Inlet Reservoir Model. Part 2: PC-Interface

Abstract : This Coastal and Hydraulics Engineering Technical Note (CHETN) is the second in the Inlet Reservoir CHETN series. This CHETN describes the Inlet Reservoir Model (IRM) interface and setting up an IRM project. Part III of the IRM series presents guidance for application and two example problems. The IRM calculates the time-dependent volumetric evolution of inlet morphologic features such as ebb and flood shoals, and estimates bypassing to adjacent beaches based on user-specified relationships (Kraus 2000, 2002). The Inlet Reservoir Model (IRM) calculates time-dependent sediment bypassing around an inlet and associated volume change for inlet morphologic features as identified by the user, as a function of longshore sediment transport along the adjacent beaches, user-defined equilibrium volumes for each morphologic feature, and engineering activities in vicinity of the inlet. In a typical wave-dominated inlet, there would be three distinct ocean-side morphologic features: an ebb shoal, bypassing bar, and an attachment bar. The concept of the Inlet Reservoir Model is based on the assumption that each feature has a maximum (equilibrium) sand-retention capacity that cannot be exceeded. Once a feature has reached capacity, all additional sediment transport to that feature will bypass to the next feature(s), until sediment arrives at the downdrift side of the inlet, or is deposited in another location such as the inlet channel or flood shoal. If a morphologic feature is partially full, it still provides partial bypassing. The Inlet Reservoir Model calculates growth of the shoals as a function of the littoral drift and equilibrium volumes of the shoals, and it accounts for the naturally long timescales of large morphologic features and time delays in exchange of sediment among the features.