1. No cut slope shall exceed a vertical height of one hundred (100) feet unless horizontal benches with a minimum width of thirty (30) feet are installed at each one hundred (100) feet of vertical height.

2. No excavation shall be made with a cut face steeper in slope than two horizontal to one vertical.

Exception: The planning commission, upon appeal, may permit the excavation to be made with a cut face steeper in slope than two horizontal to one vertical if the applicant can reasonably show the zoning administrator that the material making up the slope of the excavation and the underlying bedrock is capable of holding satisfactorily on a steeper gradient. No slopes shall be cut steeper than the bedding planes, fault or joint in any formation where the cut slope will lie on the dip side of the strike line of the fracture, bedding plane, fault or joint. No slopes shall be cut in an existing landslide, mud flow, or other form of naturally unstable slope except as recommended by a qualified geological engineer.

Where the excavation is exposed straight above the top of the cut which will permit the entry of water along bedding planes, this area shall be sealed with a compacted soil blanket having a minimum thickness of two feet. The soil for this blanket shall be relatively impervious and must be approved for such use by the soils engineering geologist. If the material of the slope is of such composition and character as to be unstable under the anticipated maximum moisture content, the slope angle shall be reduced to a stable value.

3. No excavation for construction of new utility and telephone lines shall be made in paved streets within five years after paving. During such five-year period, tunneling under such streets may be authorized or otherwise in compliance with this chapter, where to do so would facilitate construction of new utility and telephone lines. (Ord. 111 §1, amended, 1985; Prior code §12-107-6(F)(14))