GROUND WATER EXPLORATION
Disposition of Aquifer System
Field Study under NAQUIM
Evaluation of NAQUIM Through Expert Committee
GROUND WATER EXPLORATION
Disposition of Aquifer System
Field Study under NAQUIM
Evaluation of NAQUIM Through Expert Committee
Gujarat stretches along more than 1,600 kilometres of Arabian Sea shoreline, and along that sweep millions of people depend on groundwater that has slowly turned salty. Years of over-extraction, sea-level rise and seawater intrusion have pushed total dissolved solids in many coastal aquifers well beyond the 1,000 milligrams per litre threshold that marks the line between fresh and brackish water. In districts such as Kutch, Jamnagar, Porbandar, Junagadh, Bhavnagar and parts of Surat, hand pumps and tubewells increasingly yield water that tastes bitter, corrodes pipes and damages crops. For families living in villages such as Madhavpur, Abdasa or Olpad, the search for a reliable drinking-water source has become a daily negotiation with salinity.
Conventional answers such as tanker supply or large piped schemes from distant reservoirs are costly and carbon-intensive. Desalination, long associated with seawater plants in arid regions, is being reconsidered as a practical tool for the brackish water that sits beneath the feet of Gujarat's coastal communities. Brackish groundwater typically requires far less energy to treat than seawater because its salinity is lower, opening the door to smaller, modular units that can be sited close to demand. The technology is no longer experimental; what is being weighed now is feasibility at village scale.
Australia offers a useful mirror. Perth opened the Southern Seawater Desalination Plant in 2011 after the Millennium Drought drained surface dams, and today roughly half of the city's drinking water is produced from desalinated sources. Households in Sydney, Adelaide and Melbourne have lived with similar plants in their suburbs, paying tariffs that bundle the cost of energy, infrastructure and environmental offsets. Australian engineers, regulators and water utilities have spent two decades refining brackish-water reverse osmosis, brine handling and community engagement, producing a body of know-how that Gujarat's planners can study rather than reinvent.
Hydrogeological surveys carried out under the National Project on Aquifer Management describe a gradual thinning of the freshwater lens that once floated on top of denser saline water in Gujarat's coastal belt. Pumping beyond recharge has dragged the interface upward, and cyclone-driven surges have occasionally pushed salt further inland. In many blocks, the shallow aquifer that village drinking-water schemes rely on now records salinity between 1,500 and 4,000 milligrams per litre, with seasonal spikes during the summer months when irrigation demand peaks and recharge drops.
The implications go beyond thirst. Saline water stunts the growth of cotton, groundnut and cumin, the crops that anchor rural incomes in Saurashtra. Livestock that drink brackish water produce less milk, and the salt residue clogs the emitters of drip-irrigation systems that farmers have invested in heavily over the last two decades. Women, who in many parts of coastal Gujarat are responsible for fetching water, often walk further or pay informal vendors for a slightly less saline alternative, draining both time and household budgets.
Understanding the precise location and depth of these saline pockets has become easier with digital aquifer atlases. Officers and researchers looking to plan village-level water schemes can find aquifer data for their block through the portal's state and district filters, which display aquifer maps, water-quality parameters and seasonal trends side by side.
Reverse osmosis remains the workhorse of brackish-water treatment, forcing saline feed through a semi-permeable membrane that holds back dissolved salts. The pressure required scales with salinity, so a well drawing water at 3,000 milligrams per litre consumes substantially less electricity than a seawater plant operating at 35,000 milligrams per litre. For a village cluster of 200 to 500 households, a containerised brackish-water reverse osmosis unit of 50 to 200 cubic metres per day capacity can meet domestic needs while leaving a footprint small enough to fit on a patch of unused panchayat land.
Electrodialysis and capacitive deionisation are emerging alternatives that work well at moderate salinities and offer partial-recovery options that reduce brine volume. Forward osmosis, still largely in pilot phase, uses a draw solution to pull water through a membrane and may suit remote sites with intermittent power. In practice, Gujarat's coastal conditions favour hybrid systems: a low-pressure reverse osmosis stage followed by a remineralisation pass that adds calcium and magnesium back into the treated water so it is palatable and less corrosive to household plumbing.
Australian designers have standardised several of these configurations. Plants serving remote Aboriginal communities in Western Australia's Pilbara and South Australia's APY Lands have used modular brackish units for years, with telemetry that lets a technician in Perth or Adelaide troubleshoot a plant in a desert settlement from a laptop. That same remote-monitoring logic could apply to a treatment skid serving a cluster of villages in Kutch or the southern coast, where maintenance skills are thin on the ground.
Energy typically accounts for between a third and half of the lifecycle cost of a small desalination plant, so the tariff a household pays depends heavily on how the unit is powered. Gujarat has invested heavily in utility-scale solar parks, and many coastal talukas enjoy more than 300 sunny days a year. Pairing a 100-kilowatt solar array with a battery bank sized to cover the membrane pump's duty cycle can bring the levelised cost of treated water into a range that is competitive with tanker supply once social costs are included.
Hybrid configurations are often the most realistic answer. A diesel generator remains useful during the monsoon when cloud cover is persistent and demand is lower, while a small wind component can take advantage of the afternoon sea breeze that rolls across the Saurashtra plain. Where the local distribution company supports net metering, surplus midday generation can be exported to the grid and drawn back at night, smoothing cash flow for the operator. The Gujarat Energy Development Agency has experience with similar models for cold storage and rural water pumping, and that institutional familiarity lowers the perceived risk of coupling solar with a desalination unit.
Energy planning also dictates siting. A plant placed next to a 66/11 kilovolt substation avoids the cost of long low-tension lines, while a location close to a village road eases the delivery of membranes, chemicals and spare parts. These unglamorous logistics often decide whether a desalination scheme runs for twenty years or fails in twenty months.
Affordability shapes acceptance. In Australia, the typical household desalination tariff in cities such as Adelaide or the Gold Coast is bundled into a general water bill that also pays for sewers and stormwater, smoothing the shock of a major capital investment. India does not yet have an identical utility framework in rural areas, so Gujarat's pilot projects have tested several alternatives: a panchayat-owned plant that charges a metered tariff, a public-private partnership where a private operator runs the skid for ten years before handover, and a cooperative model funded through a micro-hydration charge added to local dairy collection.
Recovery ratios of around 70 to 80 percent of operational costs are achievable when a plant serves at least 150 households and operates close to its design capacity. The remaining gap is usually covered by a state grant under schemes such as the Jal Jeevan Mission, which already funds last-mile connectivity to rural taps. Including a small desalination contingency in the village action plan keeps the conversation about cost transparent and avoids the kind of billing disputes that have undermined earlier piped-water schemes in coastal districts.
Tariff design matters as much as tariff level. A flat monthly fee discourages conservation, while a purely volumetric charge can push poor households back to unsafe sources. The Australian practice of a two-part tariff, with a small fixed access charge and a rising-block volumetric component, has been adapted in some pilot Indian utilities and may offer a workable middle ground for Gujarat's coastal panchayats as well.
Brine disposal is the question that follows every desalination proposal. For a 100 cubic-metre-per-day brackish plant operating at 75 percent recovery, the daily brine stream is around 25 cubic metres, concentrated but not at the density that marine outfalls must handle. Direct discharge into a tidal creek can raise salinity beyond the tolerance of mangroves and seagrass beds, which are already under pressure from coastal development. Land-based evaporation ponds work in dry climates but require careful lining to protect groundwater.
The most promising route in Gujarat is co-management with the salt-making industry that already operates along the Rann and the Little Rann of Kutch. Salt pan operators are accustomed to handling concentrated brines and can blend desalination concentrate with their own brines to produce industrial-grade salt, turning a waste stream into a feedstock. Trials in Tunisia and the Persian Gulf suggest that a brine-to-salt pathway can recover a meaningful share of disposal costs when a plant sits within reasonable trucking distance of an existing salt works.
Monitoring is essential. Continuous conductivity probes on the discharge line, combined with quarterly sampling of nearby wells, give regulators the data they need to adjust brine routing. The country's Bureau of Indian Standards already specifies TDS limits for irrigation reuse, and adherence to those limits should be a condition of every consent issued for a new coastal desalination unit.
Australia's coastal cities were not built around desalination; most grew comfortable with river and reservoir systems that climate change and population growth have steadily eroded. The decision in Perth to build the Southern Seawater plant, and the parallel choices in Sydney, Adelaide and on the Gold Coast, came after prolonged public debate about cost, energy and marine impacts. Each city settled on a different mix of tariff structure, plant ownership and environmental offset, and that diversity offers Gujarat's planners a menu rather than a single blueprint.
Several specific lessons stand out. Public communication campaigns in Perth explained why water bills would rise, framed conservation as a civic duty and avoided blaming any single household sector. Independent technical audits of operating plants have kept performance transparent and forced operators to meet efficiency benchmarks. And state-level water reform, including the National Water Initiative, has created a regulatory environment where desalination can be deployed without becoming a fiscal surprise.
Gujarat's coastal districts face a similar turning point, but on a smaller and more dispersed scale. A network of village-sized brackish desalination units, planned against the aquifer maps that NAQUIM has produced and supported by the institutional infrastructure already in place for rural drinking water, could convert a saline liability into a resilient asset. Engineers, hydrogeologists and panchayat leaders who want to explore the underlying data can begin with the official NAQUIM platform, which puts state, district and block-level information within reach of anyone designing the next coastal water scheme. The technology is ready, the maps are drawn and the demand is urgent; what remains is the coordination to match a skid of membranes to a village that has waited too long for a glass of clean water.
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