Objectives

River dynamics and hazard assessment in the Himalayan foreland

Supported by UKIERI
UK-India Education and Research Initiative

Objectives:

	To determine the spatial variations of erosion and deposition for rivers along the Himalayan front and Gangetic Plain;
	Use this to assess the geomorphic and stratigraphic responses of these systems to local base level change;
	Understand relationships between river incision and downstream aggradation and flood hazard; and
	Assess the feedback effects of this incision upon sediment delivery processes, such as landslides, at the mountain front.

Approach and Methodology:

The primary components of this project are:

Data compilation:

Compilation of all literature and available data on geological maps, hydrological data on water discharge and sediment flux, and geomorphic maps of the study windows has been completed. All data has been archived in a GIS-based platform and are accessible to both Indian and UK teams.

Field investigations:

Field investigations have been focused on landform mapping and the understanding of erosional processes responsible for sediment flux in river systems. We have so far carried out field visits in the NW Himalaya around the Ganga and Yamuna rivers to assess the patterns of erosion and deposition and the effects of local base level change. We focused on the proximal areas of the foreland, involving mapping of depositional surfaces, logging of key sedimentary sections collection of samples for cosmogenic dating.

Another field season focused on the eastern Himalaya around the Kosi river to assess the Kosi fan building processes and flooding history. The hinterland of the Kosi river covering parts of Nepal were also examined to understand the sediment supply processes and tectonic controls.

Remote sensing and GIS based analysis:

This part of the work has involved mapping of tectonic, geomorphology and DEM analysis for understanding the response to active tectonics, computation of storage and excavation. A detailed geomorphic mapping has revealed tectono-geomorphic units in the Dehra Dun area and the computation of several geomorphic indices has provided pointers to active tectonics.

Data integration, image processing and DTM analysis for the Kosi river basin is also continuing. Compilation of flood data and historical data on water and sediment discharge from the major rivers has been completed. Additional field work will concentrate on the hinterland of the Gandak river system.

Laboratory analysis of samples:

Samples have been collected from the NW Himalaya for exposure dating and geochemical analysis. These analyses are currently underway. Additional field trips are being planned for sample collections for OSL dating.