| Typically, to estimate a water demand function, data are gathered from randomly selected residences through the means of surveys. Surveys require extensive manpower and proper selection of residences is necessary to avoid any bias. In this study, a multivariate residential water demand model has been formulated using an innovative approach to data collection.; Data on vegetation type and amount, as a basis for estimation of outdoor water use in urban residential areas, are difficult to obtain. Multispectral airborne videography offers an efficient means to collect land use/cover data in the form of digital images. A geographical information system (GIS) layer indicating land cover data for urban residential areas in the city of Orem, Utah is developed by using image processing and classification techniques on the videography data. Data on socioeconomical factors like persons per household, assessed value, and lot size are obtained from available public domain electronic datasets like census data and county assessor's data. Data on water-holding capacity of the soil are obtained from a GIS layer, indicating soil survey data from Soil Conservation Service (SCS). Databases thus generated or obtained from various sources are combined by using a computer algorithm and are reduced to form a single dataset based on which water demand functions are developed.; The logarithmic demand functions developed show that five independent variables, persons per household, assessed property value, lot area under water-demanding landscapes, water-holding capacity, and a seasonal dummy, have significant impact on the residential water use. A water demand/supply model developed previously at Utah State University was modified to include water demand functions developed in this study, which contain lot area under water-demanding landscapes as one of the independent variables. With this modification, water demand estimates for various levels of reduction in residential landscape areas can be analyzed. This will enable planners and decision makers to set goals and guidelines for a program encouraging water conservation through landscape reduction. |
