Abstract:
A hydrological model is a commonly used tool to estimate the hydrological
response of a watershed to precipitation. Hydrologic Modeling System (HEC-HMS)
is a physically based semi-distributed hydrologic modelling software developed by
the Hydrologic Engineering Center (HEC) of the U.S. Army Corps of Engineers. It is
designed to simulate the complete hydrologic processes of dendritic watershed
systems under various widely varying geographic conditions. HEC-HMS is widely
used and includes both traditional hydrologic analysis procedures such as event
infiltration, unit hydrographs, and hydrologic routing as well as continuous
simulation procedures including evapotranspiration, snowmelt, and soil moisture
accounting. It can be used in conjunction with other software for studies of water
availability, urban drainage, flow forecasting, future urbanization impact, reservoir
spillway design, flood damage reduction, floodplain regulation, and systems
operation.
In the present study Hydrologic Modeling System (HEC-HMS) is calibrated
and validated for Thuthapuzha sub basin of Bharathapuzha river basin in Kerala. The
input data required for the model like precipitation, meteorological parameters, river
discharge,
soil
characteristics,
land
use
characteristics
and
topographical
characteristics of the study area were collected from various agencies like Central
Water Commission (CWC), Kerala State Land Use Board (KSLUB), RARS Pattambi
and the Bhuvan geo-data portal of National Remote Sensing Centre (NRSC). The
model performance of the calibrated HEC-HMS model for Thuthapuzha watershed
was evaluated using the statistics -Nash Sutcliffe- model efficiency criterion,
coefficient of determination and simulated time to peak. The analysis showed that
CN, and lag time are the most sensitive parameters for the simulation of stream flow.
The Nash-Sutcliffe model efficiency (E) was (0.77-0.8) and (0.86-0.88) and the
coefficient of determination was (0.82-0.91) and (0.91-0.93) before and after the
calibration respectively, indicating the good performance of the model.
