Use of aerial photography and GIS in estimating urban lawn irrigation requirements

Urban lawn irrigation is an important component in urban water budgets. The water requirement both timing and volume are important and need to be accurately estimated for both helping landowners improve the amount of water they apply as well as to estimate the efficiency of the system. The lawn irrigation estimation process is heavily influenced by having accurate land-cover type areas. In this study land-cover data extracted from aerial photographs were used to monitor and estimate urban lawn irrigation water requirement (IWR). Five land-cover categories (grass, trees, impervious, soil, and water) were digitized from aerial photographs using GIS. Land-cover information was introduced into a consumptive use model to estimate lawn irrigation consumptive use. A demonstration of aerial photographs based lawn IWR estimation was performed on an area in Denver, Colorado. As part of the GIS dataset that was created, a lot of additional information was generated such as location of the parcels (address), impervious areas, canopy of trees, canopy of trees over grass, and canopy of trees over impervious areas. Some studies have been conducted on how to use random sampling to estimate the total area of lawns in urban areas. Combining this statistical sampling with GIS and aerial photography was found to be a cost effective methodology for assessing lawn IWR in urban areas.