Correction to: Flood hazard assessment and mapping of River Swat using HEC-RAS 2D model and high-resolution 12-m TanDEM-X DEM (WorldDEM)     

Farooq  Muhammad  Shafique  Muhammad  Khattak  Muhammad Shahzad 《Natural Hazards》2019,97(2):493-493

Natural Hazards - The original article was updated and corrected due to numbering errors in Figure 8’s subfigures and the placement of some of the article’s other figures. Additional...  相似文献   

Performance of hemi-cylindrical and rectangular submerged breakwaters   总被引：1，自引：0，他引：1  

Dimitrios G. Stamos  Muhammad R. Hajj  Demetri P. Telionis 《Ocean Engineering》2003,30(6):813-828

A parametric experimental study is conducted to compare the reflection and transmission characteristics of submerged hemi-cylindrical and rectangular rigid and water-filled flexible breakwater models. The results show that, for the rigid breakwaters, rectangular models are more effective than hemi-cylindrical ones in terms of reduction of transmitted waves. As for the flexible breakwaters, the hemi-cylindrical models may give better wave reflection than rectangular ones. However, the energy loss induced by the rectangular breakwaters is much larger and more significant to result in an overall better efficiency in terms of reduction in wave transmission. The effects of internal pressure show that the lowest pressurized flexible models considered in this work are the most effective in the reduction of the transmitted wave height. Higher wave reflection, lower wave transmission and higher energy loss are obtained consistently at the lower submergence depth ratio.  相似文献   

Hydrogeologic assessment of escalating groundwater exploitation in the Indus Basin, Pakistan   总被引：1，自引：1，他引：0  

S. Khan  T. Rana  H. F. Gabriel  Muhammad K. Ullah 《Hydrogeology Journal》2008,16(8):1635-1654

Groundwater development has contributed significantly to food security and reduction in poverty in Pakistan. Due to rapid population growth there has been a dramatic increase in the intensity of groundwater exploitation leading to declining water tables and deteriorating groundwater quality. In such prevailing conditions, the hydrogeological appraisal of escalating groundwater exploitation has become of paramount importance. Keeping this in view, a surface water–groundwater quantity and quality model was developed to assess future groundwater trends in the Rechna Doab (RD), a sub-catchment of the Indus River Basin. Scenario analysis shows that if dry conditions persist, there will be an overall decline in groundwater levels of around 10 m for the whole of RD during the next 25 years. The lower parts of RD with limited surface water supplies will undergo the highest decline in groundwater levels (10 to 20 m), which will make groundwater pumping very expensive for farmers. There is a high risk of groundwater salinization due to vertical upconing and lateral movement of highly saline groundwater into the fresh shallow aquifers in the upper parts of RD. If groundwater pumping is allowed to increase at the current rate, there will be an overall decline in groundwater salinity for the lower and middle parts of RD because of enhanced river leakage.  相似文献   

Evaluation of twenty four new Gossypium hirsutum strains for growth, yield, fibre quality and ClCuV resistance under environment of Punjab, Pakistan     

M. Hassan  M. A. Haq  M. Aslam  M. Saleem  K. P. Akhtar  S. Sarwar Alam 《International Journal of Environmental Science and Technology》2006,2(4):319-325

Twenty four new strains were tested for their yield, quality and Leaf Curl Virus (ClCuV) resistance. NIAB-111/S, NIAB-98 and NIAB-999 were significantly high fruit bearing varieties at 90 days completing 59.54, 48.26 and 46.00% fruiting respectively. Seed cotton yield of VH-142 was highest with 5417 kgha^?1 and 52 per plant boll bearing, DNH-57 and NIAB-999 remained second and third with 5234 and 5095 kg ha^?1 seed cotton yield, respectively. BH-160 and CRIS-467 were found to be second and third highest boll bearing varieties with 50.97 and 40.20 per plant average bolls respectively. Plant height in CRIS-467, MNH-642 and SLH-224 was significantly higher in comparison to other varieties.NIAB-98, CIM-499 and CIM-506 were found short stature varieties in comparison with other but out of these NIAB-98 and CIM-506 were in high yielding position and CIM-499 was found medium yielder variety. GOT% of MNH-642 remained highest having value of 45.00%. While GOT%. of NIBGE-1, CRIS-168 and CRIS-467 was at lowest position with 35.73, 35.89 and 36.62% respectively. NIAB-111, CIM-499 and BH-160 were at first position in terms of fibre fineness with micronaire values 3.98, 4.00 and 4.07 ìg/inch having fibre length 28.53, 31.38 and 30.23 mm respectively. Out of 26 varieties, 16 varieties resulted maturity index in the range of 85.03% and 90.30% with highest maturity index in case of NIBGE-1 (i.e. 90.30%) followed by NIAB-999 and MNH-642 with 89.55 and 85.5% respectively.CRIS-168, CRIS-468 and CRIS-467 were found viral susceptible.  相似文献   

A new magnitude category disaggregation approach for temporal high‐resolution rainfall intensities          下载免费PDF全文

Muhammad Rehan Anis  Michael Rode 《水文研究》2015,29(6):1119-1128

Simulation of quick runoff components such as surface runoff and associated soil erosion requires temporal high‐resolution rainfall intensities. However, these data are often not available because such measurements are costly and time consuming. Current rainfall disaggregation methods have shortcomings, especially in generating the distribution of storm events. The objectives of this study were to improve point rainfall disaggregation using a new magnitude category rainfall disaggregation approach. The procedure is introduced using a coupled disaggregation approach (Hyetos and cascade) for multisite rainfall disaggregation. The new procedure was tested with ten long‐term precipitation data sets of central Germany using summer and winter precipitation to determine seasonal variability. Results showed that dividing the rainfall amount into four daily rainfall magnitude categories (1–10, 11–25, 26–50, >50 mm) improves the simulation of high rainfall intensity (convective rainfall). The Hyetos model category approach (Hyetos_Cat) with seasonal variation performs representative to observed hourly rainfall compared with without categories on each month. The mean absolute percentage accuracy of standard deviation for hourly rainfall is 89.7% in winter and 95.6% in summer. The proposed magnitude category method applied with the coupled Hyetos_Cat–cascade approach reproduces successfully the statistical behaviour of local 10‐min rainfall intensities in terms of intermittency as well as variability. The root mean square error performance statistics for disaggregated 10‐min rainfall depth ranges from 0.20 to 2.38 mm for summer and from 0.12 to 2.82 mm for the winter season in all categories. The coupled stochastic approach preserves the statistical self‐similarity and intermittency at each magnitude category with a relatively low computational burden. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Detecting areas affected by flood using multi-temporal ALOS PALSAR remotely sensed data in Karawang,West Java,Indonesia     

Fajar Yulianto  Parwati Sofan  Any Zubaidah  Kusumaning Ayu Dyah Sukowati  Junita Monika Pasaribu  Muhammad Rokhis Khomarudin 《Natural Hazards》2015,77(2):959-985

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Study of horizontal drain effect on slope stability     

Muhammad Mukhlisin  Nurul Aini Binti Abd Aziz 《Journal of the Geological Society of India》2016,87(4):483-490

Slope failure usually occurs when soil particles are unable to build a strong bond with each other and become loose because of the presence of water. Water pressure weakens the ties between the particles and they tend to slip. Therefore, this study focused on the use of horizontal drains to reduce water entry and control the ground water level as a method of slope stabilization. Several previous studies have shown that the use of horizontal drains to lower the water level in soil is one of the fastest and cheapest slope stabilization methods. The main objective of this study is to analyze the effect of horizontal drains on slope stability. Information on slope condition during the landslides which happened at Precinct 9, Putrajaya, Malaysia was used for analytical simulation. Seep/W and Slope/W analyses were carried out with GeoStudio version 2007 software. Slopes with and without horizontal drains were then compared in terms of groundwater level and factor of safety (FOS) values. Scenarios were created for seven types of soil namely: residual, clay, silt, loam, sandy loam, sandy clay loam, and silt clay loam for a case wise analysis. The effect of daily steady rainfall and realcondition rainfall was studied. These cases were studied to find the effectiveness of horizontal drains as a slope stabilization tool. The results revealed that when a drain was installed on a slope, the groundwater level dropped immediately and the safety factor of the slope increased. Sandy loam (sL) soil was identified as the best candidate for a horizontal drain. Its highly saturated hydraulic conductivity Ks facilitated groundwater drain through the horizontal drain effectively. Silt clay loam (scL) soil was identified as the least effective candidate.  相似文献   

Precipitation variability assessment of northeast China: Songhua River basin   总被引：1，自引：0，他引：1  

Muhammad Imran Khan  Dong Liu  Qiang Fu  Muhammad Azmat  Mingjie Luo  Yuxiang Hu  Yongjia Zhang  Faiz M Abrar 《Journal of Earth System Science》2016,125(5):957-968

Variability in precipitation is critical for the management of water resources. In this study, the research entropy base concept was applied to investigate spatial and temporal variability of the precipitation during 1964–2013 in the Songhua River basin of Heilongjiang Province in China. Sample entropy was applied on precipitation data on a monthly, seasonally, annually, decade scale and the number of rainy days for each selected station. Intensity entropy and apportionment entropy were used to calculate the variability over individual year and decade, respectively. Subsequently, Spearman’s Rho and Mann–Kendall tests were applied to observe for trends in the precipitation time series. The statistics of sample disorder index showed that the precipitation during February (mean 1.09, max. 1.26 and min. 0.80), April (mean 1.12, max. 1.29 and min. 0.99) and July (mean 1.10, max. 1.20 and min. 0.98) contributed significantly higher than those of other months. Overall, the contribution of the winter season was considerably high with a standard deviation of 0.10. The precipitation variability on decade basis was observed to increase from decade 1964–1973 and 1994–2003 with a mean value of decadal apportionment disorder index 0.023 and 0.053, respectively. In addition, the Mann–Kendall test value (1.90) showed a significant positive trend only at the Shangzhi station.  相似文献   

基于热模拟实验的富有机质泥页岩成岩作用及演化特征   总被引：1，自引：0，他引：1  

栾国强  董春梅  马存飞  林承焰  张津营  吕夏霏  Muhammad Aleem Zahid 《沉积学报》2016,34(6):1208-1216

富有机质泥页岩蕴含丰富的油气资源,但成岩研究基础薄弱,已成为制约页岩油气勘探开发进程的重要因素。通过开展成岩热模拟实验,结合扫描电镜观察、流体成分测试及有机酸测试等实验测试手段,全面描述实验过程中所发生的水-岩化学反应,试图揭示泥页岩成岩过程及成岩演化规律。研究结果显示,有机质热演化过程中存在一个较宽的有机酸生成窗口,对孔隙流体性质具有重要影响;长石和方解石存在接力溶蚀现象,长石溶蚀高峰过后紧接着出现方解石溶蚀高峰,但方解石溶蚀窗较窄,此后出现方解石重新沉淀结晶;黏土矿物转化及长石的溶蚀过程中会产生大量自生微晶石英,成链状或簇状胶结泥页岩骨架。泥页岩地层作为一个相对封闭体系,各类成岩作用之间相互关联,相互影响,构成错综复杂的成岩体系,进一步增加其成岩作用研究难度。  相似文献   

Geochemistry of sedimentary rocks from Permian–Triassic boundary sections of Tethys Himalaya: implications for paleo-weathering,provenance, and tectonic setting     

Akhtar R. Mir  V. Balaram  Javid A. Ganai  Shamim A. Dar  A. Keshav Krishna 《中国地球化学学报》2016,35(4):428-436

The geochemical characteristics of two sections—the Permian–Triassic boundary (PTB) Guryul Ravine section, Kashmir Valley, Jammu and Kashmir, India; and the Attargoo section, Spiti Valley, Himachal Pradesh, India—have been studied in the context of provenance, paleo-weathering, and plate tectonic setting. These sections represent the siliciclastic sedimentary sequence from the Tethys Himalaya. The PTB siliciclastic sedimentary sequence in these regions primarily consists of sandstones and shales with variable thickness. Present studied sandstones and shales of both sections had chemical index of alteration values between 65 and 74; such values reveal low-to-moderate degree of chemical weathering. The chemical index of weathering in studied samples ranged from 71 to 94, suggesting a minor K-metasomatism effect on these samples. Plagioclase index of alteration in studied sections ranged from 68 to 92, indicating a moderate degree of weathering of plagioclase feldspars. The provenance discriminant function diagram suggests that the detritus involved in the formation of present studied siliciclastic sedimentary rocks fall in quartzose sedimentary and felsic igneous provenances. These sediments were deposited in a passive continental margin plate tectonic setting according to their location on a Si₂O versus K₂O/Na₂O tectonic setting diagram.  相似文献