Linking fan morphology to stratigraphy

What is it about?

Our geomorphic and stratigraphic investigations in this region are aimed at documenting how aquifer properties vary across the region, and relating this to the geomorphic setting of each part of the system. This will give us a conceptual or predictive model for aquifer body dimensions and how they vary across the region. The aquifer system consists of large sedimentary fans deposited by the Sutlej and Yamuna rivers. These fans were built by sandy river channel deposits which radiate outward from the fan heads at the Himalayan mountain front and which form the individual aquifer bodies within this system. These aquifer bodies are limited in both thickness (1 to ~80 m) and width (1 to 5 km), and cannot be correlated across the entire study area. The channel deposits are separated, laterally and vertically, by silt and clay deposits. Lateral shifts in channel position, termed avulsions, have built up the conical fans over time. While the present-day river channels and the most recent paleochannels are visible at the surface, it is important to realise that similar channel deposits are found everywhere below the fan surfaces, albeit at different depths in different locations.

Featured Image

Why is it important?

India, the largest agricultural user of groundwater in the world, has seen a revolutionary shift from large-scale surface water management to widespread groundwater abstraction in the last 40 years, particularly in the northwestern states of Punjab, Haryana and Rajasthan. As a result, these states are now a hotspot of groundwater depletion, with 'the largest rate of groundwater loss in any comparable-sized region on Earth' (Rodell et al., 2009; Tiwari et al., 2009). This unsustainable use of groundwater is aggravated by (a) increasing demands from a burgeoning population and industrialization, and (b) poorly understood effects of climate-driven changes in the water cycle. Despite this pressing need, there is no integrated view of the aquifer system in northwestern India. With this work we combine geomorphic and subsurface information to investigate the dimension of aquifer bodies within northwestern India.