I.
INTRODUCTION
The physical character of our communities cannot be divorced from the values they respect. Sooner or
later, these values manifest themselves in how our development decisions are made and how those
decisions shape our communities. Where our values and actions are synchronized, our communities
prosper; where they are in conflict, so are the communities.
(Riverside County Integrated Plan (RCIP), 2002)
Riverside County, (hereinafter “County”) like a quilt, is a mixture of differing landscapes
that creates a composition that is greater than its parts. The General Plan is designed to
ensure that the quilt retains its core identity by guiding future growth that respects the
diversity of the region, shapes and configures development in relation to the land it
occupies and ensures that its various parts relate to its whole. This unity of form also
promotes innovative development that actively accommodates a balance of housing,
employment, and service opportunities for the citizenry.
The Constrained Development Zone Design Standards and Guidelines (hereinafter
“Guidelines”) are a companion to the adopted Countywide Design Standards and
Guidelines for the County of Riverside. These two documents are for the use of those
property owners and design professionals submitting development applications to the
County Planning Department. As the flat valley lands are developed, the hillsides are
viewed as the next available properties. It is intended that this document will provide the
baseline criteria and standards to measure and evaluate proposals on property within the
Constrained Development Zone.
This document includes both design “standards” and design “guidelines”. Design
standards are considered mandatory requirements and usually include the term “shall”.
Standards are often quantitative or have performance criteria that can be measured.
Design guidelines are more generalized statements, alternatives or illustrations of what is
expected and encouraged. In this sense, the “guidelines” may offer ways to meet a certain
“standard”. The Planning Director will determine to what degree the Guidelines are met.
The Planning Commission or Board of Supervisors may consider variations to the design
standards if an application for a variance is filed.
A.
Design Strategies
The County has made a commitment to preserving the environment through adoption of
various environmental controls and conservation plans. Design strategies have been
developed to provide protection for the most sensitive areas of the County and the
protection of significant viewsheds. The following guidelines will:
•
•
•
Ensure that development maintains existing drainage patterns and limits soil
erosion;
Ensure that development results in minimal disturbance and that all disturbed
areas are restored with natural vegetation;
Ensure that development blends in visually and does not dominate the natural
landscape; and
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•
Encourage the use of innovative building pad and architectural designs to
achieve these purposes.
Protecting our hillsides can strengthen the physical and visual experiences creating a
better image of Riverside County. Design strategies include:
•
•
•
Protecting linear edges to our communities that, on the one hand link
communities, but on the other create distinctive edges that separate and
protect each community’s qualities and character
Identifying and protecting commonly used view points, view paths,
natural panoramas and views of major community landmarks
Preserving natural landmarks which create a special or unique community
flavor
In an attempt to advance quality and visually distinctive development responsive to the
natural environment of County, the Board of Supervisors has adopted these Guidelines.
These Guidelines have been crafted to assist those individuals submitting development
applications to better understand the design context from which the County will evaluate
project submittals.
B.
Land Disturbance
The intent of this section is to ensure that any disturbance to the natural topography of a
lot is minimized, that the created pads, roads or driveways are blended into the natural
terrain and that any physical or visual impact is mitigated through site design.
1.
2.
3.
No grading shall be allowed on natural slopes of 25 percent or greater.
No grading shall be allowed in areas located within two-hundred (200) feet of a
peak or ridge.
Total disturbance shall not exceed the following limitations:
Land Disturbance Table
Parcel/Lot Size
Less than ½ acre
½ acre – less than 1 acre
1 acre – less than 2 acres
2 acres – less than 5 acres
5 acres – less than 10 acres
10 acres or greater
Maximum Area That May Be
Disturbed
50% of the lot
10,000 sq ft or 40% of lot, whichever is
greater
17,425 sq ft or 30% of lot, whichever is
greater
26,137 sq ft or 20% of lot, whichever is
greater
43,561 sq ft or 15 % of lot, whichever is
greater
65,340 sq ft
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4.
5.
6.
7.
8.
The vertical distance of an graded slope shall not exceed fifteen (15) feet from the
toe of the slope to the top of the slope, unless a five (5) foot bench is placed
between two (2) graded slopes and the bench is planted with vegetation similar to
that growing on the portion(s) of the site that have not been disturbed.
The maximum height of a graded slope, including required benching, shall not
exceed thirty (30) feet.
The horizontal distance between a natural or man-made slope and a roof, or
portion thereof, shall not be less than twenty (20) feet.
Significantly visible rock outcroppings should be preserved and incorporated into
the site plan to the greatest extent possible.
Graded slopes should provide a variety of both slope percentages and slope
direction in a three-dimensional undulating pattern that is similar to the existing
natural terrain rather than left at a constant angle and direction, which creates an
unnatural and manufactured appearance for the site.
Sharp angles and uniform
slope banks appear
unnatural
Use varied slopes and
berms to resemble natural
features
9.
10.
Any increase in runoff resulting from the development of the site should be
directed away from any hillside areas and either into an existing or newly
improved street developed with a gutter system or public right-of-way designated
to carry surface drainage run-off.
All manufactured drainage course should simulate natural drainage courses.
Don’t do this
Do this
11.
Graded slopes should be similar to the natural slopes of the site and the angle of
any exposed slope should gradually transition to the angle of the natural slope to
create a natural look.
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Avoid harsh, easily eroded forms and
High, steep banks
Retain smooth flow of ground form
12.
Graded slopes left by cut and fill operations should be given a rounded
appearance that closely resembles the natural contours and character of the project
site.
13.
All surplus excavated material remaining after any filled slopes, landscaping
berms or other onsite usage shall be removed from the lot prior to the final
building inspection or Certificate of Occupancy. All surplus excavation materials
shall be deposited on a site approved by the County and such site shall have
obtained all necessary permits for depositing of materials.
14.
All pads, roads, and driveways should, to the fullest extent practicable, follow and
utilize the natural contours of the land to minimize disturbance.
Build parallel with the contours
Don’t build perpendicular to the contours
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15.
Pads, roads and driveways should be located in the least environmentally sensitive
location feasible as determined by a biologist. Alignments should follow existing
roads, easements, right-of-ways, and disturbed areas, as appropriate to minimize
impacts.
DO THIS
16.
17.
18.
C.
DON’T DO THIS
Pads, roads and driveways should avoid, to the greatest extent feasible, impacts to
MSHCP covered species and wetlands. If wetlands avoidance is not possible, then
any impacts to wetlands will require issuance of and mitigation in accordance
with a federal 404 and /or state 1600 permit.
Design of pads, roads and driveways should consider wildlife movement
requirements.
Any Pad, road or driveway construction that involves clearing of natural
vegetation should be conducted outside the active breeding season (March 1
through June 30).
Architecture
The intent of this section is to ensure that the visual impacts of proposed hillside
development is mitigated through site design and building massing by configuring
building pad parallel to the natural contour lines, by varied roof-plains, by terraced
building pad, or by reducing the overall height of the building.
1.
All dwellings, buildings and ancillary structures should be designed to minimize
mass and volume so as not to be prominently visible from a distance or from
surrounding properties.
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Do this
2.
Don’t do this
Building pads, foundation and roofs should be designed to conform to the natural
topography of the site and natural contours.
Step the building foundation with the natural slope
3.
4.
The use of architectural elements that increase the visual prominence such as twostoried entries, large glass doors and windows, turrets, and large chimneys should
be avoided.
Roof forms and rooflines should be broken into smaller building elements to
reflect the irregular forms of the surrounding natural features.
Roof forms should be kept small and reflect the surrounding topography
5.
The slope of the main roof should generally be oriented in the same direction as
the natural slope of the terrain.
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Do this
Don’t do this
6.
The maximum height for homes and other ancillary structures on a single level
building pad shall be 30 feet.
7.
For a terraced building pad, the maximum height of a building’s tallest elevation
shall not exceed 40 feet measured from the lowest finished floor level.
Horizontal and vertical architectural detailing of building articulation, such as
overhangs, projections, alcoves, varied roof-plains, building offsets, etc. should be
used to avoid large expanses of a wall in a single plane and to create light and
shadow.
A variety of materials, textures, and architectural details compatible with the
hillside designs should be used to add interest and to mitigate the visual impacts
of large wall areas.
8.
9.
10.
The visual contrast between manmade buildings and the surrounding natural
environment should be minimized through building colors and materials.
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11.
12.
13.
Exposed metal surfaces, contrasting color schemes, as well as mirrored glass
should be avoided. Exposed metal surfaces should be painted with earthy tones to
compliment natural colors and materials.
The color of all roofs, exposed exterior walls, retaining walls and accessory
structures should be earth tones and should have a light- reflective value of 30
percent or less.
Proposed land uses adjacent to undisturbed areas should incorporate barriers,
where appropriate in individual project designs to minimize unauthorized access,
domestic animal predation, illegal trespass or dumping. Such barriers may include
native landscaping, rocks/boulders, fencing, walls, and/or other appropriate
mechanisms.
Do this
Wood fences and gates are encouraged
14.
Don’t do this
Monumental entry gates are strongly discouraged
16.
Fencing only within the development perimeter is strongly encouraged. If fencing
of the entire property is desired, it should be designed to allow the movement of
wildlife through the property and should not block wildlife corridors identified
within the MSHCP.
Fencing should not block or obstruct a watercourse of any type, including an
arroyo, creek, stream, or dry wash.
Fences of an open agricultural nature are encouraged.
D.
Landscaping
15.
The intent of this section is to ensure that the impacts caused by landscaping is mitigated
through plant selections to assure that the native vegetation, that is required by wildlife in
the area, is not depleted due to the invasion of urban exotics and that the native wildlife
can traverse their territories without impediments caused by the man-made environment.
1.
2.
3.
The limits of construction and proposed disturbed areas should be clearly staked
in the field, with visible roping, or other distinguishing material, prior to and
during construction and shall conform to the approved individual site plan.
No disturbance shall be permitted beyond the areas designated as the limits of
disturbance both during and after construction. If land disturbance occurs outside
the approved limits, the illegally-disturbed area(s) shall be restored to its natural
grade and revegetated with plant material of the same species, size, and at a
similar density present prior to the illegal disturbance.
A cash deposit in the amount equal to the cost of revegetating all disturbed areas,
shall be placed with the County for a period of five (5) years unless a biologist or
other appropriate professional can certify that all revegetation materials are
established and viable.
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4.
5.
All disturbed land that is not otherwise used for approved development shall be
restored to the natural grade and revegetated with plant material pursuant to a
Landscape and Restoration Plan approved by the Planning Director. Disturbed,
landscaped areas that are adjacent to wildlife habitats shall be planted with local
native plant species. No invasive plant species shall be allowed in irrigated
landscapes or erosion control plantings.
When approving Landscape and Restoration Plans for development that is
adjacent to undisturbed areas, the plants listed in the following table should be
avoided and the Landscape and Restoration Plan revised to avoid the use of
invasive species. Considerations in reviewing the applicability of this list should
include proximity of planting areas to undisturbed areas, species considered in the
planting plans, the relative sensitivity of the native plants to invasion, and barriers
to plant and seed dispersal, such as walls, topography and other features.
PLANTS THAT SHOULD BE AVOIDED ADJACENT TO UNDISTURBED
AREAS
BOTANICAL NAME
Acacia spp. (all species)
Achillea millefolium var. millefolium
Ailanthus altissima
Aptenia cordifolia
Arctotheca calendula
Arctotis spp. (all species & hybrids)
Arundo donax
Asphodelus fistulosus
Atriplex glauca
Atriplex semibaccata
Carex spp. (all species*)
Carpobrotus chilensis
Carpobrotus edulis
Centranthus ruber
Chrysanthemum coronarium
Cistus ladanifer (incl. hybrids/varieties)
Cortaderia jubata [syn.C. Atacamensis]
Cortaderia dioica [syn. C. sellowana]
Cotoneaster spp. (all species)
Cynodon dactylon (incl. hybrids varieties)
Cyperus spp. (all species*)
Cytisus spp. (all species)
Delosperma ‘Alba’
Dimorphotheca spp. (all species)
Drosanthemum floribundum rosea
Drosanthemum hispidum
Eichhornia crassipes
Elaegnus angustifolia
Eucalyptus spp. (all species)
Eupatorium coelestinum [syn. Ageratina sp.]
Festuca arundinacea
Festuca rubra
Foeniculum vulgare
Fraxinus uhdei (and cultivars)
Gaura (spp.) (all species)
COMMON NAME
acacia
common yarrow
tree of heaven
red apple
cape weed
African daisy
giant reed or arundo grass
asphodel
white saltbush
Australian saltbush
sedge
ice plant
sea fig
red valerian
annual chrysanthemum
gum rockrose
jubata grass, pampas grass
pampas grass
cotoneaster
Bermuda grass
nutsedge, umbrella plant
broom
white trailing ice plant
African daisy, Cape marigold
ice plant
purple ice plant
water hyacinth
Russian olive
eucalyptus or gum tree
mist flower
tall fescue
creeping red fescue
sweet fennel
evergreen ash, shamel ash
gaura
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Gazania spp. (all species & hybrids)
Genista spp. (all species)
Hedera canariensis
Hedera helix
Hypericum spp. (all species)
Ipomoea acuminata
Lampranthus spectabilis
Lantana camara
Lantana montevidensis [syn. L. sellowiana]
Limonium perezii
Linaria bipartita
Lolium multiflorum
Lolium perenne
BOTANICAL NAME
Lonicera japonica (incl. ‘Halliana’)
Lotus corniculatus
Lupinus arboreus
Lupinus texanus
Malephora crocea
Malephora luteola
Mesembryanthemum nodiflorum
Myoporum laetum
Myoporum pacificum
Myoporum parvifolium (incl. ‘Prostratum’)
Oenothera berlandieri
Olea europea
Opuntia ficus-indica
Osteospermum spp. (all species)
Oxalis pes-caprae
Parkinsonia aculeata
Pennisetum clandestinum
Pennisetum setaceum
Phoenix canariensis
Phoenix dactylifera
Plumbago auriculata
Polygonum spp. (all species)
Populus nigra ‘italica’
Prosopis spp. (all species*)
Ricinus communis
Robinia pseudoacacia
Rubus procerus
Sapium sebiferum
Saponaria officinalis
Schinus molle
Schinus terebinthifolius
Spartium junceum
Tamarix spp. (all species)
Trifolium tragiferum
Tropaelolum majus
Ulex europaeus
Vinca major
Yucca gloriosa
gazania
broom
Algerian ivy
English ivy
St. John’s Wort
Mexican morning glory
trailing ice plant
common garden lantana
lantana
sea lavender
toadflax
Italian ryegrass
perennial ryegrass
COMMON NAME
Japanese honeysuckle
birdsfoot trefoil
yellow bush lupine
Texas blue bonnets
ice plant
ice plant
little ice plant
myoporum
shiny myoproum
ground cover myoporum
Mexican evening primrose
European olive tree
Indian fig
trailing African daisy, African daisy,
Bermuda buttercup
Mexican palo verde
Kikuyu grass
fountain grass
Canary Island date palm
date palm
cape plumbago
knotweed
Lombardy poplar
mesquite
castorbean
black locust
Himalayan blackberry
Chinese tallow tree
bouncing bet, soapwart
Peruvian pepper tree, California pepper
Brazilian pepper tree
Spanish broom
tamarisk, salt cedar
strawberry clover
garden nasturtium
prickly broom
periwinkle
Spanish dagger
Sources: California Exotic Pest Plant Council, United States Department of Agriculture-Division of Plant Health and
Pest Prevention Services, California Native Plant Society, Fremontia Vol. 26 No. 4, October 1998, The
Jepson Manual; Higher Plants of California, and County of San Diego-Department of Agriculture.
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6.
Summarized below are a series of recommendations for planting on slopes. The
goal of these efforts is to optimize soil coverage and slope stabilization. In
addition, a healthy mix of plants for viable and aesthetic character is intended.
a.
Plant Sizes: Use of small plant sizes (seeds, liners and one gallon) often
produces best growth and adaptation. Root development is often more
vigorous and acclimation to exposure and soil conditions is more quickly
determined. Root development on larger specimen trees can be very slow,
causing plants to be unstable and dependent on frequent watering
programs.
b.
Plant Variety: Any slope planting effort has better hope for success if plant
diversity is practiced. By varying ground covers, shrubs and trees, plant
performance can give and take with the site conditions. Problems with pest
and disease are often limited or restricted to only part of the plant palette.
A more balanced and flexible plant association is the desired outcome.
c.
Plant Form: The use of spreading shrubs and trees is encouraged as a
means to improve slope stabilization results. While slopes must be
engineered and constructed correctly, plants with broad spreading branch
structures will offer high levels of soil protection from excessive irrigation
or rainfall. Spreading plants will also lead to reduced long term weed
abatement needs. A recommended concept is to achieve 60 percent (60%)
soil coverage through spreading trees and shrubs. Low ground covers
should be limited to a smaller percentage of the soil area. The most
successful ground covers are often the types which intertwine and have a
vine-like habit. Mixing ground cover species is also encouraged for better
flexibility and performance under varying site conditions and different
seasons of the year.
d.
Natural Spacing: The placement of plants in natural or random spacing
patterns often contends best with varying site conditions, plant die out, and
plant maturity. Regimented plant placement looks artificial and unnatural.
Location of larger and denser plantings at the lower portions of slopes
takes advantage of greater moisture availability.
e.
Deep Irrigation: During plant establishment and long term survival, deep
irrigation practices are encouraged. Time clocks should be set to apply
numerous short applications of water during each watering cycle. Runoff
is reduced and percolation increased. Deeper root development is
encouraged, and less soil erosion occurs. The soil surface should be
allowed to dry out between watering cycles to discourage surface root
development.
E.
Exterior Lighting
The intent of the lighting guidelines is to preserve the low light level conditions that are
inherently characteristic of mountainous areas. The objective is to allow only the
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quantity and level of lighting necessary for safety, security and the enjoyment of outdoor
living while protecting against direct glare and excessive lighting; protecting the ability to
view the night sky; and preventing light trespass.
1.
2.
3.
4.
5.
6.
7.
Lights shall not be located on the portion(s) of the site that have not been
disturbed.
Lights shall not be located closer than ten (10) feet from any property line.
Lights mounted on dwellings, buildings or structures shall be fully shielded and
directed away from areas deemed inappropriate by the Planning Director.
Walls and other architectural elements shall not be lighted for decorative
purposes.
Tennis and other sport courts shall not be lighted for any purposes.
The maximum lighting intensity shall not exceed 250 lumens when measured at
the property line.
All fixtures, unless otherwise allowed, should be directed downward and properly
aimed on the targeted areas to maximize their effectiveness and minimize the total
number of lighting fixtures.
Lighting should be directed downward
8.
9.
10.
Lighting should not illuminate large areas
Motion sensor/detector light fixtures are permitted for security lighting. Security
lighting shall be controlled separately from all other lighting. Security lights shall
be on timers that regulate their operation time to a maximum of 10 minutes.
Lights, except security lighting, that illuminate the adjoining mountainside such
that the mountainside is visible from off the property shall not be allowed.
A repetitive line up of lights along driveways or walkways is discouraged,
however, random lighting is encouraged. Roads, driveway and walkway lights
should be located on the "downhill" side and aimed toward the "uphill" side and
should be fully shielded from below and only light the driveway surface.
Random lighting is encouraged
Repetitive lights are discouraged
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11.
12.
13.
Lights shall be set back from the nearest property line a minimum of ten (10) feet;
however, lighted entry markers may be placed on each side of the driveway
entrance. The entry marker shall not be placed within the road right-of-way or
private road areas and the total height of the marker and light shall not exceed
four (4) feet above finished grade adjacent to the driveway.
Fixtures should be mounted:
a.
In the ground or on a post not to exceed 36 inches above the ground.
b.
In or on a building wall not to exceed 8 feet above finished grade and
shielded in such a manner as to avoid creating concentrated light (hot
spots) on the structures to which they are mounted.
c.
On the structure to a height of not more than twelve (12) feet for security
lighting.
Landscape Lighting:
a.
Tennis court and sport court lighting shall not be allowed.
b.
Fixtures should be limited to one per 3000 square feet of disturbed area.
c.
Lights should be recessed to provide a minimum 45° cut-off.
d.
Colored lamps or bulbs and string and unshielded rope lights are not
permitted; however, temporary holiday lighting displays are permitted
between October 15th and January 15th, but shall not illuminate an area for
more than two hours after sunset.
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