SRINAGAR: The Jhelum River witnessed its highest reconstructed discharge during the early 19th century, with evidence suggesting repeated flooding across the Kashmir basin and a corresponding expansion of Wular Lake, according to a new study published in Palaeogeography, Palaeoclimatology, Palaeoecology.
The paper, Tree-ring evidence of late Little Ice Age Jhelum River floods and Wular Lake expansion in Kashmir, northwest Himalaya, India, reconstructed 459 years of Jhelum River discharge, from 1559 to 2017, using tree-ring records from Himalayan cedar trees in Kishtwar, Jammu and Kashmir. The researchers found annual to decadal variations in river flow, with the most pronounced increase occurring during the late phase of the Little Ice Age in the early 19th century. The study also found that the historical record of Wular Lake independently supports the reconstruction, with the lake showing its greatest expansion during the same period.
The study was conducted by researchers affiliated with institutions across northern India. Vikram Singh, the corresponding author, is affiliated with the Department of Geology at Bhakt Darshan Government PG College, Jaiharikhal, the Department of Geology at the University of Lucknow and the Birbal Sahni Institute of Palaeosciences, Lucknow. Ram R. Yadav, the other corresponding author, is affiliated with the Wadia Institute of Himalayan Geology, Dehradun.
Krishna G Misra is affiliated with the Birbal Sahni Institute of Palaeosciences and the Academy of Scientific and Innovative Research (AcSIR), Ghaziabad. Bahadur S. Kotlia is affiliated with the Centre of Advanced Study in Geology, Kumaun University, Nainital, while Anoop K. Singh is associated with the Department of Geology, School of Earth and Environmental Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow.
Ajay K Taloor is affiliated with the Department of Remote Sensing and GIS at the University of Jammu. Som Dutt is affiliated with the Wadia Institute of Himalayan Geology, Dehradun, and Dhruv S Singh with the Department of Geology, University of Lucknow.
Wular Expansion
The researchers found that Wular Lake, which is fed by the Jhelum, expanded to its greatest historical extent during the period when reconstructed Jhelum discharge was also at its highest.
The study places the maximum expansion at around 200 square kilometres. A 1911 topographical sheet cited by the researchers recorded a lake extent of 217.8 square kilometres, including 58 square kilometres of marshland.
The paper also cites previous research showing that Wular’s area declined from 157.74 square kilometres in 1911 to 86.71 square kilometres in 2007, a reduction of about 45 per cent.
Flood Record
The reconstructed river record is consistent with historical evidence of repeated flooding in Kashmir during the 19th century.
The researchers cite records of 14 extreme flood events during the century, with the 1893 flood described in the cited literature as the highest on record.
During the 1893 event, six of the seven bridges over the Jhelum reportedly collapsed. The flood was associated with the deaths of 49 people and 329 cattle, while 25,426 acres of land were inundated and 2,225 houses were destroyed.
Besides, the study also identifies a markedly different pattern between the mid-16th and 18th centuries.
During this period, the reconstructed Jhelum discharge remained comparatively low and stable for prolonged periods, which the researchers associate with severe dry conditions and reduced Wular Lake levels.
The contrast between these prolonged low-flow periods and the high discharge of the early 19th century forms a major part of the long-term hydrological record developed by the researchers.
Tree Evidence
To extend the Jhelum record beyond the relatively short period covered by instrumental measurements, the researchers used annual growth rings preserved in Himalayan cedar (Cedrus deodara) trees.
The study analysed 169 increment cores collected from 127 Himalayan cedar trees growing at seven moisture-stressed sites in Kishtwar, Jammu and Kashmir.
The researchers selected these sites because Himalayan cedar growth in such environments is particularly sensitive to changes in moisture availability, precipitation and temperature.
Five Centuries
The resulting reconstruction provides a 459-year record of Jhelum River discharge from 1559 to 2017.
The longest individual tree-ring chronology used in the study extends from 1393 to 2017, covering 625 years, while another chronology spans 1590 to 2017.
The researchers say the reconstruction represents the first long-term Jhelum River discharge record developed using a network of Himalayan cedar chronologies from Jammu and Kashmir.
Climate Link
The tree-ring chronologies showed a positive relationship with precipitation and a negative relationship with temperature.
The researchers therefore found that moisture availability played an important role in the radial growth of Himalayan cedar, allowing the tree-ring record to be used as an indicator of past hydrological conditions.
The reconstructed Jhelum discharge was also compared with independently developed precipitation, drought and river-discharge records from the westerly-dominated Northwest Himalaya, with the study finding strong consistency between the records.
Climate Drivers
The researchers examined the possible influence of larger climate systems on long-term Jhelum variability.
The paper links the hydrological conditions of the Northwest Himalaya with moisture carried by mid-latitude westerlies from the Mediterranean and Atlantic regions during winter and spring.
The reconstruction was also compared with climate indicators including the North Atlantic Oscillation, Pacific Decadal Oscillation and El Niño–Southern Oscillation.
Modern Contrast
The long-term reconstruction is set against the more recent fluctuations of the Jhelum. The researchers note that the 2014 Jhelum flood was among the highest recorded in the archived hydrological history of Kashmir. The valley subsequently experienced severe drought conditions in 2016 and 2017.
At Sangam, the Jhelum water level reached six feet in 2016, which the paper describes as the lowest level in 55 years. In 2017, the river level fell further to the lowest recorded level in 61 years.
Field Work
The tree-ring material used in the research was collected from the Kishtwar region during field investigations conducted in 2015, 2017 and 2018.
The researchers focused on moisture-stressed Himalayan cedar sites where individual trees could preserve long-term environmental signals in their annual growth rings.
The study says difficult access to potential tree-ring sites and the limited availability of gauged Jhelum discharge data have previously constrained such research in Jammu and Kashmir.
Historical Context
The study also compares the reconstructed hydrological record with historical population information from Kashmir.
It cites historical estimates placing Kashmir’s population at around 800,000 in 1815, declining to approximately 200,000 by 1835. The paper associates this period with broader climatic and hydrological challenges, while also citing historical accounts of famines and prolonged winter rainfall later in the 19th century.
These historical population figures are presented by the researchers as an additional record associated with periods of climatic and hydrological stress.
Long Record
The researchers conclude that the 459-year reconstruction provides a longer perspective on Jhelum River behaviour than is possible through modern instrumental records alone.
The study identifies substantial annual-to-decadal variability in discharge, with the strongest increase occurring during the late Little Ice Age in the early 19th century. The simultaneous expansion of Wular Lake, the researchers say, provides additional evidence for repeated flooding in the Jhelum basin during that period.
The researchers say the reconstructed record can strengthen understanding of high-Himalayan River discharge and provide useful information for researchers and policymakers working on sustainable development and hydrological challenges in the mountainous Himalaya.
The study ultimately places the modern Jhelum within a much longer record of floods, droughts and climatic variability, showing that the river’s extremes have fluctuated substantially over centuries.
