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Call for urgent water harvesting in capital



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By Arpana Adhikari

Kathmandu, Nov. 17: The ancient valley of Nepal, Kathmandu, has been witnessing haphazard development over the past few decades.
In the name of progress, the earth surfaces of the Kathmandu valley are being sealed by cement and concrete.
But neither the government and nor the citizens are aware that by covering the land surface with concrete haphazardly, blocking water from entering inside land surface, which has directly affected the ground water level in the valley.
Studies have shown that more than 50 billion liters of rainwater are prevented every year from its natural recharge in the valley because of the concrete sealing of land.
Till two decades back, the areas around the Kathmanduites’ homes and offices used to be unpaved and the rain water on these areas would percolate into the soil and remain there long for being drawn through shallow open well, said Prakash Amatya, a civil activist who has been working in the area of water conservation.
But with the increasing number of buildings and infrastructures, rainwater absorption into the soil has almost stopped in many parts creating water scarcity.
Due to the water scarcity in the valley, the quantity of water drawn from the soil below has increased manifold, he added.
Consequently, ancient water sources of the valley like stone spouts, ponds and dug well, which used to be the reliable source of water are now fast drying up. More than half of stone spouts inside the valley have already dried up.
The daily demand of water in the capital city has risen up to 370.7 million liters but Kathmandu Upatyaka Khanepani Limited (KUKL) has been distributing only 70.3 million liters in dry seasons and 120.8 million liters in other seasons.
And rests of the needs of water are fulfilled by either underground water extraction or through water suppliers, said Amatya.
According to the Kathmandu Valley Water Supply Management Board (KVWSMB), approximately 35-50 per cent of the valley’s populations relies on underground water.
Private water extraction by households and industries and water vendors are rampant in the valley, said Amatya adding that the KUKL itself distributes around 50 per cent of water from the ground water sources, through deep boring.
Anuj Khanal, hydrologist of the Kathmandu Valley Water Supply Management Board, said so far 700 private water extraction by households, factories, industries, hotels and hospitals among other have taken permission to install tube well and deep boring, which is 70 per cent of the total deep boring in the valley.
The tube-wells deeper than 50 meters need to get permission to operate, he added.
As per the study conducted by the Ground Water Resources Development Board, the groundwater level of the valley has been gradually declining.
In the past, water used to found at 8-10 meter below the ground of the valley, while now it is hard to find water even by digging 40-50 meters.
Sukaman Tamang of Sifal, a well driller who has been working for the past 30, said in the past, he
could easily fetch underground

water by drilling around 10-20 meters, but now he hardly gets water even after digging deeper than 40 meters.
Experts have been warning that if this situation continues to happen, then the new generation will face a high water scarcity in the valley.
Amatya said the groundwater in valley is drying up because there is no sincere attempt made to refill the ground water.
“Melamchi Water Supply Project, the most awaited project of Kathmandu denizens, is in limbo since 2000 and no one knows how many years people have to wait for it,” he added.
Even after the completion of the project, it is expected to resolve only half of the water scarcity problem faced by the valley. The project only supposed to supply extra 170 million liter per day.
Therefore, for the longer run, the government needs to take stronger and more sustainable measures to deal with the future acute water scarcity, experts have been claiming.
Rainwater Harvesting
“Kathmandu Valley receives an average of 1600 mm of rainfall every year. Considering the average rainfall per year, we can estimate that a house with a rooftop surface areas of 100 sq has the potential to collect more than 130,000 liters of rainwater annually”, said Amatya.
If every households of the valley will collect rainwater, then at least 1,280,000,000 liter rainwater will be collected in a year, he added.
“The method is simple and cost effective too. One could install rainwater harvesting system in the areas, which faces the scarcity of water at just Rs. 10,000. This is the most effective way to conserve water.”
Similarly, artificial rainwater recharge like recharge pit help divert excess rainwater into the ground and would supplement ground water level in the underlying shallow aquifers.
The valley dweller always complain about the water scarcity, but they give least concern over recharging and storing the rainwater goes waste into the drainage, said Amatya.
It is the simple collection or storing of water in the water tank through scientific techniques from the areas where the rain falls.
Khanal said when rainwater falls on the ground, it seeps down to water table through solid voids and goes to aquifers.
But normal open space percolates only 10 per cent of the rainwater from the areas where the rainfalls but by making recharge pits could percolates more water to the underground, he added.
Khanal said pits may be any shape and size, considering the available space. This could be made at every household and community, he added.
Generally, recharge pits are constructed one to two meters wide and two to three meters deep and are filled with boulders, gravel and coarse sand in graded form, which will absorb runoff water and help recharging underground water.
This will help the household to use water from the shallow ground well and use it, he added.
He added that for the longer run, there is a need to take sustainable measures for preservation of ponds, streams, forest resources and sand mounds allow rainwater seep back into the ground, deep ground water level will definitely rise in the valley.
There is a need to generate awareness about rainwater harvesting. This simple action will help community to reduce water scarcity by themselves.