With the upcoming Model Landscape Ordinance in California and increasing pressure on water resources, there has and will be many requests to provide irrigation demand estimates. Our office has been using the Landscape Coefficient Method and WULCOLS III as our reference for calculations: http://www.owue.water.ca.gov/docs/wucols00.pdf
I have trouble accepting this method because it makes me feel like I am counting planting areas twice– the calculations require the ET rate of both tree canopies and the shrubs/groundcovers on the ground plane.
Does anyone have other comments or concerns, positive or negative, about the applicability of this method?
Also, in regards to estimating future needs of master-planned communities– Does anyone have a solid reference for determining total irrigable area of different land uses at the planning level?