Inland Basins Research Articles

Petroleum system elements within the Late Cretaceous and Early Paleogene sediments of Nigeria's inland basins: An integrated sequence stratigraphic approach

Sequence stratigraphic studies have been carried out using subsurface well and 2D seismic data in the Late Cretaceous and Early Paleogene sediments of Anambra and proximal onshore section of Niger Delta Basin in the Southeastern Nigeria. The aim was to establish the stratigraphic framework for better understanding of the reservoir, source and seal rock presence and distribution in the basin. Thirteen stratigraphic bounding surfaces (consisting of six maximum flooding surfaces - MFSs and seven sequence boundaries – SBs) were recognized and calibrated using a newly modified chronostratigraphic chart. Stratigraphic surfaces were matched with corresponding foraminiferal and palynological biozones, aiding correlation across wells in this study. Well log sequence stratigraphic correlation reveals that stratal packages within the basin are segmented into six depositional sequences occurring from Late Cretaceous to Early Paleogene age. Generated gross depositional environment maps at various MFSs show that sediment packages deposited within shelfal to deep marine settings, reflect continuous rise and fall of sea levels within a regressive cycle. Each of these sequences consist of three system tracts (lowstand system tract – LST, transgressive system tract – TST and highstand system tract – HST) that are associated with mainly progradational and retrogradational sediment stacking patterns. Well correlation reveals that the sand and shale units of the LSTs, HSTs and TSTs, that constitute the reservoir and source/seal packages respectively are laterally continuous and thicken basinwards, due to structural influences. Result from interpretation of seismic section reveals the presence of hanging wall, footwall, horst block and collapsed crest structures. These structural features generally aid migration and offer entrapment mechanism for hydrocarbon accumulation. The combination of these reservoirs, sources, seals and trap elements form a good petroleum system that is viable for hydrocarbon exploration and development.

Hydrogeological and Geochemical Comparison of High Arsenic Groundwaters in Inland Basins, P.R. China

High As groundwater has been widely found in inland basins of P.R. China, which has posed a serious heath effect on local residents. Although these inland basins experience arid-semiarid climate, and are filled with Quaternary sediments, As concentrations show big variations. Three inlands basins (the Hetao basin (HT), the Yinchuan basin (YC), and the Songnen basin (SN)) have been investigated to characterize chemistry and geochemistry of groundwaters and sediments and to evaluate their controls on As concentrations. Arsenic concentrations ranged between <0.1 and 105 μg/L (average 27.8 μg/L), between <0.1 and 338 μg/L (average 94.0 μg/L), and between 0.33 and 857 μg/L (average 130 μg/L) in YC, SN, and HT, respectively. In those basins, HCO3− is the major anions, and Na+ the major cation. Both Cl− and SO42− concentrations are much lower in SN than those in HT and YC. In YC, although Fe and Mn concentrations are the highest, groundwaters have the lowest As concentration. Contents of ionically bound As (S1) and strongly adsorbed As (S2) are the highest in HT and the lowest in YC. Results show that groundwater As is predominantly regulated by active As forms in sediments (S1 and S2). At the scale of multi-basin, groundwater flushing evidently regulates groundwater As. Due to the similar groundwater flow rate at the scale of the site, redox conditions are the key factor controlling groundwater As, with high groundwater As under reducing conditions.

玛纳斯河流域盐渍化灌区生态环境遥感监测研究

PDF HTML阅读 XML下载 导出引用 引用提醒 玛纳斯河流域盐渍化灌区生态环境遥感监测研究 DOI: 10.5846/stxb201601310225 作者: 作者单位: 石河子大学,石河子大学,石河子大学 水利建筑工程学院,石河子大学理学院,石河子大学理学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41361073）；新疆研究生科研创新项目（XJGRI2015044） Assessment of soil salinization ecological environment change in the Manas river basin using remote sensing technology Author: Affiliation: Shihezi University,Shihezi University,School of Water Conservancy and Architecture Enginering, Shihezi University,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:土壤盐渍化已成为全球性问题，给生态环境及农业生产带来严重的威胁。为了快速、准确评价土壤盐渍化给区域生态坏境带来的影响，该文提出了新的完全基于遥感数据的遥感生态指数（SSEI，Soil Salinization Ecology Index）来监测玛纳斯河流域盐渍化灌区生态环境变化。该指数利用主成分分析的方法耦合与土壤盐渍化相关的土壤盐度、地表反照率、植被覆盖度和土壤湿度四大地表参数，指数构建是数据本身性质所决定，不同于以往遥感与非遥感指数加权叠加易受人为影响。研究结果表明：耦合与盐渍化信息相关的各遥感指数得到的生态指数，能够对土壤盐渍化影响区域的生态环境进行快速、定量、客观的监测。将该指数应用到新疆玛纳斯河流域灌区，结果表明在近26年优和良等级生态环境面积增加了12.89%，这说明灌区生态环境有所改善。该研究对土壤盐渍化监测与评价具有一定参考意义。 Abstract:Soil salinization has become a serious global problem, which poses a grave threat to ecological environment and agricultural production. In order to assess the effect of soil salinization on ecological environment quickly and accurately in regional-scale, a new remote sensing ecological index was proposed to detect the ecological change in arid area based on the remote sensing method in this paper. Manas river basin, a typical arid inland basin in northwest of China, was selected for the study area. Firstly, four indicators (salinity, surface albedo, vegetation coverage and wetness) which closely related to soil salinization were calculated based on the Landsat image in the Manas river basin on August 25, 1989, August 7, 2000, and September 10, 2015. Then, these indicators were normalized using min-max normalization method. Lastly, the principal component analysis (PCA) method was introduced to couple the four indicators, and the soil salinization ecology index (SSEI) was obtained. This method is different from the previous index overlaid by weighting the indexes from remote sensing and other data. It depends on the data itself, instead of subjective human states. The result shows that there is a significant relationship between SSEI and salt content observed in the fields (R2=0.9035, P < 0.01). This indicates SSEI could be used for retrieving the soil salinization on ecological environment rapidly and quantitatively. Through PCA analysis, we found that the first principal component appears stable and its share of all indicators is greater than 85%. The properties of wetness index (WI), normalized difference vegetation index (NDVI), and salinity index (SI) are consistent with the general ecological environmental parameters. The index was applied to the irrigated area of the Manas river basin. Among the bad, comparatively bad, medium, good, excellent grades, the area of bad grade had increased from 491.6 km2 to 1031.4 km2 during 1989 to 2000, but it has been decreased from 1031.4 km2 to 636.9 km2 during 2000 to 2015. The area of medium grade also increased at first but then reduced. The change area ranges from 6354.3 km2 in 1989 to 2111.4 km2 in 2015. The good and excellent grades of ecological environment has been increased by 12.9% in the last 26years, which shows the ecology environment has improved in the irrigation area. The spatial distribution of SSEI shows that the desert area without influencing by human activities still keeps a poor level, and the ecological problem is still very serious. The function of artificial oasis has been improving. Assessment of soil salinization ecological environment change using remote sensing technology could provide insight for land resource development in arid areas. 参考文献 相似文献 引证文献

Integrated assessment of ecosystem quality of arid inland river basin based on RS and GIS: A case study on Shiyang River Basin, Northwest China

The Shiyang River Basin is an important ecological area of the Eastern Hexi Corridor, and is one of the most prominent areas of water conflict and ecological environment problems. An assessment of ecosystem quality in the Shiyang River Basin can provide a reference for ecological protection in arid inland basin. Based on the concept of ecosystem quality and the statistical yearbook, remotely sensed and land cover data, an evaluation index was established with consideration of three aspects of ecosystem (i.e., productivity, stability and bearing capacity). Kruskal-Wallis (Φ2) test and entropy method were applied to determine the weights of evaluation index. With the assistance of RS, GIS and SPSS software, a comprehensive evaluation and change analysis of ecosystem quality and corresponding index were conducted for various ecosystem types in the Shiyang River Basin in 2000, 2005, 2010 and 2015. Results showed that the average ecosystem quality of the Shiyang River Basin was 57.76, and presented an obvious decrease with a magnitude of 0.72 per year du-ring 2000-2015. The spatial pattern of ecosystem quality was that the upstream was better than the midstream, and the midstream was superior to the downstream. The mean values of production capacity, stability and carrying capacity of ecosystem were 67.52, 45.37, and 58.53, respectively. Production capacity and stability had increased slightly, while carrying capacity gradually decreased. Considering various ecosystem types, the highest quality was detected for forest ecosystem with average annual value of 78.12, and this ecosystem presented the lowest decreasing magnitude of 0.28 per year; for grassland, farmland and urban ecosystems, the average annual value was 62.45, 58.76 and 50.29, respectively; the quality of wetland ecosystem was the lowest, and suffered the largest decline with an average rate of 0.98 per year.

DNA barcoding of the fishes of the genus Alburnoides (Actinopterygii, Cyprinidae) from Caucasus

Spirlins of the genus Alburnoides are widespread fishes, which taxonomy has been rapidly developing in recent years. Mitochondrial cytochrome c oxidase subunit I (COI) was used as DNA barcode marker to create a reference dataset of Caucasian Alburnoides and to test its barcoding efficiency. All four previously known Caucasian species of Alburnoides were confirmed as valid species with high genetic distances to sister species as well confirmed as Caucasian endemics. Alburnoides samiii, previously known from Sefidroud basin (Iran), was discovered in Transcaucasia. The accuracy of species identification of Ponto-Caspian Alburnoides by DNA barcodes was 100%. In addition, one potentially new species within A. gmelini was revealed. Despite the limited ability of COI to infer phylogenetic relationships, study provided evidence that Ponto-Caspian lineage of Alburnoides includes significantly larger number of species from Caspian Sea basin and inland basins of Central Asia.

A Review of the Bentong‐Raub Suture vis‐à‐vis New Insight of the Tectonic Evolution of Malay Peninsula, South East Asia

AbstractGenesis of the so‐called Bentong‐Raub Suture of Malay Peninsula does not fit to the model of subduction‐related collision. It has evolved from transpression tectonics resulting closure and exhumation of the inland basin which underwent extensive back‐arc extension during Triassic. Crust having similar thickness (average ∼35 km) below entire Malay Peninsula nagate collision of two separate continental blocks rather supports single continental block that collided with South China continental block during Permo‐Triassic. Westward subduction of intervening sea (Proto South China Sea) below Malay Peninsula resulted in widespread I‐ and S‐Type granitization and volcanism in the back‐arc basins during Triassic. Extensive occurrence of Permo‐Triassic Pahang volcanics of predominantly rhyolitic tuff suggest its derivation from back‐arc extension. Back‐arc extension, basin development and sedimentation of the central belt of the peninsula continued until Cretaceous. A‐Type granite of metaluminous to peraluminous character indicates their emplacement in an intraplate tectonic setting. Malay Peninsula suffered an anticlockwise rotation due to the rifting of Luconia–Dangerous Grounds from the east Asia in the Late Cretaceous–Early Tertiary. Extensive ductile and brittle deformation including crustal segmentation, pull‐apart fracturing and faulting occurred during the closure and exhumation of the basins developed in the peninsula during Late Cretaceous–Early Tertiary. Crustal shortening in the central belt of the peninsula has been accomodated through strike‐slip displacement, shearing and uplift.

Chlorine isotopic constraint on contrastive genesis of representative coastal and inland shallow brine in China

There are great scientific interests to reveal the shallow brine genesis in different geologic environments and also practical significance for resource production and environmental protection, which have not yet gained much attention, however. This study took shallow Quaternary brine in the coastal plain of Laizhou Bay and salt lake brine/intercrystalline brine in arid inland Qaidam Basin in China as two kinds of representative shallow brines, and comparatively analyzed the Cl stable isotopic signatures, coupled with hydrochemistry and water isotopes, aiming at finding out the salinity origin of shallow brines in the coast and inland basin, and further discussing Cl stable isotopic behavior in actual hydrogeological systems. The results indicated that shallow brine in the coastal zone originated from evaporation and precipitation formerly, and halite dissolution by tidewater or rainwater later, as a result of which, most of shallow brine exhibited enriched Cl isotopic signatures. As a contrast in arid inland basin, superficial brine originated from the dissolution of precipitated salt minerals by river water formerly, and intensive evaporation with subsequent precipitation in basin center later, for which all the brines finally exhibited the depleted Cl isotopic signatures. In addition, diffusion and ion filtration in the coast zone, and inflow of deep oilfield water in inland basin, were proposed as potential processes contributing to respective Cl isotopic signatures. In the coast, 37Cl are enriched and 81Br are depleted in most of shallow brines, while all the superficial brine (saline water) samples in arid inland basin exhibit negative δ37Cl and positive δ81Br values. Precipitation and dissolution of salt minerals were believed to contribute primarily to the contrary isotopic signatures, which would not change the Br isotopic compositions a lot for the solution in which the original Br concentration has been relatively high, which is not the case for Cl isotope, however.

Four‐decade record of pervasive grounding line retreat along the Bellingshausen margin of West Antarctica

AbstractChanges to the grounding line, where grounded ice starts to float, can be used as a remotely sensed measure of ice‐sheet susceptibility to ocean‐forced dynamic thinning. Constraining this susceptibility is vital for predicting Antarctica's contribution to rising sea levels. We use Landsat imagery to monitor grounding line movement over four decades along the Bellingshausen margin of West Antarctica, an area little monitored despite potential for future ice losses. We show that ~65% of the grounding line retreated from 1990 to 2015, with pervasive and accelerating retreat in regions of fast ice flow and/or thinning ice shelves. Venable Ice Shelf confounds expectations in that, despite extensive thinning, its grounding line has undergone negligible retreat. We present evidence that the ice shelf is currently pinned to a sub‐ice topographic high which, if breached, could facilitate ice retreat into a significant inland basin, analogous to nearby Pine Island Glacier.

On the scalability of hydrogeochemical factors controlling arsenic mobility in three major inland basins of P.R. China

High As groundwater has been widely found in inland basins of P.R. China, which has posed a serious health risk to the local residents. Although these inland basins experience the same arid to semiarid climate and are filled with Quaternary sediments, As concentrations show big variations. Three inlands basins have been investigated to characterize hydraulic conductivities and geochemistry of the groundwater and sediments, and evaluate their controls on dissolved As concentrations. Dissolved As concentrations ranged between <0.1 and 105 μg/L (average 27.8 μg/L), between <0.1 and 338 μg/L (average 94.0 μg/L), and between 0.33 and 857 μg/L (average 130 μg/L) in the Yinchuan basin (YC), the Songnen basin (SN), and the Hetao basin (HT), respectively. In the YC, although Fe and Mn concentrations are the highest, groundwater has the lowest As concentration. Ionically bound As fraction and strongly adsorbed As fraction of sediments are the highest in the HT and the lowest in the YC basin. Groundwater As is predominantly regulated by these mobilizable As forms in sediments. However, the predominant factors controlling groundwater As are dependent on the scale of the study area. At the average multi-basin scale, groundwater flushing evidently decreases groundwater As concentrations. At the individual scale of the sampling site, due to the similar groundwater flow rate, redox conditions are the key factor controlling groundwater As, with more As partitioned into groundwater of lower Eh values. Variations in these factors controlling groundwater As suggest that safe wells can be expected in the basins with high groundwater flow rates and at sites with higher groundwater Eh values.

40Ar/39Ar chronostratigraphy of late Miocene–early Pliocene continental aquatic basins in SE Galilee, Israel

A continental inland basin extended in northern Israel and the southwest Golan Heights during the Neogene. Sedimentation of carbonates, marls, and evaporites was accompanied by massive basalt flows and by minor marine ingressions. The latter were recognized in restricted areas of the eastern Lower Galilee and the Kinnerot basin, herein termed together as the SE Galilee basin. This study aims to establish a detailed chronostratigraphic framework for ∼5 m.y. of sedimentation between the top of the latest middle Miocene Lower Basalt unit and the base of the earliest Pliocene Cover Basalt unit in the SE Galilee basin, where stratigraphic exposure and lithologic variability are maximized. Data from five outcrop sections, two boreholes, and 27 40Ar/39Ar plateau ages of volcanic rocks were used. The upper Lower Basalt was eroded from tectonically uplifted blocks. Erosion products mixed with pyroclasts were deposited in structural lows between ca. 12 and 10 Ma, forming the Umm Sabune Formation. A gradual lithological transition to the overlying well-bedded lacustrine/lagoonal Bira Formation occurred between ca. 11 and 10 Ma. The transition to the overlying freshwater Gesher Formation occurred at ca. 7 Ma, around the Tortonian-Messinian boundary; hence, the gypsum beds at this transition predated the Messinian salinity crisis. The Cover Basalt flows started between 5.1 and 4.6 Ma at different locations, contemporaneously with the deposition of the upper part of the Gesher Formation and the Fejjas Tuff unit. A newly discovered unit of conglomerates and paleosols is considered to be the continental equivalent of Messinian salinity crisis evaporite deposition. This chronostratigraphic framework provides a basis for comparison with other similar late Neogene continental basins in the Levant and for the recognition on land of the Tortonian-Messinian boundary and the impact of the Messinian salinity crisis around the Mediterranean.

History of moisture change derived from slope sediments of the eastern Gonghe Basin (northeastern Qinghai–Tibetan Plateau) during the last 17 ka

AbstractThe palaeosol–loess–aeolian sand sequence in the eastern Gonghe Basin, which is located at the convergence of the Asian summer monsoon, winter monsoon and the westerlies, reveals detailed moisture changes in the northeastern Qinghai–Tibetan Plateau (NETP) during the last 17 ka. Analysis of magnetic susceptibility (MS), total organic carbon, carbonate content, grain size and geochemical parameters indicate that the region was dominated by an extremely dry climate during ~17.0–15.82 ka, accompanying large‐scale desert expansion in the last glacial maximum (LGM). Subsequently, the climate became generally dry during 15.82–14.6 ka, an interval in which loess rapidly accumulated. Enhanced humidity occurred at 14.6 ka, probably associated with increased strength of the East Asian summer monsoon. The region experienced slightly decreased moisture at around 6.5 and 5.8 ka. After 2.7 ka, the climate became wetter. This interpretation correlates with climatic records from lacustrine and aeolian deposits in the NETP during the LGM, the last deglaciation and the early–middle Holocene. High climatic moisture in the Late Holocene facilitated the formation of a well‐developed palaeosol in the NETP. The effective moisture change in the Gonghe Basin is not simply ascribed to the influences of Asian summer monsoons; instead, it was possibly influenced by the interaction of evaporation and monsoonal precipitation forced by solar insolation variation. The balance between these variables was very influential on the effective moisture change in the closed inland basin of the NETP. Copyright © 2016 John Wiley &amp; Sons, Ltd.

On shallow water rogue wave formation in strongly inhomogeneous channels

Rogue wave formation in shallow water is often governed by dispersive focusing and wave-bottom interaction. In this study we try to combine these mechanisms by considering dispersive nonreflecting wave propagation in shallow strongly inhomogeneous channels. Nonreflecting wave propagation provides extreme wave amplification and the transfer of wave energy over large distances, while dispersive effects allow formation of a short-lived wave of extreme height (rogue wave). We found several types of water channels, where this mechanism can be realized, including (i) channels with a monotonically decreasing cross-section (normal dispersion), (ii) an inland basin described by a half of elliptic paraboloid (abnormal dispersion) and (iii) an underwater hill described by a half of hyperbolic paraboloid (normal dispersion). Conditions for variations of local frequency in the wave train providing optimal focusing of the wave train are also found.

Estimating the sensitivity of runoff to climate change in an alpine-valley watershed of Xinjiang, China

ABSTRACTThe spatial-temporal variation of runoff in an inland basin is very sensitive to climate change. Investigation of runoff change in arid areas is typically limited by lack of meteorological and hydrogeological data. This study focused on runoff change in the Yarkand River source area of the Tarim Basin, China, with the aim of analysing the influence of climate change on the response characteristics of discharge. Sensitivity analysis was introduced to reflect the degree of influence of climate on runoff. Based on the sensitivity factors, over 30 sets of schemes including the IPCC Fourth Assessment Report were simulated using the MIKE 11/NAM rainfall–runoff model and the response of runoff was analysed. The results indicate that there are significant correlations and synchronous fluctuations between runoff and precipitation, evaporation and temperature. The characteristics of the sensitivity of runoff can be fitted well by Bi-Gaussian functions. The functions show that high sensitivity indexes mainly appear in the interval of 165 ± 100 m3 s-1. The influence of precipitation on runoff is greater than that of other climate factors. Through simulation using the NAM model, we found that change of annual runoff was related to the initial climate condition. Annual runoff will have an increasing trend if it has a strong sensitivity to the initial meteorological condition. Moreover, the runoff decreases linearly with evaporation. Also it has a positive relationship with temperature and precipitation. Across the four seasons, the impact in summer and winter is greater than that in spring and autumn. Estimation of the spatial-temporal influence of climate on runoff could provide insight for water resource development in arid areas.Editor Z.W. Kundzewicz Associate editor not assigned

Morphological characteristics and intraspecific structure of Triplophysa orientalis (Balitoridae: Nemacheilinae)

The morphology and intraspecific structure of Triplophysa orientalis inhabiting the inland basins of Tsaidam (northeastern edge of the Tibetan Plateau) and the basin of the upper reach of the Huang He River in China were studied. Significant morphological differences between the populations from the inland basins and the Huang He River were revealed; the latter were distinguished as a separate subspecies T. o. hwanghoensis subsp. n. Intermediate character of some traits of the new subspecies between the nominative subspecies and T. hutjertjuensis was found; as a result, the status of the latter was reduced to the subspecies level. The synonymy of T. o. elongata with the nominative subspecies was confirmed. The differences between T. orientalis and T. obscura—morphologically poorly distinguishable species, sympatric in the basin of the upper reach of the Huang He River—were defined more exactly.

Aquifer Arsenic Cycling Induced by Seasonal Hydrologic Changes within the Yangtze River Basin.

Consumption of groundwater containing >10 μg L(-1) arsenic (As) adversely impacts more than 100 million people worldwide. Multiyear trends in aquifer As concentrations have been documented, but strong seasonal variations are not commonly observed. Here we report dramatic seasonal changes in As concentrations and aquifer chemistry within the Jianghan Plain of the Yangtze River, China. At some wells, concentrations fluctuate by more than an order of magnitude within a single year (100-1200 μg L(-1)). Groundwater extraction and sustained water levels of surface channels during the dry season induces a strong downward hydraulic gradient, seasonally supplying oxidizing (oxygen, nitrate) water to the otherwise anoxic aquifer. Oxygen and/or nitrate addition promotes a transient drop in As concentrations for 1-3 months. When recharge ceases, reducing, low-arsenic conditions are reestablished by reactive, endogenous organic carbon. Temporal variability in As concentrations is especially problematic because it increases the probability of false-negative well testing during low-arsenic seasons. However, periods of low As may also provide a source of less toxic water for irrigation or other uses. Our results highlight the vulnerability and variability of groundwater resources in the Jianghan Plain and other inland basins within Asia to changing geochemical conditions, both natural and anthropogenic, and reinforce that continued monitoring of wells in high-risk regions is essential.

Risk Assessment for Ecological Planning of Arid Inland River Basins Under Hydrological and Management Uncertainties

The Shiyanghe river basin, an arid inland basin of northwest China, is taken as an example to analyze the risk for achieving the ecological planning objective in arid inland river basins under uncertainty conditions. Hydrology and management uncertainties that affect the accomplishment of ecological planning objective are analyzed quantitatively with the methods of Bayesian theory based Probabilistic model, scenario analysis and interval analysis. Bayesian probabilistic analysis method was used to analyze the hydrological uncertainties in the form of probability and interval distributions in planning period, while the scenario analysis method and interval method were used to analyze the managing uncertainties in the form of interval numbers. Instead of the ecological risk analysis, which for arid inland river basin, of studying the impact of environmental and human factor on ecological system, water resources and environment, we focused on analysing the possible impact of hydrological and management uncertainty factor on the ecological planning, and forecasting the degree of the completion under the uncertainty. Our study provided the probabilities of achieving ecological planning objective and the possible deviation of different scenarios. The more local water resources and higher level of local water resource utilization and management appeared to lead higher probability to achieve the ecological objective. This study can help environment and water resource managers and planner to formulate a rational planning for arid inland river basins under hydrological and management uncertainty.

New interpretation of the role of water balance in an extended Budyko hypothesis in arid regions

Abstract. The Budyko hypothesis (BH) is an effective approach to investigating long-term water balance at large basin scale under steady state. The assumption of steady state prevents applications of the BH to basins, which is unclosed, or with significant variations in root zone water storage, i.e., under unsteady state, such as in extremely arid regions. In this study, we choose the Heihe River basin (HRB) in China, an extremely arid inland basin, as the study area. We firstly use a calibrated and then validated monthly water balance model, i.e., the abcd model, to quantitatively determine annual and monthly variations of water balance for the sub-basins and the whole catchment of the HRB, and find that the roles of root zone water storage change and that of inflow from upper sub-basins in monthly water balance are significant. With the recognition of the inflow water from other regions and the root zone water storage change as additional possible water sources to evapotranspiration in unclosed basins, we further define the equivalent precipitation (Pe) to include local precipitation, inflow water and root zone water storage change as the water supply in the Budyko framework. With the newly defined water supply, the Budyko curve can successfully describe the relationship between the evapotranspiration ratio and the aridity index at both annual and monthly timescales, whilst it fails when only the local precipitation being considered. Adding to that, we develop a new Fu-type Budyko equation with two non-dimensional parameters (ω and λ) based on the deviation of Fu's equation. Over the annual timescale, the new Fu-type Budyko equation developed here has more or less identical performance to Fu's original equation for the sub-basins and the whole catchment. However, over the monthly timescale, due to large seasonality of root zone water storage and inflow water, the new Fu-type Budyko equation generally performs better than Fu's original equation. The new Fu-type Budyko equation (ω and λ) developed here enables one to apply the BH to interpret regional water balance over extremely dry environments under unsteady state (e.g., unclosed basins or sub-annual timescales).

Hydrogeological and hydrogeochemical control of groundwater salinity in an arid inland basin: Dunhuang Basin, northwestern China

High groundwater salinity has become a major concern in the arid alluvial plain of the Dunhuang Basin in northwestern China because it poses a significant challenge to water resource management. Isotopic and geochemical analyses were conducted on 55 water samples from springs, boreholes and surface water to identify potential sources of groundwater salinity and analyse the processes that control increasing salinity. The total dissolved solid (TDS) content in the groundwater ranged from 400 to 41 000 mg/l, and high TDS values were commonly associated with shallow water tables and flow-through and discharge zones in unconfined aquifers. Various groundwater contributions from rainwater, agricultural irrigation, river water infiltration and lateral inflows from mountains were identified by major ions and δD and δ18O. In general, HCO3− and SO42− were the dominant anions in groundwater with a salinity of 2500 mg/l. The major ion concentrations indicated that mineral weathering, including carbonate and evaporite dissolution, primarily affected groundwater salinity in recharge areas. Evapotranspiration controlled the major ion concentration evolution and salinity distribution in the unconfined groundwaters in the flow-through and discharge areas, although it had a limited effect on groundwater in the recharge areas and confined aquifers. Agricultural irrigation increased the water table and enhanced evapotranspiration in the oasis areas of the basin. TDS and Cl became more concentrated, but H and O isotopes were not enriched in the irrigation district, indicating that transpiration dominated the increasing salinity. For other places in the basin, as indicated by TDS, Cl, δD and δ18O characteristics, evaporation, transpiration and water–rock interactions dominated at different hydrogeological zones, depending on the plant coverage and hydrogeological conditions. Groundwater ages of 3H, and δD and δ18O compositions and distributions suggest that most of the groundwaters in Dunhuang Basin have a paleometeoric origin and experienced a long residence time. These results can contribute to groundwater management and future water allocation programmes in the Dunhuang Basin. Copyright © 2015 John Wiley & Sons, Ltd.

Modeling Ecohydrological Processes and Spatial Patterns in the Upper Heihe Basin in China

The Heihe River is the second largest inland basin in China; runoff in the upper reach greatly affects the socio-economic development in the downstream area. The relationship between spatial vegetation patterns and catchment hydrological processes in the upper Heihe basin has remained unclear to date. In this study, a distributed ecohydrological model is developed to simulate the hydrological processes with vegetation dynamics in the upper Heihe basin. The model is validated by hydrological observations at three locations and soil moisture observations at a watershed scale. Based on the simulated results, the basin water balance characteristics and their relationship with the vegetation patterns are analyzed. The mean annual precipitation and runoff increase with the elevation in a similar pattern. Spatial patterns of the actual evapotranspiration is mainly controlled by the precipitation and air temperature. At the same time, vegetation distribution enhances the spatial variability of the actual evapotranspiration. The highest actual evapotranspiration is around elevations of 3000–3600 m, where shrub and alpine meadow are the two dominant vegetation types. The results show the mutual interaction between vegetation dynamics and hydrological processes. Alpine sparse vegetation and alpine meadow dominate the high-altitude regions, which contribute most to the river runoff, and forests and shrub contribute relatively small amounts of water yield.

Response of Glacier and Lake Dynamics in Four Inland Basins to Climate Change at the Transition Zone between the Karakorum And Himalayas.

Inland glacier and lake dynamics on the Tibetan Plateau (TP) and its surroundings over recent decades are good indicators of climate change and have a significant impact on the local water supply and ecosystem. The glacier and lake changes in Karakoram are quite different from those of the Himalayas. The mechanisms of the complex and regionally heterogeneous behavior of the glacier and lake changes between the Karakorum and Himalayas are poorly understood. Based on satellite images and meteorological data of Shiquanhe, Hetian, and Yutian stations, we demonstrate that the overall retreat of glaciers and increase of lake area at the transition zone between the Karakoram and Himalayas (TKH) have occurred since 1968 in response to a significant global climate change. Glacial areas in the Songmuxi Co basin, Zepu Co basin, Mang Co basin and Unnamed Co decreased by -1.98 ± 0.02 km2, -5.39 ± 0.02 km2, -0.01 ± 0.02 km2, and -0.12 ± 0.02 km2 during the study period, corresponding to losses of -1.42%, -2.86%, -1.54%, and -1.57%, respectively. The lake area of the Songmuxi Co, Zepu Co, Mang Co and Unnamed Co increased by 7.57 ± 0.02 km2, 8.53 ± 0.02 km2, 1.35 ± 0.02 km2, and 0.53±0.02 km2, corresponding to growths of 30.22%, 7.55%, 11.39%, and 8.05%, respectively. Increases in temperature was the main reason for glacier retreat, whereas decreases in potential evapotranspiration of lakes, increases in precipitation, and increases in melt water from glaciers and frozen soil all contributed to lake area expansion.