2023 CSDMS meeting-034
Modeling the impact of boat wakes and wind waves on lake bed morphology: a case study of East Pond
Alejandra Ortiz, (she/ella),Colby College Waterville Maine, United States. firstname.lastname@example.org
Danielle Wain, 7 Lakes Alliance Belgrade Lakes Maine, United States. Danielle Wain <email@example.com>
Alison Bates, Colby College Waterville Maine, United States. Alison Bates <firstname.lastname@example.org>
What is the impact of boat-wake generated waves on lakebed sediment? Are large wakeboarding waves (up to 0.5 m in height) driving significant sediment resuspension or transport? Using Delft3D, we investigate the role of boat-wake waves in comparison to wind-waves on driving sediment transport and deposition in East Pond, Belgrade, ME. We approximate boat wakes using a spatially varying pressure field to simulate the boat wake over our time period. We validate our numerical model using field measurements of wave heights and near bed velocity under different boat wakes. We then test the relative importance of boat-wakes on driving morphodynamic change of East Pond in comparison to wind-generated waves given the frequency of use of wakeboarding and water skiing boats compared to the yearly wind climate. Even under the largest boat wakes (wake surfing), there are minimal velocities (< 10 cm/s) at the bed in either shallow or deep depths (4 of 7 m) but wave heights do reach up to 30 cm in deeper waters. Our analyses provide a method for estimating natural vs anthropogenic wave impacts on lake sedimentation and long-term water quality.