Reconstruction of lost Himalayan rivers: Climate change and anthropogenic interactions with reference to Sutlej-Ghaggar-Saraswati-Drishadvati, a mighty river basin

The study explores the Ghaggar-Saraswati-Drishadvati river basin, located between the Sutlej and Yamuna rivers in the Punjab-Haryana plains, a region renowned for its rich archaeological legacy. Here, attempt has been made to examine how tectonic, geomorphological, and hydrological factors shape the evolution of the ancient river system once occupying the study area. This basin has witnessed significant hydrological and geomorphological shifts over the millennia. Ancient Indian scriptures such as the Vedas and Mahabharata refer to the Saraswati River, but its direct textual documentation with the Sutlej or Yamuna is lacking. The research delineates paleochannels and traces the ancient river systems that display complex interplay of tectonic, hydrological, and historical factors shaping the river systems of Northwest India. So, tectonics dominate on multi‑millennial timescales, hydrology/climate (monsoon strength and glacial melt) dominate on millennial timescales, and historical impacts dominate on decadal–centennial timescales. While many rivers in the basin are now seasonal, sedimentological analyses and satellite imagery suggest paleochannels like the Ghaggar-Hakra represent former courses of the Sutlej River linking Himalayan glaciers with the Saraswati system. These findings offer valuable insights into the region’s hydrological evolution and archaeological significance. Thermoluminescence (TL) dating and bore-hole data have revealed evidence of a substantial paleo-channel, approximately 1.5 km wide and over 40–50 m deep, with sediment ages estimated at 5.3 ± 0.6 ka. But the modern Sutlej channel in the region seldom exceeds 150 m width. These findings align with the fluvial chronology of the Sutlej-Ghaghar-Saraswati- Drishadvati system, suggesting the existence of a significant perennial river during the mid-Holocene, likely connected Northwest India to the Yamuna River near present-day Delhi. The large paleo-channel identified near Nigambodh Ghat, Delhi corresponds to the ancient eastward flow of the Ghaggar or Sutlej paleochannel, underscoring its historical hydrological significance.