Stream monitoring units (SMUs) are anchored to concrete and placed on the stream bottom. Perforated PVC pipe protects the instruments from rocks and wood moving down the stream channel. |
Water
Quality Primer
Sensor Parameters
DuluthStreams uses state-of-the-art
stream monitoring units (SMUs) with electronic sensors to remotely
measure streamflow and three fundamental water quality parameters
(temperature, specific
electrical conductivity EC25, and turbidity).
These particular measurements of what we call water quality
parameters provide a good indication of a stream's health. This
section provides an overview of the key water quality parameters
that are continuously monitored in three Duluth streams. Specific
details about the precision and accuracy of this data stream
are found in the Quality Assurance
section.
The Chester and Tischer Creek units are
powered by batteries recharged by solar cells. The Kingsbury
unit is hard-wired at the Duluth Zoo and the St. Louis River
unit at the Duluth-Superior inlet to Lake Superior is also
hard-wired courtesy of the U.S. Army Corps of Engineers field
office in Duluth. Additional water quality parameters are
measured in the NRRI or WLSSD Laboratories from water samples
collected by staff or by a remotely activated sampler triggered
by increased flow at Kingsbury Creek.
Two other parameters
that are commonly used in automated stream and lake monitoring
units are pH and dissolved
oxygen (DO). However, these parameters were determined
to have a lower priority than the others because of sensor
cost and
because they were expected to be less dynamic than EC25
and turbidity. They are measured on occasion, manually
by collecting
samples and for lab analysis, during sampling and maintenance
trips. Nutrient and organic matter analyses are also determined
periodically. To find out more about pH and DO, and how
important they can be, go to our Water on
the Web (WOW) sections
on water quality, and to the Lake and Stream curriculum
modules [2+3] and [4+5].
Manual Parameters
This section is still in progress. Check
back soon! |
