§ 7D3-7. Water efficient landscape standards.
All landscape projects subject to the provisions of this chapter shall comply with the following standards.
A.
Plants.
1.
Selected plants shall not cause the estimated annual applied water use to exceed the maximum applied water allowance.
2.
Plants with similar water use needs shall be grouped together in distinct hydrozones and where irrigation is required the distinct hydrozones shall be irrigated with separate valves.
a.
Very low, low, and moderate water use plants can be mixed, but the entire hydrozone shall be classified as moderate water use for maximum applied water allowance calculations.
b.
High water use plants shall not be mixed with very low, low, or moderate water use plants.
3.
All non-turf plants shall be selected, spaced, and planted appropriately based upon their adaptability to the climatic, geologic, and topographical conditions of the project site.
4.
Turf shall not be planted in the following conditions:
a.
Slopes exceeding ten percent (10%).
b.
Planting areas eight feet (8') wide or less.
c.
Street medians, traffic islands, planter strips, or bulbouts of any size.
5.
Invasive plants are prohibited.
B.
Soil Amendments, Conditioning, and Mulching.
1.
Prior to the planting of any materials, compacted soils shall be transformed to a friable condition. On engineered slopes, only amended planting holes need meet this requirement.
2.
Soil amendments shall be incorporated according to recommendations of the soil report and what is appropriate for the plants selected.
3.
Compost shall be incorporated into the soil to a minimum depth of eight (8) inches at a minimum rate of six (6) cubic yards per one thousand (1,000) square feet. Soils with greater than six percent (6%) organic matter in the top six (6) inches of soil are exempt from adding compost and tilling.
4.
A minimum three-inch layer of mulch shall be applied on all exposed soil surfaces of planting areas except in turf areas, creeping or rooting groundcover, or direct seeding applications. To provide habitat for beneficial insects and other wildlife, up to five percent (5%) of the landscape area may be left without mulch. Designated insect habitat must be included in the landscape design plan as such.
C.
Water Features.
1.
Recirculating water systems shall be used for all water features.
2.
Recycled water shall be used when available on site.
3.
Surface area of water features shall be included in the high water use hydrozone area of the water budget calculation.
D.
Irrigation Systems. For each landscape project subject to this chapter applicants shall meet irrigation efficiency criteria as described in the Maximum Applied Water Allowance (MAWA) and in accordance with the following:
1.
A dedicated irrigation meter or sub-meter must be specified on landscapes projects more than one thousand (1,000) square feet.
2.
Landscapes of five thousand (5,000) square feet or larger require a high-flow sensor that can detect high flow conditions and have the capability to shut off the irrigation system automatically.
3.
Isolation valves shall be installed at the point of connection and before each valve or valve manifold.
4.
Weather-based or other sensor based self-adjusting irrigation controllers utilizing non-volatile memory shall be required.
5.
Rain sensors shall be installed for each irrigation controller.
6.
Pressure regulation and/or booster pumps shall be installed so that all components of the irrigation system operate at the manufacturer's recommended optimal pressure.
7.
Irrigation systems shall be designed to prevent runoff or overspray onto non-targeted areas.
8.
Point source irrigation is required where plant height at maturity will affect the uniformity of an overhead system.
9.
A twenty-four-inch setback of overhead irrigation shall be required where turf is directly adjacent to a continuous hardscape that flows into the curb and gutter.
10.
Slopes greater than fifteen percent (15%) shall be irrigated with point source or other low-volume irrigation technology.
11.
A single valve shall not irrigate hydrozones that mix high water use plants with moderate, low, or very low water use plants.
12.
Trees shall be placed on separate valves except when planted in turf areas.
13.
Sprinkler heads, rotors, and other emission devices on one (1) valve shall have matched precipitation rates.
14.
Head to head coverage shall be required unless otherwise directed by the manufacturer's specifications.
15.
Swing joints or other riser protection components shall be required on all risers.
16.
Check valves shall be installed to prevent low-head drainage.
17.
Master shut-off valves are required on all projects of five thousand (5,000) square feet or larger except landscapes that make use of technologies that allow for the individual control of sprinklers that are individually pressurized in a system equipped with low pressure shut down features.
18.
Relevant information from the soil analysis report, such as soil type and, shall be utilized when designing irrigation systems.
19.
The design of the irrigation system shall conform to the hydrozones of the landscape design plan.
20.
All irrigation emission devices must meet the requirements set in the American National Standards Institute (ANSI) standard, American Society of Agricultural and Biological Engineers'/International Code Council's (ASABE/ICC) 802-2014 "Landscape Irrigation Sprinkler and Emitter Standard", All sprinkler heads installed in the landscape must document a distribution uniformity low quarter of 0.65 or higher using the protocol defined in ASABE/ICC 802-2014.
21.
Up to twenty-five percent (25%) of the total landscaped area will be treated as one (1) water use classification lower (but not less than "low"), if:
a.
The irrigation need will be entirely met by onsite graywater or captured rainwater, and;
b.
The area is grouped into hydrozones that have only graywater or rainwater irrigation.
( Ord. No. 6138, § I(Exh. A) , 12-8-2015)