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.

Ganges and Brahmaputra River System: Need for a Multi-Country Plan for Cleaning, Mitigation, Restoration and Protection

The Ganges and Brahmaputra River system is in the plains of the northern Indian subcontinent. The river is a wide sluggish stream flowing through densely populated and fertile agricultural regions of the world. The Ganges is known as the Hinduism holy river. In Bangladesh, the Brahmaputra is joined by the Teesta River. The western branch of the Brahmaputra confluences with the Ganges and contains most of the river flow. The eastern branch joins the Meghna River near Dhaka. The basin covers parts of four countries including India, Nepal, China, and Bangladesh. Of greater concern, however, has been the degradation in quality of the river water itself. The primary objective of this research is to encourage the development of a multi-country clean-up, mitigation, and protection plan for the Ganges-Brahmaputra rivers. This article constitutes a real tool for the restoration, enhancement and protection of the Ganges-Brahmaputra River system and its environment. The Ganges and Brahmaputra rivers are known for stream bank erosion, shifting channels, and sandbars that continually emerge in their course. The Ganges and Brahmaputra watershed is home to hundreds of millions of people, with the result that the river’s water over much of its course is highly polluted. Arsenic contamination of groundwater in Bangladesh continues to be the largest case of human poisoning in history. Catastrophic floods have prompted the World Bank to prepare a long-term flood-control plan for the region. Scores of cities and towns contribute to treated sewage into the river and its main tributaries, and dozens of manufacturing facilities contribute industrial waste. Also contributing to high pollution levels are agricultural runoff, the remnants of partially burned or unburned bodies from funeral pyres, and animal carcasses. High levels of disease-causing bacteria, as well as such toxic substances as chromium, cadmium, and arsenic, have been found in the Ganges and Brahmaputra. External research and funding of adsorptive media systems to help mitigate the high arsenic levels in drinking water (river and groundwater) is needed. The Ganges-Brahmaputra River system is of colossal importance to its entire environment. Restoration and protection measures must be adopted appropriately and at the scale of the concerned countries.

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.

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.

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.

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 application system. Then the key technoiogies 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 electronic 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.

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.

Assessment of Salinization in the Main River Systems of Long An Province, Vietnam

Three provinces including Long An, Tien Giang and Dong Thap, located at Dong Thap Muoi area in the Mekong Delta, belong to the southern key economic region of Vietnam. These provinces run from west to east with a vast network of rivers. Among them, VCD （Vam Co Dong）, VCT （Vam Co Tay） and Soai Rap rivers are the three biggest rivers crossing the province. In recent years, the flows of rivers have changed a lot and saline intrusion has been very complicated. Salt water has intruded deeply into the field. In the 2000s, salt water only reached Tuyen Nhon （Thanh Hoa district）, but now it has reached Vinh Hung district, about 50 km far from Tuyen Nhon. In 2016, the maximum of salinity in Xuan Khanh （Duc Hoa district） in VCD river was 6.8‰ and Tuyen Nhon （Thanh Hoa district） in VCT river was 5.2‰. In the coming years, the situation of salt intrusion is going to happen more unpredictable under effects of global climate change and sea level rise.

Artificial neural network modeling of water quality of the Yangtze River system:a case study in reaches crossing the city of Chongqing

An effective approach for describing complicated water quality processes is very important for river water quality management. We built two artificial neural network(ANN) models,a feed-forward back-propagation(BP) model and a radial basis function(RBF) model,to simulate the water quality of the Yangtze and Jialing Rivers in reaches crossing the city of Chongqing,P. R. China. Our models used the historical monitoring data of biological oxygen demand,dissolved oxygen,ammonia,oil and volatile phenolic compounds. Comparison with the one-dimensional traditional water quality model suggest that both BP and RBF models are superior; their higher accuracy and better goodness-of-fit indicate that the ANN calculation of water quality agrees better with measurement. It is demonstrated that ANN modeling can be a tool for estimating the water quality of the Yangtze River. Of the two ANN models,the RBF model calculates with a smaller mean error,but a larger root mean square error. More effort to identify out the causes of these differences would help optimize the structures of neural network water-quality models.

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

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Occurrence and distribution of hydroxylated isoprenoid glycerol dialkyl glycerol tetraethers(OH-GDGTs) in the Han River system, South Korea

We investigated the occurrence and distribution of terrestrial-derived hydroxylated isoprenoid glycerol dialkyl glycerol tetraethers(OH-GDGTs) in the Han River system and their potential impact on the application of the ring index of OH-GDGTs(RI-OH) as a sea surface temperature(SST) proxy in the eastern Yellow Sea. Thereby, we analyzed various samples collected along the Han River and from its surrounding areas(South Korea, n = 34). The OHGDGTs were found in all samples investigated. OH-GDGT-0 was the dominant OH-GDGT component in the estuary and marine samples while OH-GDGT-2 was generally dominant in the soils, the lake sediments and the river suspended particulate matter(SPM). Our results thus suggests a possible warm bias of the RI-OH-derived summer SSTs in the coastal zone to which a large amount of terrestrial organic matter is being supplied. Further studies are necessary to better assess the applicability of the RI-OH proxy in the eastern Yellow Sea.

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.

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.

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.

The Response of Carbonate System to Watershed Urbanization Process in a Semi-Arid River

Different from rivers in humid areas,the variability of riverine CO_(2) system in arid areas is heavily impacted by anthropogenic disturbance with the increasing urbanization and water withdrawals.In this study,the water chemistry and the controls of carbonate system in an urbanized river(the Fenhe River)on the semi-arid Loess Plateau were analyzed.The water chemistry of the river water showed that the high dissolved inorganic carbon(DIC)concentration(about 37 mg L^(-1))in the upstream with a karst land type was mainly sourced from carbonate weathering involved by H_(2)CO_(3) and H_(2)SO_(4),resulting in an oversaturated partial pressure of CO_(2)(pCO_(2))(about 800μatm).In comparison,damming resulted in the widespread appearance of non-free flowing river segments,and aquatic photosynthesis dominated the DIC and pCO_(2) spatiality demonstrated by the enriched stable isotope of DIC(δ^(13)CDIC).Especially in the mid-downstream flowing through major cities in warm and low-runoff August,some river segments even acted as an atmospheric CO_(2) sink.The noteworthy is wastewater input leading to a sudden increase in DIC(>55 mg L^(-1))and pCO_(2)(>4500μatm)in the downstream of Taiyuan City,and in cold November the increased DIC even extended to the outlet of the river.Our results highlight the effects of aquatic production induced by damming and urban sewage input on riverine CO_(2) system in semi-arid areas,and reducing sewage discharge may mitigate CO_(2) emission from the rivers.