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Frequent natural hazards cause huge damage to human life and society in the mountainous regions along the eastern rim of the Tibetan Plateau. A massive landslide damming event has been reported in the Jishixia Gorge on the upper Yellow River as it emerges from the NE Tibetan Plateau. It was speculated that a breach of the dammed lake might have resulted in a super flood disaster that ruined the major Neolithic settlement at Lajia (4.20–3.95 ka BP) within the Guanting Basin that is located in the downstream. However, our detailed investigations along the Jishixia Gorge and Guanting Basin indicate that the dammed lake became shallower and desiccated gradually rather than breaching suddenly. The Yellow River has cut into the dammed lake deposits forming well-exposed profiles on the riverbanks. The dammed lake deposits are considered to provide an accurate natural record of the life-span of the dammed lake. Optically Stimulated Luminescence (OSL) dating was carried out on a series of eight samples taken from the profile. The OSL ages of the dammed lake deposits fall within the range of 8.25 ± 0.39 to 5.65 ± 0.21 ka at the Yisiri site about 2.5 km upstream of the landslide dam. These results indicate that the massive landslide damming event and the corresponding dammed lake occurred at 8.25 ka in the early Holocene. The dammed lake existed for about 2600 years and desiccated gradually and disappeared at 5.65 ka because the landslide dam was dissected slowly by the Yellow River. This means that the landslide dammed lake on the Yellow River disappeared about 1700 years before the Neolithic settlement at Lajia became ruins. The landslide damming event in the Jishixia Gorge is not related to the prehistorical catastrophic disasters that overcame the Lajia settlement within the Guanting Basin. [ABSTRACT FROM AUTHOR]

Multifractal detrended fluctuation analysis (MFDFA) can provide information about inner regularity, randomness and long-range correlation of time series, promoting the knowledge of their evolution regularity. The MFDFA are applied to detect long-range correlations and multifractal behavior of streamflow series at four hydrological stations (Toudaoguai, Longmen, Huangfu and Ganguyi) in the main channel and tributaries of the Yellow River. The results showed that there was one crossover point in the log-log curve of the fluctuation function Fq(s) versus s. The location for the crossover point is approximately one year, implying an unchanged annual periodicity within the streamflow variations. The annual periodical feature of streamflow was removed by using seasonal trend decomposition based on locally weighted regression (STL). All the decomposed streamflow series were characterized by long-term persistence in the study areas. Strong dependence of the generalized Hurst exponent h(q) on q exhibited multifractal behavior in streamflow time series at four stations in the Yellow River basin. The reduction of dependence of h(q) on q for shuffled time series showed that the multifractality of streamflow series was responsible for the correlation properties, as well as the probability density function of the streamflow series. [ABSTRACT FROM AUTHOR]

There are many natural and anthropogenic impacts on the vegetation in riparian wetlands. The Yellow River in the North of China is one of the biggest rivers of the world, but the riparian wetland area is very small. The monitoring of these wetlands has increased in the last years because of the high ecological importance and increasing pressure due to economic development and increasing use of water resources. We use remote sensing and hydrologic data to analyze the change of wetland vegetation in the Zhengzhou natural reserve, which is affected by a rapid population growth and change of water flow. The main findings are: (1) the vegetation cover of the study area decreased from 1984 to 2011, (2) the hydrologic boundary conditions changed dramatically after the construction of a dam upstream and floods have almost disappeared under the new water resource management, (3) there is a conflict between the protection of the wetland vegetation and its use for recreation and tourism. Actually, anthropogenic factors are the main reasons for wetland degradation, and the government and the water management department should pay more attention to the protection of the remaining wetlands and the environmental balance. [ABSTRACT FROM AUTHOR]

Holocene slackwater deposits along the river channels were used to study the magnitude and frequency of the palaeofloods that occurred prior to gauged and historical data sets all over the world. Palaeohydrological investigations along the Shanxi-Shaanxi Gorge of the middle Yellow River, China, identified palaeoflood slackwater deposits (SWDs) at several sites along the cliffs bordering the river channel. The SWDs are intercalated within Holocene eolian loess-soil profiles and clastic slope deposits. The palaeoflood SWDs were differentiated from eolian loess and soil by the sedimentary criteria and analytical results including magnetic susceptibility and particle-size distribution, similar to the flood SWDs in 2012, which indicated that these well-sorted palaeoflood SWD beds were deposited from the suspended sediment load in floodwaters. They have recorded the extraordinary palaeoflood events which occurred between 3200 and 3000 a BP as dated by the optically stimulated luminescence method in combination with pedostratigraphic correlations with the previously studied Holocene pedo-stratigraphy in the Yellow River drainage basin. Manning slope-area calculations estimate the peak discharged for these palaeoflood events to range from 43,290 to 49,830 m/s. The drainage area of the study site is 489,900 km. It is 2.0-2.5 times the largest gauged flood (21,000 m/s) that has ever occurred since 1934. These events also occurred on Yellow River tributaries, including the Weihe, Jinghe and Qishuihe Rivers. These flood events are therefore considered to be a regional expression of known climatic events in the northern hemisphere and demonstrate Holocene climatic instability. This study provides important data in understanding the interactions between regional hydro-climatic systems and global change in semiarid and subhumid regions. [ABSTRACT FROM AUTHOR]

Mapping and assessing soil-erosion risk can address the likelihood of occurrence of erosion as well as its consequences. This in turn provides precautionary and relevant suggestions to assist in disaster reduction. Because soil erosion by water in the watershed of the Ningxia-Inner Mongolia reach of the Yellow River is closely related to silting of the upper reaches of the Yellow River, it is necessary to assess erosion risk in this watershed. This study aims to identify the soil-erosion risk caused by water in the watershed of the Ningxia-Inner Mongolia reach of the Yellow River from 2001 to 2010. Empirical models called Chinese Soil Loss Equation (CSLE) and Modified Universal Soil Loss Equation (MUSLE) were used to predict the erosion modulus in slope surfaces and gullies. Then the soil erosion risk in this watershed was assessed according to the classification criteria of soil erosion intensities (SL190-2007). The study results showed that the range of values of the erosion modulus in this watershed was 0-44,733 t/km/a. More than 20% of the total watershed area was found to present an erosion risk, with the regions at risk mainly located in channels and their upper reaches, and in mountainous areas. To determine the regression coefficients of the erosion factors with respect to erosion modulus, a GWR (geographically weighted regression) was carried out using the ArcGIS software. It was found that the topographic factor has the highest contribution rate to the soil erosion modulus, while the highest contribution rate of the erosion factors to the erosion modulus and the largest values of the factors were not located in the same places. Based on this result, the authors propose that slope management is the most important task in preventing soil loss in this watershed, and the soil-conservation projects should be built according to the contribution rate of the erosion factors. [ABSTRACT FROM AUTHOR]

The phylogeography of common and widespread species helps to elucidate the history of local flora and vegetation. In this study, we selected Cotinus coggygria, a species widely distributed in China's warm-temperate zone. One chloroplast DNA (cp DNA) region and ecological niche modelling were used to examine the phylogeographic pattern of C. coggygria. The cp DNA data revealed two phylogeographic groups (Southern and Northern) corresponding to the geographic regions. Divergence time analyses revealed that divergence of the two groups occurred at approximately 147,000 years before the present ( BP), which coincided with the formation of the downstream area of the Yellow River, indicating that the Yellow River was a weak phylogeographic divide for C. coggygria. The molecular data and ecological niche modelling also indicated that C. coggyria did not experience population expansion after glaciations. This study thus supports the fact that Pleistocene glacial cycles only slightly affected C. coggygria, which survived in situ and occupied multiple localised glacial refugia during glaciations. This finding is contrary to the hypothesis of large-scale range habitat contraction and retreat into a few main refugia. [ABSTRACT FROM AUTHOR]

Although archaeological analysis emphasizes the importance of climatic events as a driver of historical processes, we use a variety of environmental and archaeological data to show that human modification of the environment was a significant factor in shaping the early history of the Yellow River region of North China. Humans began to modify site-specific and local-level environments in the Early Holocene (~11,500–7000 BP). By the Mid-Holocene (~7000–5000 BP), the effects of humans on the environment become much larger and are witnessed at regional and tributary river basin scales. Land clearance and agriculture, as well as related land use, are dominant determinants of these changes. By the Late Neolithic to Early Bronze Age (~5000–3500 BP), population growth and intensification of agricultural production expanded the human footprint across the Yellow River region. By the Mid to Late Bronze Age (~3600–2200 BP), larger populations armed with better technology and propelled by more centralized governments were altering lands throughout the Yellow River region, gradually bringing the environment under human control. By the Early Dynastic period (221 bc–ad 220), the Yellow River region was an increasingly anthropogenic environment wherein human land management practices were, in many instances, as consequential as natural forces. Throughout the Holocene history of the Middle and Lower Yellow River, anthropogenic, climatic, and natural environmental processes were acting to shape human history and behavior, making it difficult, if not impossible, to say whether human or climate processes were more consequential. There is a complex relationship in China’s early history between natural and human forcing much like there is today. The Early Anthropocene concept is useful here because it recognizes that when natural and cultural forces become so intertwined, it no longer makes sense to separate the two. [ABSTRACT FROM PUBLISHER]

Runoff and sediment loads have exhibited significant changes over the past six decades in the Yellow River Basin, China. The current study evaluates the changing trends and regime shifts in runoff and sediment loads at both the annual and monthly time scales. The associated spatial and temporal variations are analyzed by a sequential t-test analysis of the regime shifts (STARS) approach and the "breaks for additive seasonal and trend" (BFAST) model using hydrological data at eight stations from the 1950s to 2011. Both runoff and sediment loads exhibit significant declines (p < 0.05), except in the upper reaches of the river near the Tangnaihai station. The regime shifts detected by the STARS approach are not completely consistent with the results from the BFAST method. In most cases, the regime shifts occurred in 1969 and 1986, due to the construction of large reservoirs. Climate change and other human activities, such as large-scale soil and water conservation measures, can result in abrupt changes in hydrological series at some stations. The trapping effects of reservoirs not only cause regime shifts of runoff and sediment loads, but also adjust their inter-annual and seasonal distributions. Various soil and water conservation measures are responsible for the significant reduction in runoff and sediment loads in the mid-lower reaches of the Yellow River Basin. In addition, water withdrawals from both river runoff and ground water play a critical role in the changing trends in runoff and indirectly alter the sediment loads. The findings provide a good reference for the effective promotion of climate change adaptation, water resources planning and river basin management. [ABSTRACT FROM AUTHOR]

Willow tree bark samples from urban and rural sites in Inner Mongolia, Ningxia Province, and Gansu Province, in the Yellow River basin, were analyzed for polybrominated diphenyl ethers (PBDEs), dechlorane plus (DP), and dioxin-like polychlorinated biphenyls (DL-PCBs) to compare their relative levels in air in these areas (i.e., treating bark as a passive air sampler). No difference was found between the pollutant concentrations in Salix matsudana and Salix babylonica bark samples. The mean concentrations of the total PBDEs, DP, and total DL-PCBs were 13 000 ± 6400, 46 ± 44, and 26 ± 17 pg/g dry weight, respectively, with urban samples containing much higher concentrations (19 000 ± 5700 pg/g, 51 ± 27 pg/g, and 37 ± 29 pg/g dry wt in PBDEs, DP, and DL-PCBs, respectively) than rural samples (10 000 ± 5200 pg/g, 45 ± 53 pg/g, 22 ± 9 pg/g dry wt). A strong positive correlation between PBDEs and DP was found in all of the samples ( r = 0.712, p = 0.006), but correlations between PCBs and the other pollutants were only found in the rural samples. The total DL-PCB concentration in the tree bark correlated with population density. Environ Toxicol Chem 2014;33:1732-1738. © 2014 SETAC [ABSTRACT FROM AUTHOR]

It is important to examine the lateral shift rate variation of river banks in different periods. One of the challenges in this regard is how to obtain the shift rate of river banks, as gauging stations are deficient for the study of river reaches. The present study selected the Yinchuan Plain reach of the Yellow River with a length of 196 km as a case study, and searched each point of intersection of 153 cross-sections (interval between two adjacent cross-sections was 1.3 km) and river banks in 1975, 1990, 2010 and 2011, which were plotted according to remote sensing images in those years. Then the shift rates for the points of intersection during 1975-1990, 1990-2010 and 2010-2011 were calculated, as well as the average shift rates for different sections and different periods. The results show that the left bank of the river reach shifts mostly to the right, with the average shift rates being 36.5 m/a, 27.8 m/a and 61.5 m/a in the three periods, respectively. Contemporarily, the right bank shifts mostly to the right in the first period, while it shifts to the left in the second and third periods, with the average shift rates being 31.7 m/a, 23.1 m/a and 50.8 m/a in the three periods, respectively. The average shift rates for the left and right banks during the period 1975-2011 are 22.3 m/a and 14.8 m/a, respectively. The bank shift rates for sections A, B and C are different. The shift rate ratio of the left bank in the three sections is 1:7.6:4.6 for shift to the left and 1:1.7:3.8 for shift to the right, while that of the right bank is 1:1.8:1.2 for shift to the left and 1:5.6:17.7 for shift to the right during the period 1975-2011. Obviously, the average shift rate is the least in section A, while it is maximum in section B for shift to the left and in section C for shift to the right. The temporal variation of the shift rate is influenced by human activities, while the spatial variation is controlled by the local difference in bank materials. [ABSTRACT FROM AUTHOR]

Determining abrupt changes in runoff and sediment load may not only enhance identification of the principal driving factors for such changes but also help establish effective countermeasures for serious water deficit by managers in the Yellow River basin. We used the Mann-Kendall trend test and linear regression to determine trends and abrupt changes of runoff and sediment load during the period between 1950 and 2005, based on monthly hydrological data. Results show that runoff and sediment load decreased from 1950 to 2005, on annual or monthly time scales. Their changes are divided into three stages: fluctuating stage (1950-1970), slowly decreasing stage (1970-1980) and accelerated decreasing stage (1980-2005). The relationship between runoff and sediment load was most significant, and it can be expressed as a linear regression function. Precipitation was one of the most important climate factors affecting runoff before 1985, and the impact of human activities on runoff decrease grew strongly after 1985. Water balance analysis of the Yellow River basin indicates that natural climate change contributed about 55.3% and human activities about 44.7% to the runoff decrease after 1986. [ABSTRACT FROM AUTHOR]

ABSTRACT Droughts and floods are frequent disasters in the Yellow River basin in northern China. They have a strong impact on agriculture and water resource management. To explore the physical mechanisms of these droughts and floods, influences exerted by the sea surface temperature ( SST) anomalies in the mid-latitude North Atlantic on the wetness and dryness in the Yellow River basin have been investigated. The drought/flood index ( DFI), derived from a reconstructed dataset covering the last five centuries, is used. Numerical simulations are conducted with the Community Atmospheric Model version 3.0 ( CAM3) to study the influence of various mechanisms. It is found that DFI in the entire Yellow River basin experienced oscillations at about 50-60 years during the past five centuries. Droughts and floods have inconsistent patterns in different areas of the Yellow River. The periodic variation of DFI in Xi'an, a station in a semi-humid subarea, is in contrast to the North Atlantic SST (10°N-55°N and 70°W-10°W) oscillation in spring and summer; the periodic variation of the Yinchuan DFI in a semi-arid subarea (the upper reaches of Yellow River) correlates with the North Atlantic SST oscillation variation in spring and summer. The North Atlantic SST is probably one of the key sources of internal variability of the climate system, which results in Rossby wave adjusting. The warm phase of the North Atlantic SST is related to the operation of a Northern Atlantic Oscillation ( NAO) like pattern conducive to easterly wind anomalies in northern China and enhances anti-cyclones around Lake Baikal that leads to less precipitation or more frequent droughts in the semi-arid subarea in the upper reaches of the Yellow River, but wet conditions in the semi-humid subarea in the middle reaches, monsoon subarea in the lower reaches and plateau subarea in the upper reaches of the river. [ABSTRACT FROM AUTHOR]

As the fifth-longest river globally, the Yellow River is of great importance to the world's ecological protection. Due to its location as an essential ecological barrier and economic zone, it is imperative to balance energy support and ecological management in the basin. In this process, improving energy efficiency is crucial solution. Distinguished into upstream, midstream, and downstream, we measured the trajectory of green total factor energy efficiency over the past fifteen years using the Super-Epsilon-based model. Further, we identified the heterogeneity of energy efficiency within different river basins with the help of kernel density estimation. We used it to analyze the geographical and policy reasons affecting energy efficiency fluctuations. Finally, we constructed high, medium, and low GDP growth scenarios, and used a long short-term memory neural network model to predict energy efficiency forecasts in each scenario. The study results clarified that the overall energy efficiency showed an upward trend since 2013. Among them, the most significant improvement in energy efficiency was observed upstream, while the energy efficiency in the middle and lower stream showed a decreasing trend. Regarding future development trends, an economic growth rate of 6.5% was most favorable for energy efficiency compared to 6% and 7%. This finding reminded us to be alert to the ecological condition of the lower Yellow River basin. In addition, maintaining an appropriate economic growth rate is helpful for the balance between development and ecology. [ABSTRACT FROM AUTHOR]

Based on the study of field background, tectonic evolution and development history of the Yellow River valley, the authors made an in-depth study of the distribution and formation mechanism of the deep concentrated unloading of a typical bank slope developed in broad basin, and found that the concentrated unloading ranges from 2520 to 2650 m at El, the horizontal depth is 40 to 90 m in left bank and 40 to 60 m in right bank. It showed that these deep cracks in concentrated unloading zone generally dip towards the river or to the inner slope with high angle, and the cause of formation due to the category of unloading. The concentrated unloading is the product of the epigenetic deformation along the original tectonic structural planes accompanied by the stress release of slope during the formation process of river bank slope. [ABSTRACT FROM AUTHOR]

Channel planform dynamics were analyzed for the Ningxia-Inner Mongolia reaches of the Yellow River. Map data were analyzed by means of GIS and used to determine the planform characteristics and changes in width, sinuosity, and shoreline migration rates between 1958 and 2008. The study was based on topographic maps of 1958 and 1967, which had been derived from aerial photos and a field survey and from satellite imagery of 1977, 1990, 2000, and 2008. The channel planform dynamics were determined by comparing sequential changes in the position of the shorelines in these years. Sinuosity adjustments were small during the study (range: 1.34-1.45). The initial sinuosity (1.45 in 1958) gradually decreased to 1.34 in 1990, and then increased to 1.40 in 2008. Channel contraction had been the dominant planform process, but periodic floods resulted in channel expansion (1958-1990). The river's channel area expanded substantially from 1958 to 1990 (by 42.1 %), then sharply contracted from 1990 to 2000 (by 45.8 %), with no subsequent changes. The bank erosion and accretion rates were severe. The mean erosion rates ranged from 30.7 to 68.3 m/year on the left side and 27.1 to 58.3 m/year on the right side. The mean accretion rates ranged from 44.4 to 68.3 m/year on the left side and 30.5 to 60.4 m/year on the right side. The mean channel midline shifted by 57.8 m toward the right from 1958 to 2008. The mean channel midline moved 4.8 m to right from 1958 to 1967, 54.3 m to the left from 1967 to 1977, 44.2 m to the right from 1977 to 1990, 64.3 m to the right from 1990 to 2000, and 2.8 m to the right from 2000 to 2008. [ABSTRACT FROM AUTHOR]

We present a paleolimnological record from shallow Lake Wuliangsu in the Yellow River Basin, north China, using a short (56 cm) sediment core. Our objective was to investigate environmental changes in this semi-arid region over the past ~150 years. The sediment core was dated using Cs and Pb. We examined stratigraphic trends in core lithology, nutrients, stable isotopes (δC and δN) and trace element concentrations in the Lake Wuliangsu core to discern between natural sediments and those affected by human agency. A lithologic transition from yellow, coarse-grained sediment to grey, fined-grained sediment marked the lake's formation about 1860. Until ~1950, sediments displayed relatively low and constant heavy metal concentrations, indicating little human influence. In the 1950s, enrichment factors (EFs) increased, reflecting greater impact of human activities. Carbon and nitrogen stable isotopes in organic matter (OM), along with heavy metal concentrations, were used to infer past shifts in trophic state and identify pollutants that came from agriculture, industry and urbanization. In the late 1950s, the first evidence for environmental change is recorded by increases in total organic carbon (TOC), total organic nitrogen (TN), TOC/TN, EFs, δC and a decrease in δN. After about year 2000, a more rapid increase in trophic status occurred, as indicated by greater total phosphorus (TP), EFs, δN and lower δC values. Changes in isotope and TOC/TN values in the lake sediments may reflect a shift in lake ecology during this period. The first increase in trophic status during the late 1950s was mainly a result of agricultural development in the catchment. In contrast, the change after ca. AD 2000 was driven largely by urban and industrial development. Agreement between paleolimnologic data from Lake Wuliangsu, and both instrumental and written records, indicates that the lake sediments provide a reliable archive for investigating the formation and environmental history of the lake. [ABSTRACT FROM AUTHOR]

The Yellow River is the second largest river in China. The annual runoff of which is only about 2 % of China's total, but contributes to 9 % of China's GDP and directly supports 12 % of the population. Today, the water shortage in the Yellow River basin has been aggravated due to rapid population growth and global warming. In order to best maximize water resources management, the natural and observed streamflow series from six hydrologic gauging stations (Guide, Lanzhou, Hekou, Sanmenxia, Huayuankou, and Lijin) are obtained, and the linear regression, Mann-Kendall test, and wavelet transform methods were used to detect the characteristic of streamflow variation from 1956 to 2007. The results show that: (1) both the natural streamflow and observed streamflow present a downward trend over the past 52 years, and the trends are intensified downstream; the decreasing rate of observed streamflow is more rapid than that of the natural streamflow; (2) most of the abrupt changes in natural streamflow and observed streamflow appear in the late 1980s to early 1990s through the result of the Mann-Kendall test; and (3) other than the Guide station, the streamflows at the rest of the stations appear to have strongest periodicity of 19-21 years with a 52-year scale. The results of this study imply that less precipitation and warmer climate in the basin are the primary factors that cause this decreasing trend of natural streamflow. Additionally, the rapid ascent of water consumption by human being results in the reduction of observed streamflow further. Furthermore, human activities like reservoir construction, soil and water conservation measures, etc. influence the streamflow as well. It is recommended that the society takes some effective countermeasures to cope with the water shortage. [ABSTRACT FROM AUTHOR]

A numerical sediment transport model was embedded into a coupled wave-tide-circulation model to quantitatively estimate the suspended sediment fluxes (SSF) and distribution in different areas for the Yellow River derived sediment. The model is validated by comparing model simulated sediment deposition rates with those from observations. Simulated results show that the SSF of the Yellow River across two major sections (the Bohai Strait and the 37° N section) are highest during September and October, whereas for the 32° N section the flux is negligibly small (less than 0.1 kg/s). We demonstrate that the sediment flux is primarily driven by the buoyancy forcing of the Yellow River freshwater discharge and modulated by the wind-driven surface wave and circulation patterns in this region. The SSF across the Bohai Strait is about 30 % of the Yellow River discharge, while across the 37° N section it is 15.8 %. Therefore, about 70 % of the total discharged Yellow River sediments are deposited in the Bohai Sea, 14.1 % in the North Yellow Sea, and 13.9 % in the South Yellow Sea. There are two deposition branches in the Yellow Sea. The primary one is located off the eastern tip of the Shandong Peninsula and extends to the southwest off the coastline, which is consistent with the observed 'Ω'-shape deposition pattern. This simulated tongue shape deposition pattern is isolated from the north by the strong resuspension off the eastern tip of Shandong Peninsula. The secondary branch extends to the middle of the South Yellow Sea and has been strengthened by resuspension process. The two deposition branches are separated by the wintertime Yellow Sea Warm Current in the bottom layer. [ABSTRACT FROM AUTHOR]

Sediment found in China's Yangtze and Yellow River systems is characterized by large silt fractions. In contrast to sand and clay, sedimentation and erosion behaviour of silt and silt-clay-sand mixtures is relatively unknown. Therefore, settling and consolidation behaviour of silt-rich sediment from these river systems is analysed under laboratory conditions in specially designed settling columns. Results show that a transition in consolidation behaviour occurs around clay contents of about 10 %, which is in analogy with the transition from non-cohesive to cohesive erosion behaviour. Above this threshold, sediment mixtures consolidate in a cohesive way, whereas for smaller clay percentages only weak cohesive behaviour occurs. The settling behaviour of silt-rich sediment is found to be in analogy with granular material at concentration below 150 g/l. Above 150-200 g/l, the material settles in a hindered settling regime where segregation is limited or even prevented. The results indicate that for modelling purposes, multiple sediment fractions need to be assessed in order to produce accurate modelling results. [ABSTRACT FROM AUTHOR]

This note analyzes the change in water renewal time characteristics based on reservoir action and then establishes calculation models for the water renewal time in the Yellow River mainstream. The results indicate that the amount of renewable water with reservoir action can meet the annual water demand and that water flows naturally at the Lijin station near estuary. Initial storage dynamics is an important factor in water resource renewable capacity at a certain time, and rational reservoir action can promote sustainable water resource utilization. When the initial storages in the Longyang Gorge reservoir are 9.343 and 5.343 billion m, the water renewal times are 28 and 33.9 d, respectively. Flow stoppage appears in April and May. [ABSTRACT FROM AUTHOR]

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Water discharge data of the Yellow River over the past 60 years was analyzed using the continuous wavelet transform (CWT) and Mann-Kendall (MK) test methods to identify spatial and temporal variation patterns. Potential connections between water discharge in the Yellow River Basin and El Niño/Southern Oscillation (ENSO) were also examined by the cross wavelet and wavelet coherence methods. CWT results show that the periodic oscillations in water discharges had occurred at the temporal scales of 1-, 2- to 4-, 6- to 8- and 10- to 22-year. It was also found that at the annual timescale (1-year) the phase relations between water discharge and ENSO were indistinct probably due to the strong influence by human disturbances. However, over the longer time scales, the phase relation becomes much clearer with an anti-phase relation being found mainly at inter-annual scale (2- to 8-year) and in-phase relation at decadal scale (16- to 22-year). According to the MK test results water discharge at most stations except Tangnaihai have decreased significantly and the abrupt change occurred in the mid-1980s or the early 1990s. The changes in water discharge were found to be influenced by both climate changes and human activities. Before 1970 the change in water discharge was positively related to precipitation variations in the river basin, but after 1970 the decrease in water discharge has been largely caused by various human activities including constructions of reservoirs, water abstraction and water-soil conservation with water abstraction being the main cause. [ABSTRACT FROM AUTHOR]

We analyze 4000-year flood history of the lower Yellow River and the history of agricultural development in the middle river by investigating historical writings and quantitative time series data of environmental changes in the river basin. Flood dynamics are characterized by positive feedback loops, critical thresholds of natural processes, and abrupt transitions caused by socio-economic factors. Technological and organizational innovations were dominant driving forces of the flood history. The popularization of iron plows and embankment of the lower river in the 4th century bc initiated a positive feedback loop on levee breaches. The strength of the feedback loop was enhanced by farming of coarse-sediment producing areas, steep hillslope cultivation, and a new river management paradigm, and finally pushed the flood frequency to its climax in the seventeenth century. The co-evolution of river dynamics and Chinese society is remarkable, especially farming and soil erosion in the middle river, and central authority and river management in the lower river. [ABSTRACT FROM AUTHOR]

A general framework for modelling morphological responses to perturbation is proposed, based on the underpinning principle that the rates of morphological response in alluvial channels are initially high and then decrease through time as the system relaxes following disturbance. The framework includes three morphological response models, each developed from the fundamental rate law, which has the form of an exponential decay function. These models consider the possibility that characteristic behaviours of the fluvial system, such as delayed response and/or cumulative effects, may affect morphological responses, making them capable of representing relaxation paths and times for a range of morphological response variables, whatever their initial states. To test their utility, the models in the framework were applied to simulate the sequence of geomorphological responses to disruption observed in selected rivers with well-documented histories of morphological perturbation, adjustment and recovery. The results demonstrate that the models in the general framework can successfully simulate temporal and spatial patterns of morphological response in the fluvial system under a range of different circumstances, while also indicating how their reliability could be further improved. [ABSTRACT FROM PUBLISHER]

Vegetation in the upper catchment of Yellow River is critical for the ecological stability of the whole watershed. The dominant vegetation cover types in this region are grassland and forest, which can strongly influence the eco-environmental status of the whole watershed. The normalized difference vegetation index (NDVI) for grassland and forest has been calculated and its daily correlation models were deduced by Moderate Resolution Imaging Spectroradiometer products on 12 dates in 2000, 2003, and 2006. The responses of the NDVI values with the inter-annual grassland and forest to three climatic indices (i.e., yearly precipitation and highest and lowest temperature) were analyzed showing that, except for the lowest temperature, the yearly precipitation and highest temperature had close correlations with the NDVI values of the two vegetation communities. The value of correlation coefficients ranged from 0.815 to 0.951 ( p < 0.01). Furthermore, the interactions of NDVI values of vegetation with the climatic indicators at monthly interval were analyzed. The NDVI of vegetation and three climatic indices had strong positive correlations (larger than 0.733, p < 0.01). The monthly correlations also provided the threshold values for the three climatic indictors, to be used for simulating vegetation growth grassland under different climate features, which is essential for the assessment of the vegetation growth and for regional environmental management. [ABSTRACT FROM AUTHOR]

Palaeoflood slackwater deposits (SWDs), are the natural record of overbank flooding and are often found within aeolian loess-soil profiles along the river valleys of the middle Yellow River basin. These pedo-stratigraphic sequences are studied using a multi-disciplinarily approach to reconstruct Holocene hydro-climatic variations. Our field investigations along the lower Jinghe River valley have identified palaeoflood SWDs at several sites along the riverbanks based on sedimentological criteria. Analytical results, including magnetic susceptibility, particle-size distribution and concentrations of chemical elements, indicate that these well-sorted palaeoflood SWD beds were deposited from the suspended sediment load in floodwaters. We identify two episodes of extraordinary palaeoflood events along the Jinghe River valley. These hydro-climatic events were dated to 4200-4000 and 3200-2800 a BP, by using the optically stimulated luminescence method in combination with archaeological dating of retrieved anthropogenic remains, and with pedo-stratigraphic correlations with the previously studied Holocene pedo-stratigraphy in the Jinghe River drainage basin. The flooding events are therefore considered to be a regional expression of known climatic events in the northern hemisphere and demonstrate Holocene climate was far from stable. This study provides important data in understanding the interactions between regional hydro-climatic systems and global change in semi-arid and sub-humid regions. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Sedimentary records of the Holocene extraordinary floods were investigated in the upper reaches of the Weihe River, a major tributary in the middle Yellow River basin. Palaeoflood slackwater deposits (SWD) were identified at several sites on the riverbanks. These clayey silt beds are inserted into the Holocene aeolian loess-soil profiles and slope clastic deposits. They have recorded the extraordinary palaeoflood events which occurred between 3200 and 3000 yr BP as dated by OSL method and checked by the archaeological remains of the Neolithic and Bronze Age retrieved from the profile. The minimum flood peak discharges were estimated at between 22 560 and 25 960 m3/s by using palaeohydrological methods. It is 4.5–5.0 times the largest gauged flood (5030 m3/s) that has ever occurred since 1934. The palaeoflood slackwater deposits were found inserted into the pedostratigraphic boundary between the late-Holocene loess (L0) and the mid-Holocene Luvisol (S0) in the riverbank profile. This indicates that the extraordinary flood events were synchronous with the pedogenic regression at the end of the mid-Holocene climatic optimum. The climatic proxies from the studied profile and the correlative profiles in the river valley and the Loess Plateau show that the pedogenic regression was forced by climatic aridity and intensified dust storms and dust falls in connection with monsoonal shift over the Yellow River basin at about 3100 yr BP. The extraordinary flood events were documented not only on the Weihe River, but also on the mainstream and other tributaries of the Yellow River. These suggest that both extraordinary floods and droughts were parts of the climatic variability during the monsoonal shift. These findings are of great importance in understanding the interactions between hydrological system and climatic change in the semi-arid and subhumid regions of the world. [ABSTRACT FROM AUTHOR]

The Yellow River flows through an extensive area of aeolian desert and extends from Xiaheyan, Ningxia Province, to Hekouzhen, Inner Mongolia Province, for a total of 1,000 km. In the desert channel of the Yellow River, the major chemical components are SiO, FeO, AlO, Ti, CaO, MgO, Ba, P, Mn, Ce, Co in which SiO, AlO, FeO and Ti have significant value as indicators of the sources of the coarse sediment. The spatial distribution of the elements' weight percentages and the ratios of Si/Ti, Si/Al between sediment sources and riverbed sediment of the Gansu reach and the desert channel of the Yellow River, indicating that the coarse sediments deposited in the desert reach of the Yellow River are mostly controlled by the local sediment sources; and due to the higher mobility of the fine sediments, they are primarily contributed by the local sediment sources and the tributaries that originate from the loess area of the upper reach of Yellow River. The results of R-factor analysis illustrate that the first component score mainly shows negative values in the desert channel, suggesting that the coarse sediments in this reach contain a higher content of Si and a lower content of Mg + Ca + Al + Fe, which further proves that the Ningxia Hedong, Inner Mongolian Wulanbuhe, and Kubuqi deserts are the primary sources of the coarse sediment in the desert channel of the Yellow River. [ABSTRACT FROM AUTHOR]

Water-sediment regulation of the Yellow River is to regulate and control the flow and sediment transport relationship of the lower reaches through reservoirs on the main streams and tributaries to create balance between water and sediment so that sediment transport capacity of the downstream channels can be maximized, shrinking of channels be contained, and medium flood channel be restored and maintained. Many years' research by the Yellow River Conservancy Commission (YRCC) reveals the water and sediment transport relationship that will prevent sedimentation at the downstream river channels. Based on this relationship and coming sediment and water conditions in the Yellow River basin, the YRCC, with maximized use of reservoirs on the main streams and tributaries, has developed three models of water-sediment regulation: single Xiaolangdi Reservoir-dominated regulation, space scale water-sediment match, and mainstream reservoirs joint operation. Ten water-sediment regulations based on these three models have resulted in an average drop of 1.5 m in the main channel of the downstream 800 km river and an increase of carrying capacity from 1800 to 4000 m/s. Besides, the wetland ecosystems of estuarine delta has also been improved and restored significantly. [ABSTRACT FROM AUTHOR]

The construction of a dam converts the natural streamflow to human control. It is necessary to learn the accumulated effect of cascade dams on hydrological characteristics, sediment and nutrient pollution discharge. The current research describes the analysis and simulation of streamflow, sand concentration and nutrient pollutant discharge alterations caused by the construction of a cascade of eight dams along the Longliu section of the upper stream of the Yellow River. The analysis shows that the maximum monthly streamflow difference between the inlet and outlet of the Longliu section decreased from 430 to 115 m/s, after the appearance of the cascade dams between 1977 and 2006. In the same period, the correlation coefficient ( R) of monthly streamflow between the inlet and outlet of Longliu dropped from 0.959 to 0.375. The peak of streamflow shifted from June to May and October. The difference in sand concentration between two sections decreased from 0.52 to 0.39 kg/m, which was the direct consequence of the operation of the reservoirs. The R value of sand concentrations of the inlet and outlet were also reduced from 0.504 to 0.356. A t-test analysis indicates that the original hydrological nature was significantly disturbed by the cascade dams. The influence of the dams on nutrient pollutant transport was simulated by the SWAT model. This simulation suggests that the cascade dams decreased the discharge of total nitrogen and total phosphorus from 15.4 × 10 t and 1,996 t to 0.4 × 10 t and 328 t, respectively. In conclusion, the accumulated impact of cascade dams on streamflow, sand concentration and nutrient pollutant discharge were analyzed, which were helpful for understanding the environmental features of the entire watershed. [ABSTRACT FROM AUTHOR]

A holistic approach using multiple modules is used to recommend the environmental flow for fish in the lower Yellow River. The basic steps are as follows: (1) acquire the flow-related information on selected fish in the lower Yellow River, including fish species composition, abundance and habitat use in relation to flow conditions; (2) link the selected fish to key aspects of the flow regime using a conceptual model; (3) identify the environmental flow objectives; and (4) use hydraulic and hydrologic models to determine the magnitude, duration, frequency and timing of flows required to meet these objectives. [ABSTRACT FROM AUTHOR]

The concentrations of Cd, Cr, Cu, Ni, Pb and Zn were determined in the water and surface sediments from the Henan reaches of the Yellow River. Twenty-three sampling sites along the Yellow River and its tributaries were selected. Generally, metal concentrations were found to decrease in sequences of Zn > Cu > Pb > Cr > Ni > Cd in water and Zn > Cr > Pb > Ni > Cu > Cd in sediments. High levels of metal concentration were determined at a few stations of the river and its tributaries, such as Yiluo River, Si River and Qin River. The pollution of the Yellow River by Cd, Cr, Cu, Ni, Pb and Zn can be regarded as much higher compared to the background values, US EPA criteria (1999) and China water quality criteria (2002). For sediments, metal levels except Pb did not significantly exceed the average shale levels and backgrounds in several countries including China. Data analysis manifests that positive correlations were found between Cu, Ni and Zn in water, and Pb, Ni, Zn and Cr in sediments. The Pearson correlation coefficient analysis and Cluster analysis were provided to assess the possible contamination sources. The results indicate a general appearance of serious pollution along the banks of the Yellow River. The wastewaters discharged by the mine plants, smelter plants, power plants, battery plants, tannery plants, etc., and sewage inputs from the cities along the river banks may be the sources of metals. [ABSTRACT FROM AUTHOR]

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The source region of the Yellow River, China, has experienced eco-environmental deterioration in recent decades. The Yellow River discharge has reduced to zero numerous times since 1960, which has left a devastating impact on water resources and ecosystems downstream. Seeking to understand the causes of drying up, we analyze the records of discharge, temperature, and precipitation and explore the linkages among them. Using wavelet analysis, we show that the Yellow River discharge represents a comprehensive response to climatic variations in temperature and precipitation. We suggest that the discharge is best explained by variations in temperature over a 35-50 year trend and precipitation over periods of less than 10 years. Zero discharge events can be quantitatively correlated to periods of warming and reduced precipitation. Findings of this study may have a broad implication in assessing how water resources respond to climate changes. [ABSTRACT FROM AUTHOR]

Based on the study of ancient maps preserved in China and abroad, the systematic nature and practical meaning of the maps of the Yellow River and Grand Canal is demonstrated. It is pointed out that the ancient maps not only record the spatial information of the established water conservancy engineering for river harnessing but also the management systems of the rivers in history. Besides, the maps provide abundant information on nature, humanity, and geography and possess high value in academic research and art appreciation. [ABSTRACT FROM AUTHOR]

Severe soil erosion in the upper reaches of the Yangtze River and the middle reaches of the Yellow River is a serious environmental problem in western China. In order to control this soil erosion, the national government implemented the Grain for Green Program (GGP) in Sichuan Province (in the upper reaches of the Yangtze River) and Shaanxi Province (in the middle reaches of the Yellow River) in 1999. To evaluate the effects of the GGP on soil erosion, the present study investigated the relationships between annual precipitation and three parameters, annual runoff, sediment concentration, and sediment discharge, for these rivers. As the area covered by the GGP increased, sediment concentration and sediment discharge both decreased, and the correlation with the GGP area was much stronger than the correlation with annual precipitation. Therefore, China's GGP appears to be controlling soil erosion in the upper reaches of the Yangtze River and the middle reaches of the Yellow River. [ABSTRACT FROM AUTHOR]

The Yellow River in China carries large amounts of sediments in suspension at concentrations up to several hundreds of kilograms per cubic metre; the sediment is composed mainly of silt. These high sediment concentrations influence the hydrodynamics (flow velocity and turbulence) which, in turn, determine the sediment concentration profile, whereas both the high sediment concentrations and pseudo-cohesive properties of silt determine the morphodynamics of the Yellow River. The effect of sediment on the hydrodynamics is analysed using the Richardson number and the Reynolds number to provide a framework to differentiate between various flow regimes in the Yellow River, which is calibrated and validated with Yellow River data. The flow may be sub-saturated (stable flow), super-saturated (unstable flow characterized by high deposition rates, caused by collapse of turbulence), or hyperconcentrated sub-saturated (stable flow because of hindered settling effects), depending on the Richardson number. Independent of this, the flow may be turbulent, transitional or laminar, depending on the Reynolds number. Analysis of these flow types improves understanding of the flow regimes and morphodynamics of the Yellow River. The morphodynamics of the Yellow River are also affected by pseudo-cohesive behaviour caused by shear dilatance, which results in increasing critical shear stress for erosion at decreasing grain-size. This pseudo-cohesive behaviour may be partly responsible not only for the high deposition rates which characterize the lower Yellow River, but also for mass erosion during river floods. [ABSTRACT FROM AUTHOR]

This study investigated the residues of antibiotics present in the Yellow River and its tributaries. Ofioxacin, norfioxacin, roxithromycin, erythromycin, and sulfamethoxazole, were found in the river with mean concentrations from 25 to 152 ng/L, and in certain tributaries from 44 to 240 ng/L. The other four analytes were all below the limits of quantification. The results indicated that the detected antibiotics in the middle and lower Yellow River were primarily from its tributaries and ambient wastewater discharge. The concentrations of the antibiotics detected in the river were greater than that in other rivers in Europe. The antibiotics in the river and its tributaries at ng/L concentrations found in this study are unlikely to induce lethal toxicity to aquatic organism but could cause chronic ecological effects. Waler Environ. Res., 81, 248 (2009). [ABSTRACT FROM AUTHOR]

Image analysis of the Yellow River beach area since 1987 provided land use and water body patterns to support effective agricultural and environmental management. Landsat and Sentinel-2A/B images, and data from the Third National Land Survey, were used to examine the water body and land use patterns. The continuous beach land since 1987 was calculated from annual vegetation and water body indexes while that of cultivated land was extracted from the Third National Land Survey. Object-Oriented Feature Extraction was used to extract staple crops. The results showed that 58.26% of the beach area was cultivated land. Continuous beach land covered an area of 1630.98 km2 and was consisted of scattered patches that were unevenly distributed between the north and south banks of the Yellow River. The staple crop types in the beach area, winter wheat and summer corn accounted for 72.37% and 68.03% of the total cultivated land. Affected by the strategy on the Yellow River basin in China, as the ecological space and protection continue to increase, this study provides basic scientific references for the correct use of cultivated land resources and protection of the balance of soil and water resources dynamic utilization and balance of cultivated land protection and ecological protection. [ABSTRACT FROM AUTHOR]

Sediment samples were collected from the lower channel of the Yangtze River and the Yellow River and the contents of rare earth elements (REEs) were measured. In addition, some historical REEs data were collected from published literatures. Based on the δ EuN-ΣREEs plot, a clear boundary was found between the sediments from the two rivers. The boundary can be described as an orthogonal polynomial equation by ordinary linear regression with sediments from the Yangtze River located above the curve and sediments from the Yellow River located below the curve. To validate this method, the REEs contents of sediments collected from the estuaries of the Yangtze River and the Yellow River were measured. In addition, the REEs data of sediment Core 255 from the Yangtze River and Core YA01 from the Yellow River were collected. Results show that the samples from the Yangtze River estuary and Core 255 almost are above the curve and most samples from the Yellow River estuary and Core YA01 are below the curve in the δEuN-ΣREEs plot. The plot and the regression equation can be used to distinguish sediments from the Yangtze River and the Yellow River intuitively and quantitatively, and to trace the sediment provenance of the eastern seas of China. The difference between the sediments from two rivers in the δEuN-ΣREEs plot is caused by different mineral compositions and regional climate patterns of the source areas. The relationship between δEuN and ΣREEs is changed little during the transport from the source area to the river, and from river to the sea. Thus the original information on mineral compositions and climate of the source area was preserved. [ABSTRACT FROM AUTHOR]

The sustainability of wetlands is threatened by the past and present land use practices. Hydrological connectivity is one of the most important aspects to consider for wetland rehabilitation planning purposes. Circuit theory and connectivity indices can be used to model and assess hydrological connectivity. The aim of this study was to assess spatiotemporal variation in the hydrological connectivity of the Zoigê area from 2000–2019 using both methods. The study area contains a Ramsar wetland of international importance, namely the Sichuan Ruoergai Wetland National Nature Reserve. We used a global surface water observation product as the major input for both methods, and then analyzed the temporal and spatial characteristics, in terms of important components and patches. We found that the overall connectivity has increased slightly in the last 20 years, while the probability of connection between patches of surface water has increased significantly. Important components and patches represent steppingstone habitat for the dispersal of organisms in the landscape. The main determinants of hydrological connectivity are mostly human oriented, predominantly a decrease in large livestock population size and population increase. [ABSTRACT FROM AUTHOR]

The article presents a study on the long-term monotonic trend and abrupt changes for major climate variables at 23 meteorological stations in the headwater catchment of the Yellow River basin in China from 1960 to 2001 on the basis of mean air temperature, precipitation, sunshine duration and pan evaporation. It states that the abrupt changes have been examined in terms of a five-year moving averaged annual series using the moving t-test (MTT) method, Yamamoto method and Mann-Kendall method. The results indicated that the annual air temperature has increased by 0.80 degrees Celsius in the headwater catchment of the Yellow River basin during the past 42 years.

To reduce the sediment load of China's Yellow River, soil conservation measures have been progressively implemented across the Loess Plateau region since the 1950s. The effectiveness of these soil conservation measures (which were also coincident with reduced rainfall and streamflow) in controlling sediment movement remains to be ascertained. Here the association between sediment movement, hydrological variability, and the implementation of soil conservation measures is examined for the Coarse Sandy Hilly Catchments region of the Yellow River basin. The hypothesis that the soil conservation measures have reduced suspended sediment yields beyond that associated with rainfall reductions alone, principally by reducing sediment concentration, is examined. Annual sediment yield decreased significantly over time in all subcatchments, and the timing of the change (between 1971 and 1985) was consistent with the timing of change in streamflow. Annual mean sediment concentration in 7 of the 11 catchments exhibited a statistically significant decreasing trend over time, indicating that soil conservation practices reduced the mobilization of sediment in most areas, typically accounting for ∼75% of the observed reductions in annual sediment yield. Lesser reductions in area-specific sediment yield at larger catchment areas after the soil conservation measures were emplaced suggests that larger rivers may be reeroding stored sediment. As these sediment stores are likely to be relatively large given the high historic yields, relatively high area-specific sediment yields may persist at larger catchment areas even with improvements to sediment management in smaller tributaries. [ABSTRACT FROM AUTHOR]

The Soil and Water Assessment Tool (SWAT) model combined with different snowmelt algorithms was evaluated for runoff simulation of an 114,345 km2 mountainous river basin (the headwaters of the Yellow River), where snowmelt is a significant process. The three snowmelt algorithms incorporated into SWAT were as follows: (1) the temperature-index, (2) the temperature-index plus elevation band, and (3) the energy budget based SNOW17. The SNOW17 is more complex than the temperature-based snowmelt algorithms, and requires more detailed meteorological and topographical inputs. In order to apply the SNOW17 in the SWAT framework, SWAT was modified to operate at the pixel scale rather than the normal Hydrologic Response Unit scale. The three snowmelt algorithms were evaluated under two parameter scenarios, the default and the calibrated parameters scenarios. Under the default parameters scenario, the parameter values were determined based on a review of the current literature. The purpose of this type of evaluation was to assess the applicability of SWAT in ungauged basins, where there is little observed data available for calibration. Under the calibrated parameters scenario, the parameters were calibrated using an automatic calibration program, the Shuffled Complex Evolution (SCE-UA). The purpose of this type of evaluation was to assess the applicability of SWAT in gauged basins. Two time periods (1975-1985 and 1986-1990) of monthly runoff data were used in this study to evaluate the performance of SWAT with different snowmelt algorithms. Under the default parameters scenario, the SWAT model with complex energy budget based SNOW17 performed the best for both time periods. Under the calibrated parameters scenario, the parameters were calibrated using monthly runoff from 1975-1985 and validated using monthly runoff from 1986-1990. After parameter calibration, the performance of SWAT with the three snowmelt algorithms was improved from the default parameters scenario. Further, the SWAT model with temperature-index plus elevation band performed as well as the SWAT model with SNOW17. The SWAT model with temperature-index algorithm performed the poorest for both time periods under both scenarios. Therefore, it is suggested that the SNOW17 model be used for modeling ungauged basins; however, for gauged basins, the SNOW17 and simple temperature-index plus elevation band models could provide almost equally good runoff simulation results. [ABSTRACT FROM AUTHOR]

This article discusses spatial temporal climatic changes which could lead to the drying up phenomenon of the Yellow River in China. The authors used data from satellites and meteorological stations to measure the temperature, precipitation changes, and vegetation condition in the past few decades. They concluded that the temperature increased and precipitation decreased in most parts of the Yellow River basin. The evaporative demand of the atmosphere increases only in the lower reaches of the river. The vegetation condition in the irrigation districts apparently has been improved by human activities.