CCP421 Slope density formulaCITY OF SAN JUAN CAPISTRANO
COUNCIL POLICY
Subject: Effective Policy
Page Date Number
SLOPE DENSITY FORMULA
1 of 5 10/3/00 421
(a.) Purpose and intent. The purpose and intent of this City Council Policy is to
provide guidance to the Planning Commission to ensure that residential projects in
hillside areas will implement the goals and policies of the General Plan, including the
Safety Element as its relates to protection from geologic hazards (unstable soils,
prevention of erosion, and the like) and the Conservation and Open Space Element
relating to the maintenance of the natural character and amenity of hillsides as a scenic
resource of the City.
(b.) Applicability of Policy. The provisions of this Policy shall apply to all hillside areas
within the City, except as specifically excluded as set forth in subsection (h) of Section
9-3-505 of the Municipal Code. For the purposes of this Policy, Ahillside area@ shall
mean all properties in the City which have a natural slope of ten (10%) percent or more
on any existing or proposed parcel, or portion of a parcel, or portion of a parcel
proposed for development.
(c.) Principal uses and structures permitted. The principal uses and structures
permitted in the Hillside Management (HM) District shall be as permitted in the
underlying Base District.
(d.) Conditional uses and structures. The uses and structures permitted in the
Hillside Management (HM) District subject to the approval of a conditional use permit
shall be as permitted in the underlying Base District.
(e.) Calculation of total allowable dwelling units. Within the Hillside Management
(HM) District, the total allowable residential dwelling units shall be calculated based on
the total land area within each slope category pursuant to Section (f) of this Policy. All
land area included within a parcel may be included in the calculation of total allowable
dwelling units, if all land within the parcel is designated for residential development by
the Land Use Element of the General Plan.
(f.) Residential dwelling unit calculations. Using the slope calculation procedure
described in Section (h), the allowable number of residential dwelling units shall be
calculated by totaling the maximum number of dwelling units allowed within each slope
category as follows:
CITY OF SAN JUAN CAPISTRANO
COUNCIL POLICY
Subject: Effective Policy
Page Date Number
SLOPE DENSITY FORMULA
2 of 5 10/3/00 421
Slope Category Dwelling Units Per Acre
0-10 Percent 100 percent of maximum density for General
Plan residential land use designation
11-15 Percent 90 percent of maximum density for General
Plan residential land use designation
16-20 Percent 75 percent of maximum density for General
Plan residential land use designation
21-25 Percent 55 percent of maximum density for General
Plan residential land use designation
26-30 Percent 35 percent of maximum density for General
Plan residential land use designation
30-39 Percent 10 percent of maximum density for General
Plan residential land use designation
Greater than 40 Percent Zero percent of maximum density for General
Plan residential land use designation *
* Does not apply to single family lots of record at time of this adoption, for a single
residential (one) building.
(g.) Clustering of Dwelling Unit Allocations or Graduated Lot Sizes. Within a
tentative map, planned development permit, vested tentative map or any other
applicable entitlement, dwelling unit allocations calculated for land areas having slopes
in excess of, 25 percent, the applicant is to be encouraged to cluster development to
land areas having slopes of less than 25 percent,, except no dwelling units shall be
allowed on land or slopes on or adjacent to a designated ridgeline identified in the
Conservation and Open Space Element of the General Plan. When clustering of
dwelling unit allocations as described above occur, the resulting minimum lot size for a
single-family detached dwelling or land area for a multi-family dwelling unit should not
be less than 10,000 square feet per dwelling unit.
CITY OF SAN JUAN CAPISTRANO
COUNCIL POLICY
Subject: Effective Policy
Page Date Number
SLOPE DENSITY FORMULA
3 of 5 10/3/00 421
As an alternative to clustering dwelling units within a tentative map, planned
development permit, vested tentative map or other applicable entitlement, dwelling units
may be distributed throughout a property, except no dwelling units shall be located on or
adjacent to a designated ridgeline identified in the Conservation & Open Space Element
of the General Plan. In that case, the minimum lot size increases as slope increases
based on the following criteria:
Slope Category Minimum Lot Size 0-10% Minimum lot size for the applicable zoning district 11-15% 1.11 times the minimum lot size of the applicable zoning district 16-20% 1.33 times the minimum lot size of the applicable zoning district 21-25% 1.82 times the minimum lot size of the applicable zoning district 26-30% 2.86 times the minimum lot size of the applicable zoning district 31-40% 10.00 times the minimum lot size of the applicable zoning
district
(h.) Slope Calculation Procedure. The following method shall be used to determine
the slope of any land within the Hillside Management (HM) District:
The parcel of land shall be divided into subareas or cells of approximately 100 feet by
100 feet (30 meters by 30 meters). Within each cell the slope shall be calculated by the
following formula:
S = I x L x 100
A
where:
S = Average ground slope in percent, calculated for each cell to be rounded to the
nearest whole number
I = Interval, in feet, of the topographic map contour lines. The contour interval shall be
10 feet or less for calculating slope.
CITY OF SAN JUAN CAPISTRANO
COUNCIL POLICY
Subject: Effective Policy
Page Date Number
SLOPE DENSITY FORMULA
4 of 5 10/3/00 421
L = The sum, in feet, of the length of all contour lines within the cell, at the selected
contour interval AI@.
A = The total area of the cell, in square feet. A cell 100 feet by 100 feet has an area of
10,000 square feet (100 feet x 100 feet = 10,000 square feet).
The areas of cells with each slope category shall be combined to identify the total land
area within the parcel within each of the slope categories identified in Section (f) The
allowable number of residential dwelling units can then be calculated as described in
Section (f).
(i.) Slope Map Required. All computations for slope and the allowable number of
residential dwelling units, including a topographic map, shall be prepared and signed by
a registered civil engineer or a licensed land surveyor and submitted to the
Environmental Administrator. The topographic map shall have a scale of not less than
one (1) inch to two hundred (200) feet and a contour interval of not more than ten (10)
feet. This topographic map shall include all adjoining topography within 150 feet of the
site boundaries. The map shall depict the slope category of each cell so that cells
within the same category are visually recognizable.
(j.) Planning Commission authority. The Planning Commission may recommend to
the City Council to approve residential development applications subject to the
calculations for density as set forth in this City Council Policy. Recommendations to
approve a residential unit allocation above the formula must meet the criteria for
exceptions as contained in subsection (l). Residential unit allocations less than the
formula may be recommended if the Planning Commission finds that it is necessary and
proper to assure consistency with the general purpose and intent of this Policy and
applicable provisions of the City=s adopted General Plan, or to satisfy environmental
mitigation measures or provide consistency with other provisions of the City=s General
Plan that is directly related to the subject property.
(k.) City Council Authority. The City Council upon receipt of a recommendation from
the Planning Commission on a residential subdivision application that is subject to the
provisions on Section 9-3.505 (Hillside Management District regulations) may use the
criteria contained within the provisions of this Policy to evaluate the appropriateness of
the design and intensity of development for the subject application.
CITY OF SAN JUAN CAPISTRANO
COUNCIL POLICY
Subject: Effective Policy
Page Date Number
SLOPE DENSITY FORMULA
5 of 5 10/3/00 421
(l.) Exceptions. Exceptions to the residential unit allocations as determined by the
slope density formula may be considered and approved by the City Council if the project
represents a unique design that will exceed the intent and purpose of this policy in
minimizing landform alterations while also blending the residential units in a manner that
they are not visually prominent.
In no instance shall the exception exceed twenty (20%) percent of the allowable units
under the provisions of the slope density formula.
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