Indus River Research Articles

Hazards profile of the Shigar Valley, Central Karakoram, Pakistan: Multicriteria hazard susceptibility assessment

The rapid deglaciation in the Upper Indus Basin (UIB) significantly impacts local landscapes, watersheds, and basin-wide hydrology. While creating new opportunities, such as emerging landscapes and hydrological changes, deglaciation simultaneously heightens the risk of glacio-hydrological hazards in adjacent and downstream regions. With limited available land for agriculture and settlements, communities around glaciers expand human activities toward newly formed floodplains and deglaciating valleys, necessitating a comprehensive understanding of associated risks and vulnerabilities. This study employs Geographical Information System (GIS) and Remote Sensing products for a multicriteria hazards susceptibility assessment in the Shigar Valley, located in the downstream of major Himalayan glaciers – the Baltoro (63 km) and Biafo (67 km) glaciers. The research reveals that 28.3% of the valley is highly susceptible to multiple hazards, emphasizing the urgency of informed decision-making in the region. Only 0.03% area lies in the very low susceptible category, 9.7% in the low susceptible, 60.6% in the moderately susceptible, and 1.04% in the very highly susceptible categories. These findings highlight the need for proactive measures, adaptive strategies, and sustainable development in the Shigar Valley to mitigate the escalating risks posed by deglaciation and changing hydrological patterns.

Geochemical insights of arsenic mobilization into the aquifers of Punjab, Pakistan

It is well known that groundwater arsenic (As) contamination affects million(s) of people throughout the Indus flood plain, Pakistan. In this study, groundwater (n = 96) and drilled borehole samples (n = 87 sediments of 12 boreholes) were collected to investigate geochemical proxy-indicators for As release into groundwater across floodplains of the Indus Basin. The mean dissolved (μg/L) and sedimentary As concentrations (mg/kg) showed significant association in all studied areas viz.; lower reaches of Indus flood plain area (71 and 12.7), upper flood plain areas (33.7 and 7.2), and Thal desert areas (5.3 and 4.7) and are indicative of Basin-scale geogenic As contamination. As contamination in aquifer sediments is dependent on various geochemical factors including particle size (3–4-fold higher As levels in fine clay particles than in fine-coarse sand), sediment types (3-fold higher As in Holocene sediments of floodplain areas vs Pleistocene/Quaternary sediments in the Thal desert) with varying proportion of Al-Fe-Mn oxides/hydroxides. The total organic carbon (TOC) of cored aquifer sediments yielded low TOC content (mean = 0.13 %), which indicates that organic carbon is not a major driver (with a few exceptions) of As mobilization in the Indus Basin. Alkaline pH, high dissolved sulfate and other water quality parameters indicate pH-induced As leaching and the dominance of oxidizing conditions in the aquifers of upper flood plain areas of Punjab, Pakistan while at the lower reaches of the Indus flood plain and alluvial pockets along the rivers with elevated flood-driven dissolved organic carbon (exhibiting high dissolved Mn and Fe and a wide range of redox conditions). Furthermore, we also identified that paired dissolved AsMn values (instead of AsFe) may serve as a geochemical marker of a range of redox conditions throughout Indus flood plains.

Predictive modeling of water quality index (WQI) classes in Indian rivers: Insights from the application of multiple Machine Learning (ML) models on a decennial dataset

Predictive modeling of water quality index (WQI) classes in Indian rivers: Insights from the application of multiple Machine Learning (ML) models on a decennial dataset

A comprehensive study on optimizing reservoir potential: Advanced geophysical log analysis of zamzama gas field, southern indus basin, Pakistan

This study investigates the hydrocarbon and gas potential of the Pab Formation's Late Cretaceous reservoir in the Zamzama Gas Field (ZGF) situated in Pakistan's Southern Indus Basin (SIB). Vital insights to support Pakistan's escalating energy requirements. Petrophysical characteristics of the Pab Formation (PFm) zones of interest in the ZGF were determined by evaluating geophysical logs from four wells. Various techniques were employed to analyze the reservoir rock type (RRT), lithofacies, and spatial distribution of petrophysical parameters. The petrophysical assessment reveals that gas-bearing zones primarily consist of sandstone with intermittent shale layers. These reservoirs exhibit distinguishing attributes, including clean sand composition, high resistivity, total porosity (∅T), good permeability (K), minimal shale content (Vsh), and low water saturation (Sw). The total porosity ranges from 12% to 16%, permeability from 14 mD to 19 mD, water saturation levels between 34% and 44%, and hydrocarbon saturation (Sh) from 56% to 66%. The findings suggest significant gas reserves within the studied sand units of the Zamzama Block. Overall, this research provides a detailed and comprehensive understanding of reservoir characteristics, thereby increasing the potential for further hydrocarbon exploration and production in the study area.

GEOCHEMISTRY OF PAB SANDSTONE EXPOSED IN LAKI RANGE LOWER INDUS BASIN: PROVENANCE AND TECTONIC IMPLICATIONS

Geochemistry of the late Cretaceous Pab Sandstone deposited at the Laki Range, Southern Indus basin, was carried out in order to acquire a better knowledge of the source rock and paleoclimate. The unit in the studied region comprise predominantly sandstone, with some mudstone. The major element geochemistry of Pab Sandstone suggests that the samples were composed of abundant SiO2, Al2O3, CaO, and Fe2O3. Other major oxides comprises less than 2 wt. %. Major element discriminatory diagrams additionally imply that Pab sediments originated from a granitic source. The idea that the Pab sediments were generated by a granitic source is further supported by the rich concentration of trace elements including Zr, La Th, Ba, and Sr, in contrast to V, Ni, Cr, Co, and their ratio. It is conceivable that the Pab Sandstone was formed by sediments from granitic rocks, as indicated by the La/Sc and Th/Co model, as well as the TiO2 and Zr plots. The measured Plagioclase Index of Alteration (PIA) values, which range from 59.94 to 89.44, and the Chemical Index of Alteration (CIA), which ranges from 61.12 to 83.75, indicate that the studied sediments experienced moderate to strong weathering under warm, humid climate conditions. Geochemical findings indicate that the Pab Sandstone sediments originated from the vast Indian Shield (Craton); probably from the Malani Igneous Suite in India and the Nagar Parkar Igneous Complex in Pakistan.

People’s Perception of Climate Change Impacts on Subtropical Climatic Region: A Case Study of Upper Indus, Pakistan

In developing countries like Pakistan, the preservation of the environment, as well as people’s economies, agriculture, and way of life, are believed to be hampered by climate change. Understanding how people perceive climate change and its signs is essential for creating a variety of adaptation solutions. In this study, we aim to bridge the gap in current research within this area, which predominantly relies on satellite data, by integrating qualitative assessments of people’s perceptions of climate change, thereby providing valuable ground-based observations of climate variability and its impacts on local communities. Field-based data were collected at different altitudes (upstream (US), midstream (MS), and downstream (DS)) of the Upper Indus Basin using both quantitative and qualitative assessments in 2017. The result shows that these altitudes are highly variable in many contexts: socioeconomic indicators of education, agriculture, income, women empowerment, health, access to basic resources, and livelihood diversifications are highly variable in the Indus Basin. The inhabitants of the Indus Basin perceive the climate changing around them and report impacts of this change as increase in overall temperatures (US 96.9%, MS 97%, DS 93.6%) and erratic rainfall patterns (US 44.1%, MS 73.3%, DS 51.0%) resulting in increased water availability for crops (US 38.6%, MS 39.7%, DS 54.8%) but also increasing number of dry days (US 56.7%, MS 85.5%, DS 67.1%). Communities at these altitudes said that agriculture was their primary source of income, making them particularly vulnerable to the effects of climate change and the dangers that go along with it. The insights are useful for determining what information and actions are required to support local climate-related hazard management in subtropical climate regions. Moreover, it is vital to launch a campaign to raise awareness of potential hazards, as well as to provide training and an early warning system.

Dynamic Geomorphology of the Amu Darya Basin in Afghanistan: A Study of Physiography, Basin Erosion, and Channel Development

The morphological dynamics of rivers are motivated by way of a number of things, including floodplain sedimentation, channel migration, sediment transport, and hydrodynamics. A considerable information of the complicated dynamics of river structures is important to layout river initiatives which can be sustainable and environmentally conscious. Implementing thorough river control plans that include hydraulic infrastructure and ecological restoration projects is important to overcoming these boundaries. This solution will effectively manipulate competing needs for water resources whilst ensuring the preservation of the location's herbal heritage. In the cease, this study affords essential new understandings of the complex interactions between hydrological patterns, human hobby, and geological procedures within the Amu Darya Basin. The application of sustainable land control and water useful resource making plans in Afghanistan might be appreciably impacted with the aid of those findings. Afghanistan has a lot of freshwaters because the Hindu Kush Mountains receive a significant quantity of precipitation. An estimated 75 billion cubic meters of potential water resources, consisting of 57 billion cubic meters of surface water and 18 billion cubic meters of groundwater, are found in Afghanistan. The Amu Darya, Northern River Basin, Helmand River Basin, Harirud-Marghab River Basin, and Kabul River Basin make up the Indus River Basin, which provides around two-thirds of Afghanistan's freshwater resources. All of Afghanistan's rivers, with the exception of the Northern River, flow across international borders into neighboring countries. The distribution of water from the Amu Darya River was subject to limitations imposed by the USSR, which was previously known as the Union of Soviet Socialist Republics. The majority of the water is used mostly for farming. Protocol 566, formally ratified by the former USSR, allowed the transfer of water from the Amu Darya River to the four Central Asian Republics (CARs) of Tajikistan, Uzbekistan, Turkmenistan, and the Kyrgyz Republic. By investigating the bodily functions of the basin, which includes land erosion and channel development, this looks at seeks to enhance our understanding of the landscape evolution of the basin. Our intention is to improve our information of the landforms, tectonic activity history, and the consequences of climate change inside the region by utilizing geological studies and facts from faraway sensing.

Statistical Modeling of Indus River Outflow at Tarbela Dam using Generalized Gumbel Type 2 Distribution

Statistical Modeling of Indus River Outflow at Tarbela Dam using Generalized Gumbel Type 2 Distribution

Analyzing the impact of pesticides on the indus river: contamination levels in water, sediment, fish, and associated human health risks.

Pesticides are frequently used to protect crop yields and manage malaria vectors; however, their inadvertent transport into aquatic habitats poses a significant concern. Various anthropogenic activities influence the Indus River in Pakistan. This study aimed to assess the presence of eight pesticide residues at three different sites (Kalabagh, Kundian, and Chashma) in water, sediment, and the fish species (Labeo rohita) during both dry and wet seasons to measure the intensity of this pressure. Pesticide analysis was carried out using gas chromatography equipped with an electron capture detector. The results revealed the highest concentrations of pesticides during both dry and wet seasons at all sites, measuring 0.83 and 0.62μg/l (water), 12.37 and 9.20μg/g/dw (sediment), and 14.27 and 11.29μg/g/ww (L. rohita), respectively. Overall, pesticide concentrations were higher in the dry season than in the wet season across all study sites. Based on detection frequency and concentration in both seasons at all sites, dominant pesticides included cypermethrin and carbofuran (in water), as well as endosulfan and cypermethrin (in sediment and fish tissue). Levels of endosulfan and cypermethrin exceeded standard limits. Moreover, principal component analysis (PCA) indicated no correlation among pesticides in fish tissue, sediment, and water. However, pesticides exhibited different behavior in different seasons. Furthermore, endosulfan and triazophos impose great human health risk, as indicated by the THQ value (> 1). The overall HI value was greater for site 1 in the dry season (8.378). The study concluded that the presence of agricultural pesticides in the Indus River poses a risk to aquatic life and has the potential to disrupt the entire food chain. This highlights the importance of sustainable practices for the study area and Pakistan overall agricultural and environmental sustainability. It is further recommended to strengthen regulations for reduced pesticide use and promote eco-friendly pest management.

Characterizing the stable oxygen isotopic composition of the southeast Indian Ocean

New seawater stable oxygen isotope (δ18O) samples were collected from the southeast Indian Ocean as part of the Coring to Reconstruct Ocean Circulation and Carbon dioxide Across 2 Seas (CROCCA-2S) expedition in November – December of 2018. These data fill a gap in the δ18O sampling coverage of the southern Indian basin, providing new insights into the hydrologic and oceanographic processes influencing the δ18O distribution of the region and its relationship to salinity in the upper ocean. Our surface ocean data (<100 m)—in combination with decades of observations from the broader south Indian Ocean—show distinct δ18O – salinity characteristics on either side of ∼85°E. The balance between evaporation and precipitation yields a strong, robust δ18O – salinity relationship west of 85°E (δ18O = 0.50(±0.01) * S – 17.2(±0.22)). However, within the mesoscale eddy field initiated by the Leeuwin Current further east (∼85–120°E), our observations fall along a mixing line between the southwest Indian Ocean and data collected from the Australian coastal margin, illustrating for the first time how the unique eastern boundary system of the south Indian Ocean drives regional-scale variability in the δ18O – salinity relationship of the surface ocean. A comparison between our observations in the shallow subsurface (100–1000 m) and those from neighboring surveys reinforces this upper ocean connection across the Indo-Australian basin. Antarctic Intermediate Water from the Indian Ocean can be isotopically distinguished from the more regional Tasman Intermediate Water occupying the South Australian Bight, suggesting exchange between the two regions is most prevalent at surface and mode water depths. In deeper waters (> ∼1500 m), we observe a notable 0.87‰ spread in δ18O. This variability may represent interactions between distinct deep water masses in the region, although additional data are needed to confirm. Overall, our data provide a new look at the hydrography and isotopic chemistry of the southeast Indian Ocean, emphasizing the impact of the region's mesoscale eddy field and its interconnectivity with neighboring basins.

Two-Decadal Glacier Changes in the Astak, a Tributary Catchment of the Upper Indus River in Northern Pakistan

Snow and ice melting in the Upper Indus Basin (UIB) is crucial for regional water availability for mountainous communities. We analyzed glacier changes in the Astak catchment, UIB, from 2000 to 2020 using remote sensing techniques based on optical satellite images from Landsat and ASTER digital elevation models. We used a surface feature-tracking technique to estimate glacier velocity. To assess the impact of climate variations, we examined temperature and precipitation anomalies using ERA5 Land climate data. Over the past two decades, the Astak catchment experienced a slight decrease in glacier area (−1.8 km2) and the overall specific mass balance was −0.02 ± 0.1 m w.e. a−1. The most negative mass balance of −0.09 ± 0.06 m w.e. a−1 occurred at elevations between 2810 to 3220 m a.s.l., with a lesser rate of −0.015 ± 0.12 m w.e. a−1 above 5500 m a.s.l. This variation in glacier mass balance can be attributed to temperature and precipitation gradients, as well as debris cover. Recent glacier mass loss can be linked to seasonal temperature anomalies at higher elevations during winter and autumn. Given the reliance of mountain populations on glacier melt, seasonal temperature trends can disturb water security and the well-being of dependent communities.

Evolution of system connectivity to support food production in the Indus Basin in Pakistan

Sustainability challenges related to food production arise from multiple nature-society interactions occurring over long time periods. Traditional methods of quantitative analysis do not represent long-term changes in the networks of system components, including institutions and knowledge that affect system behavior. Here, we develop an approach to study system structure and evolution by combining a qualitative framework that represents sustainability-relevant human, technological, and environmental components, and their interactions, mediated by knowledge and institutions, with network modeling that enables quantitative metrics. We use this approach to examine the water and food system in the Punjab province of the Indus River Basin in Pakistan, exploring how food production has been sustained, despite high population growth, periodic floods, and frequent political and economic disruptions. Using network models of five periods spanning 75 y (1947 to 2022), we examine how quantitative metrics of network structure relate to observed sustainability-relevant outcomes and how potential interventions in the system affect these quantitative metrics. We find that the persistent centrality of some and evolving centrality of other key nodes, coupled with the increasing number and length of pathways connecting them, are associated with sustaining food production in the system over time. Our assessment of potential interventions shows that regulating groundwater pumping and phasing out fossil fuels alters network pathways, and helps identify potential vulnerabilities for future food production.

Unveiling climatic niches for deeper insights into invasion potential and enhanced distribution models of freshwater fishes

AbstractIntroduced species may exhibit variations in their preferred climatic niches between their native and introduced ranges, which can have important implications for the transferability of distribution models. In the Himalayan ecoregion, little is known about the geographic distribution and climatic niche overlap between native and introduced cold‐water species. Here, we used the COUE (centroid shift, overlap, unfilling, and expansion) framework to explore the invasive potential of rainbow (Oncorhynchus mykiss) and brown (Salmo trutta fario) trout and corresponding climatic niche overlap with native snow trout (Schizothorax plagiostomus and Schizothorax richardsonii) in the Indus and Ganges River basins. Although we found more stability in the climatic niche for O. mykiss (93%) than S. trutta (58%), both species do not conserve their climatic niches in this region (p &gt; 0.05). S. trutta has expanded more toward new environmental conditions (42%) compared to O. mykiss (7%). However, there are still available environmental gaps that O. mykiss and S. trutta can potentially occupy in the future. There was a higher overlap in climatic niches between S. plagiostomus and O. mykiss and between S. richardsonii and S. trutta. Observed shifts in climatic niches of these introduced species can negatively affect the transferability of distribution models, which may underestimate the assessments of habitat suitability for introduced trout in the Himalayas. Our study demonstrates that the information on climatic niche dynamics can inform the model‐building process and improve the transferability and predictive performance to better assess vulnerability of sensitive habitats to introduced species in the Himalayas and elsewhere.

Late Oligocene to Pleistocene thermo-tectonic evolution of the Karakoram Fault Zone: New insights from basement and detrital apatite fission track thermochronology

The Karakoram Fault Zone displays distinctive topographic and tectonic characteristics, with intricate river drainage systems. Although there are extensive thermochronological datasets for the western Tibetan Plateau, limited investigations have been carried out to uncover the low-temperature thermal history of the Karakoram Fault Zone, which connects the Lhasa terrane with the Pamir. In this contribution, apatite fission track (AFT) thermochronology was conducted on 13 basement and 4 conglomerate samples collected from the western Gangdese batholith and the Ayi Mountain Range, on either side of the Karakoram fault. Inverse thermal history modeling results reveal that the western Gangdese batholith experienced two stages of rapid basement cooling at 27–23 Ma (late Oligocene-early Miocene) and 16–4 Ma (middle Miocene-Pliocene). The adjacent Ayi Mountain Range experienced cooling in the late Miocene (∼8 Ma) and during the Pliocene to Pleistocene (4–1 Ma). We suggest that tectonic forces associated with rollback and lateral break-off of the Indian continental lithosphere, and the dextral strike-slip activity of the Karakoram fault were responsible for the first cooling phase. The second accelerated cooling phase was due to the deep fragmentation of the Indian slab, the activity of the Karakoram normal fault, and associated ∼E-W extension. Additionally, since the late Oligocene, the Indus River incision has likely also contributed to the exhumation of the western Tibetan Plateau. Subsequently, the western Gangdese batholith reached high elevations, resulting in the reversal of the Yarlung River. The dextral-normal motion of the Karakoram fault, which is still active today, was the main cause of the Pliocene to Pleistocene accelerated cooling detected in the Ayi Mountain Range.

Blood is Thicker than Water: A Genealogy of Water in Nation-State Building

This work explores the multifaceted relationship between India and Pakistan, starting with India’s very recent decision to renegotiate the terms of the Indus Waters Treaty of 1960 between the two countries. This treaty, considered to be a time-tested hallmark of peace on the Indian subcontinent, is particularly heralded by mediators like the World Bank. This desire for peace is confronted with the reality of border skirmishes and conflicts over Kashmir, a state through which the Indus River flows. Accordingly, I interrogate the interactions between various political actors over the Indus Waters themselves, specifically focusing on partition and the subsequent period that led up to the signing of the Indus Waters Treaty. This piece seeks to understand the role of nature in cohering international, national and subnational identity. Specifically, I focus on the two countries’ historical conflicts over water as well as sovereign claims to water in Punjab and Jammu and Kashmir, which are regions that must balance domestic priorities with the looming national interests of India and Pakistan. By linking water to the economic, cultural, and social language that comprises political imagination and identity, I hope to reveal new insights about how the relationship between nature and humanity has transformed from mutual cooperation to one of commodification and displacement.

Correction: A detailed investigation of Jutana formation for depositional setting in Indus Basin, Pakistan

Correction: A detailed investigation of Jutana formation for depositional setting in Indus Basin, Pakistan

Hydrologic interpretation of machine learning models for 10-daily streamflow simulation in climate sensitive upper Indus catchments

Machine learning for hydrologic modeling has seen significant recent development and has been suggested as a valuable augmentation to physical hydrological modeling, especially in data-scarce catchments. In Pakistan, surface water flows predominantly originate from the transboundary Upper Indus sub-catchments of Chenab, Jhelum, Indus, and Kabul rivers. These catchments have large drainage areas, climate-driven streamflows, high variations in elevation, and limited streamflow gauge coverage. Hence, using machine learning models for data-driven river flow modeling may be well-suited for these catchments. However, hydrologic interpretability of machine learning models is important for the practical use of such models for these catchments. Thus, the current study besides evaluating the potential of three machine learning models (XGBOOST, Classification and Regression Trees(CART), and RandomForest) for streamflow simulation also focused on the hydrologic interpretation of machine learning models using SHapley Additive exPlananations (SHAP). All of these models performed well and the range of R2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ extrm{R}^2$$\\end{document} and Nasche-Efficiency for all three models lies between 0.61 to 0.90. Moreover, SHAP correctly identified minimum temperature as the most critical feature in glacier-fed Indus and Chenab catchments. It also provides logical insights into interactions between minimum temperature and precipitation for the indus and Chenab catchment. The findings of this study strongly illustrate the usefulness of SHAP analysis in interpreting the behavior of data-scarce high-elevation climate-sensitive catchments using tree-based machine learning models.

Analysis of sediment provenance using geochemical and isotopic data for a post-LGM sediment core from the western Great Rann of Kachchh, India: Implications for climate control on source regions

This study addresses the nature and causes of post-Last Glacial Maxima (LGM) sedimentation in the Western Great Rann of Kachchh, Gujarat, India. Specifically, we report geochemical and isotopic data (87Sr/86Sr and 143Nd/144Nd) for a 46.5 m sediment core from the Nara River bed. These data indicate that up to the beginning of the Holocene, sedimentation mostly comprised contributions from monsoon-dominated rivers of Western Himalaya. Later in the early Holocene, a shift towards Indus-derived sediments occurred, with a minor reversal at ∼7 ka, attributed to the rejuvenation of the Ghaggar-Hakra channel. A renewed contribution from the Indus River routed through the Nara River and through the Kori Creek (mouth of the Nara River) occurred during the mid- to late Holocene. Persistent availability of freshwater during the mid- to late Holocene helped sustain early Iron Age and medieval cultures in the region. However, significant decline in the hydrological system anchored in the shifting Indus River through the Nara channel after the medieval period, likely caused the gradual collapse of these cultures. Our study is important as it demonstrates that, if the sediment source is from regions of contrasting climatic domains (for example, monsoon-dominated western Himalaya rivers and the westerlies-dominated Indus River), temporal changes in precipitation intensities exert a first order control in modulating the sediment provenances.

Distribution and bioaccumulation of trace elements in two Cyprinidae fish species in the Indus river, Pakistan, including the impact of hydraulic structure on macroinvertebrates' biodiversity

The concentration of trace elements (chromium, lead, zinc, copper, manganese, and iron) was determined in water, sediment and tissues of two Cyprinidae fish species - Labeo rohita and Tor putitora – collected from the eight sampling stations of Indus River in 2022 for four successive seasons (autumn, winter, spring, summer), and also study the present condition of macroinvertebrates after the construction of hydraulic structure. The obtained results of trace element concentrations in the Indus River were higher than the acceptable drinking water standards by WHO. The nitrate concentration ranges from 5.2 to 59.6 mg l−1, turbidity ranges from 3.00 to 63.9 NTU, total suspended solids and ammonium ions are below the detection limit (<0.05). In the liver, highest dry wt trace elements (μg/g) such as Cr (4.32), Pb (7.07), Zn (58.26), Cu (8.38), Mn (50.27), and Fe (83.9) for the Labeo rohita; and Tor Putitora has significantly greater accumulated concentration (Cr, Pb, Zn, Cu, Mn, Fe) in muscle and liver than did Labeo rohita species. Additionally, lower number of macroinvertebrates were recorded during the monsoonal season than pre-monsoon and post-monsoon. Local communities surrounded by polluted environments are more probably to consume more fish and expose them to higher concentrations of toxic trace elements (lead and copper). The findings also provide a basis for broader ecological management of the Indus River, which significantly influenced human beings and socioeconomic disasters, particularly in the local community.

Investigating the Influence of River Geomorphology on Human Presence Using Night Light Data: A Case Study in the Indus Basin

Human settlements have historically thrived near rivers due to enhanced navigation and trade, and the availability of water supply and resources. The use of night light data, representing economic activities, provides a novel approach to studying the interactions between human activity and rivers over time. Here, we use the Defense Meteorological Satellite Program (DMSP) stable night light data from 2000 to 2013 as a proxy for human presence and activities to quantify the statistical relationships between night light presence and intensity in the Indus Basin, Asia. We test how these data are affected by proximity to trunk channels and by channel type (single/multi-thread) in the study area. We find that night light presence is enhanced by 26% within a 0 to 5 km proximity range of the Indus River and its tributaries, relative to the basin as a whole. We interpret this to represent increased human presence and activity within this zone. However, the mean intensity is lower near the river and higher away from the river, signifying denser settlements, such as towns and cities, which are preferentially located away from the Indus and its tributaries. Moreover, the enhancement of lit pixels signifying human presence and activities is increased by 18% near single-thread sections of the Indus River, compared to segments of the Indus displaying multi-thread morphologies. We suggest that this is due to the enhanced stability of single-threaded channels, relative to mobile multi-threaded channel reaches. This study demonstrates how night lights are an important tool in studying the relationship between human presence and river dynamics in large catchments such as the Indus, and we suggest that these data will have an important role in assessing differential flood spatial and social vulnerability at a regional scale.