A project applicant shall complete the water-efficient landscape worksheet, which contains two sections:
(A) A hydrozone information table for the landscape project; and
(B) A water budget calculation for the landscape project. The project applicant shall use the WaterSense Water Budget Tool. Oregon WaterWise Gardening program documents are hereby incorporated by reference to assist the applicant in implementing landscaping to ensure water-use efficiency.
(1) Water budget calculations shall adhere to the following requirements:
(a) The plant factor used shall be from WUCOLS. The plant factor ranges are from zero 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) All special landscape areas shall be identified and their water use calculated as described below.
(d) ETAF for special landscape areas shall not exceed 1.0.
(2) The maximum applied water allowance. A project’s maximum applied water allowance shall be calculated using the following formula:
MAWA = (ETo) (0.8) (LA) (0.62) where:
• MAWA = Maximum applied water allowance (gallons per year)
• ETo = Reference evapotranspiration (inches per year)
• 0.8 = ET adjustment factor
• LA = Landscaped area (square feet)
• 0.62 = Conversion factor (to gallons per square foot)
(3) Portions of landscaped areas in public and private projects, such as parks, playgrounds, sports fields, golf courses or school yards, where turf provides a playing surface or serves other recreational purposes, are considered recreational areas and may require water in addition to the maximum applied water allowance. A statement shall be included with the landscape design plan, designating recreational areas to be used for such purposes, and specifying any needed amount of additional water above the maximum applied water allowance.
(Ord. 2021-12-01, passed 1-11-2022)