Assessment of Channel Flow Depth in a Data-Scarce Urban Catchment of
Eastern India
Abstract
Nowadays, many of the world cities and its peripheral areas are under
constant threat of flooding due to high rainfall events. Increased rate
of severe flood hazards world-wide have created a demand for
understanding the flooding behaviour across various urban and peri-urban
catchments. However, simulating the flooding scenarios under limited
hydrological data condition is a great challenge for the urban water
planners and managers, especially in developing countries. To this, in
this study, a combined modelling approach is proposed with the
physically based Variable Parameter Muskingum Stage (VPMS) routing model
to develop a local rating curve for generating the discharge data from
the available stream stage data, which was subsequently used as an input
to the Storm Water Management Model (SWMM). The coupled methodology is
applied in a typical ungauged urban and peri-urban catchment of eastern
India. The proposed SWMM-VPMS model is calibrated for the monsoon
(rainy) season of the year 2009, and validated for the monsoon seasons
of 2011 and 2014. The performance of the model is satisfactory with the
Nash-Sutcliffe efficiency (NSE) estimates of 0.82, 0.89, and 0.89 for
the years 2009, 2011, and 2014, respectively. The proposed SWMM-VPMS
model can be used for a catchment where the tributary is ungauged while
the main river is gauged at a downstream location of the confluence
point. This methodology can also be adopted in catchments with missing
rating curves. Additionally, the information regarding spatial
distribution of channel flow depth at different time can be utilised to
have an initial assessment of the flood-vulnerable areas. Keywords:
VPMS; SWMM; Urban and peri-urban catchment; Ungauged catchment