Changes In Sediment Load Research Articles

Estimating future changes in streamflow and suspended sediment load under CMIP6 multi-model ensemble projections: a case study of Bitlis Creek, Turkey

Estimating future changes in streamflow and suspended sediment load under CMIP6 multi-model ensemble projections: a case study of Bitlis Creek, Turkey

Statistical studies of the characteristics and key influencing factors of sediment changes in the upper Yangtze River over the past 60 years

Sediments in the upper Yangtze River have significantly changed over the past 60 years. The characteristics and causes of these sediment changes must be determined in the upcoming phases of the comprehensive management of the Yangtze River Basin. Based on sediment observation data from 1960 to 2020, this study examined the trends and sudden changes in the sediments in the mainstream and its significant tributaries in the upper Yangtze River. The relative contributions of precipitation change and various human activities to sediment load changes are quantified. The relationships between sediment variations and the construction and large dam projects, soil and water conservation measures, and earthquake disasters are established. The results indicate that there was a significant decline in sediment load with main changes occurring around the 1985s and 2010s. Multiple double mass curves are used to quantify the relative contributions of precipitation change and human activities to sediment load changes. The relative contribution of dams to the decrease in sediment load ranges from 53 % to 74 %. Precipitation change serves a significant role in the observed changes, accounting for a range of 10 % to 27 %. Soil conservation measures take some time to show their impact on sediment reduction. These measures work by stabilizing the soil and improving hydrological conditions. On average, they contribute between 7 % and 20 % towards reducing sediment. In recent times, there has been a noticeable rise in sediment load in rivers like the Jialing and Min Rivers. This unexpected increase could potentially be linked to a combination of factors including earthquakes, heavy precipitation, and localized sediment scouring. The results of this study offer valuable insights into the variations in river sediment load, aiding in the improved management of water resources and sediment in large dams. These findings provide helpful insights for dam management.

Changes in Runoff and Sediment Loads in the Tuhai River Basin and the Factors Influencing These Changes

In this study, rainfall, runoff, and sediment load data were collected from the Tuhai River Basin from 1972 to 2021. The Mann–Kendall test, runoff–sediment curve, and double mass curve were used to identify the characteristics and factors influencing runoff and sediment loads in the Tuhai River Basin. The results showed that the average annual runoff and sediment loads in the river basin were 4.03 × 108 m3 and 3.52 × 108 kg, respectively; furthermore, the flood season (June–September) accounted for 79.9% and 99.4% of these values, respectively. There were no apparent runoff trends in the annual, flood, and non-flood (October–May) stages, and the annual and flood season sediment loads decreased significantly. The abrupt change points of annual and flood season runoff in the Tuhai River Basin mainly occurred from 2003 to 2004 and from 2013 to 2014. Moreover, the abrupt change points of annual and flood season sediment load only occurred from 1978 to 1979. The runoff–sediment curve showed a clear power function relationship between runoff and sediment loads. The runoff in the Tuhai River Basin from 2003 to 2013 was mainly affected by precipitation. Additionally, the contributions of human activities to runoff and sediment load reduction in the Tuhai River Basin were 57.7–88.9% and 63.1–86.0%, respectively. The increase in human water consumption was the main reason for the decrease in runoff in the Tuhai River Basin. Furthermore, the measures taken in soil and water conservation and reservoir construction were the main factors behind a reduction in sediment loads in the Tuhai River Basin.

Quantifying the impacts of climate change and human activities on runoff and suspended sediment load in the Lhasa River Basin, Tibetan Plateau

AbstractQuantifying the attribution of climate change and human activities on runoff and suspended sediment load is crucial for formulating future watershed management measures, especially in the ecologically fragile alpine region, which is more susceptible to climate change and human activities. In this study, the temporal changes in runoff‐suspended sediment load and the potential impact factors (i.e., precipitation, potential evapotranspiration (PET), land use/land cover change (LULC) and reservoir operation) were investigated in the Lhasa River Basin (LRB) from 1956 to 2020. In addition, the contributions of those factors to the changes in runoff and suspended sediment load were quantitatively evaluated based on physically‐based Soil and Water Assessment Tools (SWAT). The results indicated that annual runoff and suspended sediment load showed an increasing but insignificant trend during 1956–2020, while annual precipitation and PET showed a significant increasing trend at a rate of 0.94 and 1.07 mm/yr, respectively. LULC mainly presented an increase in forestland area followed by a decrease in grassland and bare land area due to the implementation of ecological projects. Runoff and suspended sediment load changed abruptly at approximately 1995 and 2005 based on three abrupt change identification methods, thus, the study period was further divided into three substages: baseline period (P0, 1956–1994), dramatically increased period (P1, 1995–2004) and slightly decreased period (P2, 2005–2020). The attribution analysis showed that climate change was the dominant contributor to runoff and suspended sediment load increments during P1. LULC caused the decline in runoff and suspended sediment load in both P1 and P2, with their contribution increasing significantly from 0.40% and 4.73% in P1 to 50.24% and 51.79% in P2, respectively. Reservoir operation was the second key factor in runoff and suspended sediment load reduction in P2, contributing 42.07% and 43.72%, respectively. These findings provide the scientific foundation for reasonably allocating water resources and statistical support for the benefit evaluation of implementing ecological projects in the basin.

Dramatic sediment load changes and sedimentation characteristics upstream of the Three Gorges Dam due to the large reservoirs construction

Dramatic sediment load changes and sedimentation characteristics upstream of the Three Gorges Dam due to the large reservoirs construction

Changes in sediment load in the Lower Yellow River and its driving factors from 1919 to 2021

Rivers are not only an essential component of the development of civilization and the carbon cycle worldwide, but also a main contributor to natural disasters, especially the Lower Yellow River (LYR). With the functional degradation of the water–sediment regulation scheme (WSRS), LYR has reached a new stage. Thus, the changes in the sediment load in the Suspended River and its driving factors have significant practical applications. In this study, the sediment load in the LYR was analyzed from 1919 to 2021 based on improved sediment identity factor decomposition, wavelet analysis, and a double cumulative curve. The results showed that the changes in discharge and sediment exhibited poor synchronicity at different timescales. The sediment load decreased significantly, with evident periodicity of 9–10 years (years denoted as ‘a’) since 1950, and 69-a, 32-a, and 9-a since 1919. The changes in the sediment load can be divided into four phases: 1919–1959, 1960–1979, 1980–1998, and 1999–2021. Artificial levees can effectively constrain water flow and enhance sediment transport when the levee spacing is less than 6 km. To restrain deposition of the LYR, large dams control the incoming sediment coefficient so as to not exceed 0.009 kg∙s m−6. However, the WSRS reached its limit in 2010, and the wandering reach showed a deteriorating trend. Human activities control the changes in the sediment load. The reduction in the sediment load was mainly attributed to decreases in effective water yield capacity (53 %–75 %) before 1999 and sediment concentrations (46 %–65 %) after 1999. These results can provide a reference for further management of the suspended river.

Monitoring the Dynamics of Sedimentary Load Variations Along Coastal Regions Using UAVs After Monsoon and High Tide Events at Pantai Punggur and Pantai Perpat, Batu Pahat, Johor

This research investigates the changes in sedimentary load along the Pantai Punggur to Pantai Perpat coastline in Batu Pahat, Johor, particularly during the northeast monsoon period from October 2022 to February 2023. The study aims to produce a mapping diagram of the shoreline profile and volume changes across various locations and their association with monsoon changes. The research utilised aerial images captured by UAVs, which were analysed using Pix4D and Global Mapper software. Data was collected for six months from September 2022 to February 2023, with the observation period experiencing a high tide phenomenon on November 24, 2022, resulting in a significant change in the data for that month. Shoreline profile results did not establish a conclusive link between sediment load changes and erosion or accretion due to the lack of volumetric data. Consequently, an analysis of volume changes was conducted using the Global Mapper application. In conclusion, the northeast monsoon wind and high tide phenomena during November 2022 significantly impacted the shoreline profile and total volume of the Pantai Perpat and Pantai Punggur areas.

Analysis of Changes in Runoff and Sediment Load and Their Attribution in the Kuye River Basin of the Middle Yellow River Based on the Slope Change Ratio of Cumulative Quantity Method

Climate change and human activities exert significant influence on the water–sediment relationship in arid and semi-arid regions. Therefore, comprehending the underlying mechanisms is crucial for the effective management of water and soil resources, as well as integrated watershed management. This research focuses on the Kuye River watershed (KYH_W) in the middle reaches of the Yellow River in China, along with its sub-watersheds Wangdaohengtazi (WDHT_SW) and Xinmiaosi (XM_SW). This paper utilizes the Mann–Kendall non-parametric test and the double cumulative curve method to examine the interannual trends of runoff, sediment transport, precipitation, temperature, and NDVI factors. Furthermore, the method of the slope change ratio of cumulative quantity (SCRCQ) is utilized to quantitatively evaluate the impacts and contribution rates of climate change and human activities on water–sediment changes within each watershed. The results are as follows: (1) From 1969 to 2019, the entire watershed experienced a significant decrease in both runoff and sediment transport, with 1997 marking the year of abrupt change. However, following 2012, the KYH_W and WDHT_SW exhibited a noticeable rebound in runoff. (2) Human activities predominantly contribute to the reduction in water and sediment in the watershed. (3) After the abrupt change, between 1998 and 2011, the contribution rates of climate change and human activities to the annual runoff reduction in the entire KYH_W reached 33% and 64%, respectively. Moreover, these rates for sediment transport reduction reached 26% and 74%, respectively. Subsequently, after 2012, the contribution rates of both factors to the increase in watershed runoff reached 29% and 71%, respectively. Factors other than the NDVI, within human activities, played a dominant role in augmenting the watershed’s runoff. (4) Prior to 2011, changes in vegetation cover resulting from the Grain for Green Program, as measured by the NDVI, emerged as the primary factor responsible for reduced runoff in the watershed. Conversely, factors other than the NDVI assumed dominance in reducing sediment transport. The SCRCQ method offers a quantitative approach to assessing water–sediment changes. Based on this method, the study further underscores the substantial impacts of climate change and human activities on variations in runoff and sediment transport within the KYH_W in the middle reaches of the Yellow River. Notably, the water–sediment changes in the KYH_W exhibit distinct stage-wise and spatial discrepancies, which warrant increased attention in future research endeavors.

Historical climate impact attribution of changes in river flow and sediment loads at selected gauging stations in the Nile basin

The Nile basin is the second largest basin in Africa and one of the regions experiencing high climatic diversity with variability of precipitation and deteriorating water resources. As climate change is affecting most of the hydroclimatic variables across the world, this study assesses whether historical changes in river flow and sediment loads at selected gauges in the Nile basin can be attributed to climate change. An impact attribution approach is employed by constraining a process-based model with a set of factual and counterfactual climate forcing data for 69 years (1951–2019), from the impact attribution setup of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP3a). To quantify the role of climate change, we use the non-parametric Mann-Kendall test to identify trends and calculate the differences in long-term mean annual river flow and sediment load simulations between a model setup using factual and counterfactual climate forcing data. Results for selected river stations in the Lake Victoria basin show reasonable evidence of a long-term historical increase in river flows (two stations) and sediment load (one station), largely attributed to changes in climate. In contrast, within the Blue Nile and Main Nile basins, there is a slight decrease of river flows at four selected stations under factual climate, which can be attributed to climate change, but no significant changes in sediment load (one station). These findings show spatial differences in the impacts of climate change on river flows and sediment load in the study area for the historical period.

Past anthropogenic land use change caused a regime shift of the fluvial response to Holocene climate change in the Chinese Loess Plateau

Abstract. The Wei River catchment in the southern part of the Chinese Loess Plateau (CLP) is one of the centers of the agricultural revolution in China. The area has experienced intense land use changes since ∼6000 BCE, which makes it an ideal place to study the response of fluvial systems to past anthropogenic land cover change (ALCC). We apply a numerical landscape evolution model that combines the Landlab landscape evolution model with an evapotranspiration model to investigate the direct and indirect effects of ALCC on hydrological and morphological processes in the Wei River catchment since the mid-Holocene. The results show that ALCC has not only led to changes in discharge and sediment load in the catchment but also affected their sensitivity to climate change. When the proportion of agricultural land area exceeded 50 % (around 1000 BCE), the sensitivity of discharge and sediment yield to climate change increased abruptly indicating a regime change in the fluvial catchment. This was associated with a large sediment pulse in the lower reaches. The model simulation results also show a link between human settlement, ALCC and floodplain development: changes in agricultural land use led to downstream sediment accumulation and floodplain development, which in turn resulted in further spatial expansion of agriculture and human settlement.

Quantifying the consequences of unsustainable sand mining and cascade dams on aspects in a tropical river basin

Human interventions at the river basin scale, such as sand mining and hydropower dam construction, have profoundly affected hydrological and hydraulic alteration regimes, sediment budgets, and morphological changes worldwide. Quantifying the consequences of unsustainable ongoing sand mining and hydropower is crucial for obtaining sediment load data and managing hydrogeomorphology. In this study, comprehensive long-term consecutive four-field monitoring, statistical methods, and hydrological models (SWAT) were applied to quantify the spatiotemporal changes in long-term discharge and sediment load from 1996 to 2020 for the tropical river of the Vu Gia Thu Bon (VGTB) in the central region of Vietnam. The SWAT model was calibrated from 1996 to 2010, validated from 2011 to 2020 and showed good performance for daily discharge and monthly sediment. The evolution of river bathymetric data (2010, 2015, 2018, and 2021) was analysed to clarify the upstream sediment supply trapped in the riverbed and how the sand mining volume was removed. The results showed that the mean annual sediment in the Vu Gia and Thu Bon Rivers decreased by 57.3% and 23.8%, respectively, in the postdam period compared with the predam period. The thalweg elevation decreased at the Ai Nghia and Giao Thuy stations from 2010 to 2021 by 1.8 m and 3.9 m, respectively. The water level decreased by 21.1% at Ai Nghia and 44.3% at Giao Thuy. Dam development, sand mining, and changes in land use are the main factors responsible for flow discharge and sediment morphodynamic alterations. Morphological change have increased the water transfer rate from the Vu Gia River to the Thu Bon River through the Quang Hue channel. Downstream of the Vu Gia River, water transfer and riverbed incision have decreased flow discharge and water level and increased saltwater intrusion in recent years. As a result, water shortages induced by saltwater intrusion during drought periods have emerged as a significant constraint in hindering the domestic water supply and agricultural production.

Runoff and sediment load changes in the upper Yellow River and their influencing factors in recent 60 years

Runoff and sediment load changes in the upper Yellow River and their influencing factors in recent 60 years

Impacts of climate change and human activities on sediment load in Longchuan River Basin, China

Study regionLongchuan River Basin in the Hengduan mountain region, China. Study focusWith the decrease in annual precipitation, the sediment yield on the slope and sediment delivery ratio (SDR) in the river channel, both play a critical role in runoff and sediment load change. However, the response mechanism of SDR to climate change and human activities remains unclear. The RUSLE model was used to calculate the sediment yield on the slope, and the SDR is quantified by the ratio of sediment load in the channel to the sediment yield on the slope.New hydrological insights for the region: Under climate change, the reduced annual rainfall caused a significant decrease in annual runoff and sediment load in the Longchuan River Basin (LRB), since 2003. The RUSLE model was used to calculate the sediment yield on the slope in LRB, and the sediment delivery ratio (SDR) was calculated by the ratio of sediment load to sediment yield. We found a new approach relevant to the relationship of SDR with annual runoff and sediment yield, which can indicate the response mechanism of SDR to climate change. In anthropogenic activities, reservoir interception is the main reason for the sediment load reduction, instead of the land use and land cover change. With a large reservoir built in the LRB, the average SDR is reduced by 83.04 % and the average trap efficiency of the reservoir is 0.96, which was calculated by the Brune equation. This study provides a feasible method to evaluate the effect of different factors on the runoff and sediment load change in the basin.

The Lag Effect of Riverine Flow-Discharge and Sediment-Load Response to Antecedent Rainfall with Different Cumulative Durations in Red Hilly Area in China

Rainfall is an important factor that causes riverine flow and sediment transport, and extreme rainfall has a particularly significant effect on the fluctuations of riverine flow and sediment load. Based on the daily rainfall from 1990 to 2020, in the upper watershed of the Lianjiang River, which is one of the source tributaries of China’s largest freshwater lake (Poyang Lake), the 95th percentile method and minimum event interval time were employed to identify extreme rainfall events. Mann–Kendall test was used to check for abrupt changes in annual rainfall, riverine flow discharge, and riverine sediment loads, and to identify abrupt-change years; thus, different periods were divided via the abrupt change years. Multiple linear regression was applied to explore the lag effect of riverine flow-discharge and sediment-load response to antecedent rainfall, with different cumulative durations for each period. The results of the study indicated that (1) the expansion of garden land in 1995 caused a significant and abrupt change in sediment load. (2) Extreme rainfall events had a greater impact on riverine flow and sediment load as compared to ordinary rainfall. These events were found to explain more variations in riverine flow and sediment load, which led to longer lag times for both riverine flow and sediment transport. (3) The expansion of garden land under extreme rainfall conditions resulted in longer lag times for riverine flow and sediment transport, and reduced the need for antecedent rainfall with a longer pre-event time. Therefore, the analysis of antecedent rainfall and the lag response of riverine flow discharge and sediment load can help in understanding the response mechanism of riverine flow discharge and sediment load for the current era of increasing extreme rainfall. This analysis is crucial for improving the accuracy of simulating riverine flow and sediment under extreme rainfall conditions. Ultimately, it can contribute to effective watershed management during extreme rainfall events.

Climate change impacts on streamflow, sediment load and carbon fluxes in the Lena River delta

Water and sediment supply are essential to the health of deltaic ecosystems. Diverse datasets were integrated to better understand how climate change is shifting the supply of water and sediment to the largest polar distributary channel pattern – the Lena River Delta. Here the increase in warming rate from an average air temperature is from 4.1 °C for the period 1950–99 to 6.1 °C during 2000–21, which is higher than in the adjacent polar regions. Streamflow and sediment yield entering the Lena Delta have increased since 1988 by 56.3 km3 and 6.1×106 t, respectively; meanwhile, the Lena River’s increases in water temperature in June, July–August and September were found to be as much as 1.1, 0.6 and 0.05 °C. These changes have a pronounced effect on sediment regimes in particular parts of the delta. Based on analyses of correlations between various hydroclimatic drivers and sediment concentration changes across particular distributaries of the Lena Delta extracted from Landsat datasets, bank degradation driven by thermal erosional processes (which are in turn related to air and soil temperature increases) is proved to be the primary factor of the sediment regime in the delta. The study also highlights that sediment load changes are sensitive to wind speed due to remobilization of bottom sediment. Sums of daily air temperature and wind speed over 3 days are correlated with sediment concentration changes in the delta. The results also indicate that carbon transport across the delta (both POC and DOC) depends on sediment transport conditions and water discharge and might increase by up to 10 %. We conclude that the Lena Delta can be recognized as the global hot spot in terms of the hydrological consequences of climate change, which is altering sediment regimes, stream hydromorphology and carbon transport.

Update of Empirical Models for Predicting Specific Degradation in South Korea and Future Sediment Management Considering Climate Change

In this study, the existing empirical models for sediment management for ungauged watersheds in South Korea developed in 2019 were updated. The existing models were developed based on the Universal Soil Loss Equation structure with domestic river sediment data obtained from 2005 to 2014 and watershed characteristic values. To update the models, the specific degradation (SD) value was calculated first in the same way as the existing method by adding sediment measurement and daily discharge data obtained from 2015 to 2020. The calculated SD values with recent data decreased compared with the past and differed from the results predicted using the existing models and the watershed characteristics investigated in this study. For this reason, the existing models were updated using the latest watershed characteristics and SD values. The root-mean-square error values of the existing models, which ranged from 131 to 90 tons/km2·year, decreased to 102 to 62 tons/km2·year in the updated models with the same structures. Multicollinearity was tested to evaluate the reliability of the updated models, and a new 95% prediction interval for usability was estimated. In addition, quantitative changes in the future sediment load of domestic rivers were analyzed using the future rainfall data obtained from climatic change scenarios and the watershed area. The results of this study reconfirmed that periodic updates are required for the existing empirical models. It is expected that the empirical models will be used in various ways, such as for the prediction of future sediment loads for river sediment management.

Changes in flow and sediment transport caused by cascade hydropower in the upper reaches of Yangtze River and their influence on spawning of Coreius heterodon

The upper reaches of the Yangtze River (YR) constitute the largest group of hydropower cascade projects in the world. The construction of cascade hydropower systems has a significant impact on the flow regimes and sediment transport in rivers, ultimately affecting fish spawning. Previous studies have examined the effects of fluctuating flow and water temperature on spawning; however, insufficient attention has been paid to their effects on sediment transport. This study analysed changes in runoff and sediment load (SL) at the Xiangjiaba hydrologic station (XJB) and Zhutuo hydrologic station (ZT) in the upper reaches of the YR over the past 60 years. Based on the indicators of hydrological regimes and sediment transport, we used the generalized additive models (GAM) to investigate the effects of cascade hydropower operations from 2009 to 2018 on the spawning abundance of Coreius heterodon (C. H) in the upper YR Fish Reserve. Following the operation of cascade hydropower, the SL and sediment concentration decreased by 56.8% and 56.6%, respectively, while the median size of the bed-material load demonstrated an initial thinning trend followed by subsequent coarsening. In addition, the frequency of the high-flow pulse increased by 32.1%, whereas the peak flow and duration of the high-flow pulse decreased by 41.2% and 62.6%, respectively. However, no significant changes were noted in the indicators of the flooding process. The decrease in sediment transport and changes in the flow regime led to a reduction in the spawning abundance of C. H. Reductions in sediment transport and changes in high-flow pulses caused by cascade hydropower can negatively affect C. H spawning, and SL is the most important indicator of impacts on spawning abundance (contribution of 77.7%). These findings are critical for evaluating the long-term impacts of cascade hydropower on fish habitats.

Long-term analysis of sediment load changes in the Red River system (Vietnam) due to dam-reservoirs

The sediment regime of the Red River system, the second largest in Vietnam, has undergone changes since the implementation of dams and reservoirs, with implications for downstream river processes. We analyzed long-term datasets of daily discharge and suspended sediment concentrations collected at key gauging stations downstream of the three main tributaries: HB on the Da River, YB on the Red River (main channel), VQ on the Lo River, and ST, the outlet of the Red River system. The results indicated a sharp reduction in the annual sediment load transported by the Red River system, as observed at the four stations. For example, at the ST station, there was a dramatic decline of 91% in sediment load, dropping from 117.9 × 106 ton/yr in the period 2009–2021 to 10.5 × 106 ton/yr in the period 1958–1987. The Red River system experienced two notable declines in sediment load. The first decline occurred from 1988 to 2008, which can be attributed to the commencement of Hoa Binh dam's operation in 1988. The second decline has taken place since 2009, coinciding with the utilization of new dam-reservoirs. Meanwhile, an abrupt change in water discharge was observed clearly since the end of 2008 at all four stations. However, the reductions in water discharges were found to be less pronounced when compared to the sediment budget. Based on our analysis, we concluded that the impacts of dam-reservoirs have had a more substantial influence on the system compared to variations in climate, such as air temperature and precipitation.

Impact of Reduced Fluvial Sediment Supply on Saltwater Intrusion in the Yangtze Estuary

AbstractA decline of the fluvial sediment supply leads to coastal erosion and land loss. However, the fluvial sediment load may influence not only coastal morphodynamics but also estuarine hydrodynamics and associated saltwater intrusion. Previous studies revealed that suspended sediments influence estuarine hydrodynamics through various flow–sediment interactions. In this contribution, we systematically investigate how changes in fluvial sediment load and other climate‐change‐induced environmental change influence estuarine hydrodynamics and sediment dynamics. For this purpose, we utilize a well‐calibrated fully coupled model in which hydrodynamics, saltwater intrusion, and sediment transport interact with each other, to explore saltwater intrusion in the Yangtze Estuary in response to a decline in the sediment load, modified discharge, and sea‐level rise. Model results suggest that a 70% decline in the suspended sediment load weakens the impact of sediments on salinity‐induced stratification and thereby reducing saltwater intrusion. Sea‐level rise or discharge peak reduction increases saltwater intrusion. However, a fully coupled model accounting for sediment effects predicts a much larger increase in saltwater intrusion compared to noncoupled models. Whether this effect is important depends on estuarine sediment concentrations and therefore the potential role of sediments should be carefully investigated before applying a noncoupled model. This work highlights not only the relevance of a suspended sediment decline but also the use of fully coupled models for predicting saltwater intrusion in turbid estuaries and has broad implications for freshwater resource management in turbid estuarine systems influenced by human interventions and climate change.

Fluvial sediment load sensitivity to climate change in cold basins on the Tibetan Plateau: An elasticity approach and the spatial scale effect

The sensitivity of fluvial sediment load to climate change and predictions of future sediment load in cold basins remain poorly investigated, although changes in river sediment transport have important geomorphological, ecological, and societal implications. Here, we adapt a sediment elasticity approach to examine the sensitivity of fluvial suspended sediment load to changes in air temperature and precipitation in the headwater of the Yangtze River (HYR) on the inner Tibetan Plateau. Results show that every 1 °C increase in air temperature can increase the suspended sediment load by 14–27 % by intensifying thermally-driven glacial and permafrost erosional processes, and every 10 % increase in precipitation can increase the suspended sediment load by 16–24 % through enhancing pluvial-driven erosional processes. We predict an increase of 60–85 % in the suspended sediment loads in HYR by 2050 relative to the present-day period under the Representative Concentration Pathway 4.5, as both air temperature and precipitation are projected to increase. Our analysis highlights that smaller upland rivers appear to respond to modern climate change more rapidly and intensively than larger downstream rivers due to the larger glacier and permafrost coverages, poorer vegetation, as well as steeper fluvial relief, and higher sediment connectivity. This study provides a framework and a data-driven sediment elasticity approach to predict climate change and cryosphere degradation-driven changes in future fluvial suspended sediment load in cold basins, highlights the importance of the spatial scale effects in modulating fluvial responses, and has implications for assessing the impacts of climate change on channel morphology and aquatic ecosystems.