Chapter 16.212 — HILLSIDE DEVELOPMENT STANDARDS

These regulations ensure that Hillside Development complements and is sensitive to existing terrain, views, and significant natural landforms and features, and preserves and enhances Vallejo's scenic character, including its natural waterways and hillsides.

The provisions of this chapter apply to any subdivision, new use, or structure (including accessory structures), additions to existing structures and other development on any parcel with an average slope of fifteen percent or greater, hereinafter referred to as a "Hillside Parcel."

A.

Slope measurement. Average slope is the characteristic slope of the ground surface of an area of land, expressed as a percent, based on the most accurate available topographic information. Average slope shall be based upon the natural slope of the ground surface and determined based as follows:

L = Length of contour lines in scaled feet I = Vertical distance of contour interval in feet .00229 = The factor for conversion of square feet to acres times 100 percent

B.

All measurements shall be taken in no greater than ten foot increments for the vertical distance of contour lines, taking the vertical distance, or "rise," over the horizontal distance, or "run." The resulting fraction, or percentage, is the "slope" of the land.

C.

Conflicts. In the event of a conflict between the provisions of this chapter and other development code regulations, including the provisions of the applicable zoning district, the provisions of this chapter shall apply. The exception is when a project is also subject to Chapter 16.213, Residential View District, the more restrictive and greatest noticing requirements shall apply.

D.

Exceptions.

1.

The provisions of this chapter do not apply to additions to existing single-unit residences when the area of the addition is less than fifty percent of the area of the existing residence and there is no Hillside Development Permit for the existing residence.

2.

Nothing in this chapter shall prohibit the construction and occupancy of a single-unit residence on a hillside parcel created pursuant to the Subdivision Map Act and the city's subdivision ordinance. New development shall be built in compliance with this chapter.

(Ord. No. 1879 N.C.(2d), § 3(Exh. A), 3-11-2025)

16.212.02 - Requirements.

A.

Hillside Development Permit required. A Hillside Development Permit shall be required for all development on any parcel where the average slope is fifteen percent or greater and shall be processed in the same manner as a minor use permit pursuant to Chapter 16.606, Minor and Major Use Permits, subject to the requirements of this chapter.

B.

Soils and Geotechnical Report and Peer Review required. All applications for a Hillside Development Permit, shall include, in addition to the requirements of Chapter 16.606, a soils and geotechnical studies prepared by a qualified licensed geotechnical engineer and engineering geologist.

1.

The study shall include all information and materials required by the city engineer.

2.

The report shall be all such reports shall be subject to peer review by a qualified licensed geotechnical engineer and engineering geologist hired by the city and paid for by the applicant.

3.

The applicant shall incorporate all recommendations into the design of the project.

4.

This requirement may be waived if the city engineer determines that the project, because of its size, location, or design, will not have a significant impact on the hillside, or that sufficient information already exists, and further analysis is not necessary.

C.

Density Reductions. The minimum density shall be reduced on a hillside parcel such that no density is afforded for areas of the parcel that exceed a thirty percent slope.

D.

Development standards. All hillside development shall comply with the following development standards in addition to the standards for the applicable base zoning district.

1.

Slope Limits. Land with an average slope of thirty percent or more shall not be developed, except to allow necessary grading for slope stability, as approved by the City Engineer/Public Works Director. Development on land with an average slope of twenty percent or more may be permitted by the director only when all of the following findings can be made:

a.

It is substantially infeasible to locate the proposed building inside the maximum percent slope area;

b.

Where such location would have a substantially less impact on the environment;

c.

Where such location is deemed appropriate to facilitate clustered development; and

d.

Measures are included that provide adequate mitigation of environmental impacts such as visual, biological, and geotechnical impacts.

2.

Treatment of Sloped Areas.

a.

All areas with an existing average slope of thirty percent or greater shall be left undisturbed, except to allow necessary grading for slope stability, as approved by the City Engineer/Public Works Director;

b.

All areas with an existing average slope of twenty percent or more that are not covered with structures or used for access to the property shall not be paved, and shall only be disturbed as necessary to develop the site;

c.

Slopes created or altered by grading shall not exceed thirty percent; and

d.

For slopes up to fifteen percent, impervious surfaces shall not exceed forty percent of the gross land area. Slopes that exceed fifteen percent shall not have impervious surfaces that exceed thirty percent or less.

3.

Protection of Ridgeline Views. The highest point of any structure shall not be located within one hundred vertical feet of a ridgeline (i.e., a ground line located at the highest elevation of a connected series of major and minor hills).

4.

Subfloor Parking for Nonresidential Buildings. The maximum allowable floor area for nonresidential development may be increased to a maximum of twenty percent when at least twenty-five percent of the required parking spaces are provided below grade, or in a subfloor, and incorporated into the design of the building.

E.

Fences. Exterior fencing on hillside parcels shall be limited to wire mesh with wood posts or other similar natural materials that are transparent and do not significantly affect views of the site. Chain link fencing, solid wood, masonry, or other opaque fence/wall materials are prohibited.

F.

Grading control. All development subject to the requirements in this chapter shall also be subject to the provisions of Chapter 12.40 of the Vallejo Municipal Code, entitled "Excavations, Grading and Filling."

(Ord. No. 1879 N.C.(2d), § 3(Exh. A), 3-11-2025)