SEC. 91.7014. CONSTRUCTION REQUIREMENTS AND LIMITATIONS.

(Added by Ord. No. 171,175, Eff. 7/25/96.)

91.7014.1. Construction, General. (Amended by Ord. No. 185,587, Eff. 7/16/18.) No structure shall be constructed upon a slope steeper than 1 unit vertical in 2 units horizontal (50% slope). For building location and setback requirements, see Division 18, Article 1, Chapter IX of the LAMC.

EXCEPTIONS:

1. Subject to approval by the Department, construction may be placed upon slopes steeper than one unit vertical in two units horizontal (50% slope), provided reports from a soils engineer and engineering geologist recommend favorably toward construction. The reports shall include adequate information and analysis to show to the Department’s satisfaction that the underlying bedrock and natural soils and slope surface materials have strength characteristics sufficient to produce a stable slope with a factor of safety of not less than 1.5 for static loads. The reports shall incorporate provisions for downhill creep in the design of footings where applicable.

2. Where a minor amount of the structure is constructed on the slope or where the construction consists of an unroofed deck, the Department may approve the construction without engineering and geological reports.

91.7014.2. Slough Wall. (Amended by Ord. No. 179,324, Eff. 12/10/07, Oper. 1/1/ 08.) If potential sloughing hazards affecting buildings or structures are present on natural, cut or fill slopes in excess of 20 feet (6096 mm) in vertical height, slough protection devices may be required by the Department.

91.7014.3. Flood and Mudflow Protection. (Amended by Ord. No. 188,739, Eff. 9/ 23/25.) Flood and mudflow protection shall be provided for all new buildings, additions to buildings, and substantial improvements to buildings, which are located on sites determined by the Department to be subject to those conditions, in accordance with Ordinance No. 186,952.

The recommendations for mudflow protection shall be contained in a site investigation report made by persons qualified and licensed in civil engineering, engineering geology and/or soils engineering to ascertain the location, magnitude, and extent of potential mudflow hazards and to recommend measures for protection or the elimination of those hazards. The use of the minimum design parameters specified in this Code shall be justified in the report.

Minimum design parameters to be used for mud/debris flow control systems within and at the base of concentrated drainage areas are:

1. A channel flow capacity of 10 cubic feet per second (0.28 m3/s) per acre (ha) of tributary drainage area; or

2. A temporary storage capacity of 400 cubic yards (306 m3) per acre (ha) of tributary drainage area.