Planform Effects on Tidal Flushing of Marinas

Abstract

Effects of various geometry parameters on tidal flushing and internal circulation in small‐boat basins (marinas) of rectangular planform were determined in physical hydraulic models by means of a photographic technique incorporating the use of a photodensitometer. The schematic model marinas tested were scaled to have surface areas, water depths, and tide ranges comparable to “prototype” marinas in the Pacific Northwest: Results are presented in terms of spatial average tidal flushing (exchange) coefficients for each configuration tested, and by contour drawings of equal local per‐cycle exchange coefficients for a number of configurations, all at the same tide range. Emphasis is placed on planform geometry and aspect ratio, those variables over which designers may have most latitude in designing a marina for a specific site. Effects of basin length to width ratio are delineated for basins with typical single asymmetric entrances.