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Large‐scale natural gradient tracer test in sand and gravel, Cape Cod, Massachusetts: 1. Experimental design and observed tracer movement
Author(s) -
LeBlanc Denis R.,
Garabedian Stephen P.,
Hess Kathryn M.,
Gelhar Lynn W.,
Quadri Richard D.,
Stollenwerk Kenneth G.,
Wood Warren W.
Publication year - 1991
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/91wr00241
Subject(s) - tracer , aquifer , bromide , geology , hydrology (agriculture) , sorption , thermocline , precipitation , mineralogy , environmental science , groundwater , chemistry , oceanography , adsorption , meteorology , geotechnical engineering , physics , organic chemistry , nuclear physics
A large‐scale natural gradient tracer experiment was conducted on Cape Cod, Massachusetts, to examine the transport and dispersion of solutes in a sand and gravel aquifer. The nonreactive tracer, bromide, and the reactive tracers, lithium and molybdate, were injected as a pulse in July 1985 and monitored in three dimensions as they moved as far as 280 m down‐gradient through an array of multilevel samplers. The bromide cloud moved horizontally at a rate of 0.42 m per day. It also moved downward about 4 m because of density‐induced sinking early in the test and accretion of areal recharge from precipitation. After 200 m of transport, the bromide cloud had spread more than 80 m in the direction of flow, but was only 14 m wide and 4–6 m thick. The lithium and molybdate clouds followed the same path as the bromide cloud, but their rates of movement were retarded about 50% relative to bromide movement because of sorption onto the sediments.