Guidelines for river valley projects

The ecological considerations finds a central place in the environmental guidelines for river valley projects. The objective of the guideline is to detail out the concerns that require incorporation both at the planning and at the implementation stages for the economic and ecological viability of the project. The following are some of the specific aspects that require considerations in the planning of river valley projects.

The site selection for river valley project should consider the following impacts:

• Short and long-term impact on human settlements.

• Impacts on flora and fauna and their habitat both within and outside PAs.

• Impacts on site and monuments of historical, cultural and religious significance.

• Impacts on different land uses.

The following aspects of impoundment that would be created under the river valley projects also need to be considered:

• Landslides on the periphery of the reservoir.

• Siltation or sedimentation expected in the reservoir - identification of critical areas susceptible to erosion and methods of possible treatment.

• Groundwater recharge or other ground water charges.

• Expected water quality (salinity) changes over time and their effect on riverine eco-system, both in impoundment & downstream.

• Potential seismic impact of reservoir loading.

Careful evaluation of the impact should be undertaken of resource trade-off such as, loss of optional land uses due to impoundment - mineral deposit loss, forest reserve diminution, monuments inundated, recreational facilities lost, dislocation of existing settlements etc. and compatibility of dam’s creation and operation with present or planned development of the region.

Consideration also needs to be given to new health problems or vector patterns that may arise due to changes in water velocities, temperature, quality or other physical change factors caused by water impoundment and adequate public health planning to create facilities for migrant construction workers and immigrant influx. Possibility of disease aggravation or new public health problems introduced due to changes in population density and distribution also need to be looked into. Measures to control contamination of surface and ground water due to pesticides and fertilizers need also to be drawn up in advance.

During the construction phase, the following factors need to be also considered:

• All road construction and blasting operations, specially upstream of the reservoir should be completed before reservoir filling is commenced so as to reduce excessive sedimentation load.

• Excessive blasting should be controlled, specially in hilly terrain, so as to check the incidence of land slides in the area.

• Temporary labour camps must be located, to the extent possible in areas which will later be submerged so as to reduce the loss of forest cover.

• Vegetation on island formations in the reservoir above FRL should not be removed so that they may be developed as bird sanctuaries at a later stage.