Development Standards—Landscaping and Irrigation | Town Center
h. Separate valves shall be used to irrigate plants with differing water needs. i. Sprinkler heads with consistent application rates shall be selected for proper area coverage, operating pressure, and adjustment capability.
4. Flow rate (gallons per minute), application rates (inches per hour), and design operating pressure (PSI) for each station; and 5. Cross connection prevention and/or back-flow prevention device in accordance with state standards.
R. Water use – Irrigation schedules
j. Backflow preventers are required and maintained.
P. Water use – Irrigation system design, design review and audit at installation 1. 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.
Irrigation schedules consistent with the following shall be submitted: 1. A recommended irrigation program with monthly irrigation schedules based, at a minimum, on average monthly ETO shall be required for before and after establishment.
2. The irrigation schedule shall:
2. The irrigation system must be audited and accepted at installation by an IA-certified irrigation auditor.
a. Include for each station the run time (in minutes per cycle) and cycles per week; b. Indicate the amount of applied water (in the applicable billing unit used by a purveyor); c. Incorporate use of evapotranspiration data reflecting local microclimates; d. Be adjusted for additional water need in recreational areas; e. Incorporate additional operating criteria such as avoiding irrigation at times of high temperatures or winds.
Q. Water use – Irrigation design plan contents
Proposed irrigation system design plans shall be drawn on the same base project map as the landscape plan and shall identify: 1. Location and size of any proposed separate water meters for the landscape serving commercial, multifamily, school, church, or recreation land uses only; 2. Location, type, and size of all components of the irrigation system; 3. Static water pressure at the point of connection to the water supply;
Effective | January 1, 2022
Title 21: Sammamish Development Code | 521
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