growth ( NCA 1993). Consequent increases in domestic and industrial pollution, combined with strongly reduced flows in the river, will in all probability have a serious adverse effect on the riverine ecosystem and its flora-fauna, including fish. In addition, Wallingford (1993) states that the reduced silt load in the river and consequent increase in photosynthesis, linked to increased pollution concentrations, may result in eutrophication of the estuary.

Another dam-related phenomenon which causes severe damage is a flash flood, unleashed when the dam's flood gates are suddenly opened to save the dam during heavy rains. This happens frequently with Indian dams. The SSP will at best mitigate floods, reducing the volume of floodwater by about 20% ( ORG 1983b). It must be kept in mind that even this is likely to be an overestimate, since it assumes that upstream dams are in place, particularly the NSP with its very large capacity to hold flood waters. As the yearly flooding is reduced, however, the great danger is that people will encroach onto the floodplain, as has happened all over India ( CSE 1991). Wallingford (1993) lists this as a substantial risk, and states that such encroachment would result in the loss of flood control benefits, as has already happened in the Surat area with respect to the Ukai dam.

Apart from the impact on downstream communities who are heavily dependent on fish for their livelihood or as a major source of protein, the inevitable loss of land fertility due to the blockage of silt by the dam could affect agricultural yields, though Wallingford (1993) asserts that this would be offset by the irrigation provided by SSP and the Kadan dam. The reduced availability of drinking water to the human settlements downstream will have serious implications for the health and quality of life of the resident population. Wallingford (1993) concludes that the reliability and quality of river wells and freshwater intakes will deteriorate on full development of irrigation, adversely affecting direct use of river water for drinking, bathing, and other purposes.

Studies on the impact of the dam on downstream riverine ecosystem have yet to be completed. The Wallingford (1993) study is the most comprehensive and authoritative to date, yet they themselves list a substantial number of studies that need to be done for a complete assessment. Incomplete work includes a study "... to assess impacts on downstream aquatic ecosystem (and) to assess impacts on river bank ecology" (NCA 1993). Likewise, a study on "the likely future patterns of discharge from the SSP and the effects this will have on water quality, river and estuary morphology, aquatic biology and, in particular, fish ecology" is to be done.

It must be mentioned that the Rs. 3 crore Wallingford (1993) study is itself based on faulty assumptions about the quantity of flow in the river, which is the primary basis of their conclusions. Wallingford has assumed, or has been told to assume, a much higher natural flow in the river than is now accepted ( CWC 1992): this completely skews their conclusions about the timing and degree of negative impacts. In addition, the phases of project development mentioned in their study are now completely outdated, rendering much of their intermediate-term, predictions useless.