20.12.150 Estimated total water use (ETWU).
All applicable landscape shall calculate the ETWU for each project using the following formula:
ETWU = Eto x 0.62 x [((PF x HA)/IE) + SLA]
{Considering precipitation ETWA = Eto - Eppt) x 0.62 x [((PF x HA)/IE) + SLA]}
In which the following abbreviations apply:
A. ETWU = Estimated total water use in gallons per year.
C. 0.62 = Conversion factor to gallons per square foot.
D. PF = Plant factor from WUCOLS.
E. HA = Hydrozone area in square feet. Each HA shall be classified according to its water use, high, medium, or low, according to the legends on the planting plans.
F. IE = Irrigation efficiency (0.75 for overhead spray devices and 0.81 for drip systems).
G. Eppt = Effective precipitation or useable rainfall.
H. SLA = Portion of the landscape area identified as special landscape areas measured in square feet. (Ord. 3357 § 1, 2015; Ord. 3146 § 1 (Exh. A), 2009).