Journal ArticleDOI
Indirect Environmental Effects of Dikes on Estuarine Tidal Channels: Thinking Outside of the Dike for Habitat Restoration and Monitoring
TLDR
In this article, the authors analyzed historical photos of the Skagit River delta marshes (Washington, U.S.) and compared changes in estuarine marsh and tidal channel surface area from 1956-2000 in the Wiley Slough area of the South Fork Skagits delta, and from 1937-2000 on the North Fork delta.Abstract:
While the most obvious effects of dike construction and marsh conversion are those affecting the con- verted land (direct or intended effects), less immediately apparent effects also occur seaward of dikes (indirect or unintended effects). I analyzed historical photos of the Skagit River delta marshes (Washington, U.S.) and compared changes in estuarine marsh and tidal channel surface area from 1956-2000 in the Wiley Slough area of the South Fork Skagit delta, and from 1937-2000 in the North Fork delta. Dike construction in the late 1950s caused the loss of 80 ha of estuarine marsh and 6.7 ha of tidal channel landward of the Wiley Slough dikes. A greater amount of tidal channel surface area, 9.6 ha, was lost seaward of the dikes. Similar losses were observed for two smaller North Fork tidal channel systems. Tidal channels far from dikes did not show comparable changes in channel surface area. These results are consistent with hydraulic geometry theory, which predicts that diking reduces tidal flushing in the undiked channel remnants and this results in sedimentation. Dikes may have significant seaward effects on plants and animals associated with tidal channel habitat. Another likely indirect dike effect is decreased sinuosity in a distributary channel of the South Fork Skagit River adjacent to and downstream of the Wiley Slough dikes, compared to distributary channels upstream or distant from the dikes. Loss of floodplain area to diking and marsh conversion prevents flood energy dissipation over the marsh surface. The distributary channel has responded to greater flood energy by increasing mean channel width and decreasing sinuosity. Restoration of diked areas should consider historic habitat loss seaward of dikes, as well as possible benefits to these areas from dike breaching or removal. Habitat restoration by breaching or removal of dikes should be monitored in areas directly affected by dikes, areas indirectly affected, and distinct reference areas.read more
Citations
More filters
Journal ArticleDOI
Cambio hidrodinámico y evolución de fondo en ríos de planicie por espigones
Enrique León Jiménez,Liliana Lizárraga Mendiola,Fabián Rivera Trejo,Antonio Nungaray Núñez,Jhon Díaz Arcos +4 more
TL;DR: In this article, a metodologia numerica bidimensional, comparadas with metodos tradicionales, was implemented to evaluate in tres zonas the variacion hidrodinamica del campo de velocidades and evolucion of rios de planicie.
Journal ArticleDOI
Numerical simulation of hydraulic characteristics of an upstream wing submerged T-shaped groyne
TL;DR: In this article , an upstream wing submerged T-shaped groyne (ST) was proposed to prevent erosion of banks in a 60° bend movable bed experiment, and a digital terrain after the bed development was obtained, using laser scanning technology.
References
More filters
Book
The Fractal Geometry of Nature
TL;DR: This book is a blend of erudition, popularization, and exposition, and the illustrations include many superb examples of computer graphics that are works of art in their own right.
Journal ArticleDOI
The Fractal Geometry of Nature
TL;DR: A blend of erudition (fascinating and sometimes obscure historical minutiae abound), popularization (mathematical rigor is relegated to appendices) and exposition (the reader need have little knowledge of the fields involved) is presented in this article.
Journal ArticleDOI
Fluvial Processes in Geomorphology
Book
Fluvial Processes in Geomorphology
TL;DR: Fluvial processes in geomorphology, Fluvial Processes in Geomorphology as discussed by the authors, fluvial processes and geomorphological processes in the field of geology.
Related Papers (5)
Juvenile Salmon Residency in a Marsh Area of the Fraser River Estuary
D. A. Levy,T. G. Northcote +1 more