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Hydrogeological Conditions (hydrogeological + condition)

Distribution by Scientific Domains

Earth and Environmental Science	50%

Selected Abstracts

Understanding hydrological processes in a highly stressed granitic aquifer in southern India

HYDROLOGICAL PROCESSES, Issue 9 2009
D. V. Reddy
Abstract The results of a study evaluating the recharge/discharge conditions of an unconfined stressed granitic aquifer situated in a semi-arid region of Andhra Pradesh, Southern India are presented. Over the last three decades, excessive withdrawal of groundwater has drastically lowered the water table to the bedrock. The watershed studied was divided into four zones based on geomorphology and hydrogeological conditions. Using environmental chloride data pertaining to groundwater, soil depth profiles, and some hydrogeologic and hydrochemical observations, a recharge model for the watershed was developed. The model revealed that the bulk of the vertical recharge in the western elevated land occurs through preferred pathways and that a small fraction occurs through the soil matrix. In addition, the watershed has a poor hydrogeologic fabric, as indicated by the small range of matrix flow recharge (1 to 1·5% of rainfall) among the four zones. The dominating preferential flow was high (,16% of the annual average rainfall) in the valley fills, but decreased to 5,5·5% in the plains. Furthermore, although the bulk of the recharge occurs vertically, considerable lateral movement of groundwater down the slope indicates that sequential hydrochemical changes occur. Distinct geomorphological features that exist in the watershed support the proposed model. Situations similar to those described above may exist in numerous watersheds in the granitic hard rock region; therefore, information obtained from investigations conducted in this watershed can aid in the development of plans enabling the sustainable exploitation of watersheds that have not yet been developed, as well as implementation of appropriate rainwater conservation measures in over-exploited watersheds. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Aquifer interactions with a polluted mountain river of Nicaragua

HYDROLOGICAL PROCESSES, Issue 13 2008
Jose Alfredo Mendoza
Abstract The interactions between a stream and nearby shallow aquifers were investigated in a mountain basin being polluted by mercury released during mining in central Nicaragua. Hourly data series of water levels and temperatures were analysed using cross-correlation. Resistivity imaging was used to map the subsurface and to complement the hydrological data interpretation. The results show the complex hydrogeological conditions that characterize the region, with weathering and fractured rock as main contributors to groundwater transport. The resistivity images suggest the presence of two vertical dykes perpendicular to the stream, and zones rich in clay. The data series indicate a rapid response from the aquifers to recharge events, followed by immediate discharge on a yearly basis. Furthermore, alternating periods of stream infiltration and aquifer discharge were identified. This work demonstrates that surface water pollution is a threat to groundwater quality in the area. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Application of source removal and natural attenuation remediation strategies at MGP sites in Wisconsin

REMEDIATION, Issue 4 2003
James W. Lingle
This article presents site closure strategies of source material removal and dissolved-phase groundwater natural attenuation that were applied at two manufactured gas plant (MGP) sites in Wisconsin. The source removal actions were implemented in 1999 and 2000 with groundwater monitoring activities preceding and following those actions. Both of these sites have unique geological and hydrogeological conditions. The article briefly presents site background information and source removal activities at both of these sites and focuses on groundwater analytical testing data that demonstrate remediation of dissolved-phase MGP-related groundwater impacts by natural attenuation. A statistical evaluation of the data supports a stable or declining MGP parameter concentration trend at each of the sites. A comparison of the site natural attenuation evaluation is made to compare with the requirements for site closure under the Wisconsin Department of Natural Resources regulations and guidance. © 2003 Wiley Periodicals, Inc. [source]

Quantitative Analysis of Groundwater Flow near a Partially Penetrating River under Riverside Pumping

ACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 3 2004
WANG Bingchen
Abstract, According to practical geological and hydrogeological conditions of riverside water-supply well fields in northwestern China, an ideal hydrogeological model has been generalized and a three-dimensional mathematical model has been set up. A finite difference method was applied to simulating groundwater flow near a partially penetrating river under riverside pumping, and to analyzing the effects of river width, partial penetration and permeability of riverbed sediments on groundwater recharges. Results show that riverside pumping may cause groundwater to flow beneath the partially penetrating river, and that river width, penetration and riverbed permeability obviously influence flows from the partially penetrating river and constant-head boundaries. However, the pumping output is mainly from the partially penetrating river. [source]