3333 NASSAU ST 2024-08-07 - Laserfiche WebLink

• October 3, 2016 Single-Family Residence L&A Job No. 16-124 Page 7 GEOLOGIC HAZARDS AND MITIGATION Landslide Hazard The project site is underlain at shallow depth by very-dense cemented glacial till and very-stiff to hard deposits. These deposits are of very-high to high shear strength and are highly resistant to slope failure. Therefore, the hazard of deep landslides cutting into these competent basal soils would be minimal. Erosion Hazard The surficial topsoil and weathered soil are of low resistance against erosion, while the underlying very-dense cemented glacial till and very-stiff to hard transitional beds deposits are of very-high to high resistance against erosion if these soils are property and adequately drained. The weaker surficial soils on steeper portion of the site may be gradually eroded if they are devoid of vegetation cover. Progressive erosion may lead to shallow skin-type mud flows over the surface of the underlying glacial till and transitional beds deposits. To minimize such erosion hazard, vegetation cover outside of construction areas should be protected and maintained. Disturbed areas and areas devoid of vegetation from construction activities should be seeded and re-vegetated as soon as possible, and should be securely covered with clear plastic sheets until vegetation is fully established. Concentrated stormwater should not be discharged uncontrolled onto the ground within or in the immediate vicinity of the site. Stormwater over impervious surfaces, such as roofs and paved driveway and parking areas, should be captured by underground drain line systems connected to roof downspouts and catch basins installed in paved areas. Water collected into these drain line systems should be tiginlined to discharge onto a rock spall pad at bottom of gully. LIU & ASSOCIATES, INC.