How to Solve Dhaka's Serious Water Crisis by Harvesting Rainwater
The capital of Bangladesh, Dhaka, has a critical water problem. There isn't enough of it.
According to a study by the Institute of Water Modeling, based in Dhaka, the groundwater level is falling by three meters per year. The groundwater is now 60 meters down below the surface. That's compared to 10 meters in 1970. The situation is getting so bad that, last summer, the Government of Bangladesh deployed troops to manage water distribution.
The cause is a combination of population growth and industrial expansion. Since 1963, Dhaka has grown 13 times over. When Bangladesh gained its independence in 1971, Dhaka saw an influx of rural-to-urban migration. The city expanded into the low-lying marshlands at its borders. Historically, most of Dhaka’s water came from its two rivers, the Buriganga and the Shitalakkhya. But as people spread and and industry has expanded, the river water has become contaminated. Today, groundwater is expected to satisfy over 80 percent of the city’s water supply.
Dhaka has not been able to naturally refill the underground aquifers. The city has even tried mandating that 40-50 percent of building premises need to be unpaved, to allow water to seem into the ground. But as 65 percent of the city is already paved, and the top soil is largely clay, more needs to be done, like harvesting rainwater.
Turning the rain into drinking water is a practical solution to ease Dhaka’s crisis. It is estimated that rainwater harvesting systems could supply more than 15 percent of Dhaka’s thirst. Since 1997, 1,000 systems have been installed in Bangladesh, mostly in rural areas. About 150 billion liters of rainwater could be harvested during the monsoon season alone. Water can be stored for four to five months without bacterial contamination–an important fact given that 110,000 children in Bangladesh die of waterborne illnesses every year.
Bangladesh has a history of making this work too, in particular, in partnership with the private sector. In early 2008, Coca-Cola Far East Ltd teamed up with Plan Bangladesh to install RWS in five primary schools.
UN-Habitat also joined a Coke project, “The Safe Drinking Water and Sanitation Project”. It is a two-year plan to bring water to 6,000 families for just $300,000. Rainwater harvesting systems will be set up at 20 schools while drinking water and sanitation systems will be set up at 30 schools.
Nisha Kumar Kilkarni is a Senior Associate at Beyond Profit, where a version of this article appears.