Laboratory rivers: Lacey's law, threshold theory, and channel stability

More than a century of experiments have demonstrated that many features of natural rivers can be reproduced in the laboratory. Here, we revisit some of these experiments to cast their results into the framework of the threshold-channel theory developed by Glover and Florey (1951). In all the experiments we analyze, the typical size of the channel conforms to this theory, regardless of the river's planform (single-thread or braiding). In that respect, laboratory rivers behave exactly like their natural counterpart. Using this finding, we reinterpret experiments by Stebbings (1963). We suggest that sediment transport widens the channel until it reaches a limit width, beyond which it destabilizes into a braided river. If confirmed, this observation would explain the remarkable scarcity of single-thread channels in laboratory experiments