Australia has mandatory rainwater recycling plant in each and every house. It is as simple as to catch the water from their roofs, keeping that in a reservoir and using that for non-potable household works
like toilet flushing or watering the gardens
Rethinking water resources for a sustainable future
Shafique Rahman
Complexity in transboundary water issues between Bangladesh and India still remain in gray. The rivers are drying out and our agriculture, hydropower generation, urban development and ecosystems are no more a successive process of sharing river-water. Every day we are digging deep to hit the fossil water and these underground aquifers are getting to the end of their reserves. Cities are more vulnerable to supply the heavy amount of water both for drinking and household works. Everyday crisis for safe drinking water and conflicting situation in water share require us to re-think the alternative resources of water for a sustainable future in Bangladesh.
Demand for water is increasing more radically in the megacities. Over half of the world population lives in urban areas today, and the number of urban dwellers grows each day. Especially, Dhaka is an extreme example where rate of migration is around 1500 to 1600 persons per day, but it has no significant planning toward sustainable water supply for the predicted population of 20 million by 2025, a statistics by U.N. The looming catastrophic crisis of water has been reflecting in Dhaka city very prominently in day-to-day occasions. A drop in the water supply during the annual dry season from March to May strongly indicates that DWASA is unable to extract enough water to meet the demand. The overdependence of groundwater is causing the water table to fall by about one meter per year in the metropolitan area.
In Dhaka, we are developing radically with infrastructures without consideration of water sources for the dwellers. With the growing population and globalization we are also creating mega structures. By increasing hard concrete surface all over the city we have restricted the replenishing of underground aquifers. On the other hand we have no alternative reserve or water recycling system driven by rainwater. Our urban areas are expanding drastically with housing, slums, institutions, marketplaces or so many diversified groundworks, yet without any concern for the depleting groundwater reserves.
People living in the worlds desert lands is around 500 million. They know the value of water. They know how to use it sparingly. They dont have the rain or rivers; they understand the value of it. In Bangladesh, due to the lack of profound initiative, we havent yet taken in consideration the renewable source of water, which comes to us as a blessing of heavy annual rainfall in almost every corner of our country. Even though, we are digging deeper and deeper to reach the ground water to irrigate our lands, to drink, to use in households, to feed animals, which is an extremely inadequate resource of water all over the world.
Water is the most assessable resource in our earth. The three-quarter of whole surface area of this earth is water. Of this 110,300 cubic kilometers of water, two-thirds evaporates, leaving 40,700 cubic kilometers per year of rainwater run-off, feeding rivers and replenishing aquifers and available for domestic, industrial and agricultural use. Even today the majority of humankind lives on the continental coastlines or the banks of rivers and lakes for the easy access to the water. Even though, 783 million people have no access to the safe drinking water today. According to the survey of the United Nation (UN) 6 to 8 million people die annually from the consequences of water-related diseases. Water will be everywhere, but scarce will be the potable water in the upcoming decades, as we havent realized the blessings of monsoon and every day we are drilling deep to hit the ground water, which is one of the major non-renewable resources of our planet.
The underground aquifers are drying out in Bangladesh as like many other urban and rural areas around the world. In western India, for example, 30% of wells have been abandoned. We are no longer out of the threat of the predicted era of water war. Either there is a lack of wisdom or it is our lack of consciousness which is clearly taking us into the largest calamity within the brink of 21st century in Bangladesh.
All living matters are linked to the planning and design of buildings. A complex urban system exists in Dhaka city, but the lowest living matters are linked to the design of buildings or to the overall urban planning. Its not too late to realize what nature gives to us by means of wonderful monsoon in our country. The broken harmony between nature and architecture need to be instigated right today.
Like in Bangladesh, globally there is a huge variation in the availability of water for consumption and the per capita demand. However, in many countries it has become a standard practice today to replace the non-renewable ground water with the renewable resources, especially using rainwater as a potential water source for household purposes. A paradigm is Australia, a benchmark for environmental sensitivity, has mandatory rainwater recycling plant in each and every house in their country. It is as simple as to catch the water from their roofs, keeping that in a reservoir and using that for non-potable household works like toilet flushing or watering the gardens. In Melbourne, they have replaced 52% of total water consumption from the collected rainwater. In Tokyo, rainwater harvesting and utilization is promoted to mitigate water shortages, control floods, and secure water for emergencies. In Berlin, rainwater falling on the rooftops of 19 buildings is collected and stored in a 3500 m3 rainwater basement tank. It is then used for toilet flushing, watering of green areas including roofs with vegetative cover and the replenishment of an artificial pond. At the U.S. National Volcano Park, on the Island of Hawaii, rainwater utilization systems have been built to supply water for 1,000 workers and residents of the park and 10,000 visitors per day.
Thousands of examples are right in front of our eyes, what significantly we have initiated in Bangladesh? Rainwater collection is seen as an alternative to provide safe drinking water only in the arsenic affected areas in a minor scale in Bangladesh. However, in Dhaka, lack of sustainable water consumption is becoming a latent urban problem and it has been repetitively ignored by the correlated professionals within the field. Sprawling a land area of approximate 815.2 square Kilometer, Dhaka is the tenth largest city in world, frequently increasing with gigantic concrete infrastructures, but without any intention to provide sustainable water system in the buildings for its inhabitants.
All living matters are linked to the planning and design of buildings. A complex urban system exists in Dhaka city, but the lowest living matters are linked to the design of buildings or to the overall urban planning. In Dhaka, rainwater harvesting and reuse in any of the multistory structures is still a rare example. For architects, planners and policymakers, its time to understand the value of recycling rain water. Its not too late to realize what nature gives to us by means of wonderful monsoon in our country. The broken harmony between nature and architecture need to be instigated right today.
The writer is Sustainable Design Candidate, Faculty of Architecture, Design and Planning, The University of Sydney, Australia
