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 provide 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, where necessary and appropriate, 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 nonpotable/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 aboveground 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. Bioswales: Where possible, bioswales shall be incorporated into landscaped areas to help maintain, manage, and prevent runoff. All bioswales shall be a mixture of hardscape materials, i.e., rocks, boulders, riprap, and plant materials suitable for bioswales; impermeable surfacing shall be avoided in all bioswales.
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 thirty inches (30") 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 section 9.31.020, "Clear Sight Triangle", of this article 3.
12. Phased Development: Disturbed nonresidential project sites, including those that have been approved with phasing, where future development is intended within six (6) months of approval, or intended to begin within six (6) months after the completion of a previous phase shall be hydroseeded with a nonirrigated mix of annuals and natives. Supplemental water shall be provided to the hydroseeded areas to establish plant health. The hydroseeded areas shall be maintained in a weed free condition until development occurs on site. The proposed hydroseed 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 ground cover 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 Materials: Plant materials shall be a cohesive mix of evergreen and deciduous trees, shrubs, ground covers, succulents, and native plant material that are drought and infestation tolerant; turf is highly discouraged and shall be minimized and be placed in compliance with this chapter. Appropriate desert plant materials shall be selected based on their appropriate plant hardiness climate zones as defined by "Sunset Western Garden Book" and their classifications per the "Water Use Classifications Of Landscape Species", third edition (WUCOLS III) publication, available from the department of water resources.
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. 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.
5. Landscaped Setbacks: The front yard and street side yard setback areas of a parcel shall be landscaped using xeriscape landscaping techniques, which combines drought tolerant plant and hardscape materials in a variety of aesthetically pleasing designs. For sites where no disturbance of land within setbacks is proposed, landscaping shall not be required.
6. Mulch: Where appropriate, use rock mulch including cobblestones, crushed rock, and similar gravels in place of organic mulch. Rock mulch can assist in dust control as well.
7. Dust Control: If grading takes place, then a dust control plan shall be submitted for review.
8. Shade Trees: Where appropriate, shade trees 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.
9. Invasive Plants: The use of invasive plant materials shall be avoided in areas near parks, buffers, conservation areas/reserves, and other open space areas because of the potential to cause harm to environmentally sensitive areas.
10. 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.
11. 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. Nonpotable/recycled water shall not be used to irrigate edible plant material areas.
12. Fire Prone Plants: Plant materials that are fire prone and highly flammable shall be avoided.
13. Plant Material Spacing: Trees proposed within the road right of way shall be planted thirty (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 ground cover 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.
14. Plant Material Container Sizes: Plant materials shall be provided in an array of several container sizes. Container sizes for plant material shall include some of the following:
a. Trees: Fifteen (15) gallon, twenty four inch (24") box, thirty six inch (36") box, forty eight inch (48") box, fifty two inch (52") box, seventy two inch (72") box, ninety six inch (96") box, and field dug.
b. Palms: Six (6) to fifteen foot (15') brown trunk height (BTH).
c. Shrubs: One gallon, two (2) gallon, five (5) gallon, and fifteen (15) gallon.
d. Ground covers: Flats and one gallon.
15. Plant Solar Orientation: Plant materials shall be planted in a manner considerate of solar orientation to help maximize summer shade and water conservation.
16. Turf: Turf is prohibited for use as aesthetic landscaping in commercial and industrial projects. Turf is only allowed for limited uses within parks, sports fields, golf courses, and where turf provides a playing field or where turf is needed for high traffic activities. Where turf is installed, the use of warm season turf shall be strongly encouraged. Furthermore, unless subsurface or other low flow or nonspray irrigation is proposed, all turf areas shall be a minimum twenty four inches (24") away from nonpermeable surfaces as to minimize irrigation runoff and overspray.
17. Slope Design: Slopes with a five to one (5:1) ratio or greater; cut slopes with a five foot (5') vertical height or greater; and fill slopes with a three foot (3') 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 ground covers; trees shall be used where slope exceeds fifteen feet (15') vertical height. Trees and shrubs shall be planted in visually attractive groupings that provide a more natural appearance.
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, microsprays, 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, nonirrigated 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 cause flows to run onto adjacent nonirrigated 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 nonpermeable surfaces have been designed and installed to drain entirely into a landscaped area on site.
9. Meters: Meters shall be provided in accordance with Hi-Desert water district standards and requirements.
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 nonturf 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 ground covers, 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 Shutoff Valves: All irrigation systems shall be equipped with manual shutoff valves (i.e., gate valve, ball valve, butterfly valve, etc.) that are located as close as possible to the irrigation system's 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 in accordance with Hi-Desert water district and California building code standards and requirements.
g. Swing Joints/Riser Protection: In order to prevent damage that may be 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. Nonpermeable Surfaces: Conventional spray irrigation shall not be permitted within twenty four inches (24") of any nonpermeable surface. Irrigation systems that are allowed within the twenty four inch (24") setback from a nonpermeable surface range from drip, drip line, other low flow or nonspray technology. If the landscape area is adjacent to permeable surfacing and no overspray or runoff 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 (8') in any direction shall be irrigated with low volume irrigation or subsurface irrigation technology.
15. Irrigation On Slopes: Nonturf areas located on slopes greater than twenty five percent (25%) 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 runoff 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 plant's root zone.
17. Nonpotable/Recycled Water: Where available, the use of nonpotable/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 nonpotable/recycled water. If nonpotable/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 nonpotable/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 documentation package, if a project's grading exceeds fifty (50) 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. To obtain the necessary sample, determine the appropriate level of soil sampling and sampling method;
c. To determine the soil in the landscape area has sufficient depth to support proposed plants perform a soil probe test; and
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. 254, 12-16-2014)