SR 06:060 - Laserfiche WebLink

TreadwelI&RoIIo 10 November 2005 Project 4186.02 Ms. Kerry Sinnott Silver Stone Development . 1733 Woodside Road, Suite 125 Redwood City, California 94061 Subject: Supplemental Slope Stability Investigation 3909 Vineyard Avenue Pleasanton, California Dear Ms. Sinnott: This letter presents the findings and conclusions resulting from a supplemental slope stability . investigation performed by Treadwell & Rollo, Inc. for the proposed development at 3909 Vineyard Avenue in Pleasanton, California, Our services were performed in accordance with our proposal dated 28 September 2005. The site is north of Vineyard Avenue and west of Birch Creek Drive. It encompasses approximately 2.74 acres and is currently vacant. A steep bank is located north of the property line adjacent to Arroyo Del Valle. - The proposed development consists often buildings housing three to six residential units each for a total of 45 units ranging from 1269 to 1979 square feet. Partial basements are plaI1Iled, and site preparation will require minor grading to level the building pads;md prepare the sub grade for flatwork . . A storm sewer outfall to drain surface water from the site into the creek is planned, The outfall will be located on the northern slope adjacent to Arroyo Del Valle. An energy dissipation system will be used to minimize erosion of the creek bank, as shown on the Site Plan (Figure 1). . The creek channel slope has variable steepness, but is inclined at about a 2: 1 slope (horizontal: vertical), There is a total elevation difference of24 feet from the northern site boundary to the bottom of the creek channel. The slope is vegetated with shrubs, grass and. trees. . Treadwell & Rollo, Inc. Environmental & Geotechnical ConstJ/tants 555 Montgomery Street, Suite 1300, San Francisco, CA 94111 Telephone (415) 955-9040 Facsimile (415) 955.9041