کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4576957 1629987 2012 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Freshwater–seawater mixing experiments in sand columns
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
Freshwater–seawater mixing experiments in sand columns
چکیده انگلیسی

SummaryA study was performed on vertical mixing between freshwater and seawater in controlled column experiments. The aim was to quantify the variation in the thickness of the mixing zone caused by water table fluctuations in aeolian dune sandy sediments. A series of column experiments were setup: first a study on in-well mixing was completed to understand the suitability of down-hole logging in existing piezometers versus multi level sampling; then, an unsaturated–saturated column experiment with sandy aeolian dune sediments of the target aquifer was performed to characterize the mixing zone thickness; finally the third column experiment was conducted by imposing a groundwater fluctuation of 0.1 m to quantify the increase of the freshwater–saltwater mixing zone due to vertical water table oscillations. The freshwater–saltwater mixing zone increase was very limited and did not exceed 0.1 m. All experiments were modeled by means of the SEAWAT numerical code, and calibrated against saltwater concentrations. The model fit was good for all experiments, providing insights into the vertical dispersivity of sandy aeolian dune sediments and also into the reliability and precision of the freshwater–saltwater interface monitoring methods. The down-hole logging technique, in fact, was demonstrated to be inefficient when horizontal flow velocity is negligible; in this case only multi-level sampling techniques provided reliable results.


► In absence of groundwater fluxes within piezometers, a down-hole probe cause artificial mixing.
► Mixing processes induced by the water table fluctuations were quantified in laboratory.
► To avoid bias induced by artificial mixing, it is recommended to use multi-level sampler devices.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Hydrology - Volumes 448–449, 2 July 2012, Pages 112–118
نویسندگان
, , ,