Page 12 - Efficient Irrigation and Landscape Design Standards

3.3 REQUIREMENTS OF AN IRRIGATION PLAN
An irrigation plan, if not already, should be included in the list of required materials submitted as part of the water-efficient landscape documentation package. The irrigation plan should demonstrate conformance with the nationally recognized irrigation design standards identified in the most recent version of the Irrigation Association’s “Landscape Irrigation Best Management Practices”. (see appendix 7.2)

The Irrigation Design Plan must meet the irrigation design standards identified in the most recent version of the Irrigation Association’s “Landscape Irrigation Best Management Practices”.
1.The applicant shall provide the following information:
» Identity of person or entity responsible for maintenance
of the irrigation; and
» Location of shut-off valves.
2. Irrigation water shall be applied with goals of avoiding runoff, low head drainage, overspray or other similar conditions where water flows onto adjacent property, non-irrigated areas and impervious surfaces by:
» Considering soil type and infiltration rates;
» Using proper irrigation equipment and schedules, including features such as repeat cycles, to closely match precipitation rates with infiltration rates; and
» Considering special problems posed by irrigation on slopes and in median strips.
3. All irrigation water outlets, except those using alternative water sources, shall be downstream of a meter used to measure irrigation water use.
4. Irrigation systems shall be subject to the following additional provisions:
» Systems in landscape strips less than five feet in width shall be designed to ensure that overspray and/or runoff does not occur by use of system design options such as low volume emitters.
» Systems shall be designed to be consistent with the requirements of the hydrozone in which they are located. Separate valves shall be used to irrigate plants with differing water needs
» Systems shall be designed with the minimum average irrigation efficiency of 0.625.
» The use of automatic shutoff or override capabilities using rain shutoffs or moisture sensors is encouraged.
» Systems shall utilize a central control valve connected to an automatic controller.
» Systems shall make provisions for winterization either by providing:
• manual drains (automatic drain valves are not permitted at all low points), or
• means to blow out lines with pressurized air.
» Sprinkler heads with matched precipitation rates shall be selected for proper area coverage, operating pressure, and adjustment capability.
» All irrigation systems must have, at a minimum, a rain/ freeze sensor installed.
5. The 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. The Plan shall be drawn on the same base project map at the scale as the Landscape Plan and clearly identify:
» Location and size of separate water meter(s) for the landscape.
» The static water pressure in pounds per square inch (p.s.i.), at the point of connection to the public water
12 IDAHO WASHINGTON AQUIFER COLLABORATIVE