Glacial Meltwater Contributions Research Articles

ТЕСТИРОВАНИЕ ВОЗМОЖНОСТЕЙ МЕТОДИКИ ОПЕРАТИВНОГО МОНИТОРИНГА ГОРНО-ЛЕДНИКОВЫХ СИСТЕМ

The article considers the possibilities of assessing the glaciation area of ​​the Northern Ile and Ile-Kungey glacier systems based on monitoring data from a limited sample of test glaciers. During testing in each of the mentioned glacier systems, based on the data on the area of ​​two samples of 10 glaciers, their total sample (20 glaciers) and their share in the total area of ​​glaciers in each of the named glaciation regions, the area of ​​glaciers of the corresponding glacier system was calculated. According to the testing results, the values ​​of the correlation coefficient of the calculated and actual (based on the results of glacier cataloguing) values ​​of the glaciation area for the three mentioned glacier samples were 0.99, 0.98, and 0.99 for the Northern Ile glacier system and 0.99, 0.97, and 0.99 for the Ilei-Kungey, respectively. The testing results leave no doubt about the possibility of operational monitoring of the glaciation area dynamics of mountain glacier systems based on the data on the area of ​​a limited sample of glaciers of the corresponding glacier system with an error of no more than ±5 %. According to the testing results, the calculated values ​​of the glacier area of ​​the considered glacier systems in 88 % of cases were less than 5% of the actual values, and only in 4 cases out of 33 (12 %) they exceeded this threshold, with an average deviation of the calculated data from the actual values ​​of less than 2 % and the largest calculation errors of 7.8 and -9.6 %. This indicates the high efficiency of the method of operational monitoring of mountain glacier systems. It allows to rapidly (with a repeatability from once every few years to annually) assess the loss of perennial ice in the considered glacier system and the contribution of glacial meltwater to the formation of river flow. Which, in its turn, is a good basis for the corresponding modeling of current and predicted changes.

Early-Middle Holocene high lake levels of Rinqen Shubtso on the southern Tibetan Plateau and the formation mechanisms

The lake-level highstands on the southern Tibetan Plateau (TP) during the Early-Middle Holocene have traditionally been attributed to increased monsoonal precipitation. However, there has been limited discussion and evaluation regarding how the elevated shoreline indicates the formation of mega-paleolakes and the effects of glacial meltwater on rising lake levels. In this study, we conducted an investigation into the well-preserved paleoshorelines of Rinqen Shubtso, a closed-basin lake system located on the southern TP. By utilizing 14C dating and analyzing shoreline elevations, the Holocene lake-level fluctuation history of Rinqen Shubtso was reconstructed. Through examining strontium (87Sr/86Sr) and oxygen isotopes (δ18O), as well as Rb/Sr ratios in tufa samples from the shoreline, we evaluated the relative contribution of glacial meltwater and East Asian Monsoon precipitation to the lake-level expansion throughout this period. Our findings indicate that prior to 8.5 cal ka BP, the lake level reached its highest elevation before experiencing a rapid drop by approximately 44 m within a short timeframe. Subsequently, maintaining a stable highstand between 8.5 and 5.8 cal ka BP before gradually declining to its present elevation thereafter. We argue that the glacial meltwater induced by rising temperature due to solar insolation likely played a significant role in contributing to these large amplitude high lake levels prior to 8.5 cal ka BP, whereas the maximum East Asian Monsoon precipitation was responsible for sustaining high water levels during 8.5–5.8 cal ka BP when the mean latitudinal position of the summer Intertropical Convergence Zone shifted northward until reached its northernmost point at 8.5 cal ka BP. Following 5.8 cal ka BP, with the weakening of summer monsoon precipitation observed, gradually decreased lake level occurred accordingly. Our results provide valuable insights into understanding past changes in lake level, which are of great importance to predicting future lake variations on the TP.

Quantifying the glacial meltwater contribution to mountainous streams using stable water isotopes: What are the opportunities and limitations?

AbstractThis study aims to determine the opportunities and limitations of using stable water isotopes to quantify the glacial meltwater contribution to mountainous streams. For this purpose, three partially glaciated catchments in the Swiss Alps were selected as the study area. In the three catchments, stable isotope analysis (δ18O and δ2H) was conducted of the streams and the end‐members that contribute to the stream discharge (glacial meltwater, rain, snow). The investigations revealed that the contribution of glacial meltwater to mountainous streams can be quantified using stable water isotopes if three criteria are met: (A) The snow meltwater contribution to mountainous streams must be negligible due to its highly variable stable isotope signature; (B) the groundwater input needs to be either insignificant during this snow‐free period or the groundwater residence time must be short such that groundwater contribution does not delay the end‐member signal arriving in the streams; and (C) the isotope signal of the glacial melt end‐member needs to be distinct from the other end‐members. One of the three investigated catchments fulfilled these criteria in August and September, and the glacial meltwater contribution to the mountainous streams could be estimated based on stable water isotopes. During this time period, the glacial meltwater contribution to the stream discharge corresponded to up to 85% ± 2% and to 28.7% ± 10% of the total annual discharge, respectively. This high glacial meltwater contribution demonstrates that the mountainous stream discharges in August and September will probably strongly decrease in the future due to global warming‐induced deglaciation. Overall, this study demonstrates that many hydrogeological conditions need to be met so that stable water isotopes can be used to quantify the glacial meltwater contribution to mountainous streams. This highlights the challenges when using stable water isotopes for hydrograph separation and serves as a guide for future stable water isotope studies in mountainous regions.

Isotopic evidence for an intensified hydrological cycle in the Indian sector of the Southern Ocean

The hydrological cycle is expected to intensify in a warming climate. However, observational evidence of such changes in the Southern Ocean is difficult to obtain due to sparse measurements and a complex superposition of changes in precipitation, sea ice, and glacial meltwater. Here we disentangle these signals using a dataset of salinity and seawater oxygen isotope observations collected in the Indian sector of the Southern Ocean. Our results show that the atmospheric water cycle has intensified in this region between 1993 and 2021, increasing the salinity in subtropical surface waters by 0.06 ± 0.07 g kg−1 per decade, and decreasing the salinity in subpolar surface waters by -0.02 ± 0.01 g kg−1 per decade. The oxygen isotope data allow to discriminate the different freshwater processes showing that in the subpolar region, the freshening is largely driven by the increase in net precipitation (by a factor two) while the decrease in sea ice melt is largely balanced by the contribution of glacial meltwater at these latitudes. These changes extend the growing evidence for an acceleration of the hydrological cycle and a melting cryosphere that can be expected from global warming.

Contribution of glaciers to water, energy and food security in mountain regions: current perspectives and future priorities

AbstractMountain glaciers are crucial sources of fresh water, contributing directly and indirectly to water, energy and food supplies for hundreds of millions of people. Assessing the impact of diminishing glacial meltwater contributions to the security of this resource is critical as we seek to manage and adapt to changing freshwater dynamics in a warming world. Both water quantity and quality influence water (in)security, so understanding the fluxes of water, sediment and contaminants through glacial and proglacial systems is required for holistic assessment of meltwater contribution to downstream resource security. In this paper we consider the socio-environmental role of and pressures on glacier-fed waters, discuss key research priorities for the assessment of both the quantity and quality of meltwater and reflect on the importance of situating our understanding within a transdisciplinary and inclusive research landscape.

The Contribution of Glacial Melt Water to Annual Runoff of River Volga in the Last Glacial Epoch

The Contribution of Glacial Melt Water to Annual Runoff of River Volga in the Last Glacial Epoch

Glacial Change and Its Hydrological Response in Three Inland River Basins in the Qilian Mountains, Western China

Glacial changes have great effects on regional water security because they are an important component of glacierized basin runoff. However, these impacts have not yet been integrated and evaluated in the arid/semiarid inland river basins of western China. Based on the degree-day glacier model, glacier changes and their hydrologic effects were studied in 12 subbasins in the Shiyang River basin (SYRB), Heihe River basin (HHRB) and Shule River basin (SLRB). The results showed that the glacier area of each subbasin decreased by 16.7–61.7% from 1965 to 2020. By the end of this century, the glacier areas in the three basins will be reduced by 64.4%, 72.0% and 83.4% under the three climate scenarios, and subbasin glaciers will disappear completely after the 2070s even under RCP2.6. Glacial runoff in all subbasins showed a decreasing–increasing–decreasing trend, with peak runoff experienced in 11 subbasins during 1965~2020. The contribution of glacial meltwater to total runoff in the basin ranged from 1.3% to 46.8% in the past, and it will decrease in the future due to increasing precipitation and decreasing glacial meltwater. However, the scale differences in glacier runoff are significant when aggregated over the region/basin/subbasin. This suggests that the results of large-scale generalization may be misleading for subbasin glacier water resource evaluations. Therefore, the hydrological effects of glaciers should be studied more in subbasins to provide an accurate reference for practical water resource management.

Influence of glacial sediments on the chemical quality of surface water in the Ulta valley, Cordillera Blanca, Peru

The Río Santa (Ancash, Peru) and its tributaries are an essential source of drinking and irrigation water. Its discharge relies on glacial meltwater, which is diminishing due to the rapid decrease in glacial extent. As a secondary effect, water quality can be compromised (e.g. pH < 3 and high concentrations of SO42− and trace metals). Although this has previously been attributed to pyrite rich Chicama bedrock exposed by glacial retreat, little is known about the occurrence of Chicama fragments in Quaternary glacial sediments and its influence on water quality. This research aims at elucidating this effect by relating observed changes in water quality in streams to presence and chemical composition of morainic ridges in the Quebrada Ulta in the Río Santa basin. Changes in water quality before and after contact with a morainic ridge were assessed using carbonate alkalinity titration, ion analysis and elemental analysis. Moreover, relative contributions of glacial meltwater and precipitation were assessed qualitatively using stable water isotope analysis. We used a novel method to explain the provenance of contaminated glacial sediments using a reconstruction of their source area. The mineralogical composition of a morainic ridge was strongly related to the geology of the source area indicating that mineralogical composition of tills may be predicted using this technique. Effects of glacial sediments in morainic ridges on water quality were minimal but depended on their mineralogical composition. Morainic ridges with a high content of Chicama shales tended to increase solute loads of Mg and SO42−. Additionally, isotope signatures suggest that during the dry season, moraines may act as reservoirs for precipitation-derived shallow groundwater. Clear trends in water quality were observed along the whole flow path of the Río Buín, which could potentially be explained by increased groundwater contribution downstream and shifts in dominant weathering mechanisms. Future research should focus on disentangling these various drivers of water quality in glacial catchments.

Late summer glacial meltwater contributions to Bull Lake Creek stream flow and water quality, Wind River Range, Wyoming, USA

ABSTRACTThe Wind River Range in Wyoming contains more glacial ice than any other location within the USA’s Rocky Mountain states of Colorado, Idaho, Montana, and Wyoming. Bull Lake Creek watershed in the southeast portion of the range contains five major (0.6–1.5 km2) glaciers along with numerous smaller glaciers that contribute to the Wind River. Field measurements were made of discharge from the Knife Point and Bull Lake Glaciers to determine the contribution of glacial meltwater to the river system. Water samples were collected and analyzed for stable isotopes, major ions, nutrients, and selected trace elements. Meltwater from the two glaciers contributed 13.9% to Bull Lake Creek streamflow (site BL-3), with all glaciers within the Bull Lake Creek watershed estimated to be contributing 55.6% to the streamflow of Bull Lake Creek (United States Geological Survey gage) during the August 2015 study period. Hydrogen and oxygen stable isotope analysis indicated as much as 80% of late summer discharge in the upper Bull Lake Creek watershed was attributed to glacial meltwater. This study also found that nutrients (NO3 – NO2, total P) from glacial meltwater can be a significant source of nutrient loading to Bull Lake Creek.

Distribution of trace metal in Shaune Garang catchment: evidence from particles and nanoparticles

Abstract The input of colloids and nanoparticles reactive elements might even cause catastrophic melting events of polar ice caps and glaciers. Although enhancing contribution of glacial melt water into the oceans might be responsible about the element concentrations and distribution in glacial melt water fed river systems. Distribution and environmental assessment of heavy metals in the melt water draining from the glacier system during 2016 has been studied. In order to evaluate the physical and chemical distribution such as salinity, dissolved oxygen and particulate matters (Mn, Al, Si and Zn) in the form of nanoparticles, water samples were filtered by using 0.2 µm filter paper. The sampling locations were six from the snout to the downstream of Shaune Garang water channel. The conductivity of melt water is found to be same for all sampling locations while pH showed a minor variation. Variation in pH and conductivity indicates that elemental concentration of the study area is predisposed by meteorological factors and duration of rock-water contact. The leading mechanism responsible for the high concentration of nutrient is expected due to the metal dissolution from the particulate phase in the glacial river system. Mn particles observed in the catchment ranged from 0.86 to 2.43 mg/l with an average value 1.53 ± 0.48 mg/l. This could be due to the long resident time of flowing water on the rock surface. Basically, heavy metals distribution in the glacial system is controlled by different mechanism such as weathering of rocks, nature of rock, transportation by glacier as well as melt water and deposition. The findings reported here can have important implications for understanding the localized glacio-hydrological variations within the Himalayan ranges.

Does hillslope trenching enhance groundwater recharge and baseflow in the Peruvian Andes?

AbstractAs Andean glaciers rapidly retreat due to climate change, the balance of groundwater and glacial meltwater contributions to stream discharge in tropical, proglacial watersheds will change, potentially increasing vulnerability of water resources. The Shullcas River Watershed, near Huancayo, Peru, is fed only partly by the rapidly receding Huaytapallana glaciers (&lt;20% of dry season flow). To potentially increase recharge and therefore increase groundwater derived baseflow, the government and not‐for‐profit organizations have installed trenches along large swaths of hillslope in the Shullcas Watershed. Our study focuses on a nonglacierized subcatchment of the Shullcas River Watershed and has 2 objectives: (a) create a model of the Shullcas groundwater system and assess the controls on stream discharge and (b) investigate the impact of the infiltration trenches on recharge and baseflow. We first collected hydrologic data from the field including a year‐long hydrograph (2015–2016), meteorological data (2011–2016), and infiltration measurements. We use a recharge model to evaluate the impact of trenched hillslopes on infiltration and runoff processes. Finally, we use a 3‐dimensional groundwater model, calibrated to the measured dry season baseflow, to determine the impact of trenching on the catchment. Simulations show that trenched hillslopes receive approximately 3.5% more recharge, relative to precipitation, compared with unaltered hillslopes. The groundwater model indicates that because the groundwater flow system is fast and shallow, incorporating trenched hillslopes (~2% of study subcatchment area) only slightly increases baseflow in the dry season. Furthermore, the location of trenching is an important consideration: Trenching higher in the catchment (further from the river) and in flatter terrain provides more baseflow during the dry season. The results of this study may have important implications for Andean landscape management and water resources.

Glacial melt content of water use in the tropical Andes

Accelerated melting of glaciers is expected to have a negative effect on the water resources of mountain regions and their adjacent lowlands, with tropical mountain regions being among the most vulnerable. In order to quantify those impacts, it is necessary to understand the changing dynamics of glacial melting, but also to map how glacial meltwater contributes to current and future water use, which often occurs at considerable distance downstream of the terminus of the glacier. While the dynamics of tropical glacial melt are increasingly well understood and documented, major uncertainty remains on how the contribution of tropical glacial meltwater propagates through the hydrological system, and hence how it contributes to various types of human water use in downstream regions. Therefore, in this paper we present a detailed regional mapping of current water demand in regions downstream of the major tropical glaciers. We combine these maps with a regional water balance model to determine the dominant spatiotemporal patterns of the contribution of glacial meltwater to human water use at an unprecedented scale and resolution. We find that the number of users relying continuously on water resources with a high (>25%) long-term average contribution from glacial melt is low (391 000 domestic users, 398 km2 of irrigated land, and 11 MW of hydropower production), but this reliance increases sharply during drought conditions (up to 3.92 million domestic users, 2096 km2 of irrigated land, and 732 MW of hydropower production in the driest month of a drought year). A large proportion of domestic and agricultural users are located in rural regions where climate adaptation capacity tends to be low. Therefore, we suggest that adaptation strategies should focus on increasing the natural and artificial water storage and regulation capacity to bridge dry periods.

The sustainability of water resources in High Mountain Asia in the context of recent and future glacier change

Abstract High Mountain Asia contains the largest volume of glacier ice outside the polar regions, and contain the headwaters of some of the largest rivers in central Asia. These glaciers are losing mass at a mean rate of between –0.18 and –0.5 m water equivalent per year. While glaciers in the Himalaya are generally shrinking, those in the Karakoram have experienced a slight mass gain. Both changes have occurred in response to rising air temperatures due to Northern Hemisphere climate change. In the westerly influenced Indus catchment, glacier meltwater makes up a large proportion of the hydrological budget, and loss of glacier mass will ultimately lead to a decrease in water supplies. In the monsoon-influenced Ganges and Brahmaputra catchments, the contribution of glacial meltwater is relatively small compared to the Indus, and the decrease in annual water supplies will be less dramatic. Therefore, enhanced glacier melt will increase river flows until the middle of the twenty-first century, but in the longer term, into the latter part of this century, river flows will decline as glaciers shrink. Declining meltwater supplies may be compensated by increases in precipitation, but this could exacerbate the risk of flooding.

Estimating the contribution of glacial meltwater to Ranwu Lake, a proglacial lake in SE Tibet, using observation data and stable isotopic analyses

It is important for both current monitoring and paleoenvironmental research conducted on proglacial lakes and their adjacent glaciers to clarify the hydrological processes operating on these lakes. However, in remote regions with limited accessibility it may be difficult to study hydrological processes by direct monitoring. In this study, we use measurements of stable isotopic compositions to trace the multiple water sources contributing to Ranwu Lake, a proglacial lake in south-eastern Tibet. Using stable isotopic data from precipitation, inflowing rivers and the lake water, a water and isotope mass balance modelling method was used to calculate the ratio of evaporation to input. Subsequently, using hydrological and climatic data for the outflow, the largest inflow and precipitation, other hydrological elements of the lake water balance were also calculated. The results demonstrate that the ratio of evaporation to inflow is as low as 0.009, the lowest value observed for the Tibetan Plateau, indicating that Ranwu Lake is a through-flow lake with a very short retention time. Glacial meltwater accounts for at least 55% of total runoff, the highest value observed for the Tibetan Plateau, indicating that the sediments of Ranwu Lake may have considerable potential for reconstructing variations in the activity of the local glaciers. Finally, we note that it may be inappropriate in this glacier-fed lake to use the intersection of the local meteoric water line with the lake water line for determining the isotopic composition of the input water, and this possibility must be carefully considered when stable isotope mass modelling is used in proglacial lakes.

Spatial variability in mass loss of glaciers in the Everest region, central Himalayas, between 2000 and 2015

Abstract. Region-wide averaging of Himalayan glacier mass change has masked any catchment or glacier-scale variability in glacier recession; thus the role of a number of glaciological processes in glacier wastage remains poorly understood. In this study, we quantify mass loss rates over the period 2000–2015 for 32 glaciers across the Everest region and assess how future ice loss is likely to differ depending on glacier hypsometry. The mean mass balance of all 32 glaciers in our sample was −0.52 ± 0.22 m water equivalent (w.e.) a−1. The mean mass balance of nine lacustrine-terminating glaciers (−0.70 ± 0.26 m w.e. a−1) was 32 % more negative than land-terminating, debris-covered glaciers (−0.53 ± 0.21 m w.e. a−1). The mass balance of lacustrine-terminating glaciers is highly variable (−0.45 ± 0.13 to −0.91 ± 0.22 m w.e. a−1), perhaps reflecting glacial lakes at different stages of development. To assess the importance of hypsometry on glacier response to future temperature increases, we calculated current (Dudh Koshi – 0.41, Tama Koshi – 0.43, Pumqu – 0.37) and prospective future glacier accumulation area Ratios (AARs). IPCC AR5 RCP 4.5 warming (0.9–2.3 °C by 2100) could reduce AARs to 0.29 or 0.08 in the Tama Koshi catchment, 0.27 or 0.17 in the Dudh Koshi catchment and 0.29 or 0.18 in the Pumqu catchment. Our results suggest that glacial lake expansion across the Himalayas could expedite ice mass loss and the prediction of future contributions of glacial meltwater to river flow will be complicated by spatially variable glacier responses to climate change.

Seasonal glacial meltwater contributions to surface water in the Bolivian Andes: A case study using environmental tracers

Carson Scholars program at University of Arizona's (UA) Institute of the Environment; UA Vice President for Research Faculty Small Grant [455310]; UA Center for Latin American Studies' Tinker Fellowship; Geological Society of America

Paleoproductivity and organic matter sources in Late Quaternary Lake Ontario

Abstract We have examined δ 13 C of ostracode valves and clam shells, carbon and nitrogen mass accumulation rates (C- and N-MAR), atomic C/N and δ 13 C OM from Lake Ontario since ~ 16,000 cal BP to evaluate the impacts of the Laurentide Ice Sheet (LIS) and regional paleohydrology on primary lacustrine productivity and sources of OM. Samples were obtained from piston cores from each of the Niagara, Mississauga and Rochester basins, which geographically span Lake Ontario from west to east. During the glacial period, variations in inputs directly from the LIS versus up-stream glacial Lake Algonquin and (or) ancient Lake Erie controlled the DIC pool in ancestral Lake Ontario. Cold and dry conditions limited primary productivity in the Ontario basin (low C/N ~ 7.5). Increased contributions of glacial meltwater from glacial Lake Algonquin during the latter stages of deglaciation provided a uniform supply of DIC to ancestral Lake Ontario and other lakes then occupying the Huron and Erie basins, stabilizing the δ 13 C DIC pool at ~− 4‰ (VPDB). Upon hydrologic closure of early Lake Ontario at the onset of post-glacial conditions (12,300 cal BP), a growing divergence between the δ 13 C of ostracode valves (decreases to − 6‰) and clam shells (increases to + 1‰) indicates differences in summer versus spring DIC pools. The end of glacial meltwater input to early Lake Ontario also made it possible to detect changes in primary lacustrine productivity using the isotopic and C/N proxies. Increasing δ 13 C OM (from ~− 29 to − 27.5‰) and low C/N (

A review of methods for estimating the contribution of glacial meltwater to total watershed discharge

Glaciers store water over a range of temporal scales with important implications for downstream human and natural systems. Assessment of the contribution of glacial meltwater runoff to total watershed discharge is an essential part of climate change risk assessment and sustainable water management in glacierized watersheds. Over the past decade, a range of techniques for quantifying the proportional contribution of glacial meltwater has been presented in the scientific literature. Here we examine five different methodological approaches: direct discharge measurement, glaciological approaches, hydrological balance equations, hydrochemical tracers, and hydrological modeling. After a brief summary of the role of glaciers in watershed hydrology, we evaluate each approach, with regard to their respective data requirements, assumptions, and associated uncertainties. Next, we discuss factors that researchers must consider in deciding upon a particular methodological approach, then conclude with a discussion of future research needs. We underscore the need for expanded meteorological, hydrological, and glaciological monitoring networks in glacierized watersheds worldwide, for more comprehensive assessment of uncertainty and for better integration of research with the specific needs of watershed stakeholders.

Variations of water stable isotopes (δ18O) in two lake basins, southern Tibetan Plateau

Abstractδ18O measurements based on systematic sampling and isotopic modeling have been adopted to study the controls of stable isotopes in lake water in two lake basins (lakes Yamdrok-tso and Puma Yum-tso) at two different elevations on the southern Tibetan Plateau. Temporally, δ18O values in precipitation and lake water display a seasonal fluctuation in both lakes. Spatially, δ18O values in the two lake basins increase by 10% from the termini of glaciers to the lake shores, by ∽1% from the lake shores to the lake center and by 0.4% from the water surface to depth in these lakes. The clear annual δ18O variations indicate that lake water mixes sufficiently in a short time. Model results show that glacial meltwater and surface lake-water temperature are not the dominant factors in the balance process of stable isotopes in lake water. Equilibrium δ18O values decrease by 0.8% for Yamdrok-tso lake and 0.6% for Puma Yum-tso lake when glacial meltwater contributions to these lakes shrink by 60%. δ18O ratios increase rapidly during the initial stages and take a longer time to approach the equilibrium value.

Climatic and geologic controls on suspended sediment flux in the Sutlej River Valley, western Himalaya

Abstract. The sediment flux through Himalayan rivers directly impacts water quality and is important for sustaining agriculture as well as maintaining drinking-water and hydropower generation. Despite the recent increase in demand for these resources, little is known about the triggers and sources of extreme sediment flux events, which lower water quality and account for extensive hydropower reservoir filling and turbine abrasion. Here, we present a comprehensive analysis of the spatiotemporal trends in suspended sediment flux based on daily data during the past decade (2001–2009) from four sites along the Sutlej River and from four of its main tributaries. In conjunction with satellite data depicting rainfall and snow cover, air temperature and earthquake records, and field observations, we infer climatic and geologic controls of peak suspended sediment concentration (SSC) events. Our study identifies three key findings: First, peak SSC events (≥ 99th SSC percentile) coincide frequently (57–80%) with heavy rainstorms and account for about 30% of the suspended sediment flux in the semi-arid to arid interior of the orogen. Second, we observe an increase of suspended sediment flux from the Tibetan Plateau to the Himalayan Front at mean annual timescales. This sediment-flux gradient suggests that averaged, modern erosion in the western Himalaya is most pronounced at frontal regions, which are characterized by high monsoonal rainfall and thick soil cover. Third, in seven of eight catchments, we find an anticlockwise hysteresis loop of annual sediment flux variations with respect to river discharge, which appears to be related to enhanced glacial sediment evacuation during late summer. Our analysis emphasizes the importance of unconsolidated sediments in the high-elevation sector that can easily be mobilized by hydrometeorological events and higher glacial-meltwater contributions. In future climate change scenarios, including continuous glacial retreat and more frequent monsoonal rainstorms across the Himalaya, we expect an increase in peak SSC events, which will decrease the water quality and impact hydropower generation.