Verification of two hydrological models for real-time flood forecasting in the Hindu Kush Himalaya (HKH) region     

Tsering  Karma  Shrestha  Manish  Shakya  Kiran  Bajracharya  Birendra  Matin  Mir  Lozano  Jorge Luis Sanchez  Nelson  Jim  Wangchuk  Tandin  Parajuli  Binod  Bhuyan  Md Arifuzzaman 《Natural Hazards》2022,110(3):1821-1845

Natural Hazards - The Hindu Kush Himalayan region is extremely susceptible to periodic monsoon floods. Early warning systems with the ability to predict floods in advance can benefit tens of...  相似文献   

Hydrological response to climate change in a glacierized catchment in the Himalayas   总被引：3，自引：0，他引：3  

Walter W. Immerzeel  L. P. H. van Beek  M. Konz  A. B. Shrestha  M. F. P. Bierkens 《Climatic change》2012,110(3-4):721-736

The analysis of climate change impact on the hydrology of high altitude glacierized catchments in the Himalayas is complex due to the high variability in climate, lack of data, large uncertainties in climate change projection and uncertainty about the response of glaciers. Therefore a high resolution combined cryospheric hydrological model was developed and calibrated that explicitly simulates glacier evolution and all major hydrological processes. The model was used to assess the future development of the glaciers and the runoff using an ensemble of downscaled climate model data in the Langtang catchment in Nepal. The analysis shows that both temperature and precipitation are projected to increase which results in a steady decline of the glacier area. The river flow is projected to increase significantly due to the increased precipitation and ice melt and the transition towards a rain river. Rain runoff and base flow will increase at the expense of glacier runoff. However, as the melt water peak coincides with the monsoon peak, no shifts in the hydrograph are expected.  相似文献   

A geo-environmental map for the sustainable development of the Kathmandu Valley, Nepal     

Omkar M. Shrestha  Achyuta Koirala  Jörg Hanisch  Klaus Busch  Martin Kerntke  Stefan Jäger 《GeoJournal》1999,49(2):165-172

An engineering and environmental geological map of the Kathmandu Valley in Nepal has been elaborated within a project of German-Nepalese cooperation. In the Kathmandu Valley, the major geo-environmental problems arise from haphazard exploitation of geologic resources, local landslide zones, severe problems of garbage disposal, river flooding and a dramatic river pollution. The map was prepared by the use of GIS techniques. It contains all basic geological and environmental data, as geotechnical risk zones (landslide-prone areas or those of poor foundation conditions), areas for preferable extraction of construction material and those not to be allowed to be exploited, areas of immediate need of reforestation in order to prevent landslide or badland development, groundwater protection zones, and suitable garbage disposal sites. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Decadal glacial lake changes in the Koshi basin,central Himalaya,from 1977 to 2010, derived from Landsat satellite images     

Finu Shrestha  Xiao Gao  Narendra Raj Khanal  Sudan Bikash Maharjan  Rajendra Bahadur Shrestha  Li-zong Wu  Pradeep Kumar Mool  Samjwal Ratna Bajracharya 《山地科学学报》2017,14(10):1969-1984

Changes in glacial lakes and the consequences of these changes, particularly on the development of water resources and management of glacial lake outburst flood(GLOF) risk, has become one of the challenges in the sustainable development of high mountain areas in the context of global warming. This paper presents the findings of a study on the distribution of, and area changes in, glacial lakes in the Koshi basin in the central Himalayas.Data on the number of glacial lakes and their area was generated for the years 1977, 1990, 2000, and 2010 using Landsat satellite images. According to the glacial lake inventory in 2010, there were a total of 2168 glacial lakes with a total area of 127.61 km~2 and average size of 0.06 km~2 in the Koshi basin. Of these,47% were moraine dammed lakes, 34.8% bedrock dammed lakes and 17.7% ice dammed lakes. The number of glacial lakes increased consistently over the study period from 1160 in 1977 to 2168 in 2010, an overall growth rate of 86.9%. The area of glacial lakes also increased from 94.44 km~2 in 1977 to 127.61 km~2 in 2010, a growth rate of 35.1%. A large number of glacial lakes in the inventory are small in size(≤ 0.1km~2). End moraine dammed lakes with area greater than 0.1 km~2 were selected to analyze the change characteristics of glacial lakes in the basin. The results show that, in 2010, there were 129 lakes greater than 0.1 km~2 in area; these lakes had a total area of 42.92km~2 in 1997, increasing to 63.28 km~2 in 2010. The distribution of lakes on the north side of the Himalayas(in China) was three times higher than on the south side of the Himalayas(in Nepal).Comparing the mean growth rate in area for the 33 year study period(1977-2010), the growth rate on the north side was found to be a little slower than that on the south side. A total of 42 glacial lakes with an area greater than 0.2 km~2 are rapidly growing between 1977 and 2010 in the Koshi basin, which need to be paid more attention to monitoring in the future and to identify how critical they are in terms of GLOF.  相似文献   

Driftwood deposition from debris flows at slit-check dams and fans   总被引：3，自引：1，他引：2  

Badri Bhakta Shrestha  Hajime Nakagawa  Kenji Kawaike  Yasuyuki Baba  Hao Zhang 《Natural Hazards》2012,61(2):577-602

Experience shows that debris flows containing large woody debris (driftwood) can be more damaging than debris flows without driftwood. In this study, the deposition process of debris flows carrying driftwood was investigated using numerical simulations and flume experiments. Debris-flow trapping due to driftwood jamming in a slit-check dam was also investigated. A numerical model was developed with an interacting combination of Eulerian expression of the debris flow and Lagrangian expression of the driftwood, in which the fluctuating coordinates and rotation of the driftwood were treated stochastically. The calculated shapes and thicknesses of a debris-flow fan and the positions and orientations of the deposited driftwood on a debris-flow fan were consistent with experimental flume results. The jamming of driftwood in a slit-check dam was evaluated based on geometry and probability. The simulated results of outflow discharge and the proportion of driftwood passed through the slit-check dam also agreed with the experimental results.  相似文献   

Delineating and defining the boundaries of an active landslide in the rainforest of Puerto Rico using a combination of airborne and terrestrial LIDAR data   总被引：1，自引：0，他引：1  

Guoquan Wang  James Joyce  David Phillips  Ramesh Shrestha  William Carter 《Landslides》2013,10(4):503-513

Light detection and ranging (LIDAR) is a remote sensing technique that uses light, often using pulses from a laser to measure the distance to a target. Both terrestrial- and airborne-based LIDAR techniques have been frequently used to map landslides. Airborne LIDAR has the advantage of identifying large scarps of landslides covered by tree canopies and is widely applied in identifying historical and current active landslides hidden in forested areas. However, because landslides naturally have relatively small vertical surface deformation in the foot area, it is practically difficult to identify the margins of landslide foot area with the limited spatial resolution (few decimeters) of airborne LIDAR. Alternatively, ground-based LIDAR can achieve resolution of several centimeters and also has the advantages of being portable, repeatable, and less costly. Thus, ground-based LIDAR can be used to identify small deformations in landslide foot areas by differencing repeated terrestrial laser scanning surveys. This study demonstrates a method of identifying the superficial boundaries as well as the bottom boundary (sliding plane) of an active landslide in National Rainforest Park, Puerto Rico, USA, using the combination of ground-based and airborne LIDAR data. The method of combining terrestrial and airborne LIDAR data can be used to study landslides in other regions. This study also indicates that intensity and density of laser point clouds are remarkably useful in identifying superficial boundaries of landslides.  相似文献   

A Comparison of Local- and Foreign-funded Hydropower Station Construction in Nepal based on Remote Sensing     

TIMSINA Ritu Raj  WU Mingquan  NIU Zheng 《资源与生态学报(英文版)》2022,13(6):1009-1021

International investors in large infrastructure projects face numerous risks. To explore this issue, this paper compares the development of two hydropower stations in Rasuwa District, Nepal: Upper Trishuli 3A, which is fully funded by a Chinese government bank, and Rasuwagadhi, which is fully funded by local government banks. The construction of these two plants was compared between 2012 and 2020 using a visual interpretation method to extract data on roads, buildings, dams, and vehicles from 1-m-resolution remote sensing imagery. Two methods were used to compare the environmental impacts of each plant. Landsat 7/8 30-m imagery was used to monitor changes in the normalized difference vegetation index around the Upper Trishuli 3A hydropower station from 2012 to 2020 and around the Rasuwagadhi hydropower station from 2014 to 2020. Then, 1-m-resolution imagery was used to observe land-cover differences in these areas and time periods. The results indicate that: (1) despite various challenges, such as geological disasters, the COVID-19 pandemic, and a blockade by the Indian government, there was no difference in construction progress between the two hydropower stations. (2) The Upper Trishuli 3A Hydropower Station was associated with better environmental protection work, as there were continuous declines in vegetation growth near Rasuwagadhi and increased overall vegetation growth near Upper Trishuli 3A. (3) Energy projects funded by the Belt and Road Initiative have benefited developing countries enormously. Finally, local conditions should be thoroughly investigated during the construction of foreign-funded power stations.  相似文献   

The P–T–t evolution of the exhumed Himalayan metamorphic core in the Likhu Khola region,East Central Nepal          下载免费PDF全文

S. Shrestha  K. P. Larson  C. Guilmette  M. A. Smit 《Journal of Metamorphic Geology》2017,35(6):663-693

The recent identification of multiple strike‐parallel discontinuities within the exhumed Himalayan metamorphic core has helped revise the understanding of convergence accommodation processes within the former mid‐crust exposed in the Himalaya. Whilst the significance of these discontinuities to the overall development of the mountain belt is still being investigated, their identification and characterization has become important for potential correlations across regions, and for constraining the kinematic framework of the mid‐crust. The result of new phase equilibria modelling, trace element analysis and high‐precision Lu–Hf garnet dating of the metapelites from the Likhu Khola region in east central Nepal, combined with the previously published monazite petrochronology data confirms the presence of one of such cryptic thrust‐sense tectonometamorphic discontinuities within the lower portion of the exhumed metamorphic core and provides new constraints on the P–T estimates for that region. The location of the discontinuity is marked by an abrupt change in the nature of P–T–t paths of the rocks across it. The rocks in the footwall are characterized by a prograde burial P–T path with peak metamorphic conditions of ~660°C and ~9.5 kbar likely in the mid‐to‐late Miocene, which are overlain by the hanging wall rocks, that preserve retrograde P–T paths with P–T conditions of >700°C and ~7 kbar in the early Miocene. The occurrence of this thrust‐sense structure that separates rock units with unique metamorphic histories is compatible with orogenic models that identify a spatial and temporal transition from early midcrustal deformation and metamorphism in the deeper hinterland to later deformation and metamorphism towards the shallower foreland of the orogen. Moreover, these observations are comparable with those made across other discontinuities at similar structural levels along the Himalaya, confirming their importance as important orogen‐scale structures.  相似文献   

Devaluation of female work participation with urbanization: a case of peri-urban Ahmedabad     

Sikarwar  Ankit  Chattopadhyay  Aparajita  Jaiswal  Ajit Kumar  Rani  Ritu 《GeoJournal》2022,87(1):319-331

GeoJournal - Urban expansion of the Indian metropolitan cities has reached the rural peripheries. There have been social, economic, and environmental consequences of this process of...  相似文献   

NARX neural network approach for the monthly prediction of groundwater levels in Sylhet Sadar,Bangladesh          下载免费PDF全文

Abdullah Al Jami  Meher Uddin Himel  Khairul Hasan  Shilpy Rani Basak  Ayesha Ferdous Mita 《地下水科学与工程》2020,8(2):118-126

Groundwater is important for managing the water supply in agricultural countries like Bangladesh. Therefore, the ability to predict the changes of groundwater level is necessary for jointly planning the uses of groundwater resources. In this study, a new nonlinear autoregressive with exogenous inputs(NARX) network has been applied to simulate monthly groundwater levels in a well of Sylhet Sadar at a local scale. The Levenberg-Marquardt(LM) and Bayesian Regularization(BR) algorithms were used to train the NARX network, and the results were compared to determine the best architecture for predicting monthly groundwater levels over time. The comparison between LM and BR showed that NARX-BR has advantages over predicting monthly levels based on the Mean Squared Error(MSE), coefficient of determination(R~2), and Nash-Sutcliffe coefficient of efficiency(NSE). The results show that BR is the most accurate method for predicting groundwater levels with an error of ± 0.35 m. This method is applied to the management of irrigation water source, which provides important information for the prediction of local groundwater fluctuation at local level during a short period.  相似文献