Abstracts

Champ and Janis Gulens of AECL and Richard Jackson of Environment Canada) to
explain the sequential occurrence of DO, nitrate, Fe, Mn and sulphide species. Stumm
also provided guidance on the interpretation of Eh measurements by platinum electrodes
that were problematic in most aqueous environments. Champ noted that the microbial
requirements for functioning in groundwater systems were easily met by available nutrients
dissolved in groundwater, while Gulens explained the effects of various sorbed
species (e.g., DO, sulphide, cyanide from Zobell’s solution) on the measured Pt electrode
potential. Jackson wrote the paper that appeared in 1979 in the Canadian Journal of
Earth Sciences based on field data from a short (1 km) flow system he was studying at
Chalk River including data from Back and Barnes and Edmunds.
Thus chemical thermodynamics and electrochemical theory were incorporated into hydrogeology
through the necessity understanding complex groundwater quality patterns
and Eh measurements. This work in the 1970s set the stage for the adoption of monitored
natural attenuation for the biodegradation of chlorinated and fuel hydrocarbons
in the 1990s.
115 - Temporal Scales in Groundwater Science:
The Challenge to Hydrogeologists
William M. Alley
National Ground Water Association, San Diego, California, USA
One of the great challenges facing groundwater hydrologists is to communicate the highly
variable temporal characteristics of groundwater systems and their responses to human and
natural stresses. Just as hydraulic conductivity spans many orders of magnitude, temporal
scales range from real-time to many millennia. This presentation examines the different
time scales of interest to hydrogeologists with an emphasis on how these time scales relate
back to groundwater management and governance.
248 - Laboratory demonstration of confined and unconfined
aquifer storage characteristics
Robert W. Gillham
Department of Earth and Environmental Sciences, University of Waterloo, Waterloo,
Ontario, Canada
Undergraduate students of hydrogeology commonly have difficulty appreciating the differences
in processes of water storage and release in confined and unconfined aquifers.
After several attempts to teach the concepts, but with only moderate success, a laboratory
model was developed that provided a physical and visual demonstration of specific
yield, specific storage and several related phenomena. As reflected in answers to exam
questions, there was a dramatic improvement in the level of student understanding. A detailed
description of the model and a worked example is included in: Gillham, R. W. and
O’Hannesin, S. F. 1984. Apparatus for demonstrating confined and unconfined aquifer
characteristics. Journal of Geological Education, 32: 261-264.
190 IAH-CNC 2015 WATERLOO CONFERENCE