03-21-1988 Planning Packet - Laserfiche WebLink

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applicant asked the City to n light of what seems to be In fact, on at least one 1 approved a cut to create a originally proposed. A photo operty indicates that such a letracting from the natural Bts that a 3’ deep excavation /e a beneficial effect on the to other methods. Staff has d quantify the valid public ject. To this end, staff has to assess the visual and :oration methods available for t assessment process. i? Certainly, environmental onmental Plan section of the Sts that the visual impact of other properties is a valid for lake water quality. The lot necessarily a valid public rn if such a project that has lOt be feasibily completed due f owner. I am not sugges^'ing •ation, but am suggesting chat lowner into the most expensive ids are available that will ods for restoration of the 'e been discussed to a certain I, and each of which has both perty owner and the public in principals that apply to each tolling File 11223 March 6, 19tt Page 1 of • A) In general, a 2il slopo (50% slop* or 1’ vertical drop for every 2' of horiiontal distance) is considered as adequate for stabilising the slope in the clayey soil types present. B) If site factors make it unfeasible to create a continuous 2tl elope, then artificial structuel methods must be employed to provide adequate stability. These would appear to fall into two catagoriesx 1. Providing the bank with interior stability so that steeper slopes can be created that wi 11 have less of a tendency to fail. OR 2. Providing exterior vertical support, such as retaining walls, that will allow the removal of excess overburden soil so that shorter lengths of flatter slopes can be employed. In either case the goal is to decrease the ability of the soil to move sideways as a result of forces from abov.< it. A brief description of the nine options considered by staff is as follows: A. Backfill and grade the existing bank to a uniform slope with no stabilization measures. This would result in about a 1.4:1 slope which would have stability characteristica no better than what originally existed, if not worse because there would be disturbed soil in place of what was natural soil originally. This method would likely have little visual impact from the lake, but would be relatively troublesome for the re-establishment of vegetation. The short term potential impacts on lake water quality would be relatively low compared to other methods, pr'»'uming that the prime short term concern is the area of vegetated surface that will be laid bare for a period of time and subject to surface erosion. Note that use of proper erosion control methods (silt fence, hay bales, seed mesh, etc.) with each of the nine options will make the actual short-term impact relatively equal for all the options. mm..Tj.-i'--’/" ; Vl-f-: r. ■ iv - ' ^:m.