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
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Journal ArticleDOI
Centuries of Human-Driven Change in Salt Marsh Ecosystems
TL;DR: It is concluded that the best way to protect salt marshes and the services they provide is through the integrated approach of ecosystem-based management.
Journal ArticleDOI
Tracking the rapid loss of tidal wetlands in the Yellow Sea
Nicholas J. Murray,Nicholas J. Murray,Robert S. Clemens,Stuart R. Phinn,Hugh P. Possingham,Hugh P. Possingham,Richard A. Fuller +6 more
TL;DR: In this article, the authors developed a remote-sensing method to assess change over ~4000 km of the Yellow Sea coastline and discovered extensive losses of the region's principal coastal ecosystem associated with urban, industrial, and agricultural land reclamations.
Journal ArticleDOI
When is restoration not?: Incorporating landscape-scale processes to restore self-sustaining ecosystems in coastal wetland restoration
TL;DR: In this article, the authors explore restoration concepts, examples, and challenges from the Pacific and Gulf coasts and review the concepts of ecosystem trajectories, alternative restoration approaches, and the ideal attributes of functional self-sustaining restoration in the context of realities of restoration planning, design, and implementation.
Journal ArticleDOI
Ecoengineering with ecohydrology: Successes and failures in estuarine restoration
Michael Elliott,Michael Elliott,Michael Elliott,Lucas Mander,Krysia Mazik,Charles A. Simenstad,Fiona J. Valesini,Alan K. Whitfield,Eric Wolanski,Eric Wolanski +9 more
TL;DR: In this article, the authors focus on ecosystem recolonization by the biota and their functioning and separate Type A Ecoengineering, where the physico-chemical structure is modified on the basis that ecological structure and functioning will then follow, and Type B Ecoengineering where the Biota are engineered directly such as through restocking or replanting, where suitable physical conditions, especially hydrography and sedimentology, are created to recover estuarine ecology by natural or human-mediated colonisation of primary producers and consumers.
Journal ArticleDOI
Evaluating sustainable adaptation strategies for vulnerable mega-deltas using system dynamics modelling: Rice agriculture in the Mekong Delta's An Giang Province, Vietnam.
TL;DR: A new SD model is developed and test which simulates the dynamics between the farmers' economic system and their rice agriculture operations, and uniquely, integrates the role of fluvial sediment deposition within their dyke compartment, and is used to explore a range of alternative rice cultivation strategies.
References
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Journal ArticleDOI
Accretion rates of low intertidal salt marshes in the Pacific Northwest
TL;DR: In this article, the authors investigated the salt-marsh accretion rate at sites that spanned a gradient in relative rate of sealevel rise in Washington and Oregon and found that moderate and high rise-rate scenarios would threaten the existence of salt marshes in the region in the absence of increased sediment supply.
Journal ArticleDOI
Summer Oxygen Depletion in a Diked New England Estuary
TL;DR: The diked and freshened Herring River estuary experiences regular summer hypoxia and one- to three-week periods of main stream anoxia, often accompanied by fish kills.
Journal ArticleDOI
Seasonal habitat-use patterns of nekton in a tide-restricted and unrestricted New England salt marsh
TL;DR: In this article, the authors examined nekton habitat-use patterns in the tide-restricted Hatches Harbor salt marsh (Provincetown, Massachusetts) relative to a downstream, unrestricted marsh.
Journal ArticleDOI
Effects of Impoundment on Vertical Accretion of Coastal Marsh
TL;DR: In this article, the vertical accretion of impounded marsh and adjacent natural marsh at four sites in southwestern Louisiana was estimated in 1994 by determining the depth of a stratum containing137Cs deposited in 1963.
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