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| Return to: 2019 |
| Bathymetry of Hamlin Lake |
| Author | James E Clark | |||||||||||||||||||||||
| Date: | March 31, 2020 | |||||||||||||||||||||||
| Date Collected | During July and August of 2018 and 2019. A bit of data was also collected in September. | |||||||||||||||||||||||
| Equipment Used |
A Lowrance Fish Finder, model HDS-7T Lowrance Point-1 Baja GPS Antenna Depth transducer; P66-BL, 50-200 Depth-Temperature-Speed |
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| Details of Lowrance Equipment HDS-7T Vesion 6.0 |
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| Search Pattern |
The Lower Lake was run East and West every 0.05
minute N; or 304 feet The Upper Lake was run North and South every 0.07 minute W; or 306 feet The depth transducer was attached behind one pontoon in line with the bottom of the pontoon. At speed of about 8 mph the transponder ran about one-foot below a calm surface. This “foot” was added to get the data value for analysis. Several runs were made lengthwise along maximum depth areas to improve accuracy. All data less than five feet in depth was thrown out as it was deemed unreliable. Depth data for the face of the dam is totally in error. First no data was run near the dam face and second the software analysis assumes the bottom goes to zero depth along the edge of the lake. |
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| Data | The Lowrance Depth Finder generated *.SL2 files. Each transit was saved as one file. In the end there were 220 such files. | |||||||||||||||||||||||
| Software Company |
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| Data Processing | Each file was graphically examined for obvious problems. Where found, those data points were deleted. | |||||||||||||||||||||||
| Depth Contours |
Double Click on an image to get a full-size high-quality image. |
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| Maximum Depth and location |
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| Area and Volume |
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| Comparison with previous studies |
The area reported here is 4,829 which is 3% less than the
4,990 acres reported by
Progressive Engineering in its 1998 study. The volume reported here is 67,000 acre-feet which is 27% less than the 85,290 acre-feet reported by Progressive Engineering in its 1998 study. In 1942, Brown and Kilpela used an area of 5,070 acres in their Creel Survey. In 1932, Hubbs & Eschmeyer reported an area of 4,982 acre in their Lake Survey. Literature published in 1906 estimated the size at 5,000 acres. |
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| Aquatic Vegetation Heat Map/td> |
Double Click on an image to get a full-size high-quality image. |
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| Interpreting the Heat Maps |
The amount of aquatic vegetation, or weeds, is
expressed as the percent of the water column
that contains vegetation. These maps are
affectionately called "Heat Maps" since the
"red" color represents Bio-Volume extending 100%
from the bottom to the surface, The aquatic vegetation value is collected from radar signal. Thus it may not have the rigor implied by this published data. In general you can see that the border between open water and vegetation occurs at a bottom-depth of 12 feet. |
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| JClark4626@aol.com | Hamlin Lake Preservation Society | PO Box 178, Ludington, MI 49431 |
