The water crisis scenario in Guwahati has been gradually escalating, and the root cause of this situation tends to be the lack of awareness among citizens. Apart from sourcing surface-level water through various projects, one vital source is groundwater. At present, the groundwater level in Guwahati is in a 'semi-critical' condition. This will further have a detrimental effect in the future if immediate measures are not administered.
The Central Ground Water Board (CGWB) is the apex organisation responsible for carrying out scientific surveys, exploration, monitoring, management, and regulation of groundwater resources for irrigation, drinking, domestic, and industrial needs.
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While speaking to GPlus, a senior official from CGWB, Guwahati, said, "The dynamic resource (water level) of Guwahati is used up more than 70 percent, which sums up that the city is in a semi-critical condition. Although these resources replenish over time, that requires a significant amount of time based on various aspects such as infiltration and water retaining capacity."
"As the city is gradually turning into a concrete jungle, the natural process of water infiltration and replenishment is being affected. With the present condition, it is high time for the public to be concerned and use the resources judiciously. We are doing our part in raising awareness, but society should implement the same," the official said.
It is also to be noted that the extraction of water back in 2019 was approximately 40 percent, which has drastically increased in the current situation. Over-pumping leads to the depletion of aquifers. This further sabotages the natural process of restoration, posing a threat to the future. Once it reaches 90 percent, there will be a major scarcity, and the residents will have to depend solely on surface water resources. As water levels significantly recede during winters (lean period), the availability of water consequently decreases too.
However, unlike the condition of aquifers within the city, the resources near the Brahmaputra bank are comparatively better due to the physical characteristics of the ground.
The exploration of groundwater is based on drilling different rigs in search of aquifers. This process requires an expert's research to pass through the three geological forms: consolidated, semi-consolidated, and unconsolidated formations.
Background on Geological Forms:
1. Consolidated Formations: These are solid and dense rock formations where groundwater is typically stored in fractures and joints.
2. Semi-Consolidated Formations: These are partially solidified rock formations with both porous and fractured zones, allowing some water storage.
3. Unconsolidated Formations: These are loose materials like sand, gravel, and clay, which have high porosity and permeability, making them excellent for storing groundwater.
Groundwater exploration is one of the core activities of CGWB. Drilling-aided groundwater exploration provides direct information about the disposition and characteristics of the aquifers. Every year, around 650 wells are drilled by CGWB for groundwater exploration through in-house resources. CGWB has a fleet of 78 operational drilling rigs and has the capability to construct wells in various types of terrain in the country. In view of the enhanced requirements of groundwater exploration under the NAQUIM programme, CGWB has also taken up exploratory drilling through outsourcing. After conducting necessary tests and chemical quality assessments, successful wells are handed over to the state user agencies.
Groundwater level monitoring is one of the key activities of the Central Ground Water Board. The primary objective of groundwater monitoring is to record the response of various natural and anthropogenic stresses on the groundwater regime, which impacts the recharge and discharge parameters. At present, CGWB has a network of nearly 23,000 groundwater observation wells throughout the country. Groundwater levels are measured four times a year during the months of January, March/April/May, August, and November.
CGWB has 16 Regional Chemical Laboratories to carry out chemical analysis of water samples. The chemical laboratories are well equipped with sophisticated instruments like ICP-MS and Atomic Absorption Spectrophotometer (AAS). Groundwater sampling for quality monitoring is done once a year during the pre-monsoon period. In addition, groundwater samples are also collected and analyzed as part of other scientific studies. CGWB has also taken up sampling and analysis of groundwater samples for uranium content across the country. So far, nearly 20,000 groundwater samples have been collected and analyzed by CGWB. As part of the National Aquifer Mapping and Management Program (NAQUIM) studies, CGWB has constructed more than 500 wells in arsenic-affected areas with innovative designs to tap deeper arsenic-safe aquifers, avoiding contamination from shallow aquifers. The technique has been replicated by the states, and nearly 1,500 such wells have been constructed by the state governments of Uttar Pradesh and West Bengal, catering to the safe drinking water requirements of nearly 70 lakh persons.
The CGWB in Guwahati is the headquarters for the Northeast region, and similar sustainable developmental projects have been executed for the region.
Periodic assessment of dynamic groundwater resources is done jointly by CGWB and the respective state governments. The latest assessment for the year 2020 was carried out jointly by the Central Ground Water Board and State/UT Nodal/Ground Water Departments based on the methodology recommended by the Ground Water Estimation Committee -2015 (GEC-2015). For the first time, the entire assessment was done using the GIS-based web portal 'India- Groundwater Resource Estimation System (IN-GRES) that has been developed by CGWB in association with IIT-Hyderabad. IN-GRES provides a common and standardized platform for GW Resource Assessment for the entire country (Central and State Governments).
Depending on research, information is extracted for the overall utilisation of water for Guwahati. This data is collected from various schemes or depending on the population. Although it is a matter of the State to compile the information, the CGWB takes responsibility as they have expertise in that sector. Moreover, accountability is maintained with precise information.
While speaking to GPlus, a source from CGWB said, "Usually the state should look after these surveys, but they are still in a learning process. Therefore, we step in to help them out and compile the information about the litho log. However, the situation turns out to be hectic at times as we are accountable for all the NE states."
With the present 'semi-critical' condition of the water level in Guwahati, it is about time for both the residents and the authority to take measures to tackle the potential threat of scarcity. Only time will reveal whether the public buckles up.