Excessive extraction causing groundwater depletion in Kathmandu Valley

Nitu Ghale

Nitu Ghale

Excessive extraction causing groundwater depletion in Kathmandu Valley

Experts say unfettered construction activities, population growth, and changing rain patterns are also to blame

Mahalaxmi Baniya, a resident of Lalitpur Metropolitan City-26, has a tap water connection at her home but she depends on an underground well for her water needs, as the drinking water supply is unreliable. But that was until recently. These days Baniya pays money for tankers to bring water to her home, because her trusty well has dried up.

Dilli Bahadur Bista, who has been digging wells to extract groundwater for households for the past 14 years, says the situation that Baniya is facing is common around Kathmandu Valley.

“When I began this profession, we could get water just 15-20 feet underground. We now have to dig at least 40 feet to find water these days,” he says.  “In higher areas, we have to dig 300-400 feet to find water.”

Bista has observed the groundwater level decline by as much as 12 feet in a year. On average, he says one must go at least 100 feet deep to find water, even in low-lying parts of the valley like Duwakot, Imadol, and Thapathali.

Another problem, he adds, is wells drying up within a few years. This has added to the water scarcity problem.

Gyanendra Bahadur Karki, the deputy executive officer of Kathmandu Upatyaka Khanepani Ltd (KUKL), says there is a significant difference between the rate of groundwater recharge and extraction. “The groundwater level is declining due to increased extraction, and it is a fact that we now have to dig deeper to access groundwater.”

The daily demand for drinking water in Kathmandu Valley is approximately 400m liters. KUKL distributes between 140m to 180m liters per day during the wet season, and around 80m liters during the dry season. The Melamchi Water Supply Project has been providing KUKL with 17m liters of water per day.

Krishna Hari Budhathoki, the chief of KUKL’s electro-mechanical division, says there are no issues with deep wells that are more than 50 meters deep. It is the shallow wells that are drying up as a result of excessive extraction.

“The groundwater level is not falling. We are simply extracting too much water.”

He says the water level might have decreased by 2-4 meters for various reasons, while noting that  around 80 percent of tube wells that had dried up are back in operation following minor repairs.

KUKL has 105 tube wells installed in different parts of the valley. Most of them have only been in operation for the past four-five years.

Budhathoki says KUKL extracts 50-60m liters of groundwater every day, and these tube wells have a capacity of extracting 300-1,800 liters per minute.

Madhukar Upadhayay, a watershed expert, also agrees that groundwater depletion in Kathmandu Valley is a result of unregulated extraction.

“It has no correlation with climate change like many have conjectured.”

Upadhayay says there is a possibility of shallow upper floor recharging if managed efficiently, which can allow water spouts and wells to produce water again.

“The lower level cannot be recharged, though,” he adds. “We are currently extracting water from the lower level. Therefore, the only option we have is to reduce extraction.”

Meanwhile, burgeoning construction activities that are heavily reliant on cement and concrete has led to the closing of the ground surface, which prevents water from trickling below the earth’s surface to recharge the upper floor. Additionally, unplanned construction and development projects are causing rivers to dry up, and riverbeds to become hollow, further hindering the groundwater recharge process.

A 2010 study conducted by Bishnu Prasad Pandey shows that the demand for water increased as the population exploded and the number of hotels grew in Kathmandu Valley. Between 1980 and 2000, the report states that groundwater levels declined by 1.3 to 3 meters annually in 9.6m cubic meters of land area. Similarly, groundwater levels declined by 1.38 to 7.5 meters between 2000 and 2008.

Pandey warns if the relevant agencies do not take immediate action to develop groundwater, the environmental condition will deteriorate further.

According to the Underground Water Resources Management Policy, 2069, tube wells are excessively used at both upper and lower levels (deep and shallow). Various establishments such as hotels, residential areas, apartments, industries, nursing homes, schools, business complexes, government and semi-government offices, and embassies have been extracting groundwater using deep tube wells.

The policy highlights that the groundwater level in the valley is decreasing at an average rate of one meter per year; it is 2.5 meters per year in some places. As the groundwater reserve dries up, only 233 out of 389 community water spouts are supplying water, and about 30 percent of Kathmandu’s wells are drying up.

The policy stresses the need to prevent further depletion of underground aquifers, protect traditional sources of water such as streams and wells, and monitor groundwater extraction in Kathmandu Valley, which has a high population density and has a specific geographical and geological structure compared to other regions of the country.

Dr Santosh Nepal, a climate change researcher at the International Water Management Institute (IWMI), has identified two main factors contributing to low groundwater recharge: the increasing use of cement in construction and changes in rainfall patterns.

“The use of concrete in construction prevents rainwater from being absorbed into the land surface. Additionally, rapid urbanization has resulted in a decrease in natural land and open spaces, further reducing the recharge rate of groundwater,” he says.

The other factor is changes in rainfall patterns. Nepal says Kathmandu Valley has been experiencing shorter but more intense rainfalls these days, compared to long, gentle drizzles of the past.

“Rainwaters are unable to penetrate the ground during heavy rainfall events.”

Data shows that 8.8bn cubic meters of water penetrates below the land surface annually. But only 22 percent of it can be utilized. Nepal emphasizes the need for comprehensive groundwater governance, including measures to preserve groundwater in certain areas. He also underlines the need to revive natural springs and to allocate specific areas for groundwater recharge.

“There is also the need to identify areas outside the core area of Kathmandu where groundwater can be recharged and rainwater could be utilized more effectively,” he adds.

Nepal recommends that the government introduce necessary laws and regulations for water conservation, as well as provision that requires setting aside free space while constructing residential houses.

“There should also be a set of policies to encourage rainwater harvesting, and to make big consumers of water, such as hotels and hospitals, accountable.”

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