02 Mar 2018
5 min read
Water is a rare commodity in populous Kathmandu. The ever-increasing population of the city needs a staggering 400 million litres of water a day, but Kathmandu Upatyaka Khanepani Limited (KUKL), the sole government water-utility body, manages to scrape together only 120 million litres during the wet season, and around 100 million litres during the dry season. Adding to the woes of Kathmandu's people, more than 30 per cent of this water is lost in pipe leakages. With the state water services falling severely short of supplying the needed volumes, Kathmandu's residents have had no choice but to take matters in their own hands and resort to other water sources like groundwater, which today contributes about 50 per cent of the total water supply in the Valley.
All one has to do to access groundwater is bore a deep hole in the earth's surface and extract the accumulated water; this is what many households in Kathmandu have been doing since the 1990s. However, groundwater is a non-renewable resource that typically takes years to replenish, and it has to be used sustainably. In Nepal, and in most places around the world, groundwater extraction is under-regulated and poorly managed; this has led to unchecked overexploitation of the resource. This practice could mean dire consequences for the people of Kathmandu if its denizens do not rethink how they use groundwater, and if they do not learn to source the water more sustainably.
"When do we call a critical situation a crisis?" says Suman Shakya, Managing Director of SmartPaani. "When you start seeing the initial signs of something gone wrong or when it's too late to make a change?" Shakya believes it's past time that Kathmandu started becoming more judicious about how it sources water.
What is groundwater?
Groundwater is formed when fallen rain seeps into the soil and gets stored, in the tiny gaps between rocks, soil and sediments. This underground layer of rocks, soil and sediments--which store water--is called an aquifer. Aquifers are further divided into two types: shallow aquifers and deep aquifers. Deep aquifers are located several hundred metres deep beneath the earth's surface; shallow aquifers are located a few metres below the earth's surface.
In Kathmandu Valley, these aquifers are distributed all over the valley's heterogeneous terrain; different areas have different sizes of aquifers. The valley's groundwater stores lie within three groundwater districts: the northern groundwater district, central groundwater district and the southern groundwater district. On the basis of the soil in the areas, the northern and northeastern parts are considered good aquifer zones, and the southern parts of the valley have less promising aquifers.
Who uses which aquifers?
In Kathmandu, most households use shallow aquifers. "These shallow aquifers are located at around 30-50 metres below the valley's surface," says Anoj Khanal, hydrogeologist at Kathmandu Valley Water Supply Management Board (KVWSMB). "Because water is a free natural resource, the government of Nepal allows households to dig wells to access these shallow aquifers, without requiring registration or a license." There is also no limit to how much water one can extract. This lack of a monitoring system has resulted in the overexploitation of groundwater resources, particularly by unregistered small-scale enterprises.
Deep aquifers, on the other hand, are used for commercial and industrial purposes, and are sourced by corporations, hospitals, hotels, etc. These aquifers are located at a depth of more than 300 metres. KUKL, too, depends on deep aquifers (located in Gongabu, Bansbari, Kapan, Nayapati, Mulpani, Tokha, Gokarna, Bhaktapur, etc) to extract around 60 per cent of its supply. Unlike with shallow aquifers, you need to first get a license from the KVWSMB to dig wells to extract water from deep aquifers. The license for these deep wells cost a mere Rs 20,000 a year; for that fee, companies are allowed to extract a minimum of three litres of water per second, which means if a hotel extracts three litres of water per second for only 10 hours a day, the establishment can extract 108,000 litres for just Rs 54.70 (the cost of the licensing fee).
"There are around 800 to 1,000 licensed deep tubewells in Kathmandu," says Khanal. However, hydrogeology experts peg that number to be around 2,000, with more than half being used without a license--meaning, nobody can provide an estimate as to how much water is being extracted from these deep aquifers, how much is being consumed and how much does the valley actually have left in its natural reservoirs.
Why this is a cause for concern
The consequences of Kathmandu Valley's over-dependence on groundwater is slowly coming into sharp relief. It's evidenced by the drying of waterspouts, wells and springs, all of which indicate a significant decline in our groundwater reservoirs. This depletion in the water table level is happening because the rate at which water is being extracted outstrips the rate at which it is being replenished. But to know how dire Kathmandu's groundwater situation actually is, scientists need data, which is currently unavailable. The only rigorous study of Kathmandu's groundwater was conducted by JICA (Japan International Cooperation Agency), in 1990. And groundwater extraction has grown exponentially since that report was published. Currently, KVWSMB, the only institution that has the sole authority to manage and regulate groundwater, is carrying out an intensive study on Kathmanduís groundwater to get a clearer picture of the situation.
According to some studies, scientists believe that the overexploitation of groundwater since the 1990s has lowered groundwater levels by 0.37, to 7.50 metres, in the wells run by Nepal Water Supply Corporation (according to data collated between 2000-2008): the finding should sound alarm bells. More alarmingly, the city continues to get built in a manner that prevents the recharging of these natural reservoirs "Rapid urbanisation in the city has resulted in more and more land areas being covered with concrete, leaving us with ever-shrinking open ground, which is vital for groundwater to recharge. And even the rainwater that does fall on concrete gets swept into the drainage system," says Shakya. The major natural recharge areas in Kathmandu are located in the valley's northern belt, but the rapid urbanisation that is taking place there has obstructed rainwater from seeping into Kathmandu's deep aquifers. Because of this, the recharge quantity of the valleyís aquifers keeps plummeting.
A 2001 study conducted by scientists at the University of Yamanashi, Japan, said that if the extraction rate in Kathmandu continued to grow at that period's rate--that is, at 59.06 million litres a day--then the shallow and deep aquifers of Kathmandu would get emptied in less than 100 years. What has already become obvious right now is the effects such extraction is having on public health. Because of the city's poor sewage system, shallow aquifers are exposed to harmful industrial chemicals as well natural bacteria, like E coli, which seep into wells that lack proper sealing.
What can be done to resolve the problem?
"We all need water for survival, and we can't expect people to stop using groundwater when that is the only resource available to them,"says Suresh Das Shrestha, professor of hydrogeology at Tribhuvan University. "However, what should be done, and should be pushed by the government, is the sustainable use of this valuable resource.""Groundwater depletion is a result of poor planning to do with our infrastructure, with the execution of sustainable-energy plans and with rapid urbanisation. However, we can work to solve this problem," says Shrestha. The most obvious solution is to allow the valley's aquifers to recharge. It's considerably easier to recharge shallow aquifers than deep ones. But for these shallow aquifers to get recharged, there should be an availability of recharge areas. In cramped Kathmandu, this could be a problem. There is an alternative solution, though: installing recharge pits."In Kathmandu alone, approximately 40 billion litres of water can be recharged via pits annually," says Shakya. "By installing a recharge pit, not only will our water woes be put to rest, it will also extend the life of our wells." People can also opt to use interlocking bricks instead of cement to plaster the streets, so as to allow rainwater to seep underground.
That said, it takes years to recharge deep aquifers, which cannot be replenished by recharge pits. The only way Kathmandu can preserve this resource, and ensure that the city does not deplete it completely, is by using deep aquifers sustainably. To lessen dependence on groundwater, the people of Kathmandu can use an alternative source of water: harvested rainwater (see box story.) Other eco-friendly solutions include reusing greywater (water recycled from showers, sinks, tubs, washing machines) for gardening purposes, etc.
The severity of drawdown in groundwater levels could be controlled through effective groundwater management by the government. "The government should make sustainable practices mandatory," says Shakya. Besides these adaptation measures, the government can work on creating bodies that constantly monitor, regulate and identify critical/ stressed groundwater zones, encourage households to recharge their private wells and store water harvested during the monsoon for the dry season, better plan urban areas, promote reforestation and conserve potential and existing recharge zones.
Waiting for Melamchi
The Melamchi Water Supply Project has for many years been viewed as a project that will end Kathmandu's chronic water shortage. But the project, as is the case with many infrastructure projects in the country, has extended its completion deadline multiple times. Supposed to be completed in 2007,
the project will finally get done this year. Kathmandu is expected to receive its first drops of Melamchi water in
July this year.
The primary source of the water for the project is the Melamchi River, in Sindhupalchok District. A 26-km-long tunnel will carry water from the river to the Sundarijal Water Treatment Plant, which has the capacity to treat 85 million litres of water daily. By May 2018, it is expected that 170 million litres of water will be supplied to Sundarijal daily (the plant can treat 510 million litres daily.)
From Sundarijal, water will be distributed to large storage tanks in different parts of the Kathmandu, via bulk-distribution pipelines. Water from the storage plants will be supplied to existing KUKL customers, via the existing distribution network. By the time the project is completed, Kathmandu will receive a total of 510 million litres of water daily. Water will also be sourced from the Yangri and Larkey Rivers, both in Sindhupalchok District. But Melamchi alone wonít be enough to end Kathmanduís water crisisóbecausethe supply can only cover current demand, not how much the city will demand as Kathmanduís population continues to explode.
Kathmandu receives an average of 1.165 billion cubic metres of rain every year, 80 per cent of which falls in the four months of monsoon. Despite abundant rainfall, very few people in the city consider rainwater as an alternative water source for ending their water problems. "If you harvest rainwater properly, you will be water independent, if not for the whole year, at least for the four months during which we receive plenty of rainfall," says Suman Shakya of SmartPaani. A house with a roof 340 sq ft, for example, can collect an average of 36,000 litres of rainwater during the monsoon season, if they have proper rainwater-harvesting systems in place. This rainwater collected will be enough for a family of four. In rainwater harvesting, the roofs of houses work as catchment areas for rainwater, and the water collected is first filtered and then channeled to storage tank/s. "The bigger your storage capacity, the less you have to depend on other water sources," says Shakya.
Rainwater harvesting is nothing new for Kathmandu residents. For years, people in the city have (in an ad hoc basis) harvested rainwater by placing jars, cans or small tanks to collect water to use for household purposes. But with the city's interminable water shortage, which is in fact, getting worse, systematic rainwater harvesting could go a long way towards reducing the city's water woes.