Strategies for longer term availability of water

On the World Water day on March 22 last year UNICEF and WHO published a joint study according to which as many as 26 million Bangladeshi people do not have access to safe drinking water. The UN General Assembly has declared water to be a basic human right yet the unfortunate fact is that many Bangladeshis are suffering from lack of safe drinking water.
This is the result basically of bad management-too much water being used where it is not needed and too little where it is much needed. As we know Bangladesh’s population is ballooning. Climate change is making glacial water supply uncertain. Reduced snow-melts sometimes lead to less water in the system. Rainwater is wasted for lack of storage reservoirs. In addition to wasting, Bangladesh is also contaminating its water. Untreated industrial and domestic effluent is being discharged into rivers while unregulated pesticides from farms are finding its way into streams and groundwater. The existing water storage infrastructure is ageing and is unable to cope with the rising demand.
The problem of water scarcity is expected to become more acute in the future due to the adverse impact of climate change. According to experts some of the Himalayan glaciers are melting more rapidly than the global average and this could increase the frequency of floods in the short run and increase water shortages in the long term by reducing river flows in South Asia. Science and empirical evidence make it clear that existing water scarcity, when combined with the impact of climate change, could place critical stress on the economy and society of Bangladesh in particular and South Asia in general: major food shortages, increased frequency of natural disasters, large scale dislocations of population and destabilising contention between upper and lower riparian regions.
Obviously, effective management of this crisis in Bangladesh requires close cooperation with India in joint water management, increasing the efficiency of irrigation and water use, joint development of technologies, sustainable agriculture practices and institutional arrangements to manage food shortages as well as natural disasters. While water availability has declined, the manner in which we use water has remained unchanged. People waste water by leaving taps running. Industrial pollutants and household waste released into water channels contaminates water. The regulatory framework to prevent water wastage is practically non-existent. A significant amount of water is wasted because of archaic agricultural practices.
It is often said that if ever another World War is fought, it will primarily be based on water crisis. This in itself is a testament to the high importance attached to the water issue worldwide. Water is most basic to human life: one can survive for eight to ten days without food, but without water for not more than two days. Even though the rainfall trend has not reduced in recent years the ground water levels are still falling in different parts of the country. Water is an essential element for agriculture. Because of increasing population, land use is increasing and water resources are decreasing.
There is dire need for future planning to provide alternative solution for water scarcity.The early human settlements relied primarily on small dams (water storage reservoirs) for irrigation and food production, since the changing weather patterns often gave fewer but irregular natural water flows. Besides the construction of dams, calendars were created by the Mesopotamians to keep track of planting times, rainy seasons and floods.
In Bangladesh there is an urgent need to address water management issues in line with the future requirements in a more decentralised manner through promotion of rain water harvesting and ground water recharging. Numerous examples exist of using rainwater for a sustainable, participatory and equitable management of water. Water harvesting, both in rural and urban areas, is a solution that should be adopted more extensively.
Rainwater harvesting, a low-cost system that collect and store rainwater for year-round use, offers a cost-effective and practical solution to ease our water crisis. Rainwater harvesting — in one form or another — has been in practice for thousands of years. According to Paul Woods of Texas A & MUniversity, extensive water harvesting systems in the Negev Deserts of Israel more than 2,000 years ago have been documented. Additionally, Roman villas and cities were planned in such a way to take advantage of rainwater for drinking and air-conditioning. If rain water harvesting is undertaken in a serious manner here, it could help conserve groundwater and recharge the water table. About 150 billion litres 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 inBangladesh die of waterborne illnesses every year.
Amount of rainfall varies both spatially and temporally. While the maximum amount of average annual rainfall occurs in the north-eastern districts (55 cm) of Sylhet and Moulivibazar, the minimum amount falls in the western/southwestern districts (15 cm) of Meherpur, Kushtia, Chuadanga, Chapai Nawabganj, Noagaon, and Rajshahi. Also, rainfall is mainly restricted during the months of April to September. Consequently, rainwater harvesting will be relatively easier during certain months of the year in the certain parts of Bangladesh.
Groundwater contamination by arsenic is more severe in the western/south-western districts, where rainwater harvesting would be more appropriate to solve the polluted drinking water problems. Rooftops in buildings can be designed to collect rainwater. Rainwater in rural areas – away from atmospheric and industrial pollution – is fairly clean except for some dissolved gases it may pick up while travelling through the atmosphere. Rainwater offers advantages in water quality for both irrigation and domestic use. Rainwater is naturally soft and is a relatively reliable source of water for households. Rainwater collected and used on site can supplement or replace other sources of household water. Rainwater can be used as drinking water if proper treatment is done before using. Rainwater harvesting will not be able to replace all other sources of drinking water, it will certainly be able to ease the pressure on surface water and contaminated groundwater usage as the primary source of drinking water.
The development of a rainwater harvesting plan that is economically and technically feasible for the majority of the people in Bangladesh must be given high consideration as a part of the integrated water resources management plan.
We cannot drink saline water. But, saline water can be made into freshwater, which everyone needs every day. The process is called desalination, and it is being used more and more around the world to provide people with needed fresh water. A promising method to desalinate sea water is the “reverse osmosis” method. Right now, the cost of desalinisation has kept it from being used more often. But desalination technology is improving and costs are falling. As both the demand for fresh water and technology increase, one may expect to see more desalination plants getting established occurring round the world.
Saudi Arabia, a big desert country, where agriculture hardly existed on a large scale, has achieved a miracle by getting the desert lands suitable for cultivation with water from desalination plants. According to the International Desalination Association, nearly 17,000 plants are currently in operation in 120 countries. The Chinese government recently announced a large-scale plan to develop a desalination capacity of nearly 2.5 million m3/day by 2015.
Time has come for Bangladesh also to look to the sea to get large scale supply of water after desalination.