23.72.130 IRRIGATION SCHEDULING.

(a) For the efficient use of water, all irrigation schedules shall be developed, managed, and evaluated to utilize the minimum amount of water required to maintain plant health. Irrigation schedules shall meet the following criteria:

(1) Irrigation scheduling shall be regulated by automatic irrigation controllers.

(2) Overhead irrigation shall be scheduled between 8:00 p.m. and 10:00 a.m. unless weather conditions prevent it. If allowable hours of irrigation differ from the local water purveyor, the stricter of the two shall apply. Operation of the irrigation system outside the normal watering window is allowed for auditing and system maintenance.

(3) For implementation of the irrigation schedule, particular attention must be paid to irrigation run times, emission device, flow rate, and current reference evapotranspiration, so that applied water meets the estimated total water use. Total annual applied water shall be less than or equal to maximum applied water allowance (MAWA). Actual irrigation schedules shall be regulated by automatic irrigation controllers using current reference evapotranspiration data (e.g., CIMIS) or soil moisture sensor data.

(4) Parameters used to set the automatic controller shall be developed and submitted for each of the following:

(i) The plant establishment period;

(ii) The established landscape; and

(iii) Temporarily irrigated areas.

(5) Each irrigation schedule shall consider for each station all of the following that apply:

(i) Irrigation interval (days between irrigation);

(ii) Irrigation run times (hours or minutes per irrigation event to avoid runoff);

(iii) Number of cycle starts required for each irrigation event to avoid runoff;

(iv) Amount of applied water scheduled to be applied on a monthly basis;

(v) Application rate setting;

(vi) Root depth setting;

(vii) Plant type setting;

(viii) Soil type;

(ix) Slope factor setting;

(x) Shade factor setting; and

(xi) Irrigation uniformity or efficiency setting.