Determination of hydrological parameters using active tracers at radioactive waste burial site - Tarapur

Amongst various geohydrological parameters like surface and sub-surface geological conditions, sub-surface drainage, rainfall recharge and water table fluctuations, the rainfall recharge measurement and ground water movement studies are of prime importance from the radioactive waste management point of view. For augmenting the information, required to evaluate these factors in an aquifer, field investigations were carried out. These included detailed surface and sub-surface surveys, by collecting soil and rock samples, using hand augers, from trial pits and bore hole core samples. Survey of sub-surface drainage, water table fluctuations and rainfall records were made and relevant contours plotted. The rainfall recharge studies were carried out over an area of 40 hectars including the waste burial site of 10 hectars by injecting tritium into the ground during the pre-monsoon period of 1978 and monitoring of the same was done during the post-monsoon period to determine the downward movement of rain water i.e. recharge. The ground water movement studies were carried out by multiwell technique, by injecting a tracer in the central well surrounded by six monitoring wells located in a circular pattern at uniform distance. The behaviour and choice of various tracers used such a rhodamine B, tritium etc. has been dealt. The various field techniques adopted for the experiment, the results and conclusion drawn are also dealt. (author)