10-16-1995 Planning Packet - Laserfiche WebLink

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Zoning File #2056 August 18. 1995 W' Page 2 At the top of the slope, a 2-3’ boulder wall is proposed, presumably of similar construction, i.e. excavation below and fill placement above. The stated purpose of these walls is to decrease the effects of erosion and to clear the ”001 of control undergrowth" that is "extremely unsightly". From the letter of request, staff concludes the proposal will then be to clear virtually all ot the undergrowih on the hillside and replant with strips oi ornamental shrubs. Ciiy Engineer’s Comment The City Engineer indicates the design of the boulder walls is acceptable from an engineering standpoint. Discussion Having inspected the site twice this week, staff finds little justification for approval of the proposed walls, especially at the base of the slope; Normally, the City only approves new or replacement walls in the 0-75 ’ zone to solve existing or impending slope failures. In this case, there is no indication of slope failure. There is no evident fraemring of the soil above the slope suggesting that a slump may be imminent. Further, the slope ranges from 2.1 to 3:1, which is normally a very stable slope not subject to massive failure. The only visible erosion that is occurring is surficial erosion in the yard due likely to a weak root structure in the grass because it is in the shade. There is no evidence of significant surficial erosion happening on the hillside, and in fact the hillside is highly vegetated with various natural plant materials as well as many young trees in the range of 1" diameter, and a scattering of mamre trees at the toe, middle and top of the slope. While there is poison ivy in abundance on the site, excavation of the slope is not necessary’ to solve the poison ivy problem. There is no visible undermining of the shoreline that suggests the immediate need for a seawall or riprapping. The proposed location of the wall is 2* above the OHW. Excavating at the base of the hill and placing boulders with fill above them would create a terraced effect that has no apparent slope stabilizing purpose. It also creates a terrace at the lake edge where applicants apparently wanted to place a beach sand blanket. That application was denied by the Minnehaha Creek Watershed District in June. (Please review Exhibit I). MCWD staff indicate that they would not support the current proposal for excavation in the flood plain. An M(2WD permit would be required for the work as proposed. -I