Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

    We have a manual that explains all the features 

Record number 414306
Title Shallow rainwater lenses in deltaic areas with saline seepage
Author(s) Louw, P.G.B. de; Eeman, S.; Siemon, B.; `Voortman, B.R.; Gunnink, J.; Baaren, E.S.; Oude Essink, G.H.P.
Source Hydrology and Earth System Sciences 15 (2011). - ISSN 1027-5606 - p. 3659 - 3678.
Department(s) Soil Physics, Ecohydrology and Groundwater Management
Publication type Refereed Article in a scientific journal
Publication year 2011
Keyword(s) zoet water - zout water - neerslag - watervoorziening - klimaatverandering - kustgebieden - fresh water - saline water - precipitation - water supply - climatic change - coastal areas - drained lowland catchments - surface water interactions - semi-confined aquifer - coastal aquifer - saltwater intrusion - groundwater-flow - salt tolerance - interface - netherlands - fresh
Categories Hydrology
Abstract In deltaic areas with saline seepage, freshwater availability is often limited to shallow rainwater lenses lying on top of saline groundwater. Here we describe the characteristics and spatial variability of such lenses in areas with saline seepage and the mechanisms that control their occurrence and size. Our findings are based on different types of field measurements and detailed numerical groundwater models applied in the south-western delta of the Netherlands. By combining the applied techniques we could extrapolate measurements at point scale (groundwater sampling, temperature and electrical soil conductivity (TEC)-probe measurements, electrical cone penetration tests (ECPT)) to field scale (continuous vertical electrical soundings (CVES), electromagnetic survey with EM31), and even to regional scale using helicopter-borne electromagnetic measurements (HEM). The measurements show a gradual mixing zone between infiltrating fresh rainwater and upward flowing saline groundwater. The mixing zone is best characterized by the depth of the centre of the mixing zone Dmix, where the salinity is half that of seepage water, and the bottom of the mixing zone Bmix, with a salinity equal to that of the seepage water (Cl-conc. 10 to 16 g l-1). Dmix is found at very shallow depth in the confining top layer, on average at 1.7 m below ground level (b.g.l.), while Bmix lies about 2.5 m b.g.l. The model results show that the constantly alternating upward and downward flow at low velocities in the confining layer is the main mechanism of mixing between rainwater and saline seepage and determines the position and extent of the mixing zone (Dmix and Bmix). Recharge, seepage flux, and drainage depth are the controlling factors.
There are no comments yet. You can post the first one!
Post a comment
Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.