Estimate of shallow groundwater recharge in the Hadejia–Nguru Wetlands, semi-arid northeastern Nigeria     

B. J. M. Goes 《Hydrogeology Journal》1999,7(3):294-304

 The Hadejia–Nguru Wetlands are annually inundated flood plains in semi-arid northeastern Nigeria. The area has a unique ecosystem that forms a natural barrier against the encroachment of the Sahara desert. Both the rich wetland vegetation and local farmers using shallow tube wells depend on a groundwater mound (with a water table less than 6 m below the surface) that is present in the unconfined aquifer under the flood-plain area. Using well records (1991–97) and a hydrogeologic profile based on piezometers that were monitored for two years, it is shown that recharge through the annually inundated flood plains is the source of the groundwater mound. Maintenance of the groundwater-recharge function of the flood plains depends on wet-season releases from two large upstream dams. On the basis of a water-budget method, the mean (1991–97) wet-season unconfined groundwater recharge in the flood-plain area between Hadejia and Nguru and in the immediate vicinity (1250 km²) is estimated to be 132 mm (range, 73–197 mm). Outflow from the unconfined flood-plain aquifer to the unconfined upland aquifer is approximately 10% of the wet-season flood-plain recharge. The unconfined groundwater outflow from the flood-plain area can provide a significant contribution to the present-day rural water supply in the surrounding uplands, but it does not offer much potential for additional groundwater abstraction. In addition to outflow to the upland aquifer (∼14 mm), the distribution of the annually recharged water volume of the shallow flood-plain aquifer is (1) domestic uses (3 mm), (2) small-scale irrigation (∼15 mm), and (3) evapotranspiration ( 1 100 mm). Along the hydrogeologic profile, the recharge in the upland (i.e., outflow from the unconfined flood-plain aquifer and possibly diffuse rain-fed recharge) is in balance with the water uses (i.e., domestic uses, groundwater outflow, and evapotranspiration). The absence of a seasonal water-level trend in the two piezometers in the upland indicates that no rain-fed recharge occurs through preferential path-way (macropore) flow. Received, June 1998 / Revised, November 1998, January 1999 / Accepted, January 1999  相似文献   

Relation of streams, lakes, and wetlands to groundwater flow systems   总被引：24，自引：10，他引：14  

Thomas C. Winter 《Hydrogeology Journal》1999,7(1):28-45

 Surface-water bodies are integral parts of groundwater flow systems. Groundwater interacts with surface water in nearly all landscapes, ranging from small streams, lakes, and wetlands in headwater areas to major river valleys and seacoasts. Although it generally is assumed that topographically high areas are groundwater recharge areas and topographically low areas are groundwater discharge areas, this is true primarily for regional flow systems. The superposition of local flow systems associated with surface-water bodies on this regional framework results in complex interactions between groundwater and surface water in all landscapes, regardless of regional topographic position. Hydrologic processes associated with the surface-water bodies themselves, such as seasonally high surface-water levels and evaporation and transpiration of groundwater from around the perimeter of surface-water bodies, are a major cause of the complex and seasonally dynamic groundwater flow fields associated with surface water. These processes have been documented at research sites in glacial, dune, coastal, mantled karst, and riverine terrains. Received, April 1998 · Revised, July 1998, August 1998 · Accepted, September 1998  相似文献   

纽蒙特矿业公司经营活动的特色     

徐年生 《黄金地质》1999,5(1):67-72

纽蒙特矿业公司是世界上人于南非的著名的黄金勘探。生产企业、集采、逸、冶、科、工、贸于一身,从该公司海外开拓、生产与勘探的关系,环境保护意识及勘探和科研费用投入４个方面介绍了其发展史及成功的基本要素。  相似文献   

Analysis of the institutional and social responses to the eruption and the lahars of Mount Pinatubo volcano from 1991 to 1998 (Central Luzon, Philippines)     

Frédéric Leone  Jean-Christophe Gaillard 《GeoJournal》1999,49(2):223-238

Mount Pinatubo volcano erupted in June 1991 in the main island of Luzon belonging to the Philippines archipelago. Huge economic losses and population exodus have followed. This major crisis has been relayed with other crises due to rain-fed lahars which have been supplied with eruption deposits. These lahars have occurred every year since 1991 during the rainy season. They will probably last until 2005. After a brief presentation of the Philippine official response system to disasters, this paper draws up a critical analysis of the different kinds of institutional and social responses deployed to manage the different crisis and post-crisis phases of this event. Based on three viewpoints: from population, media and other actors, this analysis attempts to point out the strengths and weaknesses of the official management system, especially by studying the efficiency and the range of the solutions taken. So, it appears that the management of the June 1991 main crisis (eruption) was a success. On the other hand, difficulties have occurred with lahars risk management. Indeed, these lahars have obliged the authorities to protect and relocate thousands of people. In spite of persistent problems, the management system (monitoring/warning/evacuation) of lahar crises improves year after year. Failures appear especially within the rehabilitation program (protection/rehousing). Many direct (lack of means, preparedness, coordination, dialog, etc.) and indirect (politico-administrative, socio-economic, cultural contexts) factors come together to lock the wheels of the institutional response system. They defer the socio-economic start of this vital northern Philippines area. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

全国水文站网管理信息系统研究   总被引：2，自引：0，他引：2  

张静怡  蔡建元 《水文》1999,(6):16-19

全国水文站网管理信息系统是应用ＧＩＳ技术开发的信息管理系统,它为优化水文站网,提高站网管理水平,提供了迅速、全面的信息支持系统建成后,可实现水上网图、文、声、像信息的查询、漫游和图形报表的输出。介绍了系统的设计与研究成果。  相似文献   

边坡大变形弹塑性有限元分析[Ⅱ]   总被引：1，自引：0，他引：1  

施斌  村上裕 《水文地质工程地质》1999,26(3):18-22

本文应用Ｕｐｄａｔｅｄ Ｌａｇｒａｎｇｉａｎ有限元分析理论,分析了石龙庙滑坡的稳定性,其中包括滑坡的大变形,初始应力和超孔隙水压力。根据土的工程地质性质,滑坡体分为四层,土层被视为是弹塑性的,土的塑性屈服采用Ｄｒｕｃｋｅｒ－Ｐｒａｇｅｒ理想塑性屈服准则,挡土墙建成前后的滑坡应力和变形被分别分析和讨论,最后根据这些分析结果,提出了滑坡的整治方案。  相似文献   

SEDIMENT MANAGEMENT AT HYDROPOWER RESSERVOIRS     

《国际泥沙研究》1999,(2)

ICONDUCTINGASEDIMENTATIONSURVEYTOCONFIRMISSUESIn1996,ElectricPowerResearchinstitilteandtheFERCjointlyconductedasedimentationsurveyofprimarilyNFHPreservoirsintheUnitedstates.Theprimarypurposesofthesurveyweref(l)toascertainthescopeandseriousnessofsedimentationproblemsinthereservoirs,(2)toexplorethefeasibilityofapplyingmoderntechnologiestomitigatesedimentationproblems,(3)todeterminetheneedsfortechnicalguidelines,(4)toassistFERCstaffinthelicensingofhydroelectricprojectswith…  相似文献   

ISO14000环境管理系列国际标准简介     

吴木咸 《海洋技术学报》1999,18(1):73-76

本文概述ＩＳＯ１４０００环境管理系列国际标准的产生背景、国际环境管理标准化技术委员会、已发布的五项环境管理国际标准以及宣传贯彻该系列标准的建议。  相似文献   

An evaluation of management procedures for implementing a precautionary approach in the ICES context for North Sea plaice (Pleuronectes platessa L.)     

Kell  L. T.; O'Brien  C. M.; Smith  M. T.; Stokes  T. K.; Rackham  B. D. 《ICES Journal of Marine Science》1999,56(6):834-845

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Cessation of the Norwegian drift net fishery: changes observed in Norwegian and Russian populations of Atlantic salmon   总被引：3，自引：2，他引：1  

Jensen  A. J.; Zubchenko  A. V.; Heggberget  T. G.; Hvidsten  N. A.; Johnsen  B. O.; Kuzmin  O.; Loenko  A. A.; Lund  R. A.; Martynov  V. G.; Naesje  T. F.; Sharov  A. F.; Okland  F. 《ICES Journal of Marine Science》1999,56(1):84-95

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