Chapter 15.80


15.80.010    Average slope definition.

15.80.020    Certified report required.

15.80.030    Certified report specifications.

15.80.040    Liability.

15.80.050    Retaining walls.

15.80.010 Average slope definition.

For the purpose of this chapter, the definition of “average slope” shall be as follows: The average slope of the parcel of land or any portion thereof shall be computed by applying the formula:

S =

0.00229 IL


to the natural slope of the land before any grading is commenced, as determined from a topographic map having a scale of not less than one inch equals 100 feet and a contour interval of not less than five feet, where:

0.00229 = A conversion factor of square feet to acres;

S = Average percent slope;

I = Contour interval, in feet;

L = Summation of the length of contour lines, in feet, within the subject parcel;

A = Areas in acres of the parcel being considered. [Ord. O-03-2010 § 1 (Exh. A § 16.010)].

15.80.020 Certified report required.

It shall be unlawful for the owner, developer, or any contractor or other person to excavate, grade, level, or build upon any lot or property within the city when the average slope of the lot exceeds 25 percent. Building within 200 feet of slopes in excess of 25 percent will require a slope stability report to address the potential for landslides. Such report must be reviewed and approved by the city engineer or his/her designee. Each lot within a hillside development shall indicate a proposed building envelope and driveway location. The lot width shall be such that the maximum 12 percent driveway shall not be exceeded, unless a steeper driveway is approved by both the city engineer or his/her representative and the building department based on specific design considerations such as a southern-facing or heated driveway. Nor shall any person grade, level, or improve in any manner any parcel of land which is crossed by a natural or manmade watercourse or existing utility before such person has submitted to the city engineer a certified report from a qualified civil engineer licensed in the state of Utah containing the information set forth in EMMC 15.80.030. [Ord. O-03-2010 § 1 (Exh. A § 16.020)].

15.80.030 Certified report specifications.

The certified report required in EMMC 15.80.020 shall contain at least the following information:

A. A plat of the property showing the following:

1. Contour lines at five-foot intervals. Existing contours shall be indicated by dashed lines and proposed contours by solid lines;

2. Elevations at the corners of foundations and at the corners of driveways; and

3. Show or reference any existing or potential ground water flows which may cause unstable conditions such as debris flow or slides.

B. Assessment of the civil engineer as to the seriousness of any development problems such as erosion, drainage, flood and geologic hazards or unstable soil conditions and their potential effect on adjoining properties and on any proposed improvements to be built on the property.

C. The proposed method for handling the problems noted in subsection B of this section. [Ord. O-03-2010 § 1 (Exh. A § 16.030)].

15.80.040 Liability.

The purpose of this chapter is to point out to the owner and/or developer of any property that the liability and responsibility of such persons to protect the integrity of their own and adjoining properties, existing watercourses and utilities lies upon the person doing the development and upon the owner of the property being developed and not upon the city or any other person. The city may require additional information on any development or building which may have potential hazards. [Ord. O-03-2010 § 1 (Exh. A § 16.040)].

15.80.050 Retaining walls.

Retaining walls shall not be built over or adjacent to city utilities. Retaining walls shall not be allowed in public utility easements unless the city engineer determines the retaining wall will not unreasonably interfere with the public utility easement and approves the retaining wall in writing. [Ord. O-08-2020 § 1 (Exh. A); Ord. O-03-2010 § 1 (Exh. A § 16.050)].