§ 15.11.900. Water efficiency design requirements.

A.

Landscape areas shall be designed to achieve water efficiency as required by this chapter.

B.

Applicants may choose one of the following options to demonstrate that the landscape project meets the water efficiency criteria required by this chapter:

1.

Plant-type restriction option:

a.

Incorporate compost at the rate of at least four cubic yards per one thousand square feet to a depth of six inches into the landscape area, unless contraindicated by a soil test.

b.

Turf shall comply with all of the following:

i.

Turf shall not exceed twenty-five percent of the landscape area or one thousand two hundred fifty square feet, whichever is less in residential landscape;

ii.

There shall be no turf in non-residential landscape;

iii.

Turf shall not be planted on sloped areas which exceed a slope of one foot vertical elevation change for every four feet of horizontal length;

iv.

Turf is prohibited in parkways less than ten feet wide, except for parkways adjacent to a parking strip and used for the entry or exit of vehicles;

v.

Any turf in parkways must be irrigated by subsurface irrigation or by other technology that creates no overspray or runoff.

c.

Non-turf plant material shall comply with the following:

i.

For residential landscape areas less than or equal to two thousand five hundred square feet low water use, very low water use or no water use plants (average WUCOLS plant factor of 0.3) shall be installed in at least seventy-five percent of the portion of the landscape area where turf is not installed, excluding areas planted in edibles and areas using recycled water;

ii.

For residential landscape areas greater than two thousand five hundred square feet low water use, very low water use or no water use plants (average WUCOLS plant factor of 0.3) shall be installed in at least eighty percent of the portion of the landscape area where turf is not installed, excluding areas planted in edibles and areas using recycled water;

iii.

For non-residential areas, low water use, very low water use or no water use plants (average WUCOLS plant factor of 0.3) shall be installed in one hundred percent of the landscape area, excluding areas planted in edibles and areas using recycled water; and

iv.

A minimum of three inch layer of mulch shall be applied on all exposed soil surfaces of planting areas except turf areas, creeping or rooting groundcover, or direct seeding applications where mulch is contraindicated.

d.

If water features are installed, the surface area of the water features shall not exceed twenty percent of the landscape area.

e.

Irrigation systems for projects with a landscape area of two thousand five hundred square feet or less shall comply with the following, in lieu of the requirements of Sections 15.11.970, 15.11.980 and 15.11.990:

i.

Automatic irrigation controllers are required and must use evapotranspiration or soil moisture sensor data.

ii.

Irrigation controllers shall be of a type which does not lose programming data in the event the primary power source is interrupted.

iii.

Pressure regulators shall be installed on the irrigation system to ensure the dynamic pressure of the system is within the manufacturer's recommended pressure range.

iv.

Manual shut-off valves (such as a gate valve, ball valve, or butterfly valve) shall be installed as close as possible to the point of connection of the water supply.

v.

All irrigation emission devices must meet the requirements set in the ANSI standard, 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.

f.

Irrigation systems for projects with a landscape area of greater than two thousand five hundred square feet or less shall comply with the requirements of Sections 15.11.970, 15.11.980 and 15.11.990.

g.

For projects with a landscape area two thousand five hundred square feet or less, the applicant, if different than the property owner, must at the time of final inspection, provide the owner of the property with a certificate of completion, certificate of installation, irrigation schedule and a schedule of landscape and irrigation maintenance.

2.

Water budget calculation option:

a.

The plant factor used shall be from WUCOLS, as may be amended. The plant factor in 2015 ranges from 0 to 0.1 for very low water use plants, from 0.1 to 0.3 for low water use plants, from 0.4 to 0.6 for moderate water use plants, and from 0.7 to 1.0 for high water use plants.

b.

All water features shall be included in the high water use hydrozone and temporarily irrigated areas shall be included in the low water use hydrozone.

c.

Where low and moderate water use plants are mixed within a single hydrozone, the entire hydrozone area shall be classified as moderate water use for purposes of a water budget calculation. High water use plants shall not be mixed with low or moderate water use plants.

d.

All special landscape areas shall be identified and their water use included in the water budget calculation.

e.

The ETAF for new and existing (non-rehabilitated) special landscape areas shall not exceed 1.0. The ETAF for existing non-rehabilitated landscapes is 0.8. The ETAF for the remaining landscape area shall not exceed 0.55 residential and 0.45 for non-residential.

f.

Irrigation efficiency shall be seventy-five percent for overhead spray devices and eighty-one percent for drip irrigation devices.

g.

The maximum applied water allowance shall be calculated using the equation:

MAWA = (ETo) (0.62) [(ETAF × LA) + (1-ETAF) × SLA)]

Where:

MAWA = Maximum applied water allowance (gallons per year)

ETo = Reference evapotranspiration (inches per year)

0.62 = Conversion factor (to gallons)

Varies see 15.11.410 = Evapotranspiration adjustment factor (ETAF)

LA = Landscape area including SLA (square feet)

1-ETAF = Water allowance for SLA

SLA = Special landscape area (square feet)

h.

Estimated total water use (ETWU) shall be calculated for each hydrozone and special landscape area using the equation below. The sum of the ETWU calculated for all hydrozones shall not exceed the MAWA.

Formula for regular landscape areas

Formula for special landscape areas

Where:

ETWU = Estimated total water use per year (gallons)

ETo = Reference evapotranspiration (inches)

PF = Plant factor from WUCOLS

HA = Hydrozone area [high, medium, and low water use areas] (square feet)

SLA = Special landscape area (square feet)

0.62 = Conversion factor

IE = Irrigation efficiency (minimum 0.75 for overhead spray devices and 0.81 for drip irrigation devices.)

3.

Recycled water option:

At least ninety percent of the square footage of the landscape area shall be irrigated with recycled water.

(Ords. 29243, 29671.)