Palaeochannels of the Yamuna River in the Marginal Plain of Ganga Basin between Delhi and Agra: The Old Valley Margin Limit and Hydrogeological Perspectives

Abstract

Abstract Earlier, prior to Holocene, after its avulsion from the west of Aravali to the east of Aravali, the Yamuna River was flowing in a straight course in N-S direction, remaining ~5-25 km closer to the Indian peninsula in comparison to its active channel. The river, between Delhi and Agra, has shifted to its present location after taking an eastward turn at south of Delhi followed by a southward turn. There are geomorphic, lithologic and hydrogeologic imprints of its palaeo-courses in the left-back palaeo-valleys (width: 10-15 km) in the Marginal Alluvial Plain (MAP) between the aforesaid cities. Granular zones (up to 60 m thick), comprising fine to medium, micaceous grey sand, are preserved in the top 70 m slice of the stratigraphic framework along the palaeochannels. The sand zones create promising hydrogeological conditions in otherwise an aquifer-scarce region of MAP. The palaeochannel belt runs for almost 180 km being roughly parallel to the active course. Frequent imprints of the palaeochannels are observed between Delhi and Mathura in a length of ~120 km. The saturated palaeochannel aquifer bears the potential of yielding 7.6 BCM of fresh groundwater.