Modern Sedimentation and Estuarine Shoreline Change Around Roanoke Island, North Carolina PDF Download
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Author: David W. Hawkins
Publisher:
ISBN:
Category : Croatan Sound (N.C.)
Languages : en
Pages : 172
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Book Description
Croatan and Roanoke sounds in North Carolina (NC) are regions constantly undergoing geomorphic changes associated with sea-level rise, storm events, and anthropogenic modification. These estuaries are part of the larger Albemarle-Pamlico Estuarine System (APES), a composite of drowned coastal plain river valleys and large bar-built shallow sounds fronted by the Outer Banks barrier islands. Changes in shoreline morphology driven by erosion and accretion, associated with oceanographic/atmospheric drivers (e.g., wave energy, fetch), influence modern sedimentological patterns and sedimentation rates in the APES. This research focused on the dynamics and controls of modern sedimentary processes (e.g., accumulation) and shoreline change on an anthropogenic time-scale (~100 years) around Roanoke Island, NC. Sedimentological, geochemical, and geospatial analyses provided the necessary information for modern interpretation of the geological processes at work within the past century. Surficial sediment analyses revealed variable grain-size patterns and high loss on ignition (% LOI, organic content proxy) across the region. Sediment accumulation rates (0.12 ± 0.01 cm/y to 0.37 ± 0.04 cm/y) varied over the long-term, and one location (DH-S17) displayed rapid episodic deposition (2.3 ± 0.5 cm/month). Long-term shoreline change (1915-2012) indicated net erosion of the system (-0.68 ± 0.05 m/y), with temporal changes observed in the intermediate time-intervals, and more accretion was captured in the recent- and short-term (2007-2012: -0.24 ± 0.32 m/y). Long-term shoreline change rates (SCRs) provided insight into chronic changes (hydrodynamic and geomorphic changes), while short-term rates, due to events (e.g., hurricanes), revealed episodic variations in accretion and erosion that might not represent the long-term patterns in the system. Overall, the amount of sediment eroded from the shoreline over the 97-year interval (1915-2012) was calculated to be 8.32 x 106 m3, with a mass of 4.16 x 109-8.32 x 109 kg (assuming a dry bulk density range of 0.5-1.0 g/cm3). A sediment accumulation budget of 9.32 x 103 m3/y (7.24 x 106 kg/y) was calculated for two regions (offshore UNC CSI, Shallowbag Bay), and modern accumulation accounts for ~11% (8.57 x 104 m3/y) of the amount of annually eroded sediment. Data from this thesis indicate that the majority of eroded sediment is exported out of Croatan and Roanoke sounds. Spatial and temporal trends in shoreline change and accompanying sedimentary characteristics examined in this thesis provide insight to coastal managers and homeowners in systems similar to the Roanoke Island area.
Author: David W. Hawkins
Publisher:
ISBN:
Category : Croatan Sound (N.C.)
Languages : en
Pages : 172
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Book Description
Croatan and Roanoke sounds in North Carolina (NC) are regions constantly undergoing geomorphic changes associated with sea-level rise, storm events, and anthropogenic modification. These estuaries are part of the larger Albemarle-Pamlico Estuarine System (APES), a composite of drowned coastal plain river valleys and large bar-built shallow sounds fronted by the Outer Banks barrier islands. Changes in shoreline morphology driven by erosion and accretion, associated with oceanographic/atmospheric drivers (e.g., wave energy, fetch), influence modern sedimentological patterns and sedimentation rates in the APES. This research focused on the dynamics and controls of modern sedimentary processes (e.g., accumulation) and shoreline change on an anthropogenic time-scale (~100 years) around Roanoke Island, NC. Sedimentological, geochemical, and geospatial analyses provided the necessary information for modern interpretation of the geological processes at work within the past century. Surficial sediment analyses revealed variable grain-size patterns and high loss on ignition (% LOI, organic content proxy) across the region. Sediment accumulation rates (0.12 ± 0.01 cm/y to 0.37 ± 0.04 cm/y) varied over the long-term, and one location (DH-S17) displayed rapid episodic deposition (2.3 ± 0.5 cm/month). Long-term shoreline change (1915-2012) indicated net erosion of the system (-0.68 ± 0.05 m/y), with temporal changes observed in the intermediate time-intervals, and more accretion was captured in the recent- and short-term (2007-2012: -0.24 ± 0.32 m/y). Long-term shoreline change rates (SCRs) provided insight into chronic changes (hydrodynamic and geomorphic changes), while short-term rates, due to events (e.g., hurricanes), revealed episodic variations in accretion and erosion that might not represent the long-term patterns in the system. Overall, the amount of sediment eroded from the shoreline over the 97-year interval (1915-2012) was calculated to be 8.32 x 106 m3, with a mass of 4.16 x 109-8.32 x 109 kg (assuming a dry bulk density range of 0.5-1.0 g/cm3). A sediment accumulation budget of 9.32 x 103 m3/y (7.24 x 106 kg/y) was calculated for two regions (offshore UNC CSI, Shallowbag Bay), and modern accumulation accounts for ~11% (8.57 x 104 m3/y) of the amount of annually eroded sediment. Data from this thesis indicate that the majority of eroded sediment is exported out of Croatan and Roanoke sounds. Spatial and temporal trends in shoreline change and accompanying sedimentary characteristics examined in this thesis provide insight to coastal managers and homeowners in systems similar to the Roanoke Island area.
Author: Lisa Cowart
Publisher:
ISBN:
Category : Coast changes
Languages : en
Pages : 95
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Book Description
With continued climate change, sea-level rise, and coastal development, concern about shoreline dynamics has expanded beyond oceanfront areas to encompass more protected coastal water bodies, such as estuaries. Because estuaries are critically important ecosystems, understanding coastline changes in these areas is necessary for evaluating resource risks. Throughout the recent decades various methods have been developed to calculate shoreline change and multiple parameters have been hypothesized to correlate with estuarine erosion, including fetch, wave energy, elevation, and vegetation. A transect-based approach is commonly used to quantify shoreline change on linear (i.e., ocean) shorelines; however, due to the complex morphology of the estuarine environments, a point-based approach was developed and applied in this study. Shoreline-change rates and additional parameters (i.e., wave energy and shoreline composition) were determined using 1958 and 1998 aerial photography and available datasets. From these data the average shoreline change of Cedar Island, NC is determined to be -0.24 m yr−1, with 88% of the shoreline eroding. Of the parameters analyzed, shoreline composition appears to have an important control on shoreline erosion along Cedar Island, whereas wave energy is not significantly correlated with shoreline-change rates. The point-based approach was applied to the trunk of the Neuse River Estuary to analyze parameters associated with estuarine erosion at two contrasting scales, regional (whole estuary) and local (estuary partitioned into 8 sections, based on orientation and exposure). With a mean shoreline-change rate of -0.58 m yr−1, the majority (93%) of the Neuse River Estuary study area is eroding. Although linear regression analysis at the regional scale did not find significant correlations between shoreline change and the parameters analyzed, trends were determined at the local scale. Local-scale analysis determined higher erosion rates, higher elevation, and lower exposure and fetch up-estuary. Erosion rates, fetch, and wave exposure increase, while elevation decreases moving eastward, down-estuary. The general trends found at the local scale highlight the importance of the spatial distribution on shoreline-change rates and parameters analyzed within a complex estuarine system, like the Neuse River Estuary. Linear regression analysis between mean fetch and mean shoreline-change rates at the Local Scale determined an equation to predict shoreline-change rates. Predicted shoreline-change rates overestimate erosion on extremely high fetch shorelines and underestimate erosion on shorelines classified as sediment bank. Overall, the model is conservative in predicting shoreline-change rates by underestimating erosion and accretion within the Neuse River Estuary. Further analysis of mean fetch by specific vegetation type may offer additional insight into the influencing forces on estuarine shoreline change.
Author:
Publisher:
ISBN:
Category : Coast changes
Languages : en
Pages : 10
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Book Description
Author: Stephen Boyd Benton
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 352
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Book Description
Author: Vincent J. Bellis
Publisher:
ISBN:
Category : Beach erosion
Languages : en
Pages : 84
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Book Description
Tracings: 92.38.
Author: Linda S. Shope
Publisher:
ISBN:
Category : Coast changes
Languages : en
Pages : 378
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Book Description
Author: Stanley R. Riggs
Publisher:
ISBN:
Category : Beach erosion
Languages : en
Pages :
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Author: Michael Peter O'Connor
Publisher:
ISBN:
Category : Beach erosion
Languages : en
Pages : 2
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Book Description
Author: Stanley R. Riggs
Publisher: UNC Press Books
ISBN: 0807878073
Category : Nature
Languages : en
Pages : 161
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Book Description
The North Carolina barrier islands, a 325-mile-long string of narrow sand islands that forms the coast of North Carolina, are one of the most beloved areas to live and visit in the United States. However, extensive barrier island segments and their associated wetlands are in jeopardy. In The Battle for North Carolina's Coast, four experts on coastal dynamics examine issues that threaten this national treasure. According to the authors, the North Carolina barrier islands are not permanent. Rather, they are highly mobile piles of sand that are impacted by sea-level rise and major storms and hurricanes. Our present development and management policies for these changing islands are in direct conflict with their natural dynamics. Revealing the urgency of the environmental and economic problems facing coastal North Carolina, this essential book offers a hopeful vision for the coast's future if we are willing to adapt to the barriers' ongoing and natural processes. This will require a radical change in our thinking about development and new approaches to the way we visit and use the coast. Ultimately, we cannot afford to lose these unique and valuable islands of opportunity. This book is an urgent call to protect our coastal resources and preserve our coastal economy.
Author: Kevin McVerry
Publisher:
ISBN:
Category : Estuaries
Languages : en
Pages : 145
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Book Description
