MWA residential water demand estimation by the sub-area analysis

Abstract

The estimation of residential water demand is the essential part for water supply management and planning. Currently, the Metropolitan Waterworks Authority (MWA) applies the average water demand of 250 l/cap/day for the planning and design. This  value is inaccurate from the actual water use behavior of the population, which is a result of various factors such as income status, living conditions, housing characteristics and land use. etc. Thus, this study assesses MWA water demand of residential water users (M1) by analyzing the water consumption data based on the 7-year recoded water user database (2012 - 2018). The estimation has been classified by area / district, with the concerns of the numbers of registered population, property (vertical / horizontal) and the latent populations in the form of service business labor in 62 areas (50 in BMA, 6 in Samut Prakan, and 6 in Nonthaburi). The residential users is divided into 6 groups, which are Gr.1: the old town area, Gr.2: business areas and vertical accommodations, Gr.3: small horizontal residential areas, Gr. 4: medium-sized residential areas, Gr.5: large-sized low-rise residential areas, and Gr.6: industrial areas. The results show that the average water consumption rate of the residential groups of MWA is 125 - 263 l/cap/day; in which the lowest and highest water demands are found in Gr.1 and Gr.5, respectively.  In addition, Gr.3-a small horizontal residential area which covers Khlong Sam Wa, Bang Yai and Bang Bua Thong districts has the greatest growth rate of the water user. This may affect the excess of future water demand that MWA had previously predicted. The results of the analysis of sub-spatial water usage behavior which are in line with the urban development model will support the water management planning for consumption to be more accurate.