Date of Award

1987

Publication Type

Thesis

Degree Name

M.S.

Department

Geology

Supervisor

M. Sklash

Rights

info:eu-repo/semantics/openAccess

Abstract

The main objectives of this research program were to determine the quantity, quality and source(s) of groundwater seepage from the streambed into the St. Clair River in the vicinity of Sarnia, Ontario, Canada. Seventeen survey lines were installed on the bed of the St. Clair River in a 100 m by 7 km band between Sarnia Bay and the Sarnia Indian Reserve. The survey lines extended 100 m from shore at an angle of approximately 90° to the shore. Soil cores were collected along the survey lines in conjunction with river bottom descriptions to characterize the river bed. On the survey line locations which had at least 100 mm of granular material, seepage meters were inscalled to measure seepage rates. Moderate seepage was noted on two of the seven survey lines that contained the granular bottom sediments. Minipiezometers were used on these two survey lines to collect streambed groundwater from depths of 1.0 and/or 1.5 m below the river bed. Electrical conductivity, pH and temperature of the streambed groundwater and river water samples were determined in the field. Selected river water and streambed groundwater samples were also analyzed for: chlorinated hydrocarbons, polychlorinated biphenyls, trihalomethanes, EPA Priority Pollutants (extractables), total organic halides (TOX), chloride, and natural isotopes (oxygen-18, deuterium, and tritium). The average observed seepage rate of l. u x 10-8 m 3/s/m2 suggests higher chan expected hydraulic conductivity or hydraulic gradients in the streambed, 2 to 4 orders of magnitude greater than those determined in previous studies. Detectable levels of some organic contaminants were found in the strearnbed groundwater samples, i.e., <0.0067 ug/L total chlorinated hydrocarbons, <0.026 ug/L PCB, <2.77 ug/L trihalomethanes, and <2.4 ug/L base neutral extractables. The isotopic and electrical conductivity data indicate that: (1) the streambed groundwater is not simply river water, (2) groundwater from the freshwater aquifer does not appear to be a significant component of the streambed groundwater, (3) some of the streambed groundwater may be partially derived from shallow groundwater, and (4) a yet unidentified source of water contributes to the streambed groundwater.

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