River Engineering Works Research Articles

Holocene Sediment Production in Lillooet River Basin, British Colombia: A Sediment Budget Approach

A sediment budget approach is used to investigate the sources, storage, and yield of clastic sediment in Lillooet River watershed, in the southern Coast Mountains. The 3150 km2 basin is heavily glacierised, and includes a Quaternary volcanic complex which has been active in the Holocene. The sediment yield has been determined from the rate of advance of the delta at the basin outlet. The floodplain of the main river valley is aggrading as the delta advances, and probably has been through most of the Holocene. Major sediment sources in the basin include glaciers and Neoglacial deposits, debris flows, and landslides in the Quaternary volcanic complex. Soil and bedrock creep, bank erosion of Pleistocene glacial deposits, and sediment from logging and agriculture are probably of minor importance. Estimates of sediment production from these sources explain only about half the observed clastic sediment yield plus the rate of valley aggradation. The unexplained sediment production may be associated with paraglacial sediments exposed by glacial retreat from the nineteenth century Neoglacial maximum; alternatively the frequency of occurrence of intermediate scale debris flows and landslides has been seriously underestimated. Sediment supply is highly episodic over time scales of centuries to thousands of years. Major factors in the temporal pattern of Holocene sediment supply are periods of volcanism, large landslides, the retreat of glaciers from the Neoglacial maximum, and recent river engineering works.

Channel changes of the lower part of the Dyje River in the 1830-2001 period caused by human activities

The article deals with changes of the lower reach of the Dyje River, South Moravia, caused by river engineering works. The study area was divided into five sections and studied with the help of graphic methods and morphometric characteristics derived from historical maps. The research shows a significant shortening of the Dyje, a decrease in sinuosity and a fluctuation in area and number of oxbow lakes (oxbows).

Rapid changes of fish assemblages in artificial lowland waterways

In summer and autumn 1996 a total of 19 sites belonging to 10 levels divided by locks were surveyed in the canals Müritz-Elde-Wasserstraße (MEW) and Störwasserstraße (StW). Different stages of succession of their fish assemblages were compared to give a first estimation of succession time for changes in fish communities caused by anthropogenic impact. Of the 19 sites 2 079 fish (without 0+) were collected, and identified as comprising 19 species and one hybrid. No significant differences in fish abundance and species diversity were found between levels under reconstruction and levels in an older stage of natural succession, with exception of the relative abundance of limnophilic species and of pike. The mean proportion of limnophils in the newly embanked levels was 1.2 ± 0.3% compared to 5.3 ± 1.2% in the natural levels. The mean proportion of pike was 1.2 ± 0.3% in the newly embanked and 3.2 ± 1.1% in the natural levels. The abundance of pike reacts much faster to environmental degradation than other in situ population parameters of fish assemblages. Therefore, naturally reproducing pike populations could be used to predict the possible ecological impacts of river engineering works.

Numerical Computation of Open Channel Flow with Shock Wave using FDS method

Numerical calculation of flow including shock wave is one of the important tools in the practical river engineering works. Flux Difference Splitting, FDS, scheme is one of the numerical method to simulate the flow with shock wave. In this method, the theory of nonlinear characteristic wave and the concept of numerical flux are taken in account and it is very easy to be applied to various condition of open channel flow. In this paper, a numerical model using FDS scheme for two dimensional open channel flow is developed and was applied to several different hydraulic conditions. The calculated results are compared with the theoretical and experimental results and good agreement is obtained.

Alluvial cutoffs as indicators of former channel conditions

AbstractAlthough alluvial cutoffs record accurately the geometry, bedforms, and bed material of the channel when last active, few attempts have been made to use cutoffs in studies of channel changes. A detailed record of historical channel changes on the lower Hunter River in southeastern Australia has shown that this channel responds to naturally alternating periods of high and low flood activity, called flood‐ and drought‐dominated regimes respectively. Sinuosity decreased from 3·84 in 1870, to 2·66 in 1893 and to 1·38 in 1970 through the development of eight cutoffs. The channel also aggraded with medium sand burying the former bed material of mixed mud, coarse sand, and gravel. Channel straightening was a response to increased flood frequencies during the flood‐dominated regimes of the late 19th and 20th centuries, combined with localized river engineering works and increased sand load.Detailed stratigraphic studies were carried out on three neck cutoffs and one chute cutoff which were abandoned in 1890, 1950, 1952, and 1956. A comparison of former and present bed elevations and bed material size showed similar trends to those determined by the historical record, confirming the reliability of cutoffs as indicators of former channel conditions.The sedimentary infills of the cutoffs are not uniformly fine grained as recorded previously in the literature. Relatively thin, fine‐grained fills were deposited during the drought‐dominated regime of the first half of this century but thick, coarser‐grained fills were deposited after 1949 during the flood‐dominated regime. All fills fine upwards. Cutoff infills provide a record of changing flood activity and sediment loads.

Environmental River Engineering

ABSTRACTIn the past, river engineering works have often caused channel instability and adversely affected the river's conservation and amenity value. Recent guidelines have advocated a more natural approach to river engineering practice which retains habitat diversity within the river system. While a more natural approach is desirable, geomorphological guidance is required to ensure that the advocated changes are feasible and sustainable, both in the long and short term. The key requirement for sound environmental river engineering is a basic understanding of the natural processes controlling channel shape and dimensions. Examples are given in the paper to illustrate how such knowledge can be used to (a) stabilize rivers, (b) design environmentally‐acceptable and stable flood‐alleviation schemes, and (c) restore previously canalized rivers. The basis of the geomorphological input in the assessment and design process is a river survey which determines the factors controlling channel characteristics and how it will respond to planned changes.

La conception de l'aménagement des cours d'eau dans le cadre de la sauvegarde de l'environnement : L'exemple de la Fecht (Haut-Rhin)

Author describes how development work was put into effect on the river Fecht, a tributary of the river III in the Haut-Rhin Departement of France. To counteract erosion caused by the river's substantial bed load in the uppermost reaches and gravel accumulation further downstream, the following river engineering works were put into effect :- 1. The longitudinal river profile was stabilised by subdivision into a number of sections at the equilibrium slope for the river bed material, each section being separated from the next by a permanent sill. 2 The river banks, consisting of erodible alluvium, were stabilised by maintaining the river bend radii in either direction at least five times the river width, which almost invariably reduced river bank protection requirements to their simplest expression, and frequently eliminated them altogether on the convex side of the bends. Except for sills excecding 1.5 m in height, which are based on Creager's design, i.e. usually with a paved energy-dissipation basin, most of the river control structures are built of rubble. This method was originally developed in the Austrian Alps about twenty years ago, with artificial ramps usual1y with a slope of 20 % and a width limited to 1/20th of that of t.he river. In plan, the control structures form a curve with a radius equivalent to 1 1/4 times that of the river width, which is designed to keep the flood discharge in the cent.re of the river downstream of the control structure. The ramps are fashioned from large lumps of granite of at least 1 ton weight, which are placed side-by-side in the form of a particularly rough hedgehog structure capable of efficiently absorbing the full kinetic energy of the water. The upstream row of boulders is encased in concrete, whilst the downstream row is maintained in position by one or two rows of rails rammed to a depth of 4 m, into the river bed, spaced between 60 and 80 cm apart. This system offers the following advantages: - It does not mar the landscape ; -It is easily installed, as there are no foundation s; -No dewatering is required for work under water ; - It can undergo deformation without endangering the overall structure ; - Efficient aeration of the water assists self-purification ; - No interference with fish proceeding up-river. The same material is used in smaller sizes (smaller by 100-300 kg) for river bank protection. The material was formerly placed by hand, proceeding fish-scalewise from downstream to upstream, but power shovels are now used for the purpose, except for placing the small stones inserted between the large blocks. The foundatiom of the structure consist of rubble tipped into a pit with a trapezoidal cross-section. To improve the appearance of the site, willow cuttings have been implanted (salix purpurea-usually in autumn) underneath the rubble bed, or more frequently standing more or less upright between the lumps of rock. Thus, after only a few years, the rubble is now hidden behind a curtain of vegetation, which simply requires cutting back every five years.

River Engineering and Water Conservation Works by Roland Berkely Thorn; 520 pages; $27.00; Butterworths (Publishers), London and Washington, D.C.; 1966.

JAWRA Journal of the American Water Resources AssociationVolume 3, Issue 4 p. 56-57 River Engineering and Water Conservation Works by Roland Berkely Thorn; 520 pages; $27.00; Butterworths (Publishers), London and Washington, D.C.; 1966. R. W. Revell, R. W. Revell Harza Engineering Company Chicago, IllinoisSearch for more papers by this author R. W. Revell, R. W. Revell Harza Engineering Company Chicago, IllinoisSearch for more papers by this author First published: December 1967 https://doi.org/10.1111/j.1752-1688.1967.tb02892.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume3, Issue4December 1967Pages 56-57 RelatedInformation