Vertical Electrical Sounding (VES) test aids Kamapalli residents identify a good source for drinking waterStory
By Benstin Jenith, Chandrika Patnaik
7 August 2023
Geophysical survey uses electrical resistivity to identify suitable groundwater sources for drinking and domestic use
The WRTG team using the Vertical Electrical Sounding (VES) device to identify suitable groundwater sources for drinking and domestic use.
Photograph shared by Anas K.P
Groundwater is one of the most significant natural resources for rural communities. It serves as a critical drinking water source, supports farming irrigation, recharges surface water bodies, provides water for livestock and animal husbandry, facilitates community development and acts as a buffer during drought or seasonal water scarcity.
In 2012, long queues around the tube wells forced residents of the Kamapalli village to walk half a kilometre towards the outskirts of the village area to bathe in a pond and defecate in the fields and forests surrounding the pond.
Kamapalli has 103 households and is in the Chhatrapur block of the Ganjam district.
The residents of Kamapalli village always wished to have a similar water and sanitation system like that in their neighbouring village of Samiapalli. However, Sukuru Pradhan, 43, a farmer and village leader from Kamapalli, and a few other residents felt the cost of constructing the sanitation and water infrastructure was beyond their means. He discouraged the residents in his village by saying they could not afford such high costs.
Not one to be disheartened, Bhagirathi Pradhan, 44, a farmer and PRI member from the village, approached the staff of Gram Vikas to understand the water and sanitation process in depth.
Bhagirathi wanted the residents of his village to also benefit from water and sanitation facilities and lead a dignified life. He proposed approaching Gram Vikas after discussing it with all the residents. During this meeting in 2016, Sukura Pradhan and a few others again opposed the idea and tried to influence the households.
Community Takes Up Responsibility
Bhagirathi Pradhan remembers the intensive mobilisation he had to undertake to bring all 103 families together to a common consensus. “I had to pursue the residents for two years. After numerous meetings and discussions the households in the village agreed to the water and sanitation system. Gram Vikas supported the community in implementing the water and sanitation project in Kamapalli.”
In 2018, within eight months, all households in the village had toilets and bathrooms. The village received piped water through a borewell. Piped water supply to households began in June 2021.
Residents’ joy was short-lived upon discovering that the electricity bill was excessively high. Furthermore, some households experienced water shortages. This situation led to quarrels among the residents, with each blaming the other for excessive usage of water.
Budhia Pradhan, a 65-year-old retired army serviceman, farmer, and President of the Kamapalli Village Development Committee (VDC), says: “The water scarcity situation led to a lot of animosity among the residents. People wanted to know why they were facing shortage of water when the village spent so much on setting up the infrastructure.” The committee and the village residents then decided to have water supplied to homes only twice a day for an hour each.
The residents felt that the existing borewell did not have enough water, which caused the overhead water tank to take over twelve hours to fill and that too only half the tank.
They approached Gram Vikas to examine the reason behind water shortage and how they could avoid high electricity bills. During a meeting in August 2021, the village committee members and residents requested Gram Vikas for a new water source to end their water shortage issues.
In September 2021, the Water Resource Technology Group (WRTG) team, a technical team in Gram Vikas which deals with water-related technological interventions, conducted a baseline survey of water sources in the village. The purpose was to get an idea about the depth of groundwater level in the village, quality of groundwater and to understand the change in groundwater level and quality over time.
With the help of the community all the water sources including dugwells, tubewell, borewells and ponds, were surveyed. The team found that the yield from the existing borewell was good when the motor was switched on only once in the morning after allowing the borewell to recharge for an entire night. But after one hour of running, the water yield was reduced.
Water demand in the village increased over the years with most of the water demands in the past were met by dug wells and borewells.
But now, due to high groundwater extraction, the groundwater level in the aquifers declined. To help choose the best location for water—with sufficient yield for the entire village, the WRTG team decided to conduct a hydrogeologic study of the area to identify potential water-bearing aquifers.
Exploring Groundwater through the VES Test
Hydrogeological Study is usually conducted through a scientific test called Vertical Electrical Sounding (VES) Test. The test is commonly employed to identify water-bearing sub-surface layers at a given point on the ground.
In this test, the VES instrument sends current signals into the ground and measures the resistivity of the sub-surface layers it passes through. Based on the type of sub-surface layer, the resistivity to the current signal changes.
This phenomenon helps in identifying the sub-surface layers the current signal passes through and also identifies water-bearing layers, if there are any. For instance, if the current signal passes through a dry hard rock layer the VES instrument records a very high resistivity value, whereas if the current passes through a weathered rock layer saturated with water, it records comparatively lesser resistivity value.
How Does It Work?
The resistivity values are then plotted on the resistivity-depth graph, which is then used to identify the depth of water-saturated zones, such as fractures or aquifer, from the ground level. Based on the results, WRTG team gives recommendations if borewell digging can be done at the given point.
Ensuring Equity and Resilience for the long term
To build a more sustainable, dignified, and equitable quality of life for the community living in Kamapalli, Gram Vikas provided solar panels and a water metre for each household in March 2022 for an uninterrupted water supply.
The water metre has proven to be a success for the villagers as it measures the quantity of water each family uses, provides information on how much water a household uses in a month, and is billed according to usage.
The village committee has further devised methods for raising the maintenance fund by making each family pay a monthly fee fixed by the village committee. Each household in Kamapalli pays the operations and maintenance costs for the solar panels and the water supply system, the monthly water bill generated by the pump operator, the pump driver’s salary, and the electricity bill of the first borewell (sparingly used) as monthly cost per household for having three functional taps at home.
Residents like Bhagirathi Pradhan, a PRI member who first approached Gram Vikas for a water and sanitation system for his village, says that the effort Gram Vikas put in to ensure water for his community has paid off. It has completely ended their water scarcity issues.
Moreover, thanks to the newly installed water metres it has promoted more efficient and productive water usage and equitable distribution among residents. The women, too, contribute to their family’s income as they can finish household chores early—courtesy of a stable water supply, and travel to nearby villages to work at construction sites.
The overhead water tank of Kamapalli village in Ganjam district.
Photograph by Bibekananda Pradhan
Anas K.P, Team Lead, Water Resource Technology Group (WRTG) and Manikamala Swain, Thematic Coordinator, Planning Monitoring, Documentation and Communication and Bibekananda Pradhan, Thematic Coordinator, Water and Sanitation helped collect data for the story.
ABOUT THE AUTHOR
Benstin Jenith, Project Manager, Water Resource Technology Group (WRTG). Chandrika Patnaik leads content production within the Communications team in Gram Vikas.
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