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1.
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
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This paper deals with groundwater hydrology at a prominent fracture zone landslide slope (Nuta–Yone landslides) in Japan with
an objective to explore an efficient method for the application of landslide stability enhancement measures. The correlation
analyses between the hydrological parameters and ground surface movement data at this landslide resulted in low correlation
values indicating that the geological formation of the area is extremely complex. For the purpose of understanding the groundwater
flow behavior in the landslide area, a three-dimensional transient groundwater flow model was prepared for a part of the landslide
slope, where the levels of effectiveness of applied landslide stability enhancement measures (in the form of multilayered
deep horizontal drains) are different, and was calibrated against the measured water surface elevations at different piezometer
locations. The parameter distributions in the calibrated model and the general directions of the groundwater flow in terms
of flow vectors and the results of particle tracking at the model site were interpreted to understand the reasons for variations
in effectiveness of existing landslide stability enhancement measures and to find potentially better locations for the implementation
of future landslide stability enhancement measures. From the modeling results, it was also understood that groundwater flow
model can be effectively used in better planning and locating the landslide stability enhancement measures. 相似文献
4.
Guoqiang Wang Jingshan Yu S. Shrestha H. Ishidaira K. Takeuchi 《Environmental Earth Sciences》2010,61(4):787-797
A grid-based erosion model is developed by integrating the distributed hydrological model, BTOPMC, with the modified USLE
to estimate soil erosion and sediment outflow during single storms. The possible sheet, rill, channel erosion types, and sediment
transport processes are considered within each grid under the model structure. Instead of representing the sheet erosion and
rill erosion separately, the classic USLE method is modified to simulate the lumped sheet–rill erosion during storms. In the
modification, the runoff ratio and a relevant correction coefficient are brought into the R-factor which improves the model’s applicability in predicting erosion during single storms. Instead of representing a grid
with a unique erosion type, a channel component is assumed to exist in each grid, and its width varies with the upstream contributing
area of the grid. This assumption avoids the problems that are caused by the difference between the channel widths in the
upstream area and the downstream area if the grid is simply recognized as a channel grid. It also enables the model to be
applicable in simulating soil erosion and sediment outflow from a large catchment. Through a case study in the Lushi catchment,
China, the results show an overall satisfactory accuracy for the selected events. Moreover, by analyzing the spatial distribution
of soil erosion or deposition, the erosion-prone areas are identified for the prioritization purpose. 相似文献
5.
Kishor Panjabi Pradeep Goel Prasad Daggupati Narayan Kumar Shrestha Rituraj Shukla 《水文科学杂志》2020,65(13):2224-2232
ABSTRACT In humid regions, surface runoff is often generated by saturation-excess runoff mechanisms from relatively small variable source areas (VSAs). However, the majority of the current hydrologic models are based on infiltration-excess mechanisms. In this study, the AGricultural Non-Point Source Pollution (AGNPS) model was used to integrate the VSA concept using topographic wetness index (TWI). Both the original and AGNPS-VSA models were evaluated for a small agricultural field in Ontario, Canada. The results indicate that the AGNPS-VSA model performed better than original model. The AGNPS-VSA model predicted that only the saturated portion of the field with higher TWI values produced runoff, whereas the original AGNPS model showed uniform hydrologic response from the entire field. The results of this study are important for accurately mapping the locations of VSAs. This new model could be a powerful tool in identifying critical source areas for applying targeted best management practices to minimize pollutant loads to receiving waters. 相似文献
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Understanding of the habitat range of threatened Himalayan medicinal plants which are declining in their abundance due to high anthropogenic disturbances is essential for developing conservation strategies and agrotechnologies for cultivation. In this communication, we have discussed the habitat range of two alpine medicinal plants, Aconitum naviculare (Bruehl) Stapf and Neopicrorhiza scrophulariiflora (Pennel) Hong in a trans-Himalayan dry valley of central Nepal, Manang district. They are the most prioritized medicinal plants of the study area in terms of ethnomedicinal uses. A. naviculare occurs on warm and dry south facing slopes between 4090-4650 m asl along with sclerophyllous and thorny alpine scrubs, while N. scrophulariiflora is exclusively found on cool and moist north facing slope between 4000 and 4400 m asl where adequate water is available from snow melt to create a suitable habitat for this wetland dependent species. The soil in rooting zone of the two plants differs significantly in organic carbon (OC), organic matter (OM), total nitrogen (N) and carbon to nitrogen (C/N) ratio. Due to cool and moist condition of N. scrophulariiflora habitat, accumulation of soil OC is higher, but soil N content is lower probably due to slow release from litter, higher leaching loss and greater retention in perennial live biomass of the plant. The C/N ratio of soil is more suitable in A. navuculare habitat than that of N scrophulariiflora for N supply. Warm and sunny site with N rich soil can be suitable for cultivation ofA. naviculare, while moist and cool site with organic soil for N. scrophulariiflora. The populations of both the plants are fragmented and small. Due to collection by human and trampling damage by livestock, the population of A. naviculare was found absent in open areas in five of the six sampling sites and it was confined only within the bushes of alpine scrubs. For N. serophulariiflora, high probability of complete receding of small glaeiers may be a new threat in future to its habitat. The information about habitat conditions, together with the information from other areas, ean be useful to identify potential habitats and plan for cultivation or domestication of the two medieinal plants. 相似文献
9.
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
10.
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