Multi-spatial scale hybrid rainfall-runoff modelling - A case study of
Godavari river basin
Abstract
Transformation of rainfall to runoff is a complex hydrological
phenomenon involving various interconnected processes. Besides, the
distribution of rainfall and basin characteristics are not uniform
across time and space leading to a poor understanding of the process.
Hydrologists have been using various hydrological models to understand
transformation of rainfall into runoff. Conceptual models developed in
the 1960s represent various individual components of hydrological cycle
via interconnected conceptual elements, thus model various aspects of
the hydrological cycle. On the other hand, data-driven models such as
Artificial Neural Networks (ANNs) are widely regarded as universal
approximators due to their ability to model many complex problems. Very
few studies reported the application of a widely used conceptual model,
Sacramento Soil Moisture Accounting model (SAC-SMA), in the Indian river
basins context. Considering that the hydrological cycle is very complex
and may never be fully understood in detail, conceptual models like
Sacramento Soil Moisture Accounting model (SAC-SMA) can be integrated
with data-driven models which can take care of poorly described and
understood aspects of hydrological modelling. In this study, a hybrid
rainfall-runoff model was developed and applied over the Godavari river
basin in India at multiple spatial scales for capturing the spatial
variations in model inputs and catchment charateristics.The hybrid model
by virtue of the semi-distributed configuaration and addition of ANN
component led to improved simulations of streamflow in comparison to the
standalone SAC-SMA model.