This book is a much-needed compilation of fifteen years formative research performed at the Engineering Research Centre of Colorado State University. A major objective of the book is to make more generally available the results of a series of experimental studies, largely undertaken by students working toward advanced degrees in geology, watershed science, and civil engineering since 1969. The book, which is generously illustrated, and which includes an extremely valuable bibliography, has been designed for students and researchers, as well as for practising hydraulic engineers and economic geologists.
Experimental work on rivers has been international and extensive. The authors recognize that the major contribution of the Colorado State University (C.S.U.) relates to drainage basins, alluvial fans, valleys, and sedimentary deposits. The book is organized in three parts leading through the fluvial system, starting with the morphology and dynamics of drainage basins, through the channels: rivers and valleys, to the piedmont or coast where depositional processes predominate: alluvial fans and sedimentary deposits.
A short introduction serves to provide a definition for, and to illustrate the utility of experimental studies in geomorphology (p. 1-7). The major advantages and disadvantages of such experimental research are also discussed. Experimental geomorphology is defined (p. 3) as 'the study, under closely monitored or controlled experimental conditions, of a physical representation or model of a selected geomorphic feature'. In the majority of experiments discussed in the text, a process-similar study approach is adopted wherein the experimental model is regarded as a small system in its own right. This contrasts with formal scale-modelling more typical of engineering research. This may be permissible where information on general principles, rather than on a specific prototype, is required, and necessary where formal scale-modelling would be difficult to follow, too restrictive, and possibly unsuited. Although this procedure offers the geomorphologist a straightforward approach to laboratory studies, it does prevent the direct extrapolation of results from the analogue model to the prototype. Basic requirements proposed for a process-similar study approach are:
- that gross scaling relationships are met; 2. that the model reproduce some morphologic characteristics of the prototype; 3. that the process which produced this characteristic in the experiment can logically be assumed to have The experiments presented in the text illustrate that, with due caution, similarity-of-process studies can provide new information regarding processes, can reveal trends not obvious during field studies, can provide a basis for hypothesis generation, and should eventually lead to the application of experimental results to natural systems. However, the authors themselves repeatedly emphasize that the inherent uncertainties in the relationships between the models and their prototypes must always require field validation before the results can be utilized with confidence for either prediction or postdiction. The major difficulty to be faced is how to transfer the experimental results from studies of small landforms, by analogy, to larger landforms. Experimental Fluvial Geomorphology illustrates, in such areas as river management, gully control, geological exploration of minerals, and hazard recognition, how confirmation the same effect on the prototype.