University of Wisconsin-Eau Claire (UWEC) became involved in the
study when Dr. Harry M. Jol, Assistant Professor Geography and
Anthropology, was contacted by Arlen Albrecht, University of Wisconsin
Extension-Taylor County, in 2003. The Community Development
Foundation was looking for more methods and studies to determine the
quantity and location of logs below the sediment in Rib Lake. Jol
has been involved with ground penetrating radar (GPR) for over 10 years.
(how GPR works) In the summer of 2003 Jol
and a student spent time at Rib Lake conducting
research with the GPR unit.
The methodology used to collect the data
was unique and the equipment had to be modified to survey over open
water. The GPR antennae were effectively strapped to a small
inflatable raft and slowly towed behind a pontoon. This method
allowed for efficient and effective data collection.
In January of 2004 Dr. Jol gave a presentation to the community of
Rib Lake on the results of the research done the previous summer.
The community was excited to hear the possibilty of more logs being
located by the GPR survey. In response to the findings of Dr. Jol,
he was asked to return to Rib Lake to conduct further investigations.
As part of a class project, Jol and students from his Environmental
Hazards and Geomorphology classes, went to Rib Lake in February 2004 to
conduct further investigations. Research and data collection was
made increasingly difficult due to the large amount of snowfall and cold
temperatures. The method of data collection had, once again, to be
modified for the local environmental conditions. For this survey,
two different GPR frequencies were tested, and for one unit the GPR
anntennae were secured to a plastic sled and pulled by hand across the
snow and ice covering Rib Lake.
The GPR survey covered a loop on the north, and northwest sections of
Rib Lake, correlating with the area near the lumber mill which held the
most logs. In addition to surveying that area with two different
GPR frequencies, a high-resolution survey was conducted on a small plot
near the north shore of the lake, directly in front of Camp 28. A plot
50 meters (east-west) by 10 meters (north-south) was measured and staked
out. In this plot a reading was taken for the full 50 meters stretching
east to west at an interval of 1 meter along the north to south 10 meter
line. By conducting this survey, the data can be processed and
later viewed in three-dimensional space for further interpretation and
Along with the GPR survey, a differential global
positioning system (dGPS) survey was conducted
(how GPS works), and sediment cores were
taken. Students used two Trimble ProXR dGPS units to conduct a
highly accurate (sub-meter) survey in order to create a base map for the
project, map the locations of the GPR surveys, map the location of
sediment cores, and to also map the location of anomalies found during
the GPR survey which could correlate to the location of buried logs.
Mapping all of this data with the GPS is essential for returning to a
specific location for further study, and hopefully in the future to
pinpoint locations to remove logs.
Sediment cores were taken to
extract the sediment for further study and to also estimate the depth of
sediment covering the bottom of Rib Lake. To extract sediment for
sampling, a simple device was constructed from a long PVC tube and a
rubber stopper. The rubber stopper was fitted into the plastic
tube with, a rope tied to one side, and the tube was then lowered down
into the water through a hole in the ice. Once the PVC tube could
not be pushed any further into the sediment, the rope hooked to the
rubber stopper was pulled through the tube, while simultaneously lifting
the tube. When the rubber stopper was drawn through the PVC tube,
it created suction which in turn sucked sediment into the PVC tube.
Once recovered, the sediment was emptied out of the tube, sealed in
plastic bags, and identified with its proper location and depth.
sediment is of particular interest because it may hold a particular
economic value as a fertilizer or soil conditioner. Since the
sediment is of high organic content, it is possible that it could be
safely removed from the bottom of the lake and sold commercial as a type
of soil enhancer. Part of the study by the UWEC students was to
examine the sediment samples that were collected from Rib Lake to try
and identify the relative composition and determine if the sediment
holds any significant value as a soil enhancer.