Showing papers on "Shore published in 2010"

Ecology of freshwater shore zones

Abstract: Freshwater shore zones are among the most ecologically valuable parts of the planet, but have been heavily damaged by human activities. Because the management and rehabilitation of freshwater shore zones could be improved by better use of ecological knowledge, we summarize here what is known about their ecological functioning. Shore zones are complexes of habitats that support high biodiversity, which is enhanced by high physical complexity and connectivity. Shore zones dissipate large amounts of physical energy, can receive and process extraordinarily high inputs of autochthonous and allochthonous organic matter, and are sites of intensive nutrient cycling. Interactions between organic matter inputs (including wood), physical energy, and the biota are especially important. In general, the ecological character of shore zone ecosystems is set by inputs of physical energy, geologic (or anthropogenic) structure, the hydrologic regime, nutrient inputs, the biota, and climate. Humans have affected freshwater shore zones by laterally compressing and stabilizing the shore zone, changing hydrologic regimes, shortening and simplifying shorelines, hardening shorelines, tidying shore zones, increasing inputs of physical energy that impinge on shore zones, pollution, recreational activities, resource extraction, introducing alien species, changing climate, and intensive development in the shore zone. Systems to guide management and restoration by quantifying ecological services provided by shore zones and balancing multiple (and sometimes conflicting) values are relatively recent and imperfect. We close by identifying leading challenges for shore zone ecology and management.

Experimental Investigation of Tsunami Impact on Free Standing Structures

Abstract: As tsunami waves propagate towards the shoreline, they break where the water depth is approximately equal to the incident wave height. Following breaking, waves run up the shore in form of a hydrau...

Assessing vulnerability to sea-level rise using a coastal sensitivity index: a case study from southeast Australia

Abstract: Many of the world’s coasts appear vulnerable to the impacts of climate change and sea-level rise. This paper assesses the application of a coastal sensitivity index (CSI) to the Illawarra coast, a relatively well-studied shoreline in southeast Australia. Nine variables, namely (a) rock type, (b) coastal slope (c) geomorphology (d) barrier type (e) shoreline exposure (f) shoreline change (g) relative sea-level rise (h) mean wave height and (j) mean tide range, were adopted in calculation of the CSI (the square root of the product of the ranked variables divided by the number of variables). Two new variables, shoreline exposure and barrier type, were trialled in this analysis and the extent to which these increased the discriminatory power of the index was assessed. Four iterations of the CSI were undertaken using different combinations of ranked variables for each of 105 cells in a grid template, and the index values derived were displayed based on quartiles, indicating sections of coast with very high, high, moderate and low sensitivity. Increasing the number of variables increased the discriminatory power of the index, but the broad pattern and the rank order were very similar for each of the iterations. Rocky and cliffed sections of coast are least sensitive whereas sandy beaches backed by low plains or dunes record the highest sensitivity. It is difficult to determine shoreline change on this coast, because individual storms result in substantial erosion of beaches, but there are prolonged subsequent periods of accretion and foredune rebuilding. Consequently this variable is not a good indicator of shoreline sensitivity and the index is unlikely to provide a clear basis for forecasting future recession of beaches. The results of this study provide a framework for coastal managers and planners to prioritize efforts to enhance the resilience or consider adaptation measures in the coastal zone within a study region. Sensitivity of the coast if considered in conjunction with other social factors may be an input into broader assessments of the overall vulnerability of coasts and their communities.

Quantitative analysis of shoreline changes at the Mediterranean Coast in Turkey

Abstract: This research is focused on the coastline evolution monitoring and its potential change estimation by remote sensing techniques using multi-temporal Landsat images at the southeast coasts of the Mediterranean Sea in Turkey. The study area includes the coastal zone located in the Cukurova Delta coasts. The Cukurova Delta has accreted toward the Mediterranean Sea as a result of sediment discharge and transport from Seyhan and Ceyhan rivers. These processes have caused the morphological changes (accretion or erosion) of coastline along some parts of the southeast coasts of the Mediterranean Sea. In this study, coastline changes were researched by using radiometrically and geometrically corrected multi-temporal and multi-spectral data from Landsat Multispectral Scanner dated 1972, Thematic Mapper dated 1987, and Enhanced Thematic Mapper dated 2002. In the image processing steps, mosaicing, subset, Iterative Self-Organizing Data Analysis Technique classification, band ratioing (B5/B2), edge detection, and overlay techniques were used to carry out coastline extraction and the Digital Shoreline Analysis System was used to calculate rate of coastline changes. As a result of the analysis, in some parts of the research area, remarkable coastline changes (more than 2,900 m withdrawal and − 24.50 m/year erosion) were observed for a 30–year period.

Current challenges using models to forecast seawater intrusion: lessons from the Eastern Shore of Virginia, USA

Abstract: A three-dimensional model of the aquifer system of the Eastern Shore of Virginia, USA was calibrated to reproduce historical water levels and forecast the potential for saltwater intrusion. Future scenarios were simulated with two pumping schemes to predict potential areas of saltwater intrusion. Simulations suggest that only a few wells would be threatened with detectable salinity increases before 2050. The objective was to examine whether salinity increases can be accurately forecast for individual wells with such a model, and to address what the challenges are in making such model forecasts given current (2009) simulation capabilities. The analysis suggests that even with current computer capabilities, accurate simulations of concentrations within a regional-scale (many km) transition zone are computationally prohibitive. The relative paucity of data that is typical for such regions relative to what is needed for accurate transport simulations suggests that even with an infinitely powerful computer, accurate forecasting for a single well would still be elusive. Useful approaches may include local-grid refinement near wells and geophysical surveys, but it is important to keep expectations for simulated forecasts at wells in line with chloride concentration and other data that can be obtained at that local scale.

The Effect of Wind Power Installations on Coastal Tourism

Abstract: We surveyed more than 1,000 randomly sampled, out-of-state tourists at Delaware, USA beaches in 2007. After providing respondents with wind turbine project photo-simulations at several distances, we inquired about the effect development would have on visitation. Approximately one-quarter stated that they would switch beaches if an offshore wind project was located 10 km from the coast, with avoidance diminishing with greater distance from shore. Stated avoidance is less than: avoidance with a fossil fuel power plant located the same distance inland; attraction to a beach with offshore wind turbines; and the percentage stating they would likely pay to take a boat tour.

Quantifying recreational shore angling catch and harvest in southern Portugal (north-east Atlantic Ocean): implications for conservation and integrated fisheries management.

Abstract: Recreational shore fishing along 250 km of the south and south-west coast of Portugal was studied based on roving creel and aerial surveys. Surveys were conducted between August 2006 and July 2007, following a stratified random-sampling design and provided information on catch and effort, harvest and discards, angler demographics and fishing habits. Overall, 192 roving creel surveys, 24 aerial surveys and 1321 interviews were conducted. Based on the aerial surveys, a mean +/-s.e. total fishing effort of 705,236 +/- 32,765 angler h year(-1) was estimated, corresponding to 166,430 +/- 9792 fishing trips year(-1). Average time spent per fishing trip was 4.7 h. A total of 48 species, belonging to 22 families, were recorded in roving creel surveys. The most important species was Diplodus sargus, accounting for 44% of the total catches by number and 48% by mass. Estimated mean +/-s.e. total annual recreational shore fishing catch was 160.2 +/- 12.6 t year(-1) (788,049 +/- 54,079 fishes year(-1)), of which 147.4 +/- 11.9 t year(-1) (589,132 +/- 42,360 fishes year(-1)) was retained. Although overall shore-based recreational catches only corresponded to 0.8% of the commercial landings (only common species considered), D. sargus catches by recreational shore anglers were considerable, corresponding to 65% of the commercial landings. The implications of these results for integrated fisheries management and conservation are discussed, and future research proposed.

A Review of Sediment Budget Imbalances along Fire Island, New York: Can Nearshore Geologic Framework and Patterns of Shoreline Change Explain the Deficit?

Abstract: Sediment budget analyses conducted for annual to decadal timescales report variable magnitudes of littoral transport along the south shore of Long Island, New York. It is well documented that the primary transport component is directed alongshore from east to west, but relatively little information has been reported concerning the directions or magnitudes of cross-shore components. Our review of budget calculations for the Fire Island coastal compartment (between Moriches and Fire Island Inlets) indicates an average deficit of 217,700 m3/y. Updrift shoreline erosion, redistribution of nourishment fills, and reworking of inner-shelf deposits have been proposed as the potential sources of additional sediment needed to rectify budget residuals. Each of these sources is probably relevant over various spatial and temporal scales, but previous studies of sediment texture and provenance, inner-shelf geologic mapping, and beach profile comparison indicate that reworking of inner-shelf deposits is the sou...

Shoreline change and sea level rise along coast of Bhitarkanika wildlife sanctuary, Orissa: an analytical approach of remote sensing and statistical techniques.

Abstract: The shoreline is one of the rapidly changing linear features of the coastal zone which is dynamic in nature. The issue of shoreline changes due to sea level rise over the next century has increasingly become a major social, economic and environmental concern to a large number of countries along the coast, where it poses a serious problem to the environment and human settlements. The global effects of sealevel rise on coasts will vary spatially. As a consequence, some coastal scientists have advocated analyzing and predicting coastal changes on a more local scale. The need to predict and manage the potential impact of sealevel rise on coasts necessitates accurate study on micro level. The present study demonstrates the potential of Geospatial and statistics technique for monitoring the shoreline changes along the coast of Bhitarkanika Wildlife Sanctuary, Orissa, India since such kind of changes stand as a testimony for the past and present coastal environment. In the present study, multiresolution and multi temporal satellite images of Landsat have been utilized to demarcate shoreline positions during 1973, 1989, 2000 and 2009. The Statistical techniques called as linear regression and regression coefficient (R2) have been used for find out the change rate during the period of 19732009. Finally, an attempt has been made to find out any interactive relationship between the sea level rise and shoreline change in the concerned area. The present study demonstrates that combined use of satellite imagery and statistical methods can be a reliable method for analyzed the shoreline changes in relationship to sea level rise.

Active shoreline of Ontario Lacus, Titan: A morphological study of the lake and its surroundings

Abstract: Of more than 400 filled lakes now identified on Titan, the first and largest reported in the southern latitudes is Ontario Lacus, which is dark in both infrared and microwave. Here we describe recent observations including synthetic aperture radar (SAR) images by Cassini's radar instrument (λ = 2 cm) and show morphological evidence for active material transport and erosion. Ontario Lacus lies in a shallow depression, with greater relief on the southwestern shore and a gently sloping, possibly wave-generated beach to the northeast. The lake has a closed internal drainage system fed by Earth-like rivers, deltas and alluvial fans. Evidence for active shoreline processes, including the wave-modified lakefront and deltaic deposition, indicates that Ontario is a dynamic feature undergoing typical terrestrial forms of littoral modification.

Contrasting styles of swell-driven coastal erosion: examples from KwaZulu-Natal, South Africa

Abstract: During 2006–2007, the KwaZulu-Natal coast of South Africa was exposed to several large swell events (Ho > 3 m), near the peak of the lunar nodal cycle, causing shoreline recession. The largest swell (Hs = 8.5 m) struck the coast on the March equinox (18th–20th) and generated a strong storm-return flow. Observations made before, during and after record dramatic coastal erosion (shoreline recession of up to 40 m and substantial property damage). This swell event removed the semi-continuous nearshore bar system and ‘conditioned’ the coast such that lesser subsequent swell events accomplished much greater amounts of coastal erosion than expected (up to 100 m at certain erosion hotspots) because waves reached the coast without significant energy dissipation. Subsequent bar generation rebuilt the inshore bars within six months. The styles of erosion during the March ’07 event and other 2007 swells were markedly different. Lesser swells are focused by headlands and result in megarip development and activation of erosion hotspots. The March ’07 event still-water level was raised (equinoctial spring high tide and a storm surge of 0.33–0.45 m) to a level that rendered most headlands (and erosion hotspots) ineffective and resulted in laterally extensive erosion of soft shorelines. Results record cumulative effects of successive swell events on coastal behaviour that proved to be critical in enabling erosion to proceed at rapid rates after the coast had been initially destabilized. Unlike hurricanes and tsunamis, surges associated with swell events are relatively minor and therefore extensive erosion is linked with high lunar tides. There is circumstantial evidence that swell-induced erosion follows the broad 18.6 yr lunar nodal tidal cycle when the chances of large swells coinciding with high water levels are increased.

Azerbaijan Since Independence

Abstract: Azerbaijan, a small post-Soviet republic located on the western shore of the Caspian Sea, has outsized

Evolution of a beach–dune system following a catastrophic storm overwash event: Greenwich Dunes, Prince Edward Island, 1936–2005

Abstract: Greenwich Dunes, Prince Edward Island National Park, is a sandy mainland and barrier spit beach–dune complex stretching for about 10 km along the northeast shore of Prince Edward Island, Canada. In October 1923, surge associated with an intense storm produced catastrophic overwash along the whole length of the study area. Subsequent evolution of the system was quantified from historic aerial photographs taken in 1936, 1953, 1971, 1997, and 2005. Orthophoto mosaics were generated for each photo set using PCI Geomatica OrthoEngine, a digital photogrammetric software. Linear changes in shoreline position and areal changes in geomorphic units were evaluated for each photo set. In addition, digital elevation models (DEMs) were extracted from the 1953, 1971, and 1997 aerial photos, enabling analysis of topographic and volumetric changes. The 1936 photos show complete destruction of all foredunes, with overwash and transgressive dunes extending 300 to 600 m inland. A descriptive model of the stages of evolution ...

Potential on-shore and off-shore reservoirs for CO2 sequestration in Central Atlantic magmatic province basalts

Abstract: Identifying locations for secure sequestration of CO2 in geological formations is one of our most pressing global scientific problems. Injection into basalt formations provides unique and significant advantages over other potential geological storage options, including large potential storage volumes and permanent fixation of carbon by mineralization. The Central Atlantic Magmatic Province basalt flows along the eastern seaboard of the United States may provide large and secure storage reservoirs both onshore and offshore. Sites in the South Georgia basin, the New York Bight basin, and the Sandy Hook basin offer promising basalt-hosted reservoirs with considerable potential for CO2 sequestration due to their proximity to major metropolitan centers, and thus to large industrial sources for CO2. Onshore sites are suggested for cost-effective characterization studies of these reservoirs, although offshore sites may offer larger potential capacity and additional long-term advantages for safe and secure CO2 sequestration.

Shoreline and beach volume change between 1967 and 2007 at Raine Island, Great Barrier Reef, Australia.

Abstract: Raine Island is a vegetated coral cay located on the far northern outer Great Barrier Reef (GBR), recognised as a globally significant turtle rookery. Cay geomorphology, specifically the morphology of the beach and swale, dictate the availability of nesting sites and influence nesting success. Understanding short and long-term shoreline change is critical for managers charged with protecting the nesting habitat, particularly as climate change progresses. Historical topographic surveys, a simple numerical model and geographic information system (GIS) techniques were used to reconstruct a 40-year (1967–2007) shoreline history of Raine Island. Results show that significant shoreline change has occurred on 78% of the island's shoreline between 1967 and 2007; 34% experienced net retreat and 44% net progradation during the study interval. Shoreline retreat is mainly concentrated on the east–southeast section of the shoreline (average annual rate of − 0.3 ± 0.3 m/yr), while the shore on the western side of the island prograded at a similar rate (0.4 ± 0.2 m/yr). A seasonal signal was detected relating to oscillations in wind direction and intensity, with the southeast and west–southwest shorelines migrating an average of ∼ 17 m from season to season. The volume of sediment deposited on Raine Island between 1967 and 2007 increased by ∼ 68,000 m3 net, but accretion rates varied significantly seasonally and from year to year. The largest volumetric changes have typically occurred over the last 23 years (1984–2007). Despite the recent concern that Raine Island is rapidly eroding, our data demonstrate net island growth (6% area, 4% volume) between 1967 and 2007. Perceptions of erosion probably reflect large morphological changes arising from seasonal, inter-annual and inter-decadal patterns of sediment redistribution rather than net loss from the island's sediment budget.