Development Standards | Design Standards—Landscaping and Irrigation
6. Water use – Irrigation design plan contents
v. The use of automatic shutoff or override capabilities using rain shutoffs or moisture sensors is encouraged. vi. Systems shall utilize a master control valve connected to an automatic controller. vii. Systems shall make provisions for winterization either by providing:
Proposed irrigation system design plans shall be drawn on the same base project map as the landscape plan and shall identify: a. Location and size of any proposed separate water meters for the landscape serving commercial, multifamily, school, church, or recreation land uses only; b. Location, type, and size of all components of the irrigation system; c. Static water pressure at the point of connection to the water supply; d. Flow rate (gallons per minute), application rates (inches per hour), and design operating pressure (PSI) for each station; and e. Cross connection prevention and/or backflow prevention device in accordance with state standards.
a) Manual drains (automatic drain valves are not permitted at all low points); or
b) Means to blow out lines with pressurized air.
viii. Separate valves shall be used to irrigate plants with differing water needs. ix. Sprinkler heads with consistent application rates shall be selected for proper area coverage, operating pressure, and adjustment capability. 5. Water use – Irrigation system design, design review and audit at installation a. Irrigation plan design shall be certified by an Irrigation Association (IA) certified designer or a registered landscape architect or professional engineer with irrigation design experience. b. The irrigation system must be audited and accepted at installation by an IA-certified irrigation auditor.
7. Water use – Irrigation schedules
Irrigation schedules consistent with the following shall be submitted: a. A recommended irrigation program with monthly irrigation schedules based, at a minimum on average monthly Eto, shall be required for before and after establishment.
b. The irrigation schedule shall:
i. Include for each station the run time (in minutes per cycle) and cycles per week;
322 | Title 21: Sammamish Development Code
Effective | January 1, 2022
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