A long arid interlude in the Indian summer monsoon during ∼4,350 to 3,450 cal. yr BP contemporaneous to displacement of the Indus valley civilization

Holocene climate records from lake sediments in India: Assessment of coherence across climate zones

A 13,000 year record of environmental magnetic variations in the lake and peat deposits from the Chandra valley, Lahaul: Implications to Holocene monsoonal variability in the NW Himalaya

Multiproxy record of monsoon variability from the Ganga Plain during 400–1200 A.D.

Mid-late Holocene monsoonal records from the partially active mudflat of Diu Island, southern Saurashtra, Gujarat, western India

A densely populated city, Gorakhpur, located on the bank of Rapti river in the Ganga plain, is frequently affected by flooding. The Rapti river exhibits narrow channel within wide valley, channel bars, natural levee and river terraces. Artificial levees are constructed in the valley during low discharge period to mitigate the flood and also to provide the additional land to the society. These levees break during prolonged heavy rain and induce the catastrophic flood because it is not constructed by analyzing the capacity of the bracketed channel to accommodate the high discharge of the river. The precipitation, discharge, sediment load, and river water levels are correlated by making graphs between these parameters to analyze and identify the threshold limits and main reasons for flood. It explains that discharge and sediment load increases with precipitation during monsoon season, whereas the water storage capacity of the river decreases due to siltation and artificial levee. Hence, during heavy rain in this region, water rises in the channel, which either overtops the bank or breaks the levee and creates the flood. Flood inundation map was prepared using GIS techniques from 70 m base level to 81.5 m high level, which indicate the inundated area with every 1–2.5 m rise in the Rapti river water level. Rating curves and flood frequency curves have been prepared to identify the recurrence interval for major floods. It is concluded that prolong heavy precipitation, discharge variability of the river, siltation in the river bed, artificial levee, and anthropogenic impacts on younger river terraces and river valley leads to flood. Its affect is devastating when water level, discharge and sediment loads are above 77 m, 5000 m3/sec, and 5 metric tones respectively. The flood inundation map and recurrence interval are useful parameters for flood risk management, whereas the upland terrace is flood-free surface suitable for settlement. This study can be used as a model for other flood prone regions.

Climatically induced levee break and flood risk management of the Gorakhpur region, Rapti River basin, Ganga Plain, India

Chhoti Gandak is a meandering groundwater-fed river which originates in the terai area of Ganga Plain in the Maharajganj district of Uttar Pradesh. After travelling a distance of about 250 km, it drains into the Ghaghara River near Gothani in Siwan district of Bihar. It is one of the best studied river basins of India. The drainage basin parameters of this river were carried out for the mitigation of flood and groundwater recharge. The characteristics of the drainage basin, discharge of the river and sediment load are in direct response to the climate and tectonics which evolve the fluvial landforms. The morphometric indices indicate active tectonics in this river basin. The analysis explains that the management and development of water resource and its planning should be done in the light of drainage basin characteristics and morphometric parameters. This paper describes the multiproxy analysis of the Chhoti Gandak River which are important for better planning and mitigation of the fluvial hazards in the Chhoti Gandak River Basin which have both academic and social implications.

Shailendra Kumar Prajapati

Papers

Multiproxy record of monsoon variability from the Ganga Plain during 400–1200 A.D.

Climatically induced levee break and flood risk management of the Gorakhpur region, Rapti River basin, Ganga Plain, India

The Chhoti Gandak River: Parinirvan Place of Gautam Buddha