Sediment resuspension due to the operation of recreational motorboats in shallow lakes was investigated. Boats equipped with 28, 50, 85, 120, and 165 horsepower engines were used for this study on Lake Claire, Florida Technological University campus, and Lake Mizell, the City of Winter Park, located in Orange County, Central Florida. Grasshopper Lake was also a test site due to its clarity for underwater photography. These motorboats were run at different speeds and water depths and the induced pressure waves on the lake bottom were measured using a hydrophone and recording system. Primary and secondary wave amplitudes and frequencies were determined for the various operating conditions and motorboats. The primary waves were formed by boat wake and the secondary waves resulted from engine effects. The primary waves were generally higher in amplitude and lower in frequency than the secondary waves. The maximum amplitudes occurred just before planing. The average primary wave amplitude after planing at normal operating speeds decreased exponentially with increasing water depth for all the boats tested and followed this equation: Aw = ae-bD where: Aw = average primary wave amplitude, ft. a = constant varied between boats = 0.68 to 1.86 ft. for boats tested b = 0.17 to 0.25 ft-1 D = water depth, ft The boat waves resuspended bottom sediments and eroded shore areas, increasing the turbidity of the lake water. Particle count and size distribution in water samples were determined using a Coulter Counter. A straight line relationship between turbidity and cummulative particle count per milliliter existed on a semi-log graph. Calculated and measured bottom water velocities showed good agreement for a limited amount of data.
| Identifer | oai:union.ndltd.org:ucf.edu/oai:stars.library.ucf.edu:rtd-1348 |
| Date | 01 January 1977 |
| Creators | Larrabee, Carl R. |
| Publisher | Florida Technological University |
| Source Sets | University of Central Florida |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Retrospective Theses and Dissertations |
| Rights | Public Domain |
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