The developed maps are used as a tool for effective flood forecasting and warning of
flood hazards in the basin.
Keywords Land use/land cover · HEC-HMS · RAS · NSE · Flood risk map
Introduction
The migration of people from rural to urban areas causes changes in land use and
land cover (LULC) in the urban region (Dewan and Yamaguchi 2009). The changes
in LULC in the urban region impact surface runoff, which may reduce the travel time
of peak flow of the urban region so that flood frequency is increased. For flood risk
assessment, it is necessary to understand the dynamics of LULC change and its
influence on the urban hydrologic cycle for predicting the floodplain and hazard
maps (Suriya and Mudgal 2012). The LULC change and its implications for the
urban flooding is one of the upcoming research topics in the field of urban hydrology
(Fox et al. 2012).
For efficient flood risk assessment in the urban area, the floodplain delineation
should be done properly. In the traditional method of flood forecasting, statistical
testing was used to determine the frequency of flood depth. In recent times,
geospatial techniques are integrated with hydrologic and hydraulic modeling to
identifying the impact of LULC changes (Zope et al. 2015).
The major causes of floods include an increase in precipitation in a short span of
time, changes in LULC, and other related hydrologic impacts. For flood assessment,
various approaches such as rational formulae and empirical methods are used, but
these methods cannot be applied over large extents and are not suitable for all
regions. The other advanced method is modeling techniques used for simulation,
planning, and the management process. Flood modeling is designed for quantitative
and qualitative estimations in the hydrologic and hydraulic modeling process.
The factors that influence floods and the modeling steps are included in this
chapter in detail. Numerous factors are responsible for flood in the urban region:
prominent among these are meteorological, hydrologic, and human factors. The
meteorological factors include rainfall, cyclonic storms, and small-scale storms;
the hydrologic factors include soil moisture, groundwater level fluctuations, impervious soil cover, channel cross sections, and high tides in the case of coastal cities;
and manmade factors are LULC change, occupation of floodplains, climate change
effects, urban microclimate change, and sudden release of water from dams. All
these are prominent factors that influence flooding in urban regions.
40
S. Natarajan and N. Radhakrishnan
flood hazards in the basin.
Keywords Land use/land cover · HEC-HMS · RAS · NSE · Flood risk map
Introduction
The migration of people from rural to urban areas causes changes in land use and
land cover (LULC) in the urban region (Dewan and Yamaguchi 2009). The changes
in LULC in the urban region impact surface runoff, which may reduce the travel time
of peak flow of the urban region so that flood frequency is increased. For flood risk
assessment, it is necessary to understand the dynamics of LULC change and its
influence on the urban hydrologic cycle for predicting the floodplain and hazard
maps (Suriya and Mudgal 2012). The LULC change and its implications for the
urban flooding is one of the upcoming research topics in the field of urban hydrology
(Fox et al. 2012).
For efficient flood risk assessment in the urban area, the floodplain delineation
should be done properly. In the traditional method of flood forecasting, statistical
testing was used to determine the frequency of flood depth. In recent times,
geospatial techniques are integrated with hydrologic and hydraulic modeling to
identifying the impact of LULC changes (Zope et al. 2015).
The major causes of floods include an increase in precipitation in a short span of
time, changes in LULC, and other related hydrologic impacts. For flood assessment,
various approaches such as rational formulae and empirical methods are used, but
these methods cannot be applied over large extents and are not suitable for all
regions. The other advanced method is modeling techniques used for simulation,
planning, and the management process. Flood modeling is designed for quantitative
and qualitative estimations in the hydrologic and hydraulic modeling process.
The factors that influence floods and the modeling steps are included in this
chapter in detail. Numerous factors are responsible for flood in the urban region:
prominent among these are meteorological, hydrologic, and human factors. The
meteorological factors include rainfall, cyclonic storms, and small-scale storms;
the hydrologic factors include soil moisture, groundwater level fluctuations, impervious soil cover, channel cross sections, and high tides in the case of coastal cities;
and manmade factors are LULC change, occupation of floodplains, climate change
effects, urban microclimate change, and sudden release of water from dams. All
these are prominent factors that influence flooding in urban regions.
40
S. Natarajan and N. Radhakrishnan