Framework for Evaluating Very Small Hydraulic Models of Channel-Control Works

Presented herein is a framework for evaluating the capacity of very small hydraulics models, including micro-models, to aid the design of channel-control works involving structures such as dikes. The framework comprises considerations of similitude, relaxations, scale effects, compensating effects, and the necessary experiments to determine the limits for effective model use. The framework suggests that small models can be useful as design aids in situations where a channel thalweg has only one-degree of translation freedom for movement; i.e., the thalweg is constrained to vertical movement in a long constriction (constriction length exceeds at least one channel width) formed in uniform sediment. However, model utility diminishes quickly in situations where alluvial channels have a greater degree of translation freedom; notably, when they can move laterally or armor.