Characteristics of isotope in precipitation,river water and lake water in the Manasarovar basin of Qinghai–Tibet Plateau

The stable hydrogen and oxygen of lake, river, rain and snow waters were investigated to understand the water cycle characteristics of the drainage basin of Manasarovar Lake in Tibet. Both δD and δ ¹⁸O of river water are larger than those of lake water and the effect of altitude on both δD and δ ¹⁸O is not very significant. This phenomenon was suggested to occur because Manasarovar basin is located in Qinghai–Tibet Plateau which has low latitude, high altitude, abundant glaciers, thin air and intensive solar radiation, resulting in higher evaporation in lake water.     

A distributed hydrological–geotechnical model using satellite-derived rainfall estimates for shallow landslide prediction system at a catchment scale

This paper describes the potential applicability of a hydrological–geotechnical modeling system using satellite-based rainfall estimates for a shallow landslide prediction system. The physically based distributed model has been developed by integrating a grid-based distributed kinematic wave rainfall-runoff model with an infinite slope stability approach. The model was forced by the satellite-based near real-time half-hourly CMORPH global rainfall product prepared by NOAA-CPC. The method combines the following two model outputs necessary for identifying where and when shallow landslides may potentially occur in the catchment: (1) the time-invariant spatial distribution of areas susceptible to slope instability map, for which the river catchment is divided into stability classes according to the critical relative soil saturation; this output is designed to portray the effect of quasi-static land surface variables and soil strength properties on slope instability and (2) a produced map linked with spatiotemporally varying hydrologic properties to provide a time-varying estimate of susceptibility to slope movement in response to rainfall. The proposed hydrological model predicts the dynamic of soil saturation in each grid element. The stored water in each grid element is then used for updating the relative soil saturation and analyzing the slope stability. A grid of slope is defined to be unstable when the relative soil saturation becomes higher than the critical level and is the basis for issuing a shallow landslide warning. The method was applied to past landslides in the upper Citarum River catchment (2,310 km²), Indonesia; the resulting time-invariant landslide susceptibility map shows good agreement with the spatial patterns of documented historical landslides (1985–2008). Application of the model to two recent shallow landslides shows that the model can successfully predict the effect of rainfall movement and intensity on the spatiotemporal dynamic of hydrological variables that trigger shallow landslides. Several hours before the landslides, the model predicted unstable conditions in some grids over and near the grids at which the actual shallow landslides occurred. Overall, the results demonstrate the potential applicability of the modeling system for shallow landslide disaster predictions and warnings.     

A coupled 1D–2D hydrodynamic model for flood simulation in flood detention basin

Natural Hazards - A coupled 1D–2D hydrodynamic model linking the channel and flood detention basin for flood simulation with complex topography and irregular boundary was presented in this...     

Flash flood in the mountainous region of Rio de Janeiro state (Brazil) in 2011: part I—calibration watershed through hydrological SMAP model

Natural Hazards - Flooding and water logging possess severe hazards to human population in many parts of the world. Mumbai, the study area, is one of the cities in India and has been frequently...     

Synchronous release of labile phosphorus,labile ferrum,and labile arsenic in water–sediment interface using ZrO–Chelex measured in the Aibi Lake of Northwest China

In the work presented here, a Zr-oxide diffusive gradients in thin films (DGT) was used to monitor the release flux of phosphorus (P), ferrum (Fe), and arsenic (As) in the water–sediment interface of Aibi Lake—a typical shallow lake located in the arid regions of Northwest China. Results showed that: (1) In the water–sediments interface of Aibi Lake, the ranges (average values) of labile As, labile P, and labile Fe levels in DGTs are 3.846–101.840 (43.934) µg L^?1, 0.006–0.232 (0.070) mg L^?1, and 0.202–52.984 (15.832) mg L^?1, respectively. Among 0–20 cm of the vertical profile there was a stable distribution of three elements, while below the interface as 0 cm–(??80) cm there were relatively large changes of these. (2) Fitting analysis showed that there were significant correlations between labile Fe and labile P, and labile As in four DGTs, which showed that in the water–sediments of Aibi Lake, Fe, P, and As are released simultaneously. (3) Combined with former research, we found that the redox of Fe³⁺ to Fe²⁺ may cause the release of P and As to the sediments and water body from the former Fe–P and Fe–As; the proportion of P/Fe of four DGTs was all relatively lower than 1, suggesting that the redox of Fe³⁺ caused the P to be released. (4) This research showed that the concentrations of P, Fe, and As of the water–sediments interface of the lake was obviously lower than that of the water body and sediments of Aibi Lake as well as others of central and eastern China. ZrO-DGT can accurately reflect the distribution of P, Fe, and As of Aibi Lake. These findings can provide initial verification for the use of ZrO-DGT technology in the research of elements at the water–sediment interface in lakes of Xinjiang Province in Northwest China.     

Relationship of underground water level and climate in Northwest China’s inland basins under the global climate change: Taking the Golmud River Catchment as an example

To identify the response of groundwater level variation to global climate change in Northwest China’s inland basins, the Golmud River Catchment was chosen as a case in this paper. Approaches of time series analysis and correlation analysis were adopted to investigate the variation of groundwater level influenced by global climate change from 1977 to 2017. Results show that the temperature in the Golmud River Catchment rose 0.57°C every 10 years. It is highly positive correlated with global climate temperature, with a correlation coefficient, 0.87. The frequency and intensity of extreme precipitation were both increased. Generally, groundwater levels increased from 1977 to 2017 in all phreatic and confined aquifers and the fluctuation became more violent. Most importantly, extreme precipitation led to the fact that groundwater level rises sharply, which induced city waterlogging. However, no direct evidence shows that normal precipitation triggered groundwater level rise, and the correlation coefficients between precipitation data from Golmud meteorological station located in the Gobi Desert and groundwater level data of five observation wells are 0.13, 0.02, –0.11, 0.04, and –0.03, respectively. This phenomenon could be explained as that the main recharge source of groundwater is river leakage in the alluvial-pluvial Gobi plain because of the high total head of river water and goodness hydraulic conductivity of the vadose zone. Data analysis shows that glacier melting aggravated because of local temperature increased. As a result, runoff caused groundwater levels to ascend from 1977 to 2017. Correlation coefficients of two groundwater wells observation data and runoff of Golmud River are 0.80 and 0.68. The research results will contribute to handling the negative effects of climate change on groundwater for Northwestern China.© 2021 China Geology Editorial Office.     

Tectonic evolution of Tarim basin in Cambrian–Ordovician and its implication for reservoir development,NW China

In order to find the impact of regional tectonic evolution of Tarim basin on the inside distribution of sedimentary facies and reservoir development, this paper, based on the research of plate-tectonic evolution of Tarim basin, conducts an in-depth analysis on the basin’s inside sedimentary response to the Eopaleozoic regional geodynamic reversion from extension to convergence around Tarim plate, and concludes that the regional geodynamic environment of surrounding areas closely contributes to the formation and evolution of paleo-uplifts, differentiation of sedimentary facies in platform, distribution of high-energy reef and bank facies belts, conversion of sedimentary base level from fall to rise, obvious change of lithology from dolomite to limestone, and formation of several unconformity surfaces in Ordovician system in the basin. A series of sedimentary responses in the basin are controlled by regional dynamic setting, which not only controls the distribution of reservoirs in reef and bank facies but also restricts the development and distribution of karst reservoirs controlled by the unconformity surfaces. This offers the macro geological evidences for us to further analyze and evaluate the distribution of favorable reservoirs.     

Hydrochemical model and probable pollution in the water of Euphrates River (Qaem–Falluja)

The study of hydrochemical models and probable pollution in Euphrates River from Qaem–Al-Falluja was performed through regime observation in ten water points. The hydrochemical properties of Euphrates River waters are determined by using the analysis results of 21 physico-chemical variables during the water year (2008). The interpretation of the hydrochemical phenomena is achieved in accordance with the statistical results of Polynomial Regression Statistic, calculating the coefficient of variation among the physico-chemical components of the water terminating by 14 models. The results of monitoring during the water year 2008 indicate a pollution case by SO₄ and Cd in Ramadi and downstream stations; TDS, Mg, Na, Cl, Mn, and CO₂ in Ramadi station; TDS, Ca, Na, Cl, and Fe in Baghdadi station; and Ca and H _T in Qaem station and Mg in Obaydi station. The research suggests the best locations for hydrochemical monitoring as continuous hydrologic stations used for the long-term monitoring. These stations are in Qaem city as inlet location and Al-Baghdadi and Ramadi cities terminating in Falluja city as outlet location. Furthermore, daily record system is recommended for the other stations in each city to complete the regime observation of Euphrates water type. From the configuration approach of hydrochemical models with the pollution phenomena, there are potential point sources of pollution such as municipal effluent pipes and reused water from mining process for building materials in the first sector of river, which extends between Qaem and Haditha dam. Also groundwater seepages and springs discharge of mineralized water mixed with sewage water from cities act as potential point sources of pollution on the river water in the second sector extended between Haditha and Ramadi scheme. The third sector of the river is affected by all reasons in the first and second sectors as well as the effectiveness of agricultural activities throughout drainage canals and irrigation projects extended between Ramadi and Falluja cities.     

Drought severity modeling of upper Bhima river basin,western India,using GIS–AHP tools for effective mitigation and resource management

Natural Hazards - The combination of geographic information system (GIS) and analytic hierarchy process (AHP) performs the drought vulnerability assessment of larger areas efficiently. The drought...     

Application of the content–area (C–A) fractal model and prediction–area (P–A) plot for mineral prospectivity modeling in the Luchun area of Yunnan Province,China

This method of assigning weights based on expert opinion introduces bias when we are evaluating the relative importance of evidence values. In this paper, we used a prediction–area (P–A) plot method and content–area (C–A) fractal model to estimate the weight of each evidence map. In this paper, we used the content region (C–A) fractal model to divide the evidence maps to the threshold of the corresponding dimensions. The P–A plot approach is an objective data-driven approach for evaluating map weights. Using geochemical layer and remote sensing, hydroxyl layers as weight evidence maps are the highlights of this study. We use the P–A method from which we can evaluate the predictive ability of each evidence map with respect to the known ore occurrences. We used the P–A plot for weighting each evidence map and choosing the appropriate threshold for predictor maps in the Luchun area of Yunnan Province, China. The method adopted in this paper can improve the prediction efficiency of ore prospecting.     

A multi-period optimization model for conjunctive surface water–ground water use via aquifer storage and recovery in Corpus Christi,Texas

The present study develops and evaluates a decision support system for the conjunctive management of the current surface and proposed aquifer storage and recovery (ASR) facility of the city of Corpus Christi, TX using a simulation–optimization approach. The objective of the model is to maximize water storage in the surface and subsurface storage units while meeting (1) the freshwater inflow requirements to the Corpus Christi estuary and (2) the water demands of the city and its service area. The model is parameterized using streamflow data from the U. S. Geological Survey gauging stations on the Nueces River and its tributaries as well as long-term climatic data and regional hydrogeologic information. Results indicate that a single-well field ASR facility is capable of storing approximately 925 ha-m (7,500 ac-ft) of water over a 5-year period in the Evangeline Aquifer with a total potential storage of about 2,715 ha-m (22,000 ac-ft) of water over the jurisdictional area of the Corpus Christi Aquifer Storage and Recovery Conservation District. Surplus surface water sources are seen to contribute approximately 49–96 % of the water stored in the ASR during the simulation period. The remaining storage came from either Choke Canyon Reservoir or Lake Corpus Christi, which also resulted in a slight reduction in evapotranspiration in both reservoirs. The analysis indicates that the proposed ASR system is not limited on the supply side but multiple well fields may be required to increase the storage capacity within the aquifer.     

In situ and laboratory treatment tests for lowering of excess manganese and iron in drinking water sourced from river–groundwater interaction

Manganese and iron are essential nutrients at low doses. However, long-term exposure in high doses may be harmful. Human activities and natural sources are responsible for manganese and iron contamination in water. This study aimed to investigate the source of high manganese and iron contents in shallow groundwater, where the groundwater is used for drinking purpose, and to decrease the excess manganese and iron from shallow groundwater. Based on the on-site analytical results taken from the wells in the study area, iron contents in water samples varied between 30 and 200 μg/L, which were under the allowable limits of Turkish Drinking Water Standards (TDWS) (Water intended for human consumption, http://rega.basbakanlik.gov.tr/eskiler/2005/02/20050217-3.htm, 2005). However, manganese levels varied from 30 to 248 μg/L, which some of them are higher than the allowable limits of TDWS (Water intended for human consumption, http://rega.basbakanlik.gov.tr/eskiler/2005/02/20050217-3.htm, 2005) (50 μg/L), and EPA (http://water.epa.gov/drink/contaminants/index.cfm, 2006) (50 μg/L). The source of excess manganese is originated mainly from geogenic source besides Porsuk River interaction in shallow aquifer in the specific section of the study area. To decrease high manganese content from the well water and reservoir water, laboratory and in situ treatment tests were applied. Among these tests, chlorination, associated with filtration (by fine sand, active carbon and zeolite) and the use of different filtration procedures by cation exchange resin were determined as the most effective methods, which was not previously applied on-site as a combinative approaches to reduce the excess manganese in water.     

Experimental study of octanol–water partition coefficients for2,4,6-trichlorophenol and pentachlorophenol: Derivation of an empirical model of chlorophenol partitioning behaviour

The octanol–water partition coefficients (log K_ow) of 2,4,6-trichlorophenol and pentachlorophenol were determined as functions of pH, ionic strength and aqueous metal content. For both chlorophenols, the log K_ow exhibits pH dependence in the range pK_a−1<pH<pK_a+3. At lower and higher pH values, the behaviour of the chlorophenols is independent of pH. The present data, in conjunction with that of pre-existing data, indicate that a linear relationship exists between log K_ow and log ionic strength of the aqueous solution for pentachlorophenol, and the data also suggest that aqueous metal–chlorophenolate complexation can significantly alter the partitioning behaviour. The data reported here was used to obtain an empirical model of the partitioning behaviour based on speciation of the aqueous chlorophenol. The model requires knowledge of the low pH partitioning behaviour, as well as the acidity constant for the particular chlorophenol of interest. Although K_ow values have been measured as a function of pH and/or ionic strength for only pentachlorophenol, the input parameters for our empirical model are readily accessible in the literature for many chlorophenols. The model greatly expands our ability to quantify the hydrophobicity of chlorophenols, enabling accurate estimations of the pH and ionic strength dependencies of the partitioning behaviour over a wide range of pH and ionic strength values of environmental interest.     

Soil slip susceptibility assessment using mechanical–hydrological approach and GIS techniques: an application in the Apuan Alps (Italy)

This study aims at contributing to the soil slip susceptibility assessment in a typical basin of the southern Apuan Alps, Italy. On June 1996, this basin (Cardoso Torrent, 13 km² large) was hit by an extremely heavy rainstorm (maximum intensity of about 160 mm/h), which caused many landslides (debris slide–debris flows) and valley bottom flows (hyperconcentrated flows), destruction and deaths. Detailed surveys provided the characterization of the main factors (geological, geomorphologic, hydrological, hydrogeological and geotechnical) which contributed in triggering landslides. In order to evaluate the soil slip susceptibility in this area, a physically based model was applied and a GIS analysis of digital elevation model was performed. This approach couples a mechanical model based on an infinite slope form of the Mohr–Coulomb failure criterion, and a steady-state hydrological one (a modified version of Shalstab, which considers the cohesion of the debris material potentially involved in landsliding). GIS techniques allowed evaluating the effects of topographic convergence and drainage area on slope failure. In this way, based on the infiltration rate, the triggering of the June 1996 landslides was simulated and the critical rainfall thresholds assessed at about 200–250 mm/24 h.     

Air–water CO<Subscript>2</Subscript> flux in an algae bloom year for Lake Hongfeng,Southwest China: implications for the carbon cycle of global inland waters

The carbon cycle of global inland waters is quantitatively comparable to other components in the global carbon budget. Among inland waters, a significant part is man-made lakes formed by damming rivers. Man-made lakes are undergoing a rapid increase in number and size. Human impacts and frequent algae blooms lead to it necessary to make a better constraint on their carbon cycles. Here, we make a primary estimation on the air–water CO₂ transfer flux through an algae bloom year for a subtropical man-made lake—Hongfeng Lake, Southwest China. To do this a new type of glass bottles was designed for content and isotopic analysis of DIC and other environmental parameters. At the early stage of algae bloom, CO₂ was transferred from the atmosphere to the lake with a net flux of 1.770 g·C·m^?2. Later, the partial pressure (pCO₂) of the aqueous CO₂ increased rapidly and the lake outgassed to the atmosphere with a net flux of 95.727 g·C·m^?2. In the remaining days, the lake again took up CO₂ from the atmosphere with a net flux of 14.804 g·C·m^?2. As a whole, Lake Hongfeng released 4527 t C to the atmosphere, accounting for one-third of the atmosphere/soil CO₂ sequestered by chemical weathering in the whole drainage. With an empirical mode decomposition method, we found air temperature plays a major role in controlling water temperature, aqueous pCO₂ and hence CO₂ flux. This work indicates a necessity to make detailed and comprehensive carbon budgets in man-made lakes.     

Dynamics of ammonia-oxidizing archaea and bacteria in relation to nitrification along simulated dissolved oxygen gradient in sediment–water interface of the Jiulong river estuarine wetland,China

Dissolved oxygen (DO) is a very important factor controlling the nitrogen cycle in wetlands. However, it is still unclear to what extent the presence of ammonia-oxidizing archaea (AOA) and bacteria (AOB), and related nitrification, are influenced by DO in estuarine wetlands. The aims of this study were to determine changes of nitrification at the sediment–water interface, to examine the abundance and diversity of archaeal and bacterial ammonia oxidizers in estuarine sediments, and to identify the correlation between nitrification and ammonia-oxidizing microorganisms along a simulated dissolved oxygen gradient in a Chinese estuarine wetland. The results showed that the nitrification rate was positively correlated with the diversity and abundance of AOA but not AOB, and the abundance and diversity of AOA can explain 87 % of the total variance of the first axes in the redundancy analysis. This indicates that AOA were primarily involved in ammonia oxidation in this study. Additionally, AOB were much more influenced by DO than AOA inferred from the assessment of dominant species and principal coordinates analysis of AOA and AOB. Higher diversity and abundance of AOA occurred in the mangrove sediments, which explain the higher nitrification rates in the mangrove sediments compared to the bare mudflat sediments. Notably, the trend of nitrification rate in the bare mudflat sediments was different from that in the mangrove sediments, suggesting that the extent of nitrification as impacted by DO depends largely on the sediment biotic and nutrient properties, and its environmental conditions including DO levels.     

Analysis on the situation and countermeasures of water resources supply and demand in the cities of small and medium-sized river basins along southeast coast of China — taking Xiamen City as an example

The small and medium-sized river basins along southeast coast of China hold comparatively abundant water resources. However, the rapid resources urbanization in recent years has produced a series of water problems such as deterioration of river water quality, water shortage and exacerbated floods, which have constrained urban economic development. By applying the principle of triple supply-demand equilibrium, this paper focuses on the estimation of levels of water supply and demand in 2030 at different guarantee probabilities, with a case study of Xiamen city. The results show that water shortage and inefficient utilization are main problems in the city, as the future water supply looks daunting, and a water shortage may hit nearly 2 × 10⁸ m³ in an extraordinarily dry year. Based on current water supply-demand gap and its trend, this paper proposes countermeasures and suggestions for developing and utilizing groundwater resources and improving the utilization rate of water resources, which can supply as a reference for other southeast middle-to-small-sized basin cities in terms of sustainable water resources and water environment protection.     

Petrogenesis and geodynamics of plagiogranites from Central Turkey (Ekecikdağ/Aksaray): new geochemical and isotopic data for generation in an arc basin system within the northern branch of Neotethys

International Journal of Earth Sciences - In the Late Cretaceous, throughout the closure of the Neotethys Ocean, ophiolitic rocks from the İzmir–Ankara–Erzincan ocean branch were...