However, the Wallingford study has confidently asserted that "... there are no downstream impacts whose magnitude and impacts are such as to cause doubts over the wisdom of proceeding with the Sardar Sarovar Projects provided that appropriate monitoring and mitigation measures are applied." ( Wallingford 1993) (Note the inevitable escape clause!). The NCA, with even less accountability at stake, has chosen to do away with even the escape clause, asserting that "there would be no downstream impacts whose magnitude and effect would be sufficient to threaten the viability of the project." ( NCA 1993). We are at a loss to understand how such a definitive conclusion has been reached when studies are as yet incomplete.

Estuary

Summary: For the same reasons as given above (water and silt flow reduction, pollution, flash floods), the Narmada estuary is likely to be adversely affected by the SSP. Saltwater ingress at the mouth of the river could be the most serious impact, with consequent declines in fisheries. Salinisation and increased pollution of underground water used for drinking and irrigation could take place around the estuary. Coastal geomorphology is likely to change, and bank erosion could occur.

River estuaries are complex, dynamic ecosystems, created over millenia by the interplay between seasonally fluctuating freshwater flows, sea tides, silt deposition, mangrove and other vegetative growth, and other factors. A major change in any one of these `ingredients' can affect the entire ecosystem, and in turn the other components of the ecosystem. Such changes can be caused by a dam, for the same reasons stated above (changes in water flow and silt deposition, increase in pollution concentration, and flash floods). The Narmada estuarine area is an important site for fisheries, and is also the location of the one of India's oldest ports, Bharuch.

Saline ingress affects the river till about 72 km upstream from the river mouth at present, while tidal effects are felt as far up as 100 km upstream ( Wallingford 1993). Reduced flow in the Narmada due to the SSP would cause salinity to increase in large parts of the river. The river would literally flow backwards during the tides in the dry season, transferring salt and pollution from Bharuch upstream. Estuarine species are finely attuned to the daily and monthly variations in salt content of the water. Changes in the salt regime can affect the entire ecosystem, disrupting breeding and physiological functioning. In addition to low water flow affecting hilsa and the freshwater shrimp discussed above, the negative effect of salt ingress is likely to have a serious impact on other fauna and flora, but "little information is available on the marine ecology at the mouth of the estuary" ( Wallingford 1993). However, the livelihood of the fisherfolk downstream of the dam is likely to be lost, and indeed both the Wallingford (1993) report and an earlier NCA (1992) document talk of "rehabilitating" the 4700-plus fisherfolk families.