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Tapping Ground water, a blessing or a risk?

In recent months, I have heard of several unconfirmed cases of parties interested in and already exploring groundwater extraction in Bhutan. While there is no straight answer if it’s a blessing or a risk, I wanted to highlight some pros and cons of the resource extraction.

Water is an indispensable resource for life. More than 70 percent of earth’s surface is covered in water. Globally, only 1 percent of water is useable for human consumption and 99 percent of that is stored as groundwater.

Water shortages are common around the world, including Bhutan, which is quite unfortunate given that we have abundant running rivers and streams around us.  In this context, the temptation and experience of tapping the groundwater for human use is obvious first choice. Groundwater is water under the surface of the ground in the cracks of soil, sand and rocks. Whenever surface water such as lakes and rivers are limited or inaccessible, groundwater is tapped for drinking, irrigation, and industrial use. There is a natural balance in the groundwater balance—water budget, which is recharged by precipitation through infiltration and water is dispensed through outlets out of the subsurface.

With human civilization, ground water has been tapped using borewells, tubewells and infiltration gallery/wells which are connected with pumps. These are done by simply drilling a hole into the ground to access an aquifer with water. The water is then pulled up by the pump using a screen as filter. The well and pump sizes and depths vary according to local conditions.

The availability of abundant water from groundwater extraction for human use is a blessing in many ways as below:

– Groundwater extraction is fairly easy and fast,

– It could help boom agriculture production with abundance of water,

–  It aids in maintenance of sanitation and hygiene of the population with easy availability of water,

– Use of groundwater requires minimum treatment, piping network and maintenance, which is quite convenient and economical for the households and service providers.

– In many places, the availability of fresh groundwater in the beginning is also not difficult or complex at varying depths.

On the other hand, there are certain risks associated with extraction of the groundwater artificially. The USGS compares groundwater source—the aquifer, to a bank account and the ground water in an aquifer similar to the money in the account. In a natural context, there is proper balance of what is coming in and going out. When we keep extracting, there will be a time when the withdrawal is beyond what goes in. The bank balance will run out and the equilibrium will be distorted. There are also other issues such as following:

– Due to pumping, the ground water cycle is modified. Groundwater levels will keep decreasing making it harder to pump every year. The need of more power and technical means to pump would increase every time.

– Similarly, when the groundwater is removed, the surface water flow is altered which would lead to drying of surface water sources, wetlands and loss of riparian vegetation and wildlife habitat. The use of surface water for irrigation and drinking would be extremely challenging, as the water would dry up easily.

– Serious groundwater removal is also analogous to taking away the chair from underneath you. Technically called land subsidence, they occur when subsurface materials move underneath when water is taken out of the soil and the soil collapses compacts and sinks.

– In many areas, there are also risks associated with contamination of groundwater due to the pumping.

Having mentioned both the advantages and disadvantages of groundwater use, it is not easy to draw a conclusion if groundwater use is a blessing or too risky an adventure. Nevertheless, I would recommend and request all agencies concerned, individuals and the public at large on how some of the problems could be avoided or minimised.

Carrying out a thorough and complete investigations to confirm the depth, presence and sustainability of the groundwater is the magical solution. Some of the commons tests to understand the groundwater presence and planning of a well are videographing or camera test, electrical sounding and other geophysical surveys and hydrogeological studies.

The chief reason for conducting the investigation would be to save your neighborhood. The existing farmlands, water sources and irrigation systems are in danger due to your well! The next benefit would also be to prevent you from an unnecessary and extravagant investment to bore a well without knowing the actual groundwater depth and looking at other sustainable and economical options. This holds particularly true for Bhutan’s case as we have many viable and sustainable surface water sources. It is all about coming together and exploring together.

In addition to carrying out technical investigations and study, it would also be necessary to study the resource from a holistic policy perspective. Groundwater is a common pool resource, therefore the rules and regulations on who gets to extract and how, who will monitor and regulate and how are critical questions to be answered. We would also benefit from having a comprehensive study of all ground water resources across the country and coming up with a masterplan on what could be done.

 

Contributed by  Chhimi Dorji 

Consultant on water resources, engineering and environment. www.chhimidconsulting.com

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