Sustainable household water-saving and demand management options for Kabul City

Abstract

Increasing water demand has led to water scarcity in many urban areas in the arid and semi-arid regions. Indeed, population growth and the expansion of urban and industrialized areas have put great pressure on water resources. Currently, Kabul city is facing groundwater shortage, which is the main source of potable water. Due to rapid urbanization and population growth, and climate impacts, the groundwater level is lowered (∼ 1m/year), which has led to many wells drying out in recent years since 1998. Therefore, this study focuses on alternative options to sustain water resources and achieve water sustainability through implementing water-saving practices, including tapping new water resources (rainwater harvesting), and some of the options (faucet aerators, low-flow showerheads, and dual flush toilets), others as gray-water reuse. To analyze the potential of rainwater in Kabul city, long-term precipitation data from 1960-1980 and 2006-2013 from several stations around the city are used. The rooftops of the dwellings assumed to account for 30% of the total land area, according to the State of Afghanistan City 2015 report. Moreover, existing household water efficiency is compared to the most efficient available technologies. The result indicated 346 mm annual average precipitation, and 38.0 million m3/Year the potential precipitation volume that could be harvest from dwellings rooftops in Kabul city. Moreover, the rainwater harvesting could produce an average of 29 L/capita/day (LCD) of water for domestic usage, with a maximum of 75 LCD in February, a minimum of 5 LCD in September, and an annual 9593 L/capita/year (LCY). If we manage the maximum months, then it could produce the full domestic usage (38.1 LCD) until July. Furthermore, in terms of demand management, we have performed a case study on Macrorayon’s (1st, 2nd, 3rd, 4th) apartments that if low flow fixtures were utilized, how much water could be saved? The Macrorayon Department estimates the service population of its system at 100,000 people, the volume of consumption calculated to be 12,500 m3/day (125 LCD). Results show that after application of low flow fixtures, per capita consumption can be reduced to 57 LCD, 2.08 MCM/Year would be saved; and an additional population of 119,298 people would be covered by water supply. The result of this study is essential for policymakers to adopt current and future water challenges in Kabul city.