In this study, morphometric analysis and prioritization of eight microwatersheds of Valiyathodu subwatershed of Manimala River, Kottayam district, Kerala, India is carried out using GIS. The morphometric parameters are stream length, bifurcation ratio (Rb), (linear parameters), drainage density (Dd) (relief parameters), texture ratio (T), stream frequency (Fs), circulatory Ratio (Rc), constant channel maintenance (Ccm) and length overland flow (Lof) (aerial parameters). The highest bifurcation ratio among all microwatersheds is 3.33 which indicates the strong structural control on the drainage. The maximum value of drainage density is 3.24 for the microwatershed named V8, which has weak or permeable subsurface material.

High value of stream frequency 12.24 indicates the high relief and low infiltration capacity of microwatershed V2. The higher texture ratio value of 3.15 of V2 can be attributed to the high relief and low infiltration capacity of the area. Specific scores and weightage were given to calculated values of morphometric parameters based on the water holding capacity and five classes of prioritized zones were demarcated. Here it has been found that the very high zone (12.6 km²) shows the maximum water holding capacity.