Analytical and Experimental Studies of the Benthic Boundary Layer and Their Applicability to Near-Bottom Transport in Lake Erie

Abstract

With there being few if any well organized field experiments in Lake Erie on benthic boundary layer (BBL) physics to review, this paper summarizes theoretical and experimental observations from the ocean, estuary, and continental shelf research, contrasts the Lake Erie setting with these results, and recommends future considerations for Lake Erie BBL research. From among empirical, boundary layer, and structural analysis viewpoints, the boundary layer approach is emphasized because of its ability to yield predictive hypotheses which can be experimentally tested. The initial discussion centers on the definition of the various classes of physical mechanisms existing in Lake Erie and a summary of various classes of boundary layers that have been hypothesized to exist. The various boundary layers are loosely classified based on the strength of the forcing functions and the subsequent review of steady, wave, and wave-current induced layers reveals that the complexity of the in-situ BBL physics is not often included in available theory. Experimental studies in support of these theories are numerous but with the exception of a few cases do not contain sufficient spatial and temporal resolution to verify the theoretical formulae nor make full correlations with the lower frequency forcing functions such as tides, seiches, Kelvin waves, etc. Momentum boundary layers for steady conditions have been fully validated with high quality data. Sediment layers of all types have yet to be fully validated. Lack of instrumentation is seen as a major impediment to full validation.