Hi-Tech Douglas Lake Survey Confirms Accuracy of 1921 Bathymetry Map
Ninety-two years after the first bathymetric survey of Douglas Lake, very little has changed under its surface. We know this because of the University of Michigan’s Department of Surveying and Geodesy’s 1921-1922 survey of Douglas Lake, and a more recent survey by UMBS researcher, Dr. Guy Meadows.
Over the course of two summers, Camp Davis surveying crews mapped the bathymetry of Douglas Lake in great detail. Using little more than a weighted rope, a boat, and a desire to escape the bugs at the shore, students sounded and recorded the lake's depths.
Minor alterations where made in 1934 to correct and supplement the original survey. For the next 74 years, this survey of the lake's depth served as a valuable resource for the Biological Station and the surrounding community.
In 2008, Meadows, then faculty in Atmospheric, Oceanic, and Space Sciences at the University of Michigan’s College of Engineering, revisited the task. Using a small coastal survey vessel with on board precision acoustic depth sounding and differential Global Positioning System (GPS) instrumentation, Meadows remapped Douglas Lake's bathymetry.
With such sophisticated equipment and techniques one would assume a significantly superior product. In many ways it is. There is fine grain detail with respect to the specific shapes of the kettle depressions. And the data is stored in digital format that allows for additional analysis, like the calculation of lake volume.
Yet it is surprising how similar the two bathymetry maps are. With a row boat and a long piece of rope, one could closely approximate the product of 21st century technology and years of expertise in its use.
The UMBS Research Gateway has the 1934 and 2008 datasets as well as PDFs of the two maps available for download.