Interesting story from the Mille Lacs Messenger. Go to their website for pics. Have been seeing these guys out there for the last couple months.
Mapping (the bottom) of Mille Lacs Lake
Posted: Friday, October 5, 2018 6:00 am
by Andre LaSalle [email protected] | 0 comments
For the past few months, Kyle Davis and his colleagues have gotten to know Mille Lacs Lake pretty well. Davis, a marine surveyor for Garmin Ltd., has been busy using state-of-the-art multi-beam sonar technology to “collect bathymetric data for the purposes of contour generation.”
Translation? He’s creating a detailed map of the bottom of Mille Lacs Lake, complete with finely-tuned contour lines and first ever side-scan imagery.
Davis man’s one of four boats that Garmin has been sending out on the lake since mid-July. The custom boats, each complete with proprietary sonar gear, a computer and the latest Garmin chart plotters, heads to a specific area of the lake and proceed to motor back and forth, recording data from swaths of lake bottom. To gather precise imagery, the boats travel at speeds averaging around five miles per hour.
Updating old data
Anyone who fishes Mille Lacs is likely already aware that Garmin has contour maps available of most of the lake. But these maps were created using older technology and likely include some interpolated contour lines, Davis explained. Put in simpler terms, the contour lines might not be detailed enough to show small rock structures or changes in the lake bottom in somewhat flat areas.
“It’s going to be a major improvement,” Davis said of the new data, which he expects will be available sometime in 2019.
Garmin has already re-mapped many lakes in Minnesota including Lake Minnetonka, Lake Vermillion, Gull Lake and Cass Lake.
He attributed the decision to map Mille Lacs to the quality of the lake’s fishery both for smallmouth bass and walleye. Davis explained that there must be a certain amount of demand to warrant the time-consuming process of re-mapping the contour lines and creating side-scan data of a lake.
The process
Mounted on the back of the custom aluminum boats is a heavy duty swing-arm sonar that is pivoted down into the water. Davis will head out to the section of the lake he plans to record and then start making straight-line passes back and forth as the sonar sends imagery and data back to the computer mounted inside the boat’s cabin. Depending on the depth of the bottom, the sonar can record a swath of lake bottom anywhere from 20 to 70 meters wide in each pass.
One might expect this process to get monotonous, but Davis said it’s actually quite engaging.
“You’re constantly watching data come through,” Davis said. He equated the task to being similar to running an auto-steer tractor or combine.
New features
Davis said the new side-scan data will be a wonderful tool for anglers on Mille Lacs.
“With good side-scan data, anglers will have the best chance of catching fish,” Davis said.
Although he has yet to spot one on the bottom of Mille Lacs, Davis explained that side-scan provides the type of detailed imaging that would show shipwrecks.
Beyond using sonar, Davis and his team have also employed a bit of photography in their mapping. The new charts will be complete with photographs of launches, fuel docks, bridges and more.
“We try and take pictures of any points of interest around the lake so boaters could see them on their chart plotter before they get there,” Davis said. In the case of a bridge, a picture can be a valuable resource to a boater who is unsure if his vessel will be able to navigate under it.
Wrapping up soon
The Garmin team expects to be finished collecting data on Mille Lacs Lake by early October, at which point he’ll head back to Garmin headquarters in Olathe, Kansas where he will “clean-up” the data he’s collected and prepare it for end-users.
According to Davis, his time in Mille Lacs has been a lot of fun.
“Everybody has been very friendly,” Davis said. His team has launched out of Terry’s Boat Harbor and, more recently, Izatys Resort. His team’s only struggle has been dealing with the weather. “Your seasons change a lot quicker up here,” Davis added.
The new chart plotter data should be available to anglers sometime in 2019, and Davis said it will also be available for ice fishing bundles.
