a protective cover on soil and exposed rock. It absorbs the impact of raindrops, reduces the velocity of runoff and retards erosion. If seeding is done too early; however, such as before September, seed loss by birds and wind may be significant. Graded slopes on this project may be more erodible than natural. Therefore, maintenance of vegetative cover following grading is especially important. A Landscape Architect should consult with the project GeotechnicaI Engineer on this matter. F. Maintenance and Monitoring Schedule Inspection of the Covered Area should be done at least twice each year. As a prudent measure, the budget reserves will accommodate at least two additional inspections for years of heavy rainfall. The inspections will take place in August (prior to the first significant rainfall) and in early April (at the end of the rainy season). At least one mid-winter site inspection could be added as dictated by heavy rainfall activity. The frequency of the additional inspections depends on the intensity and recurrence of rainfall. Site inspections will increase commensurate with increases in rainfall. At a minimum, inspections shall be made within 5 days, whenever rainfall exceeds 2 inches in a 24~hour period as reported by the nearest Alameda County Flood Control District monitoring station. Additional inspections may be performed at the discretion of the 4992.5.001.01 February 28, 2003 12 DRAFT 2