Flood Hydrograph Estimation Using Watershed Bounded Network Model

Storage routing models are becoming more widely accepted for flood hydrograph synthesis. The network models represent a considerable advance in this direction even though these models are based on many assumptions and empirical relationships. Watershed Bounded Network Model (WBNM) is one such model. This model maintains a good relationship between the hydrological and geomorphological properties of a watershed and is capable of accurate flood hydrograph synthesis. The model can account for the non-uniform distribution of rainfall over the watershed. Lag is a dominant factor to be known for the successful application of WBNM. In this paper the theoretical basis of WBNM and its application to Pageru watershed in southern India is presented. The watershed contains three well spread rain gauges. Isolated flood events from a four years record were considered for the calibration of the model. Validation of the model revealed that the predicted hydrographs are compared well with observed hydrographs for the given rainfall excess hyetographs. Therefore, with its sound geomorphological basis, Watershed Bounded Network Model has a valid and versatile application over a wide range of conditions. _______________________________________________________________________