Flood-Prone Ghatal Region, India: A Study on Post-‘Phailin’ Inundations of 2013: Fid-Bau Portal

Flood-Prone Ghatal Region, India: A Study on Post-‘Phailin’ Inundations of 2013

Kar, Nabendu Sekhar / Das, Sayantan

Located at the base of the Chhota Nagpur Plateau’s fringe fan system, the Ghatal region in the Indian state of West Bengal is highly vulnerable to recurring Flood. The region typically becomes Flood 3–5 times in a year; usually floodwaters remain stagnant for a long period of time owing to the typical basin-shaped topography of the area. A complex drainage system has evolved due to, on the one hand, the low gradient of the Shilabati–Dwarkeshwar–Rupnarayan Rivers and their numerous tributaries and distributaries and, on the other hand, to man-made Irrigation channels. These rivers struggle to carry surplus run-off water during high discharge events. In addition, these rivers receive significant run-off from the upstream reservoirs of the Damodar Valley Corporation (DVC) and Kangsabati Project (KP). These factors combine into a disastrous Flood scenario. In October 2013, due to the cyclone ‘Phailin’, both the Chhota Nagpur Plateau region of Jharkhand and the western part of West Bengal received extremely high levels of Rainfall within a short amount of time, which caused much Flood in the Ghatal region. Almost 75% of the Ghatal Community Development (CD) Block was inundated; some areas remained Flood for a month thereafter. This study attempts to figure out the characteristics of the post-Phailin Flood crisis through a field survey combined with satellite images and a digital elevation model (DEM) analysis, as well as secondary information acquired from various sources. The physiographic setting and drainage characteristics are analysed with the help of said DEM as well as multi-dated satellite images, various hydro-geomorphic techniques, spatial overlay and ground truth verification (GTV). Information on geology, Rainfall, Flood history, tidal character, demography, etc. was obtained from administrative departments and from various reports and literatures. Oral interviews with administrative personnel and local citizens helped understand the floodwater flow pattern—most especially the role of circuit embankments of Ghatal erected in the nineteenth century under British Raj in obstructing the natural drainage of this region. The present drainage system does not follow the natural slopes—ill-thought-out construction of embankments led to the formation of potential Flood valleys cutting through the Shilabati and Dwarkeshwar courses a number of times. This results in breaches within the embankments and recurring Flood. The region’s low gradient and the routine reversal of river flows due to upstream tidal flows are responsible for prolonged inundations. The 1980s Ghatal Master Plan (GMP) and the 2009–2011 WAPCOS Project prioritized the construction of a continuous, high-level embankment on the Shilabati’s left bank and the artificial resuscitation of the river’s lower areas. However, the implementation of these plans can lead to a variety of unintended consequences.