Morphometric analysis of the Catchments of Himayatsagar and Osmansagar Reservoirs - Hyderabad

The linking of the geomorphological parameters with the hydrological characteristics of the basin provides a simple way to understand the hydrologic behaviour of the different basins particularly of the ungauged basins because the hydrologic and geomorphic effects of natural and human process with in a catchment are focused at its outlet. The development of morphometric techniques was a major advance in the quantitative description of the geometry of the drainage basins and its network which helps in characterizing the drainage network. The geomorphological properties which are important from the hydrological studies point of view include the linear, aerial and relief aspect of the watersheds. In the present study morphological study has been carried in the catchments of Himayatsagar and Osmansagar reservoirs. The catchments of Himayatsagar and osmansagar reservoirs cover the area of 1315.14 and 748 km within the elevation rang of 575 to 715 and 585 to 705 m resepectively.the drainage pateern varies from dentric to subdentric. They are 5th and 4th order drainage basins respectively. The stream length and stream areas to stream number relation follows the Hortons laws. Stream density shows low value for all stream orders. The bifurcation ratio is high for Osmansagar reservoir catchment. This is due to the variation in stream frequencies in successive orders. Lower value of drainage density and stream frequency indicates the region of highly permeable subsoil strata and the catchment will not generate runoff soon. The length of overland flow and time of concentration for the catchments of Himaytsagar and osmansagar is estimated to be .68, .70 and 16.74, 15.81hours resepectively. From the values of Circularity ratio, elongation ratio, form factor, and compactness coefficient of the catchments of Himayatsagar and Osmansagar reservoirs it is expected that the catchment is highly irregular, strong relief, steep ground slope and elongated hydrograph. The high ruggedness number of the catchment of Himayatsagar and Osmansagar reservoir shows the high roughness or unevenness.