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(a) Design Standards. The elements within the landscape documentation package (i.e. planting, irrigation, construction, etc.) shall incorporate the following:
(1) Cohesive Landscape Design. Landscaped areas shall be made an integral part of the overall project design and shall not be simply located in excess space after parking areas and structures have been planned on-site. Additionally, landscaped areas should have a coordinating design that blends with the architectural influence of the site. Larger developments may utilize a variety of themes throughout landscaped areas to distinguish key areas and elements within the development, yet these design concepts shall be consistent with the unifying concept established for the development.
(2) Scale and Character. Landscape materials (i.e. planting and hardscape) shall be selected so that the scale and character are appropriate to the site architecture and/or use of the site.
(3) Functional Landscapes. Landscaped areas shall be utilized to enhance and define entrances, sidewalks, and pedestrian areas. Additionally, landscaped areas shall be utilized to control microclimates as well as enhance views. Plant materials that provided seasonal color via flowers or foliage shall be provided as an accent to entrances and sidewalks, and shall be considered throughout the landscape.
(4) Landscape Design Features. Aesthetic landscape design features such as sculptures, decorative paving, benches, trellises, arbors, etc. shall be strongly encouraged within landscaped areas. Aesthetic landscape design features do not include driveways, parking areas, and/or storage areas.
(5) Sidewalks. All sidewalks shall be shown on the landscape plans (i.e., planting, irrigation, construction, etc.). This will ensure proper planting and irrigation design around proposed sidewalks.
(6) Alternative Hardscape Materials. Decomposed granite, pea gravel, mulch, bark, recycled tire mulch, play area surfacing, and other similar materials may be used in functional activity areas (i.e., patios, rear entry walks, trails, etc.).
(7) Water Features. If a water feature such as a pond or fountain is used within a project’s landscape then the project's water budget calculations (MAWA) will need to include the surface area of the water feature with the evaporation rate equivalent to that of a high water use plant. Where available, if not utilized by the public as a recreation source, a non-potable/recycled water source shall be used for any decorative water features. Decorative water features shall be on a recirculating system and shall be maintained on a regular basis.
(8) Screening. Planting material and/or hardscape material, such as block walls, wood fencing, vinyl fencing, etc., shall be required to screen storage areas, trash enclosures, parking areas, air conditioning units, and other such elements (except residential driveways). Additionally, any above ground public utilities, such as, but not limited to electrical substations, water storage facilities, and treatment plants shall also be provided with perimeter landscape screening to the extent possible.
(9) Bio-Swales. Where possible, bio-swales shall be incorporated into landscaped areas to help maintain, manage, and prevent run-off. All bio-swales shall be a mixture of hardscape materials, i.e. rocks, boulders, rip rap, and plant materials suitable for bio-swales; impermeable surfacing shall be avoided in all bio-swales.
(10) High Maintenance Landscaping. High maintenance landscaped areas shall be kept to a minimum. If high maintenance landscaped areas are proposed as part of a project’s landscaping, these areas shall be located near primary uses and high activity areas.
(11) Maximum Height for Clear Sight Triangles. Any planting material and/or hardscape elements over 30 inches in height shall not be allowed within a clear sight triangle formed by the intersection of public rights-of-way, parking lot entrances and exits, pedestrian rights-of-way, driveways, or alleys as described in § 83.02.030 (Clear Sight Triangles).
(12) Phased Development. Disturbed nonresidential project sites, including those that have been approved with phasing, where future development is intended within six months of approval, or intended to begin within six months after the completion of a previous phase shall be hydro-seeded with a non-irrigated mix of annuals and natives. Supplemental water shall be provided to the hydro-seeded areas to establish plant health. The hydro-seeded areas shall be maintained in a weed-free condition until development occurs on-site. The proposed hydro-seed mix shall be submitted for review and approval.
(b) Planting Plan Requirements. Planting plans shall include the following:
(1) Plant Material Varieties. Plant materials shall include water-conserving trees (deciduous and evergreen), shrubs, and groundcover that are attractive and useful for erosion control. The use of one predominant species shall be avoided to prevent spread of disease and pests.
(2) Plant Material Selection. Plant material shall be selected based on mature width and spreads, level of maintenance, durability, aesthetic appeal, thematic qualities, horticulture attributes, resistance to pests and diseases, soil type, slope coverage, topography, and geologic conditions. Plant materials shall also be selected based on their appropriate plant hardiness climate zones as defined by Sunset Western Garden Book and their classifications per the WUCOLS III publication.
(3) Coordination of Plant Materials. Plant types shall be grouped together based on their water, soil, sun, and shade requirements, as well as their relation to natural watercourses on-site, existing vegetation that is to remain, and their relationship to building orientation. Plant types with different water needs shall be placed on separate irrigation valves within specific hydrozones. Plant types with similar classifications such as high and moderate, moderate and low, low and very low, per the WUCOLS III publication, shall be grouped together in planting areas.
(4) Existing Plant Materials. To the extent feasible, mature plant materials that are existing on-site and are deemed to be healthy shall be protected and preserved. Protected plant material shall be retained on-site or be protected in place, unless otherwise approved in writing by the Director or the proper removal permit is granted in compliance with Chapter 88.01 (Plant Protection and Management).
(5) Native and Drought-Tolerant Plant Materials. Native and drought-tolerant plant materials capable of surviving with a minimal amount of supplemental water shall be utilized.
(6) Mature Trees. Mature trees should be incorporated into landscape plans, because specimen trees or groupings of existing trees can provide a new development with immediate character, and should be considered as design elements.
(7) Shade Trees. Shade trees, a mixture of deciduous and evergreen, shall be provided for residential, commercial, institutional, and industrial buildings, parking lots, open space areas, etc. The trees shall be incorporated to provide natural cooling opportunities and water conservation.
(8) Invasive Plants. The use of invasive plant materials shall be avoided in areas near parks, buffers, greenbelts, water bodies, conservation areas/reserves, and other open space areas because of the potential to cause harm to environmentally sensitive areas.
(9) Vines. To aid in the prevention of graffiti, self-clinging vines shall be planted to help ensure full coverage of the public-facing side of all walls.
(10) Edible Plants. If edible plant material is proposed as part of the landscape design, it shall be clearly defined and kept separate from all other plant material. Non-potable/recycled water shall not be used to irrigate edible plant material areas.
(11) Fire-Prone Plants. Plant materials that are fire-prone and highly flammable shall be avoided.
(12) Plant Material Spacing. Trees proposed within the road right-of-way shall be planted 30 linear feet on-center from one another, unless another on-center spacing is specified within the project’s conditions of approval. In open space areas, trees shall be planted in odd number groupings to allow for a more natural look and feel. The on-center spacing for shrub and groundcover materials shall be based on the size of the specific plant species at maturity. Careful consideration shall be given to proposed plant materials height and spreads so that at maturity they do not interfere with service lines, a driver’s or pedestrian’s view of public rights-of-way (e.g., the view of approaching, merging, or intersecting traffic, etc.), or otherwise impair public safety, or interfere with the safe operation of a motor vehicle on public streets.
(13) Plant Material Container Sizes. Plant materials shall be provided in an array of several of container sizes. Container sizes for plant material shall include:
(A) Trees: 15 gallon, 24-inch box, 36-inch box, 48-inch box, and 52-inch box, 72-inch box, 96-inch box, and field dug.
(B) Palms: six- to 15-foot brown trunk height (BTH).
(C) Shrubs: one-gallon, two-gallon, five-gallon, and 15-gallon.
(D) Groundcovers: flats and one-gallon.
(14) Plant Solar Orientation. Plant materials shall be planted in a manner considerate of solar orientation to help maximize summer shade and water conservation.
(15) Turf. Turf areas shall be used in response to functional needs of the project, not solely for aesthetic purposes, and shall be in compliance with the project’s water budget calculations (MAWA). Where turf is installed, the use of warm season turf shall be strongly encouraged. To help minimize irrigation runoff and overspray landscape designs shall avoid proposing small, irregularly shaped turf areas. Furthermore, unless subsurface or other low-flow or non-spray irrigation is proposed, all turf areas shall be a minimum 24 inches away from non-permeable surfaces as to minimize irrigation runoff and overspray.
(A) Turf on Slopes. Turf shall not be allowed on slopes that are greater than 25 percent and/or where the toe of the slope is adjacent to an impermeable hardscape surface.
(B) Turf in Rights-of-Way. The placement of turf within County road rights-of-way shall be minimized. If turf is to be used in County road rights-of-way, there shall be no runoff or overspray from irrigation systems located in the turf areas. If irrigation runoff and overspray cannot be obtained, than turf shall not be used in that application.
(16) Mulch. All non-turf planting areas (except those areas that have been hydro-seeded) shall be mulched to help in the retention of moisture, suppress weeds, to help moderate damage to trees and shrubs, and help moderate soil temperature. All non-turf planting areas shall be mulched with a two-inch minimum layer of mulch. In those areas where groundcover has been planted from flats, the mulch layer shall be one and one half inches.
(A) Mulch on Revegetation Projects. The requirement for mulch may be omitted for native revegetation projects upon the recommendation of the project biologist.
(B) Hydro-Seeding Mulch Requirement. The mulching portion of the seed/mulch slurry mix for hydro-seeding applications shall meet the mulching requirements.
(C) Mulch on Slopes. The application of a stabilizing mulch product shall be used on all slopes to help with water retention and erosion control.
(17) Slope Design. Slopes with a 5:1 ratio or greater; cut slopes with a five-foot vertical height or greater; and fill slopes with a three-foot vertical height or greater shall be protected against damage from erosion. In addition to the stabilizing mulch, drought-tolerant plant material and hardscape features shall be utilized on slopes to promote water retention and erosion control. Decorative boulders and other suitable hardscape materials may be utilized on slopes, but the dominant visual character of the slope shall be made up of drought-tolerant plant materials. Shrubs shall be used in combination with lateral spreading groundcovers; trees shall be used where slope exceeds 15 feet vertical height. Trees and shrubs shall be planted in visually attractive groupings that provide a more natural appearance.
(18) Root Barriers. Any tree planted within five feet of hardscape material shall incorporate the use of a root barrier to help minimize hazards to the public. Where possible, trees shall be planted in areas of public view adjacent to structures, either individually or in groupings.
(c) Irrigation Plan Requirements. Irrigation plans shall include the following:
(1) Efficiency. Irrigation systems shall be designed, installed, maintained, and managed to achieve the highest efficiency rate as possible, and shall meet and maintain an average efficiency rate of 0.71, as defined by State law. High efficiency methods of irrigation (i.e., drip irrigation, efficient rotators, rotary nozzles, micro sprays, etc.) are recommended within the irrigation design.
(2) Water Pressure. Static water pressure, dynamic, or operating pressure and flow reading of the water supply shall be measured at the point of connection (POC). These pressure and flow measurements shall be conducted at the design stage to help aid in the design of the irrigation systems. If these measurements are not available at the design stage, the measurements shall be obtained at time of construction and the irrigation design adjusted accordingly. The design of the irrigation systems will ensure that each emission device is within the manufacturer’s recommended dynamic pressure range for optimal performance.
(3) Variables in Static Pressure. If the measured static pressure is above or below the required dynamic pressure for optimal performance of the irrigation system then pressure-regulating devices (i.e. inline pressure regulators, booster pumps, etc.) shall be specified and installed in order to meet the dynamic pressure required for optimal performance of the irrigation systems.
(4) Matched Precipitation Rates. Irrigation heads (i.e., spray heads, rotors, etc.) and other emission devices shall have matched precipitation rates unless otherwise directed by the manufacturer’s specifications.
(5) Capacity. The capacity of the irrigation system shall not exceed the capacity required based on the water budget calculations for peak water demand, meter capacity, and/or the backflow preventer type and device capacity. If the project is served by a local water purveyor then it is recommended that the project developer contact the water purveyor and inquire about peak water demands (on the main water supply system) and any known water restrictions that could possibly impact the effectiveness of the irrigation systems.
(6) Runoff and Overspray. Soil types and infiltration rates shall be taken into account when irrigation systems are designed and installed. Irrigation systems shall be designed and installed to prevent runoff, low head drainage, overspray, or other similar conditions where water flows onto adjacent property, non-irrigated areas, sidewalks, roadways, or structures. The use of check valves shall be required on all irrigation systems to prevent low head drainage. Proper irrigation design, equipment, and schedules, including repeating cycles, shall be used in order to match application rates and help minimize runoff.
(7) Head-to-Head Coverage. Irrigation systems shall be designed to utilize head-to-head coverage with matched precipitation rate nozzles. Rotors and spray heads shall be zoned separately. When using rotors, half arc rotors and full rotors shall be zoned separately, unless matched precipitation rate nozzles are utilized.
(8) Water Waste. Water waste is the result of inefficient irrigation due to runoff, overspray, low head drainage, and other similar conditions that causes flows to run onto adjacent non-irrigated areas, walks, roadways, parking lots, etc. It shall be the responsibility of the property owner to prevent water waste on their property by properly maintaining, managing, and replacing irrigation equipment per the regular maintenance schedule. Restrictions in regards to overspray may be considered and modified if the following occur:
(A) The landscaped area is directly adjacent to a permeable surface and no runoff occurs; or
(B) If the directly adjacent non-permeable surfaces have been designed and installed to drain entirely into a landscaped area on-site.
(9) Meters. For irrigated landscape areas in excess of 2,500 square feet, separate water meters shall be installed for landscaping, which will help facilitate water management. This requirement shall not apply to single-family residential projects or those projects that utilize a well source for water on-site. Lettered lots or easements for landscaping or recreational purposes shall have a separate meter.
(10) Valves. Separate valves shall be provided for those planting areas with similar water uses, so plantings with similar water needs are on the same irrigation valve. All turf areas shall be placed on a separate valve from non-turf areas. Where feasible, trees shall be placed on a separate deep root watering system with its own valve.
(11) Equipment. All irrigation systems shall be equipped with the following:
(A) “Smart” Irrigation Controller. All irrigation systems shall be equipped with a smart irrigation control, which automatically adjusts the frequency and/or duration of irrigation events in response to changing environmental conditions. Landscaped areas shall be zoned together in relation to moisture control zones, which shall be based on similarity of water needs (i.e., turf separate from shrubs and groundcovers, sun exposure areas separate from shade areas, top of slope separate from toe of slope, etc.).
(B) Weather Sensing Devices. All irrigation systems shall be equipped with weather sensing devices (i.e., rain, wind, freeze, etc.), either integral or auxiliary, that suspend or alter system operations during unfavorable weather conditions.
(C) Flow Sensor. A flow-sensing device is recommended for all irrigation systems so that irregular flows within the system can be detected and repaired.
(D) Manual Shut-Off Valves. All irrigation systems shall be equipped with manual shut-off valves (i.e., gate valve, ball valve, butterfly valve, etc.) that are located as close as possible to the irrigation systems point of connection (POC) and also where jointed transitions occur on the mainline to minimize water loss in case of an emergency and/or scheduled routine repair.
(E) Pressure Regulator. All irrigation systems shall be equipped with a pressure regulator that regulates when the static pressure is above or below the recommended operating pressure for the designed irrigation system.
(F) Backflow Preventers. All irrigation systems shall be equipped with a backflow prevention device. Upon approval from the Land Use Services Department in residential settings, an anti-siphon valve maybe used in lieu of a backflow prevention device.
(G) Swing Joints/Riser Protection. In order to prevent damage that maybe caused to irrigation heads adjacent to hardscape and high traffic areas, all irrigation systems shall utilize swing joints and other riser protection.
(12) Soils. Relevant information provided in the soil management report, such as soil types and infiltration rates shall be utilized when irrigation systems are designed.
(13) Non-Permeable Surfaces. Conventional spray irrigation shall not be permitted within 24 inches of any non-permeable surface. Irrigation systems that are allowed within the 24-inch setback from a non-permeable surface range from drip, drip line, other low-flow or non-spray technology. If the landscape area is adjacent to permeable surfacing and no overspray or run off occurs, then there shall be no restrictions on the irrigation system type.
(14) Irregular Shaped Areas. Those areas that are long, narrow, and/or irregular shaped, including turf areas, less than eight feet in any direction shall be irrigated with low-volume irrigation or subsurface irrigation technology.
(15) Irrigation on Slopes. Non-turf areas located on slopes greater than 25 percent shall be irrigated with a drip irrigation system or other low volume irrigation technology. This requirement may be modified and an alternative design and/or technology proposed if that design/technology demonstrates that no run-off or erosion will occur.
(16) Mulched Planting Areas. In planting areas that utilize a form of mulch, the use of a low volume irrigation system shall be required in order to maximize water infiltration into the plants root zone.
(17) Non-Potable/Recycled Water. Where available, the use of non-potable/recycled water to irrigate planting areas shall be utilized. If facilities are made available, water systems for common open spaces (i.e., parks, preserves, etc.) shall use non-potable/recycled water. If non-potable/recycled water is used for irrigation systems then all systems shall be designed to meet all applicable local agency and State codes regarding the use of non-potable/recycled water.
(18) Hydrozones. Irrigation systems shall be zoned in accordance to plant water use, slope aspects, and sun/shade microclimates.
(d) Hydrozone Plan. Each irrigation design plan shall include a separate hydrozone plan outlining the hydrozones that are valved separately within all landscaped areas.
(e) Grading Plan Requirements. For the efficient use of water, grading of the project site shall be designed so that soil erosion, runoff, and water waste are minimized. As part of the landscape document package, if a project's grading exceeds 100 cubic yards, then the project developer shall submit the most recent rough and/or precise grading plan(s) that have been prepared and signed by a licensed professional as authorized by law.
(f) Soil Management Report. A soil management report is required as part of the landscape documentation package when mass grading is not proposed. When mass grading is proposed, the soil management report shall be submitted with the certificate of completion.
(1) Development of the Soil Management Report. The steps listed below are intended to help guide the developer in the preparation of the soil management report:
(A) Perform a preliminary site inspection.
(B) Obtain the necessary sample, determine the appropriate level of soil sampling and sampling method.
(C) Determine the soil in the landscape area has sufficient depth to support proposed plants perform a soil probe test.
(D) Obtain appropriate soil sample.
(2) Soil Sample(s). Once a soil sample(s) has been obtained from the project site it shall be submitted to the appropriate laboratory for analysis and recommendations. Minimum requirements for the soil analysis should include soil texture, infiltration rate determined by lab tests or soil texture infiltration rate table, pH, total soluble salts, sodium, and any recommendations.
(Ord. 4011, passed - -2007; Am. Ord. 4043, passed - -2008; Am. Ord. 4057, passed - - 2008; Am. Ord. 4136, passed - -2011; Am. Ord. 4393, passed - -2020)