干旱区生态环境知识资源中心(Arid): Recharge Estimation Using CMB and Environmental Isotopes in the Verlorenvlei Estuarine System, South Africa and Implications for Groundwater Sustainability in a Semi-Arid Agricultural Region

Arid

DOI	10.3390/w12051362
	Recharge Estimation Using CMB and Environmental Isotopes in the Verlorenvlei Estuarine System, South Africa and Implications for Groundwater Sustainability in a Semi-Arid Agricultural Region
	Watson, Andrew; Eilers, Anya; Miller, Jodie A.
通讯作者	Miller, JA
来源期刊	WATER
EISSN	2073-4441
出版年	2020
卷号	12 期号:5
英文摘要	Groundwater recharge remains one of the most difficult hydrogeological variables to measure accurately, especially for semi-arid environments where the recharge flux is much smaller than in humid conditions. In this study, groundwater recharge was estimated using chloride mass balance (CMB) in the Verlorenvlei catchment, South Africa where the effects of recent severe drought conditions in an already semi-arid environment have impacted both agricultural activity as well as the RAMSAR-listed Verlorenvlei estuarine system. Chloride, O-18 and H-2 tracers were used to improve understanding of the groundwater flow patterns and allowed the fresh parts of the groundwater system, defined by Ca2+-HCO3- groundwater types, to be separated from those where additional salts were being introduced through groundwater mixing, and thus characterized as Na+-Cl- groundwater types. Recharge rates calculated from CMB in the fresh parts of the system were between 4.2-5.6% and 11.4-15.1% of mean annual precipitation for the headwater valley and mountains of the Krom Antonies and are largely consistent with previous studies. However, much lower recharge rates in the valleys where agriculture is dominant contrasts with previous results, which were higher, since groundwater-mixing zones were not recognised. Although the chloride concentration in precipitation is based on only one year of data between 2015 and 2016, where 2015 had on average 28% less precipitation than 2016, the results provide a snapshot of how the system will respond to increasing drought frequency in the future. The results suggest that low rates of groundwater recharge under dry spell conditions will impact on low flow generations which are required to sustain the Verlorenvlei estuarine lake system. Overall, the study highlights the importance of combining hydrochemical tracers such as bulk chloride and stable isotopes with numerical modelling in data-scarce catchments to fully understand the nature of hydrological resilience.
英文关键词	recharge chloride mass balance Verlorenvlei semi-arid environments
类型	Article
语种	英语
开放获取类型	gold
收录类别	SCI-E
WOS记录号	WOS:000555915200141
WOS关键词	CHLORIDE-MASS-BALANCE ; NORTHERN SANDVELD ; CLIMATE-CHANGE ; WESTERN CAPE ; RAINFALL ; DROUGHT ; AQUIFER ; COAST
WOS类目	Environmental Sciences ; Water Resources
WOS研究方向	Environmental Sciences & Ecology ; Water Resources
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/325422
作者单位	[Watson, Andrew; Eilers, Anya; Miller, Jodie A.] Stellenbosch Univ, Dept Earth Sci, Private Bag X1, ZA-7602 Matieland, South Africa
推荐引用方式 GB/T 7714	Watson, Andrew,Eilers, Anya,Miller, Jodie A.. Recharge Estimation Using CMB and Environmental Isotopes in the Verlorenvlei Estuarine System, South Africa and Implications for Groundwater Sustainability in a Semi-Arid Agricultural Region[J],2020,12(5).
APA	Watson, Andrew,Eilers, Anya,&Miller, Jodie A..(2020).Recharge Estimation Using CMB and Environmental Isotopes in the Verlorenvlei Estuarine System, South Africa and Implications for Groundwater Sustainability in a Semi-Arid Agricultural Region.WATER,12(5).
MLA	Watson, Andrew,et al."Recharge Estimation Using CMB and Environmental Isotopes in the Verlorenvlei Estuarine System, South Africa and Implications for Groundwater Sustainability in a Semi-Arid Agricultural Region".WATER 12.5(2020).