Rainwater Harvesting in Dhaka: A Sustainable Approach to Urban Water Crisis
Rainwater Harvesting in Dhaka: A Sustainable Approach to Urban Water Crisis
Dhaka, the capital city of Bangladesh, has grown rapidly over the past few decades, both in population and physical infrastructure. With over 20 million people residing in and around the metropolitan area, the demand for essential services has increased dramatically. One of the most critical issues Dhaka faces today is a severe and deepening water crisis. The primary source of water for the city is groundwater, but excessive extraction has led to a drastic decline in underground water levels. As the city continues to expand and natural resources become increasingly stressed, rainwater harvesting emerges as a promising and sustainable alternative to alleviate this urban water shortage.
Rainwater harvesting is a method of collecting and storing rainwater for later use. It typically involves capturing rain that falls on rooftops or other surfaces, filtering it to remove impurities, and then storing it in tanks or reservoirs. In Dhaka, where heavy rainfall occurs during the monsoon season, the potential for harvesting rainwater is considerable. Yet, due to lack of awareness, poor urban planning, and underinvestment in sustainable technologies, most of this water flows away unused, often contributing to waterlogging and urban flooding.
The necessity of rainwater harvesting becomes even more evident when we consider the ongoing depletion of groundwater in the city. Studies conducted in recent years have shown that the water table in Dhaka is dropping at a rate of 2 to 3 meters annually in some areas. This decline is largely due to the overuse of deep tube wells for household, commercial, and industrial purposes. Dhaka WASA (Water Supply and Sewerage Authority) currently depends on groundwater to meet about 78% of the city’s water needs. However, during the dry season, the authority often fails to provide an adequate supply, forcing many residents to rely on alternative sources that are either expensive or unsafe.
“The rain that floods our streets today could quench
our thirst tomorrow—if we learn to harvest it.”
In this context, rainwater harvesting can play a vital role in reducing dependence on underground sources. The rainwater collected during monsoon months can be stored and used throughout the year for various purposes such as washing, cleaning, irrigation, or even drinking when properly treated. This not only conserves groundwater but also offers households and buildings a level of self-sufficiency. Moreover, the use of harvested rainwater can reduce utility bills and help create a more resilient urban water system.
Another pressing challenge Dhaka faces during the monsoon season is flooding caused by poor drainage systems and unmanaged rainwater. The city often witnesses severe waterlogging, disrupting transport, damaging property, and increasing health risks. By capturing rainwater at the source and storing it, rainwater harvesting can reduce the volume of surface runoff. This, in turn, can ease the burden on drainage systems and help minimize urban flooding. Thus, the technique serves a dual purpose: it mitigates both water scarcity and excessive surface water during rains.
Encouragingly, the government of Bangladesh has recognized the potential of rainwater harvesting. Recent building codes and urban policies have included provisions that require large buildings and housing societies to incorporate rainwater harvesting systems. Some progressive developers and institutions in Dhaka have already implemented such systems, setting valuable examples. Schools, hospitals, and apartment complexes with rainwater harvesting mechanisms have reported significant savings on water usage and reduced dependency on WASA supply or deep tube wells.
Despite this progress, the widespread adoption of rainwater harvesting remains limited. Several barriers continue to hinder implementation. Many people are unaware of how the system works or assume that the installation cost is too high. In reality, the initial investment is often affordable, especially for multi-storied buildings, and pays off over time. Additionally, there is a shortage of skilled technicians and service providers who can design, install, and maintain effective rainwater harvesting systems. Without proper training and support, many installed systems become non-functional after a few years.
To make rainwater harvesting a common practice in Dhaka, several measures are essential. Public awareness campaigns can help educate people about the benefits and ease of the system. Government incentives or subsidies could encourage homeowners and developers to invest in rainwater harvesting infrastructure. Training programs and technical support must also be expanded to ensure that systems are properly designed and maintained. Furthermore, enforcing existing regulations more strictly will ensure that all new buildings follow water conservation guidelines.
“Every rooftop in Dhaka has the potential
to become a water-saving machine;
we just need to tap into it.”
In conclusion, rainwater harvesting is a simple yet powerful method to combat Dhaka’s urban water crisis. It utilizes a natural and renewable resource that is otherwise wasted, providing a practical solution to both water shortage and flooding. If properly implemented on a city-wide scale, it can reduce stress on groundwater, lower water bills, improve water availability during dry seasons, and support sustainable urban development. With thoughtful planning and community cooperation, rainwater harvesting could become a key pillar of Dhaka’s journey toward a water-secure future.
