Karun and Shatt Al-Arab River System: Historic and Modern Attempts to Manage Iran’s Lifeline

The Islamic Republic of Iran’s principal rivers are the Karun and Shatt al-Arab. The Karun River has a 950 km length. The Karun River starting point is the convergence of the Amand, Kuhrang, and Bazoft rivers. From their headwater sources in the mountains of eastern Iran, these rivers descend through valleys and gorges and flow into the plains of Iran. The Shatt al-Arab River drains an area of 879,790 square kilometers which includes land in Iran, Syria, Türkiye, Kuwait, and Iraq. The Karun joins Shatt al-Arab 110 km downriver from the confluence of the Euphrates and Tigris Rivers and flows 85 km into the Persian Gulf. The Karun river flows in a southwestern direction through the central plain and provides about 10 per cent of the water balance of Iran’s largest wetland, the Shadegan, which includes permanent marshes, lakes, and riparian habitats. The article summarizes a vast array of publications on the stated topic and this civilizationally important region in order to draw additional attention to its interdependent environmental, economic and political problems the successful resolution of which is only possible with the participation of the entire research community.

Proposing Adjustments to the Dry Season Inter-Reservoir Operation Rules of the Red River System to Improve Water Use Efficiency of the Reservoirs

The Red-Thai Binh River system is an important water resource to the Northern Delta, serving the development of agriculture, people’s livelihood and other economic sectors through its upstream reservoirs and a system of water abstraction works along the rivers. However, due to the impact of climate change and pressure from socio-economic development, the operation of the reservoir system according to Decision No. 740/QD-TTg was issued on June 17, 2019 by the Prime Minister of Government promulgating the Red-Thai Binh River system inter-reservoir operation rules (Operation rules 740) has some shortcomings that need adjustments for higher water use efficiency, meeting downstream water demand and power generation benefits. Through the results of water balance calculation and analysis of economic benefits from water use scenarios, this research proposed adjustment to the inter-reservoir operation during dry season in the Red River system. The result showed that an average water level of 1.0 - 1.7 m should be maintained at Hanoi during the increased release period.

Environmental and ecological water requirement of river system: a case study of Haihe-Luanhe river system

In order to reduce the environmental and ecological problems induced by water resources development and utilization, this paper proposes a concept of environmental and ecological water requirement. It is defined as the minimum water amount to be consumed by the natural water bodies to conserve its environmental and ecological functions. Based on the definition, the methods on calculating the amount of environmental and ecological water requirement are determined. In the case study on Haihe-Luanhe river system, the water requirement is divided into three parts, i.e., the basic in-stream flow, water requirement for sediment transfer and water consumption by evaporation of the lakes or everglades. The results of the calculation show that the environmental and ecological water requirement in the river system is about 124×108 m3, including 57×108 m3 for basic in-stream flow, 63×108 m3 for sediment transfer and 4×108 m3 for net evaporation loss of lakes. The total amount of environmental and ecological water requirement accounts for 54% of the amount of runoff (228×108 m3). However, it should be realized that the amount of environmental and ecological water requirement must be more than that we have calculated. According to this result, we consider that the rational utilization rate of the runoff in the river systems must not be more than 40%. Since the current utilization rate of the river system, which is over 80%, has been far beyond the limitation, the problems of environment and ecology are quite serious. It is imperative to control and adjust water development and utilization to eliminate the existing problems and to avoid the potential ecological or environmental crisis.

Hydrochemical characterization and irrigation suitability of the Ganges Brahmaputra River System:review and assessment

The hydrochemical characterization and irrigation suitability assessment of the GangesBrahmaputra River System(GBRS)has immense importance for the livelihoods of people and ecosystem sustainability in the region.This study aims to assess the hydrochemical characteristics and evaluate the irrigation suitability of water in the GBRS by reviewing published literature of the major tributaries.The studied rivers were categorized into two groups namely Group-1 and Group-2 considering the similarities of climatic patterns,hydrochemical attributes,and drainage characteristics.The hydrochemistry of the river water was characterized by the Piper diagram,Gibbs plot,mixing plots,and ionic ratios.Furthermore,irrigation water qualities were evaluated by electrical conductivity(EC),sodium percentage(Na%),sodium adsorption ratio(SAR),magnesium hazard(MH),and Wilcox diagram.The results indicated that the hydrochemistry of the GBRS was slightly alkaline to alkaline(7.42-8.78)in nature.The average concentrations of most of the chemical attributes showed higher in Group-1,whereas the average concentrations of K^(+) and NO_(3)^(-) were found higher in Group-2.The average concentration of the major ions followed the dominancy order Ca^(2+)>Mg^(2+)>Na^(+)>K^(+) for cations and HCO_(3)^(-)>SO_(4)^(2-)>Cl^(-)>NO_(3)^(-) for anions in both groups.Gibbs plot and mixing plot indicated that carbonate rock weathering dominates the hydrochemical process,which was further confirmed by the Piper diagram and the ionic ratios.From the analyses of irrigational water quality,almost all the rivers(except Gomti River in terms of MH and Rangit River in terms of Na%)in the GBRS were found to be suitable based on EC,SAR,Na%,MH,and Wilcox diagram.Finally,the majority of river systems in the GBRS were characterized by carbonate dominated lithology and irrigational water quality is mostly suitable for utilization.This study could be useful for water quality management in the glacial-fed Himalayan river under the context of global climate change.

River system in Japan from a landscape ecological aspect

The objective of this study was to elucidate characteristics associated with rivers by classification of major rivers in Japan into several types based on riparian conditions. As the results of principal component analysis (PCA) with use of parameters reflecting forms and artificial alterations of respective rivers, four major components such as “comprehensive riparian size', “intactness of water front', “continuity of streams' and “simplicity of landform in river basin' were extracted. Subsequently, cluster analysis was performed based on principal component scores, leading to successful classification of major rivers into 6 types. These findings disclosed that (1) the extracted principal components provide effective viewpoint for classification of rivers; (2) distribution of respective classes indicates area properties; and (3) the employed quantitative procedures were found effective for classification of major rivers.

STUDIES ON TERRACES AND RIVER SYSTEM CHANGES OF THE UPPER YELLOW RIVER

There are seven steps of terrace both in the Guide basin and Gonghe basin along the Yellow River. More close to the source, less the steps of terrace. Three ancient terraces are found in Gonghe basin. The upper reaches of the Yellow River was joined up by a series of stream captures at different periods of time, the ancient Yellow River linked up the Gonghe basin and Guide basin at the end of the middle Pleistocene, the Longyangxia gorge developed around 60 Ka.B.P., and the gorge between Maqu and Tangnag developed around 20 Ka.B.P.

Characteristics Research of Immersed and Waterlogged Subterranean River System of Reservoir Areas of Hydroelectric Stations

The karst immersion and waterlogging is one of the typical and the m os t harmful natural disasters in southern karst areas of China. It is threat to th e local production and life for a long time. In recent years, due to the constru ction of more reservoirs, the disaster became serious. This article takes immers ion and waterlogging of Banwen's subterranean rivers in Yantan reservoir area as an example, researches the daily rainfall's reflection to the water level of re servoir depression, discusses characteristics of immersion and waterlogging of t he valley, analyzes the disaster index in detail, such as water level process, t he highest water level, sensitive rainfall, original waterlogged rainfall and de layed day numbers etc., and provides the reference as a basis to the disaster an alysis.

Background contents of heavy metals in sediments of the Yangtze River system and their calculation methods

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Particulate n-alkanes and fatty acids in the Changjiang river system

Particulate samples were collected from the Changjiang river system during a flood period, in May 1997, and POC, stable isotope and lipids associated with particles were examined. Results showed the decrease （0.84% ～ 1.88%） of organic carbon content from the upper reaches to the estuary.δ^13 values of particulate organic carbon was in the range of -24.9×10^-3 to -26.6×10^-3, which were close to the isotopic signature of continental C3 vegetation. Total particulate n-alkanes concentrations varied from 1.4 to 10.1μg/dm^3,or from 23.7 to 107μg/g of total suspended matter. Fatty acids were present in all the samples, from 1.4 to 5.4μg/dm^3, with saturated and unsaturated straight-chain and branched compounds in the carbon number range from C12 to C30. Both δ^13 and the ratio of carbon content to nitrogen content indicate the predominance of terrestrial inputs （soil organic matter） among the particles. The biomarker approach has been used to identify the relative portion of terrigenous and autochthonous fraction in the particulate samples. The distribution of fatty acids suggests a striking phytoplanktonic and microbial signal in most particle samples. The terrestrial alkanes are used to estimate the contribution of terrestrial inputs along the mainstream.

IMPACT OF URBANIZATION ON STRUCTURE AND FUNCTION OF RIVER SYSTEM—Case Study of Shanghai,China

Urbanization can affect the physical process of river growth, modify stream structure and further influence the functions of river system. Shanghai is one of the largest cities in the world, which is located in Changjiang (Yangtze) River Delta in China. Since the 1970s, the whole river system in Shanghai has been planned and managed by the Shanghai Water Authority. The primary management objectives in the last 30 years have been to enhance irrigation and flood-control. By using Horton-Strahler classification and Horton laws as a reference, a novel method of stream classification, in conjunction with the traditional and specially designed indicators, was applied to understanding the structure and functions of the river system in Shanghai. Correlation analysis was used to identify the interrelations among indicators. It was found that the impact of urbanization on the river system was significant although natural laws and physical characteristics marked a super-developed river system. There was an obvious correlation between the degree of urbanization and the abnormal values of some indicators. Urbanization impacts on river system such as branches engineered out, riverbank concreting and low diversity of river style were widely observed. Each indicator had distinct sensibility to urbanization so they could be used to describe different characteristics of urban river system. The function indicators were significantly related to structure indicators. Stream structure, described by fractal dimension and complexity of river system, was as important as water area ratio for maintaining river’s multi-function.

Rare earth element content in the SPM of Daliao river system and its comparison with that in the sediments, loess and soils in China

Content and distribution patterns of rare earth dements （REEs） in the suspended particulate material （SPM） of Daliao River system were investigated and compared with those in the fiver and sea sediments, loess, and soils of China. Twenty-seven samples of SPM were taken in Daliao River system and digested with various acids followed by ICP-MS analysis for REEs and ICP-OES analysis for Al, Fe, Mn, Ti, Mg, Ca, Na, and K, to measure the total concentrations of these elements. Results indicated that the spatial change in the content of REEs was great, with the coefficient of variance （CV） from 84% to 105%, while the contents of REEs were significantly correlated with each other. Chondrite-normalized patterns of REEs were characterized by higher enrichment of light REEs than heavy REEs, and a depletion of Eu in the SPM was generally found. The positive anomaly of Eu in the SPM of Xi River was due to anthropogenic source in Shenyang City. Furthermore, chondfite- and upper continent crust-normalized patterns of REEs in the SPM of Daliao River system, sediments of Yangtze River and Yellow River, sediments of Yellow Sea, East Sea, South Sea of China, and loess and soil of China, were very similar to one another. These demonstrated that the weathering and sedimentary processes resulted in constant REE distribution not only in the typical sedimentary rocks, but also in the modem riverine particle, sea sediments, loess, and soils.

Virtual Huanghe River System:Framework and Technology

Virtual Reality provides a new approach for geographical research. In this paper, a framework of the Virtual Huanghe (Yellow) River System was first presented from the view of technology, which included five main modules —data sources, 3D simulation terrain database, 3D simulation model database, 3D simulation implementation and ap- plication system. Then the key technologies of constructing Virtual Huanghe River System were discussed in detail: 1) OpenGL technology, the 3D graphics developing instrument, was employed in Virtual Huanghe River System to realize the function of dynamic real-time navigation. 2) MO and OpenGL technologies were used to make the mutual response between 3D scene and 2D electronic map available, which made use of the advantages of both 3D scene and 2D elec- tronic map, with the macroscopic view, integrality and conciseness of 2D electronic map combined with the locality, reality and visualization of 3D scene. At the same time the disadvantages of abstract and ambiguity of 2D electronic map and the direction losing of virtual navigation in 3D scene were overcome.

Morphometric Analysis of a Tropical Medium River System: A Case from Bharathapuzha River Southern India

Baseline morphometric information at a sub basin level is essential to develop appropriate strategy for sustainable, socially acceptable, ecologically benign and economically viable development of a river basin. The present study was carried out in one of the less studied Bharathapuzha river basin (BRB), the second longest river in the state of Kerala, India. The annual discharge of the river is 3.94 km3. Nevertheless the basin, which receives about 1828 mm of annual rainfall, in recent years has been facing dearth of water. We used GIS and RS tools to study the morphometric characteristics of the basin. The seventh order main river is formed by several lower order streams forming a dentritic flow pattern. Basin geology, slope and rainfall pattern in the basin determine the morphometric characteristics of the basin. The linear aspects of the basin including stream length ratio and bifurcation ratio indicate the role of relief in the basin while the areal ratios indicate the elongate nature of the basin.

The Pliocene-Recent Euphrates river system:Sediment facies and architecture as an analogue for subsurface reservoirs

The Tigris-Euphrates is a continental-scale fluvial system,around 2800 km in length,which drains over 1 million km2 of SWAsia.The system originated in the Late Miocene and developed into the principal axial drainage system of the region,which follows broad regional structural features of the Mesopotamian Foreland Basin.Good preservation and outcropping of the Pliocene and Quaternary Euphrates deposits yield a viable local analogue for subsurface fluvial reservoirs in the region,and for other fluvial systems that have developed in foreland basin settings.This paper documents the first detailed study of the sedimentary characteristics of these Pliocene and Quaternary fluvial deposits along the middle reaches of the present-day Euphrates in Syria.The Euphrates fluvial system developed from small and probably short-lived isolated cut-and-fill channels in the Pliocene,characterised by abundant debrite and slump facies,through to a broad meandering system at present.The Quaternary deposits represent a braided to meandering system that was more energetic than that of the modern day Euphrates.The Quaternary facies include a dominance of gravels,pebbly sands and sands as channel associations,coupled with sands,muds and paleosols representing channel abandonment,overbank and crevasse-splay associations.Channel widths,where observed,range from 50 to 500 m,and minimum fill thicknesses range from 3 to 7 m.The combined channel-fill for stacked channels is up to 25 m thick.Lateral correlation of channel elements over at least 1 km of section indicates that rapid and extensive lateral migration has occurred.Crevasse splay lobes can be identified in the overbank deposits,with a width of 30e60 m and sand thickness of 0.5e1.5 m.The geometry,nature and dimensions of these architectural elements provide a useful analogue for subsurface reservoirs.The high-energy channel facies of the Quaternary system show very good reservoir attributes,with good correlation and connectivity.At the bed-scale there is significant heterogeneity of characteristics that would impact fluid-flow for hydrocarbon production from a subsurface reservoir.However,incomplete preservation of these Quaternary fluvial deposits at outcrop remains a challenge for accurately determining the scale of sedimentary features and also the size of the paleo-river.

Generation and transmission of greenhouse gases in river system

The research progress on the current domestic and foreign about river water system of the greenhouse gas methane(CH4),and nitrous oxide(N2O)generation,transmission and release mechanism are reviewed in this paper.At present,at home and abroad of river water system of methane production and release of the driving factors and mechanism has been basically clear,but the N2O production mechanism is not clear,multi factor interaction of river water system of N2O production and release of complex,in different regions and time of result differences.The calculation of water flux of N2O river discharge coefficient of river IPCC released based on N2O,the release amount may underestimate the river water N2O.

Spatio-temporal evolution and topographic gradient effect of land use and ecosystem service value in the Lhasa River Basin

The Lhasa River Basin forms an essential human settlement area in the southern part of the Qinghai-Tibet Plateau.This study employed ecosystem service value(ESV)evaluation model,terrain gradient grading,and Geodetector to analyze land use and ESV in the Lhasa River Basin from 1985 to 2020.The findings reveal that:(1)From 1985 to 2020,grassland was the dominant land use.There was a trend of grassland reduction and the expansion of other land types.(2)ESV has increased over the research period(with a total increase of 0.84%),with higher values in the southeast and lower values in the northwest.Grassland contributed the most to ESV,and climate regulation and hydrological regulation were the ecosystem services that contribute the most to ESV.(3)Natural factors like NDVI and altitude,as well as economic factors like population density and distance from roads,influenced the spatial differentiation of ESV,the explanatory power of NDVI reached up to 0.47.The interaction between factors had a greater impact than individual factors.These research results can provide theoretical support for national spatial planning and ecological environment protection in the Lhasa River Basin and other similar areas.

Impacts of multi-scenario land use change on ecosystem services and ecological security pattern: A case study of the Yellow River Delta

The Yellow River Delta(YRD), a critical economic zone along China's eastern coast, also functions as a vital ecological reserve in the lower Yellow River. Amidst rapid industrialization and urbanization, the region has witnessed significant land use/cover changes(LUCC), impacting ecosystem services(ES) and ecological security patterns(ESP). Investigating LUCC's effects on ES and ESP in the YRD is crucial for ecological security and sustainable development. This study utilized the PLUS model to simulate 2030 land use scenarios, including natural development(NDS), economic development(EDS), and ecological protection scenarios(EPS). Subsequently, the InVEST model and circuit theory were applied to assess ES and ESP under varying LUCC scenarios from 2010 to 2030. Findings indicate:(1) Notable LUCC from 2010 to 2030, marked by decreasing cropland and increasing construction land and water bodies.(2) From 2010 to 2020, improvements were observed in carbon storage,water yield, soil retention, and habitat quality, whereas 2020–2030 saw increases in water yield and soil retention but declines in habitat quality and carbon storage. Among the scenarios, EPS showed superior performance in all four ES.(3) Between 2010 and 2030, ecological sources, corridors, and pinchpoints expanded, displaying significant spatial heterogeneity. The EPS scenario yielded the most substantial increases in ecological sources,corridors, and pinchpoints, totaling 582.89 km^(2), 645.03 km^(2),and 64.43 km^(2), respectively. This study highlights the importance of EPS, offering insightful scientific guidance for the YRD's sustainable development.

Spatiotemporal Characteristics of Typical Ecosystem Services and Their Spatial Responses to Driving Factors in Ecologically Fragile Areas in Upper Yellow River,China

The identification of dominant driving factors for different ecosystem services(ESs)is crucial for ecological conservation and sustainable development.However,the spatial heterogeneity of the dominant driving factors affecting various ESs has not been adequately elucidated,particularly in ecologically fragile regions.This study employed the integrated valuation of ESs and trade-offs(InVEST)model to evaluate four ESs,namely,water yield(WY),soil conservation(SC),habitat quality(HQ),and carbon storage(CS),and then to identify the dominant driving factors of spatiotemporal differentiation of ES and further to characterize the spatial heterogeneity characteristics of the dominant driving factors in the eco-fragile areas of the upper Yellow River,China from 2000 to 2020.The results demonstrated that WY exhibited northeast-high and northwest-low patterns in the upper Yellow River region,while high values of SC and CS were distributed in central forested areas and a high value of HQ was distributed in vast grassland areas.The CS,WY,and SC exhibited decreasing trends over time.The most critical factors affecting WY,SC,HQ,and CS were the actual evapotranspiration,precipitation,slope,and normalized difference vegetation index,respectively.In addition,the effects of different factors on various ESs exhibited spatial heterogeneity.These results could provide spatial decision support for eco-protection and rehabilitation in ecologically fragile areas.

Response of ecosystem carbon storage to land use change from 1985 to 2050 in the Ningxia Section of Yellow River Basin,China

Regional sustainable development necessitates a holistic understanding of spatiotemporal variations in ecosystem carbon storage(ECS),particularly in ecologically sensitive areas with arid and semi-arid climate.In this study,we calculated the ECS in the Ningxia Section of Yellow River Basin,China from 1985 to 2020 using the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model based on land use data.We further predicted the spatial distribution of ECS in 2050 under four land use scenarios:natural development scenario(NDS),ecological protection scenario(EPS),cultivated land protection scenario(CPS),and urban development scenario(UDS)using the patch-generating land use simulation(PLUS)model,and quantified the influences of natural and human factors on the spatial differentiation of ECS using the geographical detector(Geodetector).Results showed that the total ECS of the study area initially increased from 1985 until reaching a peak at 402.36×10^(6) t in 2010,followed by a decreasing trend to 2050.The spatial distribution of ECS was characterized by high values in the eastern and southern parts of the study area,and low values in the western and northern parts.Between 1985 and 2020,land use changes occurred mainly through the expansion of cultivated land,woodland,and construction land at the expense of unused land.The total ECS in 2050 under different land use scenarios(ranked as EPS>CPS>NDS>UDS)would be lower than that in 2020.Nighttime light was the largest contributor to the spatial differentiation of ECS,with soil type and annual mean temperature being the major natural driving factors.Findings of this study could provide guidance on the ecological construction and high-quality development in arid and semi-arid areas.