Abstract for 1997 GLOBE Airlie Conference

Assessing Water Quality: When, Why and Where

Roger C. Bales
Department of Hydrology and Water Resources
University of Arizona

Some very important water-quality assessments have
been based on sampling a set of lakes or streams
only once or twice, usually in summer. In most
parts of the world streams and lakes undergo
seasonal changes in water quality, changes that are
associated with seasonal patterns of precipitation,
runoff, sunlight and plant growth. Must one do
quarterly, monthly, weekly or more frequent
sampling in order to capture these changes? The
answer to the questions of when to sample, and how
often to sample, must start with the question why.
What is the question that motivated the sampling in
the first place? Being both frequent and
widespread, GLOBE hydrology observations offer the
potential to address a number of questions. Often
new scientific or policy questions come up well
after a water quality monitoring effort is
underway. GLOBE has several features that will give
it the flexibility to help answer a range of future
water quality questions.