The geometry of a meander is that of a random walk whose most frequent form minimizes the sum of the squares of the changes in direction in each unit length. Changes in direction closely approximate a sine function of channel distance. Depth, velocity, and slope are adjusted so as to decrease the variance of shear and the friction factor in a meander over that in an otherwise comparable straight reach of the same river.
This monograph discusses the mechanics of Meandering Rivers with the help of the mathematical and modeling tools built up in the previous monograph of the same Authors (monograph 1 of the present series). After introducing the reader to the ubiquitous character of meandering streams, we discuss the hydrodynamics of curved channels with fixed beds and banks. Next, we extend the analysis to account for the mobile character of the bed and show that it gives rise to the alternate sequence of riffles and pools that characterize river meanders. Allowing for the erodible character of the river banks then allows to build up a rational theory of meander formation able to explain most of the features observed in nature: meander growth, migration, skewing, multiple loops, cutoffs and meander belts.
As the vast expanses of natural forests and the great populations of salmonids are harvested to support a rapidly expanding human population, the need to understand streams as ecological systems and to manage them effectively becomes increasingly urgent. The unfortunate legacy of such natural resource exploitation is well documented. For several decades the Pacific coastal ecoregion of North America has served as a natural laboratory for scientific and managerial advancements in stream ecology, and much has been learned about how to better integrate ecological processes and characteristics with a human-dominated environment. These in sightful but hard-learned ecological and social lessons are the subject of this book. Integrating land and rivers as interactive components of ecosystems and watersheds has provided the ecological sciences with impor tant theoretical foundations. Even though scientific disciplines have begun to integrate land-based processes with streams and rivers, the institutions and processes charged with managing these systems have not done so successfully. As a result, many of the watersheds of the Pacific coastal ecoregion no longer support natural settings for environmental processes or the valuable natural resources those processes create. An important role for scientists, educators, and decision makers is to make the integration between ecology and con sumptive uses more widely understood, as well as useful for effective management.
Conference Proceedings of Euromech 192: Transport of suspended solids in open channels, Munich, Neubiberg, 11-15 June 1985. Rapid growth in water requirements makes it necessary to increase the amount of water drawn from rivers. The dams necessary for capturing river water have to be built to resist damage when large floods occur, and an idea of the possible destructive power of floods is given by the front cover photograph.
Originally published in 1982, this book presents a detailed review of alluvial river form and process and integrates the distinct but related approaches of geomorphologists, geologists and engineers to the subject. It outlines the environmental catchment factors that control the development of channel equilibrium and provides a detailed account of the sediment transport processes that represent the physical mechanisms by which channel adjustment occurs. Where possible it evaluates theoretical analyses in the context of the empirical evidence. Rivers should prove a valuable textbook for geomorphology students on advanced undergraduate courses on river behaviour and will also be of interest to students of hydraulics and sedimentology and to those concerned with civil and environmental engineering, river management and channel design, maintenance and management in the water industry
This textbook discusses the fundamental principles of sediment transport in the geophysical context of rivers. It is intended as both a course textbook and as a guide for the practical engineer. It begins begin by describing phenomena such as bed load and suspension transport from a classical perspective. Concepts from turbulent flow regime are introduced to address the limitations of the classical approach to various aspects of sediment transport.
