CHAPTER 21.44
SLOPES
21.44.010 Purpose and intent.
21.44.020 Applicability.
21.44.030 Slope development standards.
21.44.040 Exceptions to setback requirements.
21.44.050 Site plan requirements for slope development.
21.44.010 Purpose and intent. This chapter regulates development activity and structures in areas affected by slopes, bluffs, coastal bluffs and ravines, and provides the means for additional review and protection to encourage safe and orderly growth to promote the health, welfare and safety of Homer residents.
21.44.020 Applicability. a. This chapter applies to all development activity that disturbs the existing land surface, including without limitation clearing, grading, excavating and filling in areas that are subject to any of the following conditions:
1. Lots with average slopes 15% or greater, bluffs, coastal bluffs and ravines;
2. Located within forty (40) feet of the top or within fifteen (15) feet of the toe of a steep slope, bluff, coastal bluff or ravine; and
3. Any other location where the City Engineer determines that adverse conditions associated with slope stability, erosion or sedimentation are present.
b. This chapter imposes regulations and standards in addition to the requirements of the underlying zoning district(s).
21.44.030 Slope development standards. The following standards apply to all development activity on a site described in HCC 21.44.020.
a. No development activity, including clearing and grading, may occur before the issuance of a zoning permit under HCC Chapter 21.70.
b. Area of development.
1. Except where the City Engineer approves a site plan under HCC 21.44.050 that provides for a larger area of development, the area of development on a lot with an average slope:
a. Of 15 to 30 percent shall not exceed 25 percent of the total lot area.
b. Greater than 30 percent but less than 45 percent shall not exceed 10 percent of the total lot area.
2. The area of development on a lot with an average slope of 45 percent or greater shall not exceed the area of development described in a site plan approved by the City Engineer under HCC 21.44.050.
c. Setbacks. Subject to the exceptions to setback requirements in HCC 21.44.040, all development activity is subject to the following setback requirements.
1. No structure may be closer to the top of a ravine, steep slope or non-coastal bluff than the lesser of:
i. 40 feet; or
ii. 1/3 of the height of the bluff or steep slope, but not less than 15 feet.
2. No structure may be closer than 15 feet to the toe of a bluff other than a coastal bluff.
3. No structure may be closer than 40 feet to the top of a coastal bluff and closer than 15 feet to the toe of a coastal bluff.
d. Natural Drainage. The site design and development activity shall not restrict natural drainage patterns, except as provided in this subsection.
1. To the maximum extent feasible, the natural surface drainage patterns unique to the topography and vegetation of the site shall be preserved. Natural surface drainage patterns may be modified only pursuant to a site plan approved by the City Engineer under HCC 21.44.050, and upon a showing that there will be no significant adverse environmental impacts on the site or on adjacent properties. If natural drainage patterns are modified, appropriate soil stabilization techniques shall be employed.
2. The site shall be graded as necessary to ensure that drainage flows away from all structures for a distance of at least 10 feet, especially where building pads are cut into hillsides.
3. The development activity shall not cause an adverse effect on adjacent land and surrounding drainage patterns.
e. Erosion control.
1. Erosion control methods approved by the City Planner and City Engineer, including without limitation sediment traps, small dams and barriers, shall be used during construction and site development to protect water quality, control soil erosion and control the velocity of runoff.
2. Winter Erosion Control Blankets. If development on a slope is not stabilized by October 15, erosion control blankets (or a product with equivalent performance characteristics) must be installed upon completion of the seasonal work, but no later than October 15. The erosion control blankets shall remain in place until at least the following May
3. Vegetation shall remain undisturbed except as necessary to construct improvements and to eliminate hazardous conditions, in which case it must be replanted with approved materials including ground cover, shrubs and trees. Native vegetation is preferred for replanting operations, and will be used where practicable.
4. Grading shall not alter the natural contours of the terrain except as necessary for building sites or to correct unsafe conditions. The locations of buildings and roads shall be planned to follow and conform to existing contours as nearly as possible.
21.44.040 Exceptions to setback requirements. a. Any of the following may be located within a setback required by HCC 21.44.030(c):
1. A deck extending no more than five feet into the required setback.
2. An unoccupied accessory structure having a building area not greater than 200 square feet that is no closer than 15 feet to the top of any bluff or ravine.
3. A boardwalk, sidewalk, foot path or stairway that provides access to a beach, bluff or accessory structure, and that is located at or within three feet above ground level.
4. Development activity that the City Planner determines is reasonably intended to stabilize an eroding coastal bluff.
b. No structure other than a structure described in (a) of this section may be located in a required setback without a conditional use permit issued in accordance with HCC Chapter 21.71 and a site plan approved by the City Engineer under HCC 21.44.050.
21.44.050 Site plan requirements for slope development. a. No permit for development activity for which HCC 21.44.030 or 21.44.040(b) requires a site plan may be approved unless the City Engineer approves a site plan for the development activity that conforms to the requirements of this section. The City Engineer shall accept or reject the plan as submitted or may require that specific conditions be complied with in order for the plan to meet approval.
b. The site plan shall be prepared by a qualified geotechnical engineer licensed to practice in the state of Alaska and shall include the following information.
1. The location of all watercourses, water bodies, and wetlands within 100 feet of the location of the proposed development activity.
2. The location of all existing and proposed drainage structures and patterns.
3. Site topography shown by contours with a maximum vertical interval of five feet.
4. The location of all proposed and existing buildings, utilities (including onsite well and septic facilities), driveways and streets.
5. The location of all existing vegetation types including meadow, forest and scrub lands, identifying all areas of vegetation that will be removed as well as vegetation to be preserved or replaced. Specifications for revegetation shall also be included.
6. Specific methods that will be used to control soil erosion, sedimentation, and excessive storm water runoff during and after construction.
7. A description of the stability of the existing soils on site and a narrative and other detail sufficient to demonstrate the appropriateness of the development and construction methods proposed.
8. A grading plan for all areas that will be disturbed by the development activity.
9. A slope stability analysis including the following:
i. Summary of all subsurface exploration data, including subsurface soil profile, exploration logs, laboratory or in situ test results, and ground water information;
ii. Interpretation and analysis of the subsurface data;
iii. Summary of seismic concerns and recommended mitigation;
iv. Specific engineering recommendations for design;
v. Discussion of conditions for solution of anticipated problems;
vi. Recommended geotechnical special provisions;
vii. An opinion on adequacy for the intended use of sites to be developed by the proposed grading as affected by soils engineering factors, including the stability of slopes. (Ord. 10-56 §2, 2011).