Water -- a life source for humanity as well as other living creatures -is getting scarcer by the day.
The world is observing a fast depletion of sources of water every second. Among others, it is the urban areas that are using surface water as well as groundwater to the utmost level leading it to the verge of depletion.

Even Kathmandu Valley and its residents are facing scarcity of drinking water even during the rainy season. Kathmandu Upatyaka Khanepani Limited (KUKL) is unable to fulfil the daily demand of drinking water of Kathmanduities.
"We have estimated the daily demand for drinking water in Kathmandu on average is 300 million litres per day (MLD) but we are able to supply only 150160 MLD during rainy season, and around 90 MLD in the dry season," said Tilak Mohan Bhandari, Deputy Manager of Water Operation Department at KUKL. But life is impossible without water and to fulfil their water needs people extract water that is underground.
"Water supplied from KUKL is never sufficient for our needs. So I extract underground water besides relying on KUKL water supply," shared Basudev Bista, a resident of Shantinagar. Besides the general public, housing colonies and hotels rely on groundwater to fulfil their daily water demand.
"We have installed a 290-metre deep boring system through which we extract required water for our daily needs," said Ena Karmacharya, an architect at Shangrila Housing Private Limited. Even KUKL extracts nearly 20 MLD-30 MLD of water daily.

Depleting groundwater
Water that exists beneath the earth's surface in aquifer, well or underground water is groundwater. Groundwater is recharged naturally by rain, melting of snow and to some extent from sources like rivers and lakes. Water from such sources moves beneath the ground and recharges the groundwater by which its level is maintained.
Groundwater is stored in shallow and deep aquifer. The water level up to 100-metre in depth is generally characterised as shallow aquifer, which is easy to recharge as water from surface easily penetrates there. However, the level that is deeper than 100 metres is deep aquifer, which stores fossil water, which has been stored for thousands of years. According to hydro-geologists, water from deep aquifer is termed as fossil water as it can't be recharged as easily as shallow aquifer water.
"There is haphazard extraction of water from both shallow and deep aquifer in Kathmandu Valley at present. The extraction of groundwater in Kathmandu Valley is higher than the recharging, which is reducing the level of groundwater," warned hydro-geologist Dr Suresh Das Shrestha.
According to a study conducted by the Japanese International Cooperation Agency in 1990, the extraction rate of groundwater should not exceed 15 MLD. But the report of Melamchi Drinking Water Project published in 2002 shows that the extraction rate has reached 60 MLD.
"It is estimated that the groundwater of Kathmandu Valley is decreasing by 2.5 metres per year on an average. However, it differs according to the places as the geological structure within Kathmandu valley is diverse," Dr Shrestha added.

Impacts
"If the extraction rate remains the same, groundwater will be sufficient for the next 90 years only. But what after that?" questioned Dr Shrestha. "People will have to face a lot of problems before that. When groundwater level reduces, there are chances of subsidence of the earth's surface," he warned. This finally leads to cracking and breaking down of foundation of house roads, poles and other infrastructure. Besides this, destruction of vegetation occurs in the absence of moisture content in the soil. Destruction of bio-diversity and desertification are impacts that can be caused by depletion of groundwater level.

Road ahead
Experts suggest harvesting of rainwater and recharging the groundwater so as to reduce the amount of water extraction from underground. Many households are already attempting to harvest rainwater.
"The effort at individual level is not sufficient to protect depletion of groundwater. Efforts from the community, institutions and government level is a must," said Dr Roshan Raj Shrestha, Chief Technical Advisor for South Asian Regions at UN HABITAT. "If housing colonies and hotels, extract groundwater, they should make a provision for recharging it and apply an integrated water resource management approach," he added. "The absence of policies and regulations to monitor groundwater management is also responsible for it.".
Nawaraj Shresth, a senior divisional hydrologist at Groundwater Resources Development Board informed, "We are doing our homework so as to introduce policies and regulations regarding the management of groundwater and they will be introduced soon."

Source: The Himalayan Times, August 21, 2009