CS(AR)-7/96-97 : Hydrological soil classification of Dudhnai Sub-basin : (Assam/Meghalaya PT-II)

Abstract

Hydrologic soil classification at Dudhnai sub-basin for an area of 476 sq km has been made based on the regional information collected from various agencies supplemented by own field & laboratory experiments on the soil samples collected from time to time. In requirement of various soil classification systems, soil properties together with other information have been studied and grouped into different classes as a reference base for future hydrological studies of the basin. Isoresistivity of the basin has been mapped for the available electric sounding data, at a depth of five meter and the results are interpreted for water bearing stratum of shallow sub surface. Soil water retention curves for different soil compositions have been analysed from the results of bar pressure plate and interpreted for the soil water retention characteristics. Statistical methods are applied after selecting three descriptive variables from the soil parameters to study the clusters and their deviation.

Soils are generally heterogeneous and anisotropic i.e. having unequal physical properties along different axes. This results nonuniform field conditions. Then the soil properties at places undergo considerable changes with time. This calls for systematic monitoring of soil parameters for its effective management. The present work has also the scope for further improvement by incorporating more and more future investigations in the basin which has been selected for long term representative basin studies.