The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Karl F Nordstrom - One of the best experts on this subject based on the ideXlab platform.
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facilitating landform migration by removing Shore Protection structures opportunities and constraints
Environmental Science & Policy, 2016Co-Authors: Karl F Nordstrom, Nancy L Jackson, Charles T RomanAbstract:Abstract Recent studies have identified the need to adapt to climate change by allowing landforms and habitats to migrate landward, although implementation of actual adaptation responses is limited. Removing the barriers that Shore Protection structures create between coastal and upland habitats can reestablish exchanges of sediment and the ecological functions of the natural ecotone. The potential for removing these structures was evaluated in 12 national parks managed by the U.S. National Park Service. Criteria for removal included condition of structures, influence of natural processes, environmental benefits, public safety, and visitor access and use. We found that 145 structures out of a total of 407 could be removed or allowed to deteriorate. We highlight three adaptation projects that are currently being conducted, two of which involve removing structures. Reasons for not taking a more pro-active approach to removing Protection structures include (1) conflicting policy directives; (2) presence of key access roads and critical archaeological and historic sites; (3) lack of data; (4) lack of funds and human resources; (5) reluctance to replace known problems with an unknown set of problems; (6) consideration of visitor desires; and (7) reluctance to allow erosion to occur. Demonstration projects are needed to provide information about adaptation strategies that promote enhancement of ecosystem functions. Projects to remove Protection structures are likely to be viewed as successful only if results are specified as a positive product, and the distinction between the concept of loss (erosion of existing landforms and habitats) and the concept of gain (evolution of new landforms and habitats) is made clear.
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Living with Shore Protection structures: A review
Estuarine Coastal and Shelf Science, 2014Co-Authors: Karl F NordstromAbstract:Abstract Shore Protection structures will continue to be built and maintained to protect coastal infrastructure. This review identifies factors influencing our ability to retain or restore natural features or construct artificial habitats on beaches and dunes in the presence of these structures. Protection structures are visual and physical intrusions into natural landscapes, and they alter natural processes and introduce exotic habitat. Impacts on landforms and habitats vary depending on the type of structure and its size, shape, orientation, type of materials used, age and state of repair. Changes will occur to any structure through time, and decisions must be made to supplement, rebuild, replace, or remove them or allow them to deteriorate. Decisions about removing Protection structures are problematic because they might already have habitat value, and the effects of removal are as difficult to predict as the effects of their original emplacement. Creative alternatives to traditional structures can be applied to retain or enhance some of the natural values of landforms and habitats. This can occur by making structures smaller, placing them below ground or water level, selecting construction materials that enhance habitat, or using beach fill to overcome undesirable effects. Decisions are required on whether the enhancement of habitat by modifying traditional structures is actually desirable. Humans must now be considered intrinsic agents of landscape evolution, and decisions on how, when and where to place, modify or remove Protection structures depend on numerous human inputs, requiring interventions that have an interdisciplinary perspective and are placed in a societal context.
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removing Shore Protection structures to facilitate migration of landforms and habitats on the bayside of a barrier spit
Geomorphology, 2013Co-Authors: Karl F Nordstrom, Nancy L JacksonAbstract:Abstract Coastal landforms and habitats require space to reform in response to storm damage to increase the likelihood of long-term sustainability. The purpose of this study is to evaluate the potential for removing Shore Protection structures to allow natural Shoreline processes to prevail as part of a strategy to adapt to sea level rise associated with climate change. The location of the study was Sandy Hook Spit, New Jersey, a site managed by the U.S. National Park Service (NPS). A field investigation was conducted to identify the structures that impede migration of landforms and habitats, the function of each structure in protecting resources, and the opportunities to facilitate landform migration by removing the structures or allowing them to deteriorate. Nineteen Shore-parallel walls are present along the ocean and bay Shore of a 10 km long portion of the spit. Most of the Shore Protection structures were built when the spit was formerly used by the US Army, and many bulkheads on the bay Shore have deteriorated. Sediment will become available to the longShore transport system where Protection structures are removed, contributing to spit growth at the ends of drift cells, possibly mimicking the spits that were more conspicuous on the bay Shore prior to human alterations. Observations indicate that new habitat can be created by loss and re-creation in a different location by longShore extension, not just by landward migration. Allowing Shore Protection structures to deteriorate will leave human infrastructure in the landscape. Removing these structures is more costly but can result in a more rapid reversion to a natural system. The time horizon is critical in determining the social, political and economic feasibility of removing structures and the expectations for geomorphic and habitat change. The feasibility of protecting threatened buildings and roads will decrease in the future as sea level rises and the existing Protection structures degrade or fall below new design standards. We suggest that functional buildings with less historic value remain in use until threatened by erosion, but little reason exists to build new structures to protect them. A case is made for allowing developed sites to revert to natural processes to establish a precedent and provide good demonstration areas for promoting stakeholder acceptance of retreat strategies.
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aeolian sediment transport and landforms in managed coastal systems a review
Aeolian Research, 2011Co-Authors: Nancy L Jackson, Karl F NordstromAbstract:Abstract Humans modify beaches and dunes and aeolian transport potential by building structures, walking or driving, extracting resources, accommodating recreation, increasing levels of Protection, removing storm deposits, or restoring landforms and habitats. The effects of human adjustments are reviewed here in terms of cross-Shore zones because humans tend to compartmentalize landforms and habitats through their actions and regulations. Common human modifications in the beach zone include nourishing beaches, constructing Shore Protection structures and raking to remove litter. Modifications affecting the dune zone include altering the location, size and stability of dunes using sand-trapping fences, vegetation plantings and bulldozers or replacing dunes with Shore-parallel structures. Modifications affecting the landward zone include buildings, roads, and parking lots. Landform and habitat resilience requires levels of dynamism and geomorphic complexity not often found in managed systems. Preserving or enhancing dynamism and complexity requires emphasis on innovative designs rooted in geomorphological and aeolian research. Future studies are suggested for: (1) quantifying the effect of small and large scale beach nourishment designs and sediment characteristics on dune initiation, development, and evolution; (2) quantifying the extent to which size and spacing of human structures and landform alterations inhibit sediment transfers alongShore or onShore; (3) identifying the advantages or disadvantages of “niche” dunes formed by structures; (4) providing quantitative data on the effects of raking or driving on the beach; (5) identifying the role of aeolian landforms on private properties; and (6) identifying alternative ways of employing sand fences and vegetation plantings to increase topographic and habitat diversity.
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increasing the dynamism of coastal landforms by modifying Shore Protection methods examples from the eastern german baltic sea coast
Environmental Conservation, 2007Co-Authors: Karl F Nordstrom, Reinhard Lampe, Nancy L JacksonAbstract:Redesign of Shore Protection projects in Mecklenburg-Vorpommern (Germany) is allowing landforms to become more dynamic after centuries of employing structures to increase stability. Current policies are designed to maintain sediment transfers, re-establish wetlands, ensure zero net loss of coastal habitat and apply the user-pays principle for restoring damaged habitat. Projects that achieve new nature-oriented goals include (1) relocating dykes landward or allowing dykes or protective dunes to erode to expose more land to episodic inundation by the sea; (2) reinstating sediment transfers from bluffs to adjacent low-lying Shores; (3) increasing sediment transport rates through groyne fields; and (4) removing exotic vegetation from dunes. These actions create new habitat, add portions of the coast to the public domain, and provide a wider buffer against accelerated sea-level rise for developed lands further inland. The management actions have been relatively small in scale, applied where there has been little threat to human facilities and done to achieve specific environmental goals, but they provide examples of workable options to increase the dynamism of stabilized landforms on other exposed coasts. The need to restore natural functions while providing some stability places emphasis on a strategy of controlling dynamism rather than preventing it.
Nancy L Jackson - One of the best experts on this subject based on the ideXlab platform.
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facilitating landform migration by removing Shore Protection structures opportunities and constraints
Environmental Science & Policy, 2016Co-Authors: Karl F Nordstrom, Nancy L Jackson, Charles T RomanAbstract:Abstract Recent studies have identified the need to adapt to climate change by allowing landforms and habitats to migrate landward, although implementation of actual adaptation responses is limited. Removing the barriers that Shore Protection structures create between coastal and upland habitats can reestablish exchanges of sediment and the ecological functions of the natural ecotone. The potential for removing these structures was evaluated in 12 national parks managed by the U.S. National Park Service. Criteria for removal included condition of structures, influence of natural processes, environmental benefits, public safety, and visitor access and use. We found that 145 structures out of a total of 407 could be removed or allowed to deteriorate. We highlight three adaptation projects that are currently being conducted, two of which involve removing structures. Reasons for not taking a more pro-active approach to removing Protection structures include (1) conflicting policy directives; (2) presence of key access roads and critical archaeological and historic sites; (3) lack of data; (4) lack of funds and human resources; (5) reluctance to replace known problems with an unknown set of problems; (6) consideration of visitor desires; and (7) reluctance to allow erosion to occur. Demonstration projects are needed to provide information about adaptation strategies that promote enhancement of ecosystem functions. Projects to remove Protection structures are likely to be viewed as successful only if results are specified as a positive product, and the distinction between the concept of loss (erosion of existing landforms and habitats) and the concept of gain (evolution of new landforms and habitats) is made clear.
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removing Shore Protection structures to facilitate migration of landforms and habitats on the bayside of a barrier spit
Geomorphology, 2013Co-Authors: Karl F Nordstrom, Nancy L JacksonAbstract:Abstract Coastal landforms and habitats require space to reform in response to storm damage to increase the likelihood of long-term sustainability. The purpose of this study is to evaluate the potential for removing Shore Protection structures to allow natural Shoreline processes to prevail as part of a strategy to adapt to sea level rise associated with climate change. The location of the study was Sandy Hook Spit, New Jersey, a site managed by the U.S. National Park Service (NPS). A field investigation was conducted to identify the structures that impede migration of landforms and habitats, the function of each structure in protecting resources, and the opportunities to facilitate landform migration by removing the structures or allowing them to deteriorate. Nineteen Shore-parallel walls are present along the ocean and bay Shore of a 10 km long portion of the spit. Most of the Shore Protection structures were built when the spit was formerly used by the US Army, and many bulkheads on the bay Shore have deteriorated. Sediment will become available to the longShore transport system where Protection structures are removed, contributing to spit growth at the ends of drift cells, possibly mimicking the spits that were more conspicuous on the bay Shore prior to human alterations. Observations indicate that new habitat can be created by loss and re-creation in a different location by longShore extension, not just by landward migration. Allowing Shore Protection structures to deteriorate will leave human infrastructure in the landscape. Removing these structures is more costly but can result in a more rapid reversion to a natural system. The time horizon is critical in determining the social, political and economic feasibility of removing structures and the expectations for geomorphic and habitat change. The feasibility of protecting threatened buildings and roads will decrease in the future as sea level rises and the existing Protection structures degrade or fall below new design standards. We suggest that functional buildings with less historic value remain in use until threatened by erosion, but little reason exists to build new structures to protect them. A case is made for allowing developed sites to revert to natural processes to establish a precedent and provide good demonstration areas for promoting stakeholder acceptance of retreat strategies.
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aeolian sediment transport and landforms in managed coastal systems a review
Aeolian Research, 2011Co-Authors: Nancy L Jackson, Karl F NordstromAbstract:Abstract Humans modify beaches and dunes and aeolian transport potential by building structures, walking or driving, extracting resources, accommodating recreation, increasing levels of Protection, removing storm deposits, or restoring landforms and habitats. The effects of human adjustments are reviewed here in terms of cross-Shore zones because humans tend to compartmentalize landforms and habitats through their actions and regulations. Common human modifications in the beach zone include nourishing beaches, constructing Shore Protection structures and raking to remove litter. Modifications affecting the dune zone include altering the location, size and stability of dunes using sand-trapping fences, vegetation plantings and bulldozers or replacing dunes with Shore-parallel structures. Modifications affecting the landward zone include buildings, roads, and parking lots. Landform and habitat resilience requires levels of dynamism and geomorphic complexity not often found in managed systems. Preserving or enhancing dynamism and complexity requires emphasis on innovative designs rooted in geomorphological and aeolian research. Future studies are suggested for: (1) quantifying the effect of small and large scale beach nourishment designs and sediment characteristics on dune initiation, development, and evolution; (2) quantifying the extent to which size and spacing of human structures and landform alterations inhibit sediment transfers alongShore or onShore; (3) identifying the advantages or disadvantages of “niche” dunes formed by structures; (4) providing quantitative data on the effects of raking or driving on the beach; (5) identifying the role of aeolian landforms on private properties; and (6) identifying alternative ways of employing sand fences and vegetation plantings to increase topographic and habitat diversity.
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increasing the dynamism of coastal landforms by modifying Shore Protection methods examples from the eastern german baltic sea coast
Environmental Conservation, 2007Co-Authors: Karl F Nordstrom, Reinhard Lampe, Nancy L JacksonAbstract:Redesign of Shore Protection projects in Mecklenburg-Vorpommern (Germany) is allowing landforms to become more dynamic after centuries of employing structures to increase stability. Current policies are designed to maintain sediment transfers, re-establish wetlands, ensure zero net loss of coastal habitat and apply the user-pays principle for restoring damaged habitat. Projects that achieve new nature-oriented goals include (1) relocating dykes landward or allowing dykes or protective dunes to erode to expose more land to episodic inundation by the sea; (2) reinstating sediment transfers from bluffs to adjacent low-lying Shores; (3) increasing sediment transport rates through groyne fields; and (4) removing exotic vegetation from dunes. These actions create new habitat, add portions of the coast to the public domain, and provide a wider buffer against accelerated sea-level rise for developed lands further inland. The management actions have been relatively small in scale, applied where there has been little threat to human facilities and done to achieve specific environmental goals, but they provide examples of workable options to increase the dynamism of stabilized landforms on other exposed coasts. The need to restore natural functions while providing some stability places emphasis on a strategy of controlling dynamism rather than preventing it.
Juan Reciomolina - One of the best experts on this subject based on the ideXlab platform.
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geosynthetic wrap around revetments for Shore Protection
Geotextiles and Geomembranes, 2007Co-Authors: Kazuya Yasuhara, Juan ReciomolinaAbstract:Abstract Geosynthetic structures for Shore Protection have demonstrably lower construction and lifetime costs than those of hard structures. This paper outlines the recent development of a geosynthetic structure that is commonly used for Shore Protection: geotextile wrap-around revetments (GWRs). Its advantages are also explained. Model tests described in this paper show that these structures are stable against wave action and that their stability can be increased with some simple modifications. Additionally, GWRs have been shown to adapt extremely well against differential settlement and scour erosion. Knowledge obtained from model tests has facilitated the creation of modified design charts. Efficiency of these systems against storm surges, rising sea level, and tsunami is also discussed. Analyses show that many uncertainties involving these structures remain, but that geosynthetic structures should not be regarded as an alternative Shore construction method. Rather, they are a preferable solution for numerous coastal problems.
Ping Wang - One of the best experts on this subject based on the ideXlab platform.
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dynamic equilibrium of sandbar position and height along a low wave energy micro tidal coast
Continental Shelf Research, 2018Co-Authors: Jun Cheng, Ping WangAbstract:Abstract NearShore sandbars play an essential role in dissipating incident wave energy and protecting the beach landward. Thus, understanding the dynamic equilibrium of nearShore bars is valuable to beach management and Shore Protection. This study examines the sandbar equilibrium in terms of bar height and cross-Shore bar location, in order to assess how the dynamic equilibrium is maintained and influenced by storms along a low wave energy micro-tidal coast. The bar height and bar position were extracted from 51 beach profiles surveyed every two months, spaced at 300 m along a 15-km stretch of beach from October 2010 to August 2014. For the studied coast, alongShore variation in equilibrium bar position measured from the Shoreline ranges between 40 and 80 m and equilibrium bar height between 0.20 and 0.70 m. Greater equilibrium sandbar height tends to occur around a headland, where waves are higher. AlongShore variations of bar behavior were observed during storms, with both onShore and offShore bar migration observed during one storm. Water depth over the pre-storm sandbar crest is a major factor controlling the storm-induced onShore or offShore bar migration. On average, the depth over the onShore migrating sandbar is found to be 0.20 m deeper than that over the offShore migrating bar during both summer and winter storms. There is no significant correlation between incident wave angle and sandbar height changes, while significant correlation exists between wave angle and sandbar movement under certain wave conditions, with more oblique waves being associated with further offShore movement of the sandbar. Energetic storm conditions tend to make the bar higher than the equilibrium height, while post-storm adjustment would restore the equilibrium height within 4–6 months. Although the exact values may vary at different locations, the concept of dynamic equilibrium of bar height and distance to Shoreline could apply at many locations.
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longShore sand transport initial results from large scale sediment transport facility
This Digital Resource was created from scans of the Print Resource., 2002Co-Authors: Ping Wang, Bruce A Ebersole, Ernest R SmithAbstract:Abstract : Accurate predictions of the total rate of longShore sand transport (LST) and its cross-Shore distribution pattern in the surf zone are central to many coastal engineering studies. Present understanding and methods for calculating the LST rate are largely developed based on field studies (e.g., Komar and Inman 1970; Inman et al. 1981; Kraus et al. 1982; Bodge and Dean 1987a, b; Dean 1989; Schoonees and Theron 1993; Miller 1998; Wang, Kraus, and Davis 1998; Wang 1998; Wang and Kraus 1999; Miller 1999). The Coastal Engineering Research Center (CERC) formula (Shore Protection Manual 1984), which is based on field measurements, is often used to calculate the total LST rate. Accuracy of the CERC formula is believed to be 30-50 percent and several parameters that logically might influence LST are excluded in the formula, such as breaker type and grain size. The GENESIS Shoreline change model, a tool commonly used in Shore Protection and beach-fill project design, utilizes the CERC formula. In the GENESIS model, the cross-Shore distribution of LST is assumed to be uniform across the surf zone. Laboratory data (Bodge 1986; and Kamphuis 1991) and field data (Zenkovitch 1960; Ingle 1966; Bodge and Dean 1987a, b; Miller 1998) suggest that the distribution is not uniform.
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total longShore sediment transport rate in the surf zone field measurements and empirical predictions
Journal of Coastal Research, 1998Co-Authors: Ping Wang, Nicholas C Kraus, Richard A DavisAbstract:The total rate of longShore sediment transport was measured by streamer traps at 29 locations along the southeast coast of the United States and the Gulf Coast of Florida. The rate was also measured concurrently by traps and by short-term impoundment at Indian Rocks Beach, west-central Florida. Data on beach profiles, breaking wave conditions, and sediment properties were taken together with the transport rate. The measured total rates of longShore sediment transport were compared to predictions obtained with published empirical formulas, most of which have been calibrated mainly by sediment tracer measurements made on the (high-wave energy) Pacific coast. Transport rates measured in this study by the streamer sediment traps and the short-term impoundment along low-wave energy coasts were considerably lower than the rates predicted by empirical formulas. The empirical predictions appear to be unrealistically high for the low-wave energy settings investigated in this study. The linear relationship between wave energy flux factor and the total rate of longShore sediment transport contained in the commonly used CERC predictive formula is supported by the streamer trap measurements. However, a lower value of the empirical coefficient, 0.08 instead of the 0.78 recommended by the Shore Protection Manual, was determined by the trap data for low-energy coasts. The total rates of longShore sediment transport predicted by the KAMPHUlS (1991) formula which includes the influences of wave period, beach slope, and sediment grain size were about 3 times lower than the CERC predictions and closer to the measured values.
Charles T Roman - One of the best experts on this subject based on the ideXlab platform.
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facilitating landform migration by removing Shore Protection structures opportunities and constraints
Environmental Science & Policy, 2016Co-Authors: Karl F Nordstrom, Nancy L Jackson, Charles T RomanAbstract:Abstract Recent studies have identified the need to adapt to climate change by allowing landforms and habitats to migrate landward, although implementation of actual adaptation responses is limited. Removing the barriers that Shore Protection structures create between coastal and upland habitats can reestablish exchanges of sediment and the ecological functions of the natural ecotone. The potential for removing these structures was evaluated in 12 national parks managed by the U.S. National Park Service. Criteria for removal included condition of structures, influence of natural processes, environmental benefits, public safety, and visitor access and use. We found that 145 structures out of a total of 407 could be removed or allowed to deteriorate. We highlight three adaptation projects that are currently being conducted, two of which involve removing structures. Reasons for not taking a more pro-active approach to removing Protection structures include (1) conflicting policy directives; (2) presence of key access roads and critical archaeological and historic sites; (3) lack of data; (4) lack of funds and human resources; (5) reluctance to replace known problems with an unknown set of problems; (6) consideration of visitor desires; and (7) reluctance to allow erosion to occur. Demonstration projects are needed to provide information about adaptation strategies that promote enhancement of ecosystem functions. Projects to remove Protection structures are likely to be viewed as successful only if results are specified as a positive product, and the distinction between the concept of loss (erosion of existing landforms and habitats) and the concept of gain (evolution of new landforms and habitats) is made clear.
