FORECASTING WATER DEMAND FOR EFFECTIVE WATER MANAGEMENT DURING DROUGHT PERIODS IN THE GREATER GABORONE AREA, BOTSWANA

摘要

In December 2004, the Water Utilities Corporation (WUC), which is responsible for urban water supply in Botswana, imposed water restrictions on non-essential uses in the Greater Gaborone Area (GGA) as a way of reducing water demand within this area by 25%. This was motivated by drastic drop in water levels from Gaborone Dam to as low as 17% due to drought. Within six months WUC reported 35% drop in water use within the study area which was attributed to water restrictions. This intervention led to reduced revenues from WUC water sales and possibly had serious socio-economic impacts to water users, including loss of jobs from water-related companies like landscaping, gardening and car wash. While restrictions were purely based on water conservation and demand management strategies, the scale of imposition should have been informed by available forecasted demand in order to lessen their socio-economic effects. The purpose of this study is to provide simple forecasting model which can be used in coming up with options and scales of water demand management including restrictions. Trend analysis and autoregressive models have been applied to suggest future demand trends forecasted on a monthly time step.