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DOI	10.5194/hess-23-5175-2019
	A three-dimensional palaeohydrogeological reconstruction of the groundwater salinity distribution in the Nile Delta Aquifer
	Van Engelen J.; Verkaik J.; King J.; Nofal E.R.; Bierkens M.F.P.; Oude Essink G.H.P.
发表日期	2019
ISSN	1027-5606
起始页码	5175
结束页码	5198
卷号	23 期号:12
英文摘要	Holocene marine transgressions are often put forward to explain observed groundwater salinities that extend far inland in deltas. This hypothesis was also proposed in the literature to explain the large land-inward extent of saline groundwater in the Nile Delta. The groundwater models previously built for the area used very large dispersivities to reconstruct this saline and brackish groundwater zone. However, this approach cannot explain the observed freshening of this zone. Here, we investigated the physical plausibility of the Holocene-transgression hypothesis to explain observed salinities by conducting a palaeohydrogeological reconstruction of groundwater salinity for the last 32 ka with a complex 3-D variable-density groundwater flow model, using a state-of-the-art version of the SEAWAT computer code that allows for parallel computation. Several scenarios with different lithologies and hypersaline groundwater provenances were simulated, of which five were selected that showed the best match with the observations. Amongst these selections, total freshwater volumes varied strongly, ranging from 1526 to 2659 km3, mainly due to uncertainties in the lithology offshore and at larger depths. This range is smaller (1511- 1989 km3) when we only consider the volumes of onshore fresh groundwater within 300m depth. In all five selected scenarios the total volume of hypersaline groundwater exceeded that of seawater. We also show that during the last 32 ka, total freshwater volumes significantly declined, with a factor ranging from 2 to 5, due to the rising sea level. Furthermore, the time period required to reach a steady state under current boundary conditions exceeded 5.5 ka for all scenarios. Finally, under highly permeable conditions the marine transgression simulated with the palaeohydrogeological reconstruction led to a steeper fresh-salt interface compared to its steady-state equivalent, while low-permeable clay layers allowed for the preservation of fresh groundwater volumes. This shows that long-term transient simulations are needed when estimating present-day fresh-salt groundwater distributions in large deltas. The insights of this study are also applicable to other major deltaic areas, since many also experienced a Holocene marine transgression. © Author(s) 2019.
语种	英语
scopus关键词	Aquifers; Groundwater flow; Groundwater resources; Interface states; Lithology; Offshore oil well production; Sea level; Brackish ground water; Groundwater Flow Model; Groundwater salinities; Holocene transgression; Long term transient; Marine transgression; Parallel Computation; Permeable conditions; Three dimensional computer graphics; freshwater; groundwater flow; Holocene; hypersaline environment; paleohydrology; reconstruction; saline intrusion; salinity; software; transgression; Egypt; Nile Delta
来源期刊	Hydrology and Earth System Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/159539
作者单位	Van Engelen, J., Department of Physical Geography, Utrecht University, Utrecht, 3584 CB, Netherlands, Unit Subsurface and Groundwater systems, Deltares, Utrecht, 3584 BK, Netherlands; Verkaik, J., Department of Physical Geography, Utrecht University, Utrecht, 3584 CB, Netherlands, Unit Subsurface and Groundwater systems, Deltares, Utrecht, 3584 BK, Netherlands; King, J., Department of Physical Geography, Utrecht University, Utrecht, 3584 CB, Netherlands, Unit Subsurface and Groundwater systems, Deltares, Utrecht, 3584 BK, Netherlands; Nofal, E.R., Research Institute for Groundwater, National Water Research Center, El-Kanater El-Khairiya, Egypt; Bierkens, M.F.P., Department of Physical Geography, Utrecht University, Utrecht, 3584 CB, Netherlands, Unit Subsurface and Groundwater systems, Deltares, Utrecht, 3584 BK, Netherlands; Oude Essink, G.H.P., Department of Physical Geography, Utrecht University, Utrecht, 3584 CB, Netherlands, Unit Subsurface and Groundwater systems, Deltares, Utrecht, 3584 BK, Netherlands
推荐引用方式 GB/T 7714	Van Engelen J.,Verkaik J.,King J.,et al. A three-dimensional palaeohydrogeological reconstruction of the groundwater salinity distribution in the Nile Delta Aquifer[J],2019,23(12).
APA	Van Engelen J.,Verkaik J.,King J.,Nofal E.R.,Bierkens M.F.P.,&Oude Essink G.H.P..(2019).A three-dimensional palaeohydrogeological reconstruction of the groundwater salinity distribution in the Nile Delta Aquifer.Hydrology and Earth System Sciences,23(12).
MLA	Van Engelen J.,et al."A three-dimensional palaeohydrogeological reconstruction of the groundwater salinity distribution in the Nile Delta Aquifer".Hydrology and Earth System Sciences 23.12(2019).