Showing papers on "River engineering published in 1988"

Fluvial Processes in River Engineering

Abstract: This text collects and collates the significant advances in analytical methods for alluvial channel design, river morphology, and mathematical simulation of river channel changes. It presents a complete analytical treatment of river morphology and its responses to environmental and human-made changes from the engineering point of view. For professionals in flood control, bridge design, irrigation and waterways, this book is a current, comprehensive refresher and reference. It is also a textbook in river sedimentation. Analytical and empirical methods are detailed for solving erosion and sedimentation problems, hydraulic design of channels, bridges, and related structures. From a sound physical foundation, mathematical techniques are presented for simulating river channel changes, and computer-aided analysis and design for river projects are illustrated by abundant examples.

Channelized rivers : perspectives for environmental management

Abstract: Conventional River Engineering ENVIRONMENTAL LEGISLATION Legislative Framework EFFECTS OF CHANNELIZATION Physical Effects Biological Impacts Downstream Consequences RECOMMENDATIONS Revised Construction Procedures Mitigation, Enhancement, and Restoration Techniques POSTSCRIPT AND PROSPECTS Appendix References Indexes

Channel change, fluvial geomorphology and river engineering: The case of the Afon Trannon, Mid‐Wales

Abstract: The Afon Trannon, a gravel-bed river in mid-Wales with a catchment area of 72 km2, has recently been the subject of an engineering flood protection scheme. Following the enlargement and grading of the channel, lateral instability has produced considerable problems of maintenance. Geomorphological investigations are described which attempt to pinpoint the lessons of the scheme. Historical studies of floodplain sediments and channel change indicate firstly, an initially rather stable channel, but secondly a considerable, early history of channelization which may still have repercussions for system stability. This early channelization has now been modified in the recent scheme. Contemporary field study by survey and sediment tracing using the magnetic technique indicates the present instability of the sediments in a meandering channel given a trapezoidal cross-section and varied banks. Low-flow adjustments are as important as flood adjustments in the lower, straightened reach. Lessons for engineering schemes include the desirability of assessing erosion risk by rapid, cheap field techniques and historical investigations, and the consideration of more ecologically acceptable channel designs.

The impact of river engineering on water birds on an English lowland river

Abstract: Waterbirds were surveyed using Waterways Bird Survey procedures before, during and after extensive river engineering work was carried out on a 6.5 km stretch of river. Surveys of major habitat features showed that dredging and re-grading work resulted in a 68-74% reduction in the extent of fringing marginal vegetation and bushes in part of the study area, which was matched by a 70% reduction in the total number of breeding territories. Elsewhere, at least 85% of the major habitat features remained and there was a much smaller (15%) decrease in the total number of breeding territories. Loss of nesting habitat appeared to be the dominating effect of the river engineering work and Coot and Moorhen, which depend on bankside bushes and marginal vegetation for nesting, were most severely affected. Ways in which the general effects of such work on habitat and birds might be reduced are discussed.