Climate change impact on Maharashtra - a case study of Mumbai floods
Student name: Mr Prasoon Singh
Guide: Dr Prateek Sharma
Year of completion: 2013
Host Organisation: The Energy and Resources Institute (TERI), New Delhi
Supervisor (Host Organisation): Mrs Suruchi Bhadwal
Abstract: Climate change has significant impact on hydrological phenomenon causing
extremes of weather condition and leaving hydrological system more
unpredictable. Flood and flood related problems have become more rampant
all over the world and leads to the human loss, infrastructure damage and
epidemics every year. Many large metropolitan cities all over the world are
situated on the coastal regions and become vulnerable for flooding due to
storm water and sea level rise. Rapid urbanization and unplanned city
development are further worsening the situation.
In the present study by using hydrodynamic simulation of DHI MIKE 21 a
model has been created to understand the process and effects of extreme flood
condition over Mumbai for the much localized extreme rainfall event of 26-27
July 2005. This rainfall event is being simulated in MIKE 21 model for two
different Land Use condition of 1973 and 2005 to see the impact of land use
over flooding. Land Use map has been created and classified for the year 1973,
1992, 2001 and 2005 to analyze the urban growth. According to the land use
bed roughness map is developed for the model. The bathymetry file based on
DEM is processed in ArcGIS and MIKE 21 toolbox. MIKE 21 2D flow model is
simulated for this rainfall event. Two land use condition of 1973 and 2005 is
used for this study and flood mapping has been done, which shows the spatial
flood risk information in terms of flood depth and flood water velocity. It is
found that the low lying areas near the creaks and Methi river catchment has
maximum impact as for as the flood water depth is concern. Flood water level
gets accumulated upto 1.5 to 3.5 m in these areas. Average flood velocity was
found to be 0.06 m/s which is nominal but at some steep areas it went upto 6 to
9 m/s. Impact of land use over flooding shows that both water depth and water
velocity get affected with the change in land use.
Keywords: Mumbai, Climate Change, DHI MIKE 21, 2D Flood Mapping,
Manning Map
