Knowledge Resource Center for Ecological Environment in Arid Area
DOI | 10.1007/s12665-018-7911-7 |
Characterisation of groundwater recharge conditions and flow mechanisms in bedrock aquifers of the Johannesburg area, South Africa | |
Leketa, Khahliso1; Abiye, Tamiru1; Butler, Michael2 | |
通讯作者 | Leketa, Khahliso |
来源期刊 | ENVIRONMENTAL EARTH SCIENCES
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ISSN | 1866-6280 |
EISSN | 1866-6299 |
出版年 | 2018 |
卷号 | 77期号:21 |
英文摘要 | Groundwater is the major source of water and a critical resource for socioeconomic development in semi-arid environments like the Johannesburg area. Environmental isotopes are employed in this study to characterise groundwater recharge and flow mechanisms in the bedrock aquifers of Johannesburg, which is known for polluted surface water. With the exception of boreholes near the Hartbeespoort Dam, groundwater in the study area was derived from meteoric water that has undergone some degree of evaporation before recharge, possibly via diffuse mechanisms. Boreholes that tap groundwater from the Transvaal Supergroup Formation show depletion in O-18 and H-2 values. This is attributed to diffuse recharge through weathering fractures at high elevation that are undergoing deep circulation or recharge from depleted rainfall from the high-latitude moisture sources. The influence of focused recharge from the Hartbeespoort Dam was observed in the boreholes north of the dam, possibly as a result of the north-south trending fault lines and the north-dipping fractures in the bedding planes of quartzites. This is also supported by a reservoir water budget method which indicated a mean annual net flux of 2,084,131m(3) from Hartbeespoort Dam recharging groundwater per annum. Using tritium in the dam and boreholes located at 750m and 5400m downstream, average groundwater flow velocity was estimated as 202m/year. An open system was observed in shale, andesite and granitic-gneiss aquifers indicating soil CO2 as a dominant source of carbon (C-13) in groundwater. A closed system was also observed in dolomitic aquifers indicating carbonate dissolution as the predominant source of carbon. |
英文关键词 | Groundwater recharge Crystalline aquifer Open and closed carbon system Focused recharge mechanism Johannesburg |
类型 | Article |
语种 | 英语 |
国家 | South Africa |
收录类别 | SCI-E |
WOS记录号 | WOS:000448661300003 |
WOS关键词 | WATERS ; BASIN ; CAPE |
WOS类目 | Environmental Sciences ; Geosciences, Multidisciplinary ; Water Resources |
WOS研究方向 | Environmental Sciences & Ecology ; Geology ; Water Resources |
资源类型 | 期刊论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/209016 |
作者单位 | 1.Univ Witwatersrand, Sch Geosci, Private Bag X3,POB Wits 2050, Johannesburg, South Africa; 2.iThemba Labs, Private Bag 11, ZA-2050 Johannesburg, Gauteng, South Africa |
推荐引用方式 GB/T 7714 | Leketa, Khahliso,Abiye, Tamiru,Butler, Michael. Characterisation of groundwater recharge conditions and flow mechanisms in bedrock aquifers of the Johannesburg area, South Africa[J],2018,77(21). |
APA | Leketa, Khahliso,Abiye, Tamiru,&Butler, Michael.(2018).Characterisation of groundwater recharge conditions and flow mechanisms in bedrock aquifers of the Johannesburg area, South Africa.ENVIRONMENTAL EARTH SCIENCES,77(21). |
MLA | Leketa, Khahliso,et al."Characterisation of groundwater recharge conditions and flow mechanisms in bedrock aquifers of the Johannesburg area, South Africa".ENVIRONMENTAL EARTH SCIENCES 77.21(2018). |
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