Res 01-103-- RESOLUTION NO. 01-103
A RESOLUTION OF THE CITY OF POWAY, CALIFORNIA,
APPROVING SLOPE CALCULATION STANDARDS AND PROCEDURES
WHEREAS, it is the duty of the Poway City Council to review and amend
the Poway Municipal Code whenever the public interest requires or whenever,
because of ambiguity or otherwise, its provisions are subject to being
misinterpreted or require greater specificity; and
WHEREAS, Section 17.08.170.A.3. of the Poway Municipal Code requires
amendment to clarify the ministerial nature of slope calculation and the
applicable formula and standards and procedures therefore; and
WHEREAS, such amendment is necessary in order to assure that the
required slope calculation report for a development project is completed in
accordance with the public counter handout titled: "City of Poway Slope
Calculation Standards and Procedures;" and
NOW, THEREFORE, the City Council does hereby resolve as follows:
Section 1: The City Council finds that the adoption of this Resolution is
Exempt from the requirements of the California Environmental Quality Act
(CEQA) pursuant CEQA Guidelines Section 15061 (b) (3), General Rule, as
follows:
"The activity is covered by the general rule that CEQA applies only to
projects, which have the potential for causing a significant effect on the
environment. Where it can be seen with certainty that there is no possibility that
the activity in question may have a significant effect on the environment, the
activity is not subject to CEQA."
Section 2: The City Council hereby adopts the following standards and
procedures for the calculation of slope pursuant to Section 17.08.170. A, 3. of the
Poway Municipal Code.
Prel~aring Average Slope Analysis (Slope Calculation) for Subdivision
Maps and Legal Lots
The average slope analysis (slope calculation) technical report for
subdivision maps and legal lots (hereinafter subject property) shall
be prepared by a civil engineer registered by the State of California,
and shall follow the standardized format as approved by the City of
Poway.
The average slope analysis may be prepared in either a manual
format or an electronic format. If an electronic format is used by the
Resolution No. 01-103
Page 2
preparer, it shall be submitted on a CD-ROM in a format compatible
with AutoCAD (I.E. DWG, DXF). As described in Item 3, below, the
supportive materials for both the manual and electronic format
options are the same unless otherwise noted.
Averaqe Slope Analysis Procedures and Supportive Materials
A topographic contour map (topo map) shall be prepared for
the subject property based upon the most current and best
available aerial photography information/flown topo data.
The subject property boundaries shall be depicted on the topo
map described in Item "a" above. Such boundaries shall be
based on a current survey and legal description and shall
show adequate bearings and distances.
c. The net area of the subject property shall be determined as
follows:
The net area of subject property equals the gross area
of the subject property minus the following:
ii. Any existing and proposed public and private
categories of vehicular access (streets and easements);
iii.
Any area(s) located within the 100-year floodway of any
drainage course; and
iv. Any land area with a natural slope of 45% or greater.
Using the topo map described in Item 3.a. above, submit a
colored topographic slope category map and corresponding
table depicting the following four (4) slope categories shown in
the following pastel, muted colors, and acreage within each
slope category:
Slope Cateqorv (%)
Color Acreage (1)
0 - 15 Green 00.00
15 - 25 Yellow 00.00
25 - 45 Blue 00.00
45 + Red 00.00
Resolution No. 01-103
Page 3
(1) - Manual Format:
Topo Map Scale = 50 Feet
Contour Interval = 5 Feet
- Electronic Format: Topo Map Scale = Any
Contour Interval = 2 Feet
The 45 + slope category "area" shall be based on the
average measurement of the rise-over-run (in
inches) as measured between the contour lines
where such 45 + slope exists. The determination of
this measurement shall be explained by the preparer
in the completed average slope analysis report.
Submit tables (tabular listing), signed by the preparer,
indicating the length of each topographic contour elevation
(in inches) according to the topo map for the subject
property, as indicated by the following example in Table A
and Table B.
TABLE A
(Manual Format - Map Scale = 50 Feet, Contour Interval = 5 Feet)
Contour Elevation 0-15% 15-25% 25-45% 45+%
750 00.00 00.00 00.00 00.00
755 00.00 00.00 00.00 00.00
760 00.00 00.00 00.00 00.00
Total 00.00 00.00 00.00 00.00
TABLE B
(Electronic Format - Map Scale = Any, Contour Interval = 2 Feet)
Contour Elevation 0-15% 15-25% 25-45% 45+%
750 00.00 00.00 00.00 00.00
755 00.00 00.00 00.00 00.00
760 00.00 00.00 00.00 00.00
Total 00.00 00.00 00.00 00.00
Resolution No. 01-103
Page 4
Submit one set of average slope analysis calculations for the
entire subject property proposed for subdivision to determine
percent of average natural slope. Also, submit one set of
average slope analysis calculations for each of the proposed
lots to show compliance with the slope criteria for the entire
subject property. To compute average slope the following
formula shall be used:
(CLx I x S)
NA
Where:
CL = Length of Contours (in inches)
= Contour Interval
S = Scale of Topographic Map
NA = Net Area in Square Feet
For electronic slope analysis computations, the
contour interval used for the determination of the
variable CL shall be the same contour interval in the
determination of the variable NA to maintain the
validity of the length-to-area ratio of the formula
above.
The 45+ slope category area shall be based on the
average measurement of the rise-over-run (in inches)
as measured between the contour lines where such
45+ slope exists.
It is critical that the length of the contour lines
measured adjacent to areas over 45% slope be
accurately accounted for. The attached Figure 1
provides two examples of correctly (RIGHT)
accounting for said lines and one example of not
correctly (WRONG) accounting for said lines.
Submit graphic (at minimum 100-foot scale) showing
proposed development-grading design (development
footprint) superimposed on the colored slope category map.
This graphic is essential in determining the project's
Resolution No. 01-103
Page 5
compliance with the City's use requirements and
development standards.
Determination of the potential "theoretical" density and the
potential "allowable" density for the subject property:
The potential "theoretical" density is calculated using
the average slope of the net area of the subject
property as described in Item "f" above.
ii.
The potential "allowable" density of the subject
property is calculated based upon the demonstration
by the project proponent, through submission of a
conventional subdivision design, that each of the
proposed lots is consistent with the slope requirement
for the total site (entire subject property).
The number of lots allowable shall be calculated
based upon the average and individual slope criteria
and minimum lot size formula. The maximum
allowable density shall be the number of lots
approved by the Poway City Council.
As required by the General Plan, the maximum allowable
area of the lot that may be graded for driveway, residence
and accessory functions is determined by the degree of
average natural slope as follows. This requirement shall
apply to all lots within all zoning categories.
Slope
Graded Area *
0 - 14.9
Entire lot
15 - 19.9
50% or 35,000 sq. ft. whichever is greater
20 - 24.9
20% or 25,000 sq. ft. whichever is greater
25 - 44.9
10% or 20,000 sq. ft. whichever is greater
45+
** No grading or development permitted
and no developable acreage credit given
Resolution No. 01-103
Page 6
* Sensitive biological
environmental constraints may
application of stricter standards.
or other
require the
Section 3:
** Exemptions apply to the High Valley
area for slopes in excess of 45 percent for
determining parcel size, (Amended per GPA
93- 02C).
This Resolution shall become effective on November 27, 2001.
PASSED, ADOPTED and APPROVED by the City Council of the City of
Poway, State of California, this 27th day of November 2001.
ATTEST:
nne Peoples, City Cl~rk -
Michael P. Cafagna~
STATE OF CALIFORNIA )
)SS
COUNTY OF SAN DIEGO )
I, Lori Anne Peoples, City Clerk of the City of Poway, do hereby certify,
under the penalty of perjury, that the foregoing Resolution No. 0~-103 , was
duly adopted by the City Council at a meeting of said City Council held on the
27th day of November 2001, and that it was so adopted by the following vote:
AYES:
NOES:
ABSTAI N:
ABSENT:
L'~'ri ~,nne Peoples, City Cl'erk
City of Poway
n:\city\planning\Olreport~oa~oaOl-O5.slope calculation proposed resolution.doc
Resolution No. 01-103
P~ge 7
II.
CITY OF POWAY
Slope Calculation Standards and Procedures
Introduction
Slope calculations and the density potential, which result from such calculations
under the provisions of this Chapter, are matters requiring technical engineering
expertise, and are ministerial, not discretionary, in nature. In the RR-A through
RR-C and RS-1 zones, slope calculations shall be based on the measured dse
over run calculations of a topographic map of the property prepared in
accordance with the standards set forth in this section by a registered civil
engineer retained by the applicant. The City may retain at the applicant's cost a
registered civil engineer to vedfy the calculations of the applicant's engineer, and
to ascertain whether or not the calculations were made in accordance with the
standards set forth in this Section. In the event that the civil engineer retained by
the City determines that the calculations were made in accordance with the
standards set forth in this Section, the City shall accept the calculations as
accurate. In the event that the civil engineer retained by the City determines that
the calculations were not made in accordance with the standards set forth in this
Section, the City shall not accept the calculations as accurate. No application for
development of property, which requires slope calculation, shall be deemed
'complete until the Director of Development Services has accepted the slope
calculation.
In the RR-A through RR-C and RS-1 zones, the following standards and
procedures shall be applied for the purpose of determining:
- The minimum size, shape, and location of lots
The average natural slope (hereinafter "average slOpe analysis") for
subdivision maps and legal lOts (hereinafter "subject property").
The potential "theoretical" and potential 'allowable" rural residential
density on the subject property ~
'-General Plan strategies, and Zoning Development Code Definitions and
Property Development Standards
The General Plan strategies, and Zoning Development' Code definitions and
property development standards, which are relevant to the slope of property, are
listed in Attachment A hereof.
Resolution No. 01-103
P~ge 8
III.
Preparina Avera;e Slope Analysis (Slope Calculation) for Subdivision
'MaPs and Legal Lots
The average slope analysis technical report for subdivision maps and legal lots
(hereinafter subject property) shall be prepared by a civil engineer registered by
the State of California, and shall follow the standardized format as approved by
the City of Poway.
The average slope analysis may be prepared in either a manual format or an
electronic format. If an electronic format is used by the preparer, it shall be
submitted on a CD-ROM in a format compatible with AutoCAD (I.E. DWG, DXF).
As described in Item 3, below, the supportive materials for both the manual and
electronic format options are the same unless otherwise noted.
3. Average Slope Analysis Procedures and Supportive Materials
A topographic contour map (topo map) shall be prepared for the subject
property based Upon the most current and best available aerial
photography info,',¥~ation / flown topo data.
Bo
The subject property boundaries shall be depicted on the topo map
described in Item A above. Such boundaries shall be based on a current
survey and legal description and shall show adequate bearings and
distances.
C. The net area of the subject property shall be dete..ined as follows:
The net area of subject property equals the gross area of the subject
property minus the following:
Any existing and proposed public and private categories of
· vehicular access (streets and easements);
Any area(s) located within the 100-year floodway of any
drainage course; and
- Any land area with a natural slope of 45% or greater.
D~
Using the topo map described in Item A above, submit a colored
topographic slope category map and corresponding table depicting the
following four (4) slope categories shown in the following pastel, muted
colors, and acreage within each slope category:
2
Total
g SOlution No. 01-103
e9
Slope Category (%)
Color Acreage (1)
0 - 15 Green 00.00
15 - 25 Yellow 00.00
25 - 45 Blue 00.00
45 + Red 00.00
(1) - Manual FOrmat:
Topo Map Scale = 50 Feet
Contour Interval = 5 Feet
- 'Electronic Fo[mat: Topo Map Scale = Any
Contour Interval = 2 Feet
- The 45 + slope category "area" shall be based on the
average measurement of the rise-over-run (in inches) as
measured between the contour lines where such 45 + slope
exists. The determination of this measurement shall be
explained by the preparer in the completed average slope .
analysis .report.
Submit tables (tabular listing), signed by the preparer, indicating the length
of each topographic contour elevation (in inches) according to the topo
map for the subject property, as indicated by the following examples:
TABLE A
(Manual Format - Map Scale = 50 Feet, Contour Interval = 5 Feet).
Contour
Elevation
0-15% 15-25% 25-45%
750 . 00.00 00.00 00.00
-755 00.00 00.00 00.00
760 00.00 00.00 p0.00
00.00 00.00 00.00
45+%
00.00
00.00
00.00
00.00
Resolution No. 01-103
Page 10
Total
TABLE B
(Electronic Format - Map Scale = Any, Contour Interval = 2 Feet)
Contour
Elevation
0-15% 15-25% 25-45% 45+%
75O
755
76O
00.00 00.00 00,00 00.00
00.00 00.00 00.00 00.00
00.00 00,00 00.00 00.00
00.00 00.00 00.00 00.00
Fo
Submit one set of average slope analysis calculations for the entire
subject property proposed for subdivision to determine percent of average
natural slope. Also, submit one set of average slope analysis calculations
for each of the proposed lots to show compliance with the slope cdteda for
the entire subject property. To compute average slope the following
formula shall be used:
(CLx I x S)
NA
Where:
CL = Length of Contours (in inches)
= Contour Interval
S : Scale of Topographic Map
NA = Net Area in Square Feet
For electronic slope analysis computations, the contour interval
used for the dete..ination of the variable CL shall be the same
- contour interval in the dete[mination of the variable NA to maintain
the validity of the length-to-area ratio of the fom~ula above.
The 45+ slope category area shall be based on the average
measurement of the rise-over-run (in inches) as measured between
the contour lines where such 45+ slope exists.
It is critical that the ength of the contour lines measured adjacent to
areas over 45% slope be accurately accounted for. The attached
-4
Go
Resolution No. 01,103
Page 11
Figure 1 provides two examples of correctly (RIGHT) accounting for
said lines and one example of not correctly (WRONG) accounting
for said lines.
Submit graphic (at minimum 100-foot scale) showing proposed development-
grading design (development footprint) superimposed on the colored slope
category map. This graphic is essential in determining the project's compliance
with the City's use requirements and development standards.
Determination of the potential "theoretical" density and the Potential "allowable"
density for the subject property:
1. The potential "theoretical" density is calculated using the average slope of
the net area of the subject property as described in Item F above.
The potentia? "allowable" density of the subject property is calculated
based upon the demonstration by the project proponent, through
submission of a conventional subdivision design, that each of the
proposed lots is consistent with the slope requirement for the total site
(entire subject property).
The number of lots allowable shall be calculated based upon the average
and individual slope criteria and minimum lot size fo~'~ula. The maximum
allowable density shall be the number of lots approved by the Poway City
Council.
As required by the General Plan, the maximum allowable area of the lot that. may
be graded for driveWay, residence and accessory functions is detem~ined by the
degree of average natural slope as follows. This requirement shall apply to all
lots within all zoning categories.
Slope
Graded Area
0 - 14.9 Entire lot
15 - 19.9
50% or 35,000 sq. ft. whichever is greater
20 - 24.9
25 - 44.9
20% or 25,000 sq. ft. whichever is greater
10% or 20,000 sq. ft. whicheVer*is greater
45+
No grading or development permitted
and no developable acreage credit
given
5
Resolution No. 01-103
Page 12
Sensitive biological or other environmental constraints may
require the application of stricter' standards.
Exemptions apply to the High Valley area for slopes in
excess of 45% for dete.~ining parcel size, (Amended per
GPA 93- 02C)
N:~ty~olannlng\01repon~zoa~slope calculations standards and procedures.dod.doc
Rgsolution No. 01-103
~'P@g~R1LSA OVER ¢5%
~ CONTOUR PORTION INCLUDED
IN TABULATION
~ RIGHT
~ RIGHT
...... ~ ~ NOTE AREAS UNDER
¢5% NOT ACCOUNTED
FOR WITH CORRESPONDING
CONTOUR TABULATION
" , WRONG
., FIGURE ..t,
~ -~ '~n CONTOUR TABULA'nON
:~' ~a,,~ SCALE: NTS
~ .. - DRAWN BY: BK DATE: 6/07/01
,. ADDRESS: CITY OF" POWAY
Resolution No. 01-103
Page 14
City of Poway General Plan Strate;ies
and Zoning Development Code Definitions
and Property Development Standards
The following General Plan strategies, and Zoning Development Code definitions, and
property development standards are relevant to the slope of property.
General Plan Strategies
Lot and Ddveway Design
1. New development Should be of a density and design compatible with
surrounding, existing develoPment.
o
o
o
Lot sizes and shapes should allow for properly spaced buildings, provide areas
for landscaping and reduce conflicts between incompatible land uses.
Lot size andspacing should encourage a variety in the design, orientation and
placement of structures.
Lot sizes and shapes should follow a rectangular pattern with a lot depth to lot
width ratios between 2:1 and 3:1.
e
Lot widths and depths should be varied where feasible.
The use of rural residential flag lots is encouraged where necessary to reduce
land alteration.for roadways.
Within the'High Valley area (boundaries on file at the Development Services
· Department) the following criteria shall apply:
two net acres shall be the minimum lot size; -.
- all lots proposed for division' less than eight' net acres in size shall include
-. aminimum of one contiguous net acre building site with an average slope
of less than 25%; and
the building site shall be logically located in regard to access consistent
with City ordinances and policies and the preservation of significant
natural resources such as wat6rcourses, significant tree stands, rock
outcroppings, or ridgelines.
o
o
Resolution No. 01-103
Page 15
10.
11.
12.
't'
No exts ~ng, legally subdivided parcels shall be deemed nonconforming by virtue
of the slope requirements In the rural residential land use categories.
Within the rural residential land use and zoning categories, lot averaging is
encouraged where it will preserve areas of unique topographic features, riparian
woodlands or other significant open space areas of community importance. The
following guidelines shall apply:
Lot averaging shall not result in an increase to the overall density of the
subdivision. The project proponent shall cleady demonstrate, through
submission of a conventional subdivision design, that the proposed
number of lots could be created without lot averaging;
The number of lots allowable shall be calculated based upon the average
and individual slope criteda and minimum lot size formula;
Open space areas to be preserved shall be included as separate lettered
lots, which shall when appropriate be dedicated in-fee to the City;
Other than dedicated lettered open space lots, no lot may be created
which is sn3aller than the minimum for the zone; and
- . Lots created as a result of lot averaging may not be further subdivided.
Proponents may be required to prove that a.lot requested for subdivision was not
created as a result of lot averaging.
DeVelopers shall be required to employ proper site planning so as to minimize
the amount of grading needed for development and utility construction.
Development should be concentrated in the least environmentally sensitive
locations in order to preserve open space, retain natural vegetation and protect
natural, cultUral and historic features.
Hillside Developments
13.
14.
15.
'-Prominent ridgelines and hilltops shall not be built upon.
Buildings should be sited so as not to project above the natural-landform when
possible.
Intermediate ridges and hilltops shall be preserved in a natural state to the
maximum extent possible. Development on intermediate ridges shall only be
permitted in association with the preservation of significant open space, habitat,
tree and rock outcroppings, unique geographic features and/or cultural or
16.
17.
18.
19.
20.
Resolution No. 01-103
Page 16
agricultural uses within the same project. Open space proposed for dedication to
the City should perform multiple functions such as view maintenance, resource
protection and .hazard avoidance.
Driveways shall be designed to avoid cuts or fills in excess of ten feet in height
and at no greater than 2:1 inclination.
For projects with slopes of 15% or greater, a visual impact analysis shall be
prepared to determine the most suitable location(s) for the.building pad(s).
The maximum allowable area of the lot that may be graded for driveway,
residence and accessory functions is determined by the degree of average
natural slope as follows:
Slope Graded Area *
0 - 14.9 Entire lot
15 - 19.9
50% or 35,000 sq. ft. whichever is greater
2O - 24.9
20% or 25,000 sq. ft. whichever is greater
25 - 44.9
10% or 20,000 sq. ft. whichever is greater
45+
** No grading or development permitted and no
developable acreage credit given
* Sensitive biological or other environmental constraints
may require the applid, afion of stdcter standards.
** Exempfiqns apply to the High Valley area for slopes in
excess of 45% for, determining parcel size, (Amended per
GPA 93 - 02C)
Hillside development should vary the location and design of structures,
landscaping and access to give a more natural appearance and should be
designed to follow the natural contour of the land and to limit land alteration.
Where construction is proPosed on portions of lots where the slope exceeds
15%, the use of custom homes with multiple foundation levels is encouraged.
Where construction is proposed on portions of lots where the slope exceeds
25%, the use of custom homes with multiple foundation levels is required.
10
Resolution No. 01-103
Page 17
21. Building pads, driveways, roads and structures, including recreational courts and
accessory buildings, in hillside areas shall follow and not significantly alter the
natural contour of the land.
Floodplains and Floodways
22. Watershed areas with slopes greater than 25% shall be retained in parcel sizes
of 40 acres or more.
23. Development within the 100-year floodway is prohibited.
24. For purposes of land division, floodway areas shall not be included in the
calculation of net area.
Applicable Zoning Development Code Definitions
25. The following Zoning Code Sections and
incorporated herein by this reference.
Section 17.04.275
Section 17.04.280
Section 17,04.430
Section 17,04.440
Density
Development
Le,qal Lot
Lot
associated definitions are fully
Section 17.04,455
Section 17.04.460
Section 17.04.505
Section 17.04,540
Lot depth
Lot, fla.q
Lot width
Net area
Zoning Development Code Property Development Standards
Lot Shape, Minimum Lot Size, and Average Slope of Property
26.
Any legal lot may be used as a building site if the proposed use is permitted in
the zone and all grading requirements set forth in the Comprehensive Plan and
the Poway Municipal Code are strictly satisfied without variance, provided that no
building permit shall be issued for a lot of a size less than 4,000 square feet.
11
Resolution No. 01-103
Page 18
,,
27.
28.
29.
The ratio of the depth of a lot to the width of a lot shall not exceed a maximum
ratio of 3:1. If that ratio is exceeded, the lot shall be deemed an unusually
shaped lot. Unusually shaped !ots may only be allowed within the RR-A through
RR-C and RS-1 zones and only where the City Council, in its discretion, finds
that unusually shaped lots are necessary to ensure the preservation of unique
topographic features, ripadan woodland areas, and other areas of significant
community importance as open space. This development standard shall apply to
all lots proposed to be created by the subdivision or parcel map process.
Flag lots shall meet the minimum lot dimension requirements in the "flag" portion
of the lot. The flagpole portion of a flag lot shall not be counted toward the
minimum lot area requirement.
In the RR-A through RR-C and RS-1 zones, slope calculations shall be based on
the measured rise over run calculations of a topographic map of said property to
establish lot sizes. Density of development shall also take into consideration the
availability of public water to the property. To compute slope the following
fo[mula shall be used:
(CLx I x S)
NA
Where:
CL = Length of Contours (in inches)
I = Contour Interval
S -' Scale of Topographic Map
NA = Net Area in Square Feet
The average slope of each parcel shall be consistent with the slope requirement
for the total site. Lot sizes shall be as follows:
ZONES
SLOPE DENSITY
(In Percent)
RR-A
When parcels will
When parcels ,will
be served by City not be served by
water City water
0 - 15 1 parcel per four · 1 parcel per twenty
net acres net acres
15- 25 1 parcel per 1 parcel per twenty
eight net acres net acres
25 - 45 I parcel per 1 parcel per forty
twenty net acres net acres
12
ZONES SLOPE
(In Percent)
· Resolution No. 01-103
~ page 19
DENSITY
45 + No credit No credit
RR-B 0 - 15 I parcel per two
net acres
Requires City water
15 - 25 I parcel per four
net acres
25 - 45 1 parcel per
eight net acres
45 + No credit No credit
RR-B within No slope 1 parcel per two City water not
High Valley criteria net acres (see required
Area also note below)
RR-C 0 - 15 1 parcel per one
RS-1 net acre
Requires City water
15 - 25 1 parcel per two
net acres
25 - 45 I parcel per four
net acres
45 + No credit No credit
· Note: Within the High Valley Area, all lots prepared for division less than eight net
acres in size shall include a minimum of one contiguous net acre building site with an
average slope of less than 25%. The building site shall be logically located in regard to
access consistent with City ordinances and policies and the preservation of significant
natural resources such as watercourses, significant tree stands, rock outcroppings or
ridgelines.
The slope cdteria and minimum parcel sizes for property zoned RR-A, RR-B and
RR-C 'shall not be modified to permit increased density or rescinded unless and until
such modification or rescisSion is approved by ordinance adopted by the voters of the
City at a special or general election, or first approved by the Poway City Council and
then adopted by the voters of the City at a special or general election.
13