Abrupt behaviours of streamflow and sediment load variations of the Yangtze River basin,China     

Qiang Zhang  Vijay P. Singh  Chong‐Yu Xu  Xiaohong Chen 《水文研究》2013,27(3):444-452

Monthly sediment load and streamflow series spanning 1963–2004 from four hydrological stations situation in the main stem of the Yangtze River, China, are analysed using scanning t‐test and the simple two‐phase linear regression scheme. Results indicate significant changes in the sediment load and streamflow from the upper reach to the lower reach of the Yangtze River. Relatively consistent positive coherency relations can be detected between streamflow and sediment load in the upper reach and negative coherency in the middle and lower reaches. Interestingly, negative coherency is found mainly for larger time scales. Changes in sediment load are the result mainly of human influence; specifically, the construction of water reservoirs may be the major cause of negative coherency. Accentuating the human influence from the upper to the lower reach results in inconsistent correlations between sediment load and streamflow. Decreasing sediment load being observed in recent years has the potential to alter the topographical properties of the river channel and the consequent development and recession of the Yangtze Delta. Results of this study are of practical significance for river channel management and evaluation of the influence of human activities on the hydrological regimes of large rivers. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Fluoride enrichment in aquifers of the Thar Desert: controlling factors and its geochemical modelling     

Chander Kumar Singh  Rina Kumari  Neha Singh  Javed Mallick  Saumitra Mukherjee 《水文研究》2013,27(17):2462-2474

The groundwater is the only source of drinking water in the Jaisalmer district of Rajasthan, India. The study area is a part of the Thar Desert. It has low and scattered population and no industries; hence, the possibility of anthropogenic input of fluoride is almost negligible. Thus, the enrichment of fluoride is only possible due to geochemical processes taking place in the groundwater of the region. A total of 100 groundwater samples, 34 samples from Jaisalmer and 66 samples from the Pokharan administrative blocks, were collected. It was observed that the concentration of fluoride ranged from 0.08 mg/l to 4.56 mg/l in the groundwater of Jaisalmer and from 0.56 mg/l to 6.60 mg/l in the samples of the Pokharan block. The alkaline condition (average pH, 7.7 ± 0.22 and 8.01 ± 0.25 in Jaisalmer and the Pokharan administrative block, respectively) in the region favours fluorite dissolution. Ion exchange, dissolution of calcite, semi‐arid climate, alkaline conditions and weathering are responsible for fluoride enrichment in the groundwater of the study area. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

The influence of dam and lakes on the Yangtze River streamflow: long‐range correlation and complexity analyses     

Qiang Zhang  Yu Zhou  Vijay P. Singh  Xiaohong Chen 《水文研究》2012,26(3):436-444

Employing long‐range correlation, complexity features and clustering, this study investigated the influence of dam and lake‐river systems on the Yangtze River flow. The impact of the Gezhouba Dam and the lake systems on streamflow was evaluated by analysing daily streamflow records at the Cuntan, the Yichang and the Datong station. Results indicated no evident influence of the Gezhouba Dam on streamflow changes. Distinct differences in scaling behaviour, long‐range correlation and clustering of streamflow at the Datong station when compared with those at the Cuntan and Yichang stations undoubtedly showed the influence of water storage and the buffering effect of the lake systems between the Datong station and other two hydrological stations on streamflow in the lower Yangtze River basin. Decreased regularity, enhanced long‐range correlation and increased clustering of streamflow in the lower Yangtze River basin due to the effect of water storage of the lake systems were corroborated. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Breach erosion of earthfill dams (BEED) model   总被引：1，自引：0，他引：1  

V. P. Singh  P. D. Scarlatos  J. G. Collins  M. R. Jourdan 《Natural Hazards》1988,1(2):161-180

A computer model has been developed for simulation of breach erosion of earthfill dams (BEED). The model incorporates the processes of surface erosion and slope sloughing to simulate breach enlargement. Depletion of reservoir water is approximated by a volume continuity equation while broad-crested weir hydraulics is utilized to describe flow over and through the breach. Due to the implicit form of these equations, an iterative solution is proposed with convergence achieved within only a few iterations. The BEED model is written in both FORTRAN 77 and BASIC computer languages. Testing of the model using historical data of the failures of Teton and Huaccoto dams showed that timing, shape, and magnitude of the predicted outflow hydrograph were adequately simulated by this model. The same is true for the dimensions of the terminal breach. A sensitivity analysis indicated that internal friction angle and the relation for surface erosion were the major factors affecting the model results.  相似文献   

A simple criterion for the machinability of hard rocks     

S. P. Singh 《Geotechnical and Geological Engineering》1989,7(3):257-266

Conclusions The application of mechanical methods for rapid excavation requires more detailed and precise knowledge of the site, but there is no single parameter which can provide a comprehensive measure for the selection and performance of a tunnel boring machine.The machinability index proposed in this paper is based on four different parameters which influence the performance of a tunnelling machine and are widely accepted by the engineers and geologists. In order to develop a comprehensive measure regarding the borability of rocks,in situ conditions must be evaluated. The machinability index coupled with thein situ information would facilitate judicious decisions regarding the application and selection of tunnel boring machines.The geological conditions and rock characteristics cannot be controlled but their knowledge can prevent costly mistakes in equipment selection and assist in identifying alternative excavation systems, therefore a thorough site investigation can substantially reduce the economic and technical risks associated with tunnelling and mine development.  相似文献   

Generation of low-frequency oscillations in the subsolar venus ionopause     

R N Singh  Hari Om Upadhyay 《Journal of Earth System Science》1989,98(3):297-308

  相似文献   

Temporal change detection in river courses and flood plains in an arid environment through satellite remote sensing     

Surendra Singh  K. D. Sharma  Nepal Singh  D. N. Bohra 《Journal of the Indian Society of Remote Sensing》1988,16(4):53-56

Temporal changes in ephemeral river courses and associated flood plains, which could not be detected by Landsat MSS due to its poor spatial resolution of 80m, have been identified and mapped within 10% accuracy by Landsat TM False colour composite because of its higher spectral and spatial resolution of 30 m. Over a period of 28 years (1958–86) the river courses widened upto 1.8 times through bank erosion due to the recurring flash floods. The flash floods have also caused morphological, soil fertility and landuse changes in the associated flood plains, which could also be monitored by the Landsat TM.  相似文献   

Correlation between point load index and compressive strength for quartzite rocks   总被引：1，自引：0，他引：1  

V. K. Singh  D. P. Singh 《Geotechnical and Geological Engineering》1993,11(4):269-272

Summary The relationship of the point load test with uniaxial compressive strength was examined using quartzite rocks to substantiate the existing correlations.  相似文献   

Evaluation　of　Forecast　Performance　of　an　Economical　Explicit　Time　Integration　Scheme　in　a　Limited　Area　Model　over　Indian　Region     

A. Bandyopadhyay  S.S. Singh 《大气科学进展》1994,11(1):101-110

ＥｖａｌｕａｔｉｏｎｏｆＦｏｒｅｃａｓｔＰｅｒｆｏｒｍａｎｃｅｏｆａｎＥｃｏｎｏｍｉｃａｌＥｘｐｌｉｃｉｔＴｉｍｅＩｎｔｅｇｒａｔｉｏｎＳｃｈｅｍｅｉｎａＬｉｍｉｔｅｄＡｒｅａＭｏｄｅｌｏｖｅｒＩｎｄｉａｎＲｅｇｉｏｎＡ．Ｂａｎｄｙｏｐａｄｈｙａｙａ...  相似文献   

DISCUSSION OF "Computer Note on a Program to Analyze Aquifer Test Data and Check for Validity with the Jacob Method," by Malcolm S. Field     

V. S. Singh  C. P. Gupta 《Ground water》1994,32(1):145-145

  相似文献