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Kalpasar: The Dam May Be Finished Before the Water Is Ready
A road across the Gulf of Khambhat would shorten a journey. A dependable freshwater reservoir could change lives.
Kalpasar promises both. But building the barrier and delivering usable water are two different engineering tasks.
The distinction matters because a completed dam can still contain salty water. A large reservoir can still receive inadequate inflow during difficult years. And changing the gulf can affect water levels and sediment beyond the project boundary.
Our view is straightforward: Kalpasar’s economic case should be judged from the point at which it can reliably deliver usable water, with the cost of achieving and maintaining that service fully included.
Two research studies explain why.
The salt-removal clock starts after closure
In 2008, Edward McBean and Homayoun Motiee examined salinity management for an older Kalpasar configuration.
Their model assessed how the impounded water could reach a stable salinity below 1,000 milligrams per litre. It reported a 37% probability of reaching that condition within three years, 71% within four years and 83% within five years. One historical inflow sequence required approximately nine years. [1]
These results belong to an older design. They cannot be presented as the commissioning timetable for today’s proposal. The study’s salinity target also does not establish drinking-water safety.
What remains relevant is the finding that the sequence of river inflows can substantially change the time required to achieve usable water conditions.
A favourable sequence of monsoons may help remove salt faster. Poor inflows may delay the process.
That delay has an economic consequence. If the civil works finish before the expected water service becomes available, financial and operating obligations may continue while irrigation benefits are still developing.
The appraisal should account for that period explicitly.
Where will the salt go?
A useful salt balance asks how much salt enters, how much leaves and how much remains.
Freshwater inflow can dilute the reservoir. Discharging mixed water can export salt. Saline seepage and groundwater may add salt. Evaporation removes water while leaving dissolved salt behind.
Consider a simple illustration: if a well-mixed body of water loses 20% of its volume through evaporation alone, without gaining or losing salt, its salt concentration rises by 25%.
That is not a Kalpasar estimate. It explains why water availability and water quality must be calculated together.
The 2008 paper also discussed possible vertical stratification and withdrawal of less-saline water near the surface. [1] This raises an operational question: what happens at the intake when reservoir levels change or water layers mix?
An average salinity figure cannot answer that completely.
For the current design, the important evidence is the predicted water quality at the intended intake locations and depths, through commissioning, seasonal changes and difficult inflow sequences.
The reservoir’s name cannot substitute for that evidence.
The sea outside the dam also needs an answer
René Kersten’s 2018 TU Delft master’s thesis examined an older, approximately 30-kilometre Kalpasar closure.
Its model showed the initial tidal range near the dam increasing from 7.88 metres to 10.25 metres, approximately 30%. It also identified possible changes in sediment behaviour and concerns involving Dahej, Hazira, Surat and Alang. [2]
The limitations are important. This was a master’s thesis examining an older geometry. It stated that its morphological results should be interpreted qualitatively because predictive skill had not yet been established.
These figures are therefore not predictions for the present proposal.
Nevertheless, the study challenges the assumption that a closure affects only the water behind it.
For the current layout, engineers must establish what happens to tides, currents, erosion and deposition on the seaward side. Port approach channels deserve particular attention.
If additional deposition affects a navigation channel, maintaining access could require more dredging. If erosion develops elsewhere, protection works may be needed. These are possible consequences to investigate, not outcomes established here.
Any costs attributable to the project belong in its economic assessment. The accounting boundary should include affected coastal infrastructure.
A bigger reservoir does not create more river water
Storage capacity tells us how much a reservoir can hold. It does not establish how much water it can reliably supply.
A tank capable of holding 1,000 litres may receive only 300 litres during a difficult season. Increasing its capacity does not produce the missing inflow.
Kalpasar’s dependable supply must therefore be assessed after considering competing water demands, flushing requirements, evaporation, operating limits and conveyance.
The appraisal should examine consecutive poor inflow years and explain which users receive priority during shortages.
For a farmer, the relevant quantity is usable water reaching the field during the required season.
Renewable capacity needs an operating calculation
The Ministry of Jal Shakti’s parliamentary reply dated 27 July 2026 described approximately 2,470 MW of proposed hybrid renewable capacity, with pumping among its intended uses. It also reported that the DPR was at an advanced stage of finalisation. [3]
Installed capacity alone does not establish the cost or reliability of water delivery.
An illustrative calculation shows the difference. Lifting one cubic metre of water through a total pumping head of 40 metres, at an overall efficiency of 75%, requires approximately 0.145 kilowatt-hours. At an assumed electricity price of ₹5 per kilowatt-hour, pumping electricity alone would cost approximately ₹0.73 per cubic metre.
Those assumptions are hypothetical. This is not a Kalpasar tariff estimate, and it excludes capital recovery, maintenance, treatment and other costs.
The actual assessment needs the project’s pumping heads, flow schedules, equipment efficiencies and energy arrangements.
The useful result is the lifetime cost of reliably delivered water.
What soil and materials testing must resolve
For a project of this scale, “soil testing required” is too vague.
The investigation should answer specific design questions:
Construction stability: How will foundation strength and pore pressures respond as loading increases?
Settlement: How much movement is expected, particularly where embankments meet gates, culverts or other structures?
Seepage: Could flowing water transport soil particles, and will the proposed filters control that risk?
Materials: Will the selected construction materials meet the required performance?
Monitoring: Which measurements will trigger action, and who will act?
The US Bureau of Reclamation’s embankment-dam standards provide a useful reference framework for these subjects, although they are not the governing specification for Kalpasar. [4]
A test earns its value when it informs a design choice, construction sequence or operating limit.
For a testing laboratory, the contribution is representative, traceable evidence that engineers can use. Laboratory testing alone cannot establish the feasibility of the complete scheme.
The case for Kalpasar must survive difficult conditions
The proposed benefits deserve serious consideration.
The July 2026 parliamentary reply described a potential reduction in the Bhavnagar–Surat travel route from approximately 356 kilometres to 177 kilometres. [3] Dependable additional water supply could also provide substantial value.
The question is whether those benefits remain convincing after allowing for slow salt removal, difficult inflows, pumping costs and attributable coastal consequences.
GTSM Testing Labs LLP’s position is conditional support: continue the investigation and design, but make irreversible closure depend on independently reviewed evidence of reliable service and acceptable lifetime costs.
This article does not establish that the current DPR lacks those assessments. It identifies the evidence that should carry the decision.
If the project remains worthwhile under difficult conditions, the case for proceeding becomes stronger. If it works only under favourable assumptions, the design or economics needs revision.
When summer arrives, the farmer will ask a simpler question:
“What water will actually reach my field?”
Kalpasar’s engineering and economics should be able to answer it.
References
1. McBean, E. A., and Motiee, H. (2008). Modelling of Salinity for Maintaining a Freshwater Reservoir—Gulf of Khambhat in India. International Journal of Ecology & Development. Historical configuration and conditional model results.
2. Kersten, René (2018). Hydraulic and morphological impact of a closure dam in the Gulf of Khambhat. TU Delft master’s thesis. Older layout; model findings must be read with the stated limitations.
3. Ministry of Jal Shakti / Press Information Bureau (27 July 2026). Socio-economic impact and technical progress of the Kalpasar Project. Parliamentary reply, Rajya Sabha USQ 885.
4. US Bureau of Reclamation. Reclamation Design Standards: Embankment Dams. Engineering reference framework.
Research commentary by GTSM Testing Labs LLP. Sources reviewed on 9 October 2026. Historical model results are not forecasts for the current design. This article does not constitute a review or approval of the complete current DPR.
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