the command area has,groundwater that is completely unfit for irrigation, while an additional 25% of the command area only has very deep aquifers (> 100-150 m depth), from which would be very cosdy to pump water.
An additional factor is that the main soils in Z 7-9, are medium deep black soils, while Z2-4, have substantial areas of black soils (ORG 1982:15). Black soils are known to be unsuitable for canal irrigation in a sustained fashion due to their propensity to get waterlogged. The experience with the Ukai dam, just south of the proposed SSP system, is illustrative : The Ukai command had substantial areas of black cotton soils. Before canal irrigation, less than 0.5% of the command reported waterlogging, but after 15 years, 17-35% of the command area reports waterlogging (Mukhopadhyay and D'Souza 1992). Similarly, Tawa Dam in a similar soil zone in Madhya Pradesh has had 20% of the command area taken out of production partially or completely due to waterlogging, just 10 years after irrigation was started.
Taking irrigability classifications and areas of black soils and saline aquifers into account, about 55% of the command area appears to be in danger of waterlogging and salinisation, an environmental disaster of epic proportions in the making.
Detailed studies appear to indicate that the actual potential for waterlogging and salinisdtion is even worse than what was indicated by the preliminary study. A study of Zones 1-4 of the SSP command (Table 9) conducted by Core Consultants (1982) concluded that 54% of Z2, 64% of Z3 and 100% of Z4 is liable to be affected by waterlogging and salinity. The report said "...increased recharge will cause water tables to rise by 1-2 m/year. Over much of the study area the water table will rise and within a few years encroach on the crop root zone causing waterlogging and salinisation, resulting in the decrease or complete loss of soil production". Comparison of Tables 9 and 10 shows that while the preliminary study indicates 20.9% of Zones 1-4 as prone to waterlogging and salinisation, the detailed report puts that figure at 45.5%, almost double the original. Even if we exclude the problematic Zone 4, the relative area prone to waterlogging and salinisation increases from 8% to 36.5%!