AWWA SOURCES55627

AWWA SOURCES55627 Analysis of Institutional Water Demand: A Standardized Approach
Conference Proceeding by American Water Works Association, 01/01/2002

Davis, William Y.;Holland, Edward A.;DuBose, Raymond E.

More info

Full Description

Nearly one-third of water provided by the Orange Water and Sewer Authority (OWASA) is used by the University of North Carolina at Chapel Hill and the UNC hospital facilities. This paper describes an analysis of water demand among the OWASA institutional customers. The analytical approach offers a standardized methodology applicable to other institutional settings. Water use accounts for the University and UNC hospital facilites were divided into seven subsectors: classrooms, laboratories and research, offices and administration, student housing, patient care, other, and utilities. OWASA and University staff worked together to organize historical billing records by subsector. The University provided historical facility gross square footage by subsector. Historical monthly water use per gross square foot and corresponding weather data were used to develop monthly water demand models for each institutional subsector. Binary variables were included in the models to capture the monthly seasonality within each subsector. Weather variables measured the monthly departure from normal for maximum temperature, precipitation, and cooling degree days. Distinct seasonal water use patterns were found in four of the seven subsectors, and statistically significant weather elasticities were estimated for six of the seven subsectors. The estimated monthly parameter coefficients range from 0.0366 gallons per day per gross square foot for classrooms in December to 0.2794 gallons per day per gross square foot for patient care services in August. These estimated water use coefficients are compared with similar gallon per day per square footage coefficients as reported in the AWWARF Commercial Land Institutional End Uses of Water. Inclusion of weather departure variables allows the analysis to adjust for actual weather conditions during the historical billing period. Separation of the institutional customer class into subsectors identify user groups that contribute to system peaks, provide information for targeting of conservation programs, and allows for more consistent modeling of institutional water use. Includes tables, figures.