The groundwater level in the city is falling at a rate of 9.21 feet per year, revealed a recently conducted study. During the last seven years, the groundwater level of Dhaka city has recorded a fall of 65.61 feet.
The reason of such alarming fall can be attributed to indiscriminate use of groundwater. The water table in the city will fall by more than 393 feet within 2050 if the underground water continues to maintain the present rate of depletion, showed Unnayan Onneshan, a private think tank in its recently conducted study.
The Bangladesh Agriculture Development Corporation (BADC) also conducted a research two years ago on groundwater level. The BADC findings revealed the water level in 416 observation wells fell at a depth below the mean sea level between 2004 and 2010.
The upsetting fall in groundwater level has prompted the Water Supply and Sewerage Authority (WASA) to embark upon a plan to recharge aquifers with rain water. This is for the first time that Dhaka WASA has taken steps to overcome the crisis arising out of depleting groundwater table because of widespread use of deep tubewells to meet the growing need of water for an ever-increasing number of city dwellers.
The WASA authorities have taken a plan for massive recharging of underground aquifers at a minimum cost. It also plans to reduce the dependence on groundwater by 50% during the next one decade through installation of water treatment plants in different parts of Dhaka city, official sources said .The plants will treat river water. about 88% of the total water of Dhaka WASA now comes from a total of about 600 deep tubewells and the rest from the existing water treatment plants, the source added.
The Dhaka WASA undertook a scheme more than three years ago to harvest rain water to gradually reduce dependence on groundwater in the city. The project remained stalled due to bureaucratic bottleneck. In 2012, the project started on a trial basis, official sources said requesting anonymity.
The government has decided to amend the Building Construction Rules 2008 with a provision to make harvesting of rain water mandatory for all new houses in Dhaka city. Under the rule, the new buildings will have to retain rain water. The Rajdhani Unnayan Kartripakkha (RAJUK) says that the amendment to the existing construction rules will facilitate harvesting of rain water and groundwater recharge.
We know that harvesting of rain water has been proved effective in some countries of the world. During monsoon the Dhaka city experiences rainfall of about 2000 mm, another source said. The rain water may be stored on rooftops during this period. The wetlands around Dhaka have also been filled up by the developers for housing projects. If half of the rooftops in Dhaka city can be utilized for storing water during monsoon the demand of citizens for water supply will be met to a great extent.
The government may launch mass awareness campaign to encourage people owning existing buildings to make provision for conserving rain water. The rain water thus collected in the rooftops may be supplied to underground tanks through pipes. The owners of old buildings may be provided with loans on easy terms for making provisions to collect rain water on their rooftops.
Mass awareness campaign should be launched to encourage people to come forward and participate voluntarily in rain water harvesting to meet the growing demand of water.
