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41.
Abdessamad Najine Mohammed Jaffal Kamal El Khammari Tahar Aïfa Driss Khattach Mahjoub Himi Albert Casas Said Badrane Hicham Aqil 《Comptes Rendus Geoscience》2006,338(10):676-682
This study is based on the analysis and the interpretation of the gravity data of the Tadla basin. Its purpose is to increase the knowledge of this basin structure. A residual anomaly map was first calculated from the Bouguer anomaly data witch are strongly affected by a regional gradient. The computed map provides information on the ground density variation but it does not bring enough of new elements. Data filtering allows us to emphasize the structures affecting the basin. We chose the horizontal gradient coupled to the upward continuation techniques that permit to highlight news structures and to give information on their dip. The elaborated structural map of the study area constitutes a useful document for rationalizing the future groundwater exploration in the Tadla basin. To cite this article: A. Najine et al., C. R. Geoscience 338 (2006). 相似文献
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Proposed groundwater withdrawals in the San Luis Valley of Colorado may lower the water table in Great Sand Dunes National
Monument. In response, the National Park Service initiated a study that has produced a generalized conceptual model of the
hydrologic system in order to assess whether a lowering of the water table might decrease the surface flow of lower Medano
Creek. Based upon information obtained during the drilling of several boreholes, there appear to be five important hydrostratigraphic
units underlying lower Medano Creek within the upper 30 m of the ground surface: 1. a perched aquifer overlying an aquitard
located between about 5 and 6 m below the ground surface; 2. the aquitard itself; 3. an unconfined aquifer located between
the upper and lower aquitards; 4. an aquitard located between about 27 and 29 m below the ground surface; and 5. a confined
underlying the lower aquitard. Because the areal extent of the aquitards cannot be determined from the borehole data, a detailed
conceptual model of the hydrogeologic system underlying lower Medano Creek cannot be developed. However, a generalized conceptual
model can be envisioned that consists of a complex system of interlayered aquifers and leaky aquitards, with each aquifer
having a unique hydraulic head. Water levels in the perched aquifer rise rapidly to their annual maximum levels in response
to the arrival of the flow terminus of Medano Creek during the spring runoff event, and the location of the flow terminus
is directly dependent upon the discharge of the creek. Water levels in the deeper, non-perched aquifers do not appear to fluctuate
significantly in response to the arrival of the flow terminus, demonstrating that it is unlikely that the proposed groundwater
withdrawals will decrease the surface flow of lower Medano Creek.
Received: 27 December 1995 · Accepted: 20 February 1996 相似文献
44.
《China Geology》2021,4(3):498-508
The surface watershed and groundwater basin have fixed recharge scale, which are not only the basic unit for hydrologic cycle research but also control the water resources formation and evolution and its corresponding eco-geological environment pattern. To accurately identify the boundary of the surface watershed and groundwater basin is the basis for properly understanding hydrologic cycle and conducting the water balance analysis at watershed scale in complicated geologic structure area, especially when the boundary are inconsistent. In this study, the Dalinuoer Lake located in the middle of the Inner Mongolian Plateau which has complicated geologic structure was selected as the representative case. Based on the multidisciplinary comprehensive analysis of topography, tectonics, hydrogeology, groundwater dynamics and stable isotopes, the results suggest the following: (1) The surface watershed ridge and groundwater basin divide of Dalinuoer Lake are inconsistent. The surface watershed was divided into two separate groundwater systems almost having no groundwater exchange by the SW-NE Haoluku Anticlinorium Fault which has obvious water-blocking effect. The surface drainage area of Dalinuoer Lake is 6139 km2. The northern regional A is the Dalinuoer Lake groundwater system with an area of 4838 km2, and the southern regional B is the Xilamulun Riverhead groundwater system with an area of 1301 km2. (2) The groundwater in the southern of regional A and the spring-feeding river are the important recharge sources for the Dalinuoer Lake, and it has greater recharge effects than the northern Gonggeer River system. (3) It is speculated that the trend of Haoluku Anticlinorium Fault is the boundary of the westerlies and the East Asian summer Monsoon (EASM) climate systems, which further pinpoints the predecessor’s understanding of this boundary line. At present, the Dalinuoer Lake watershed is proved to have gone through a prominent warming-drying trend periods, which leads to the precipitation reduction, temperature rise, human activities water usage increasement. So the hydrological cycle and lake eco-environment at watershed scale will still bound to be change, which may pose the potential deterioration risk on the suitability of fish habitat. The results can provide basic support for better understanding water balance evolution and lake area shrinkage cause as well as the ecological protection and restoration implementation of Dalinuoer Lake watershed.© 2021 China Geology Editorial Office. 相似文献
45.
通过对巨野煤田梁宝寺井田含水层、隔水层及断层导水规律的分析,指出了对煤矿生产所造成的影响及生产中应注意的问题,认为梁宝寺井田开采上组煤的水文地质类型为裂隙、岩溶类简单至中等类型,开采下组煤的水文地质类型为岩溶裂隙类中等至复杂型。 相似文献
46.
This work demonstrates how available knowledge can be used to build more transparent and refutable computer models of groundwater systems. The Death Valley regional groundwater flow system, which surrounds a proposed site for a high level nuclear waste repository of the United States of America, and the Nevada National Security Site (NNSS), where nuclear weapons were tested, is used to explore model adequacy, identify parameters important to (and informed by) observations, and identify existing old and potential new observations important to predictions. Model development is pursued using a set of fundamental questions addressed with carefully designed metrics. Critical methods include using a hydrogeologic model, managing model nonlinearity by designing models that are robust while maintaining realism, using error-based weighting to combine disparate types of data, and identifying important and unimportant parameters and observations and optimizing parameter values with computationally frugal schemes. The frugal schemes employed in this study require relatively few (10–1000 s), parallelizable model runs. This is beneficial because models able to approximate the complex site geology defensibly tend to have high computational cost. The issue of model defensibility is particularly important given the contentious political issues involved. 相似文献
47.
Under the organization of China Geological Survey,relevant departments have made industry specifications and technical requirements based on hydrogeological survey data collection at the scale of 1:50 000.Among them,groundwater resource map is a must.According to nationally unified technical requirements of mapping groundwater resources put forward in 2018,this paper mainly interprets relevant principles,content,methods,diagrams as well as legend,and further to point out future directions:Higher precision will equal to higher demand of application,so that is there any more effective way to further interpret application aspect rather than only rules? 相似文献
48.
Dorothy J. Vesper Rachel V. Grand Kristen Ward Joseph J. Donovan 《Environmental Geology》2009,58(3):667-678
The distribution and chemistry of the springs in the Tuscarora Creek watershed is controlled by both geologic structure and
karst dissolution. The watershed is located in eastern West Virginia in the structurally complex Great Valley of the Appalachian
Valley and Ridge province. The upper portion of the stream parallels strike along a mapped fault zone and is bordered by clastic
rocks that comprise North Mountain. The lower reaches of the stream flow cross-strike through Cambro-Ordovician carbonates.
The controlling chemical signature in the spring water is carbonate dissolution. Little evidence was seen for the recharge
from adjacent clastic rocks although differences in the Ca/Mg molar ratio between springs indicated the presence of localized
spring basins in headwater reaches. Na, Cl and Ca generally increased from upstream to downstream in the cross-strike reaches.
Comparison of stream and cumulative spring discharge was consistent with significant groundwater base-flow contribution directly
to the creek, particularly in the strike-parallel region. The largest spring in the watershed (>162 L/s) was sampled during
and after a large storm event along with the adjacent creek. The creek displayed a typical dilution response with each flood
pulse, whereas the spring had only a limited or delayed response. The overall chemical and thermal stability of the spring,
relative to the creek, indicated the lack of significant direct hydraulic connection between the two. The conceptual model
for the area includes localized flowpaths in the headwater region where the stream flow is parallel to strike and a thrust
fault. In addition to the shallow localized flowpaths, a deeper, more regional flowpath likely exists for a large spring further
downstream. 相似文献
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