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1.
The Coastwatch (CW) project is aimed at monitoring the coastline with the involvement of volunteers. Between 2003 and 2007 a beach profiling method was informally proposed to CW participants in Portugal as an extra activity to include in the surveys. Beach profiling contributes to a better understanding of coastal processes by providing quantitative information on the spatial/temporal evolution of beaches, which is crucial for coastal management. The profiling method proposed to the CW project is based on the physical principle of communicating vessels, and only requires a simple and inexpensive homemade ??profiler??. The simplicity of putting together and using the profiler, added to the arithmetic straightforwardness of data analysis, makes this method adequate for several kinds of users and for most levels of education. Eight workshops were held that included a classroom explanation of the method, the construction of a profiler, the actual profiling of a beach, and a final classroom session of data processing and graphing. About 140 participants received such training, and several among them independently undertook beach profiling. Surveyed participants found the workshop and the beach profiling method interesting and useful, and considered it a valuable tool for teaching and for management. External stakeholders (coastal managers) highlighted the importance of beach profiling data for management decisions and considered that this method produces robust data, even when carried out by volunteers. Further advantages of the application of the method, in the context of coastal management initiatives, for scientists, managers, and volunteers are discussed.  相似文献   

2.
Integrated Coastal Zone Management as a strategy for achieving conservation and sustainable multiple use of the coastal zone includes various types of management initiatives. Due to natural phenomena such as tides and winds and to social and economic activities, coastal areas undergo transformation. Coastal erosion and the disappearance of beaches as a result of wrong planning decisions and lack of effective legislation are among the most damaging effects and to reverse them requires application of a series of engineering techniques. Beach nourishment projects as a way towards shore protection and utilization through recreational purposes in the Spanish and Italian coasts are noteworthy in this respect. In beach nourishment projects, the roles of various entities, both public and private, should be clearly indicated and in the evaluation and execution stage a series of questions should be answered for the successful completion of any nourishment project. Past projects in the Mediterranean and experiences from recent Italian projects in Anzio and Nettuno confirm this. For example, dredging of the entrance channel of the port of Anzio enabled middle-sized ferryboats once again to enter the port (which had not been possible before). This will in turn increase the tourism potential of the town. Nourishment of two beaches at these sites prevented further erosion and provided more area for recreational purposes. Expected economic contribution of beach nourishments to the regional authority was estimated for Nettuno and Anzio; the resulting theoretical payback period was found to be 3 yr for the former and 15 yr for the latter.  相似文献   

3.
Beach nourishment is a policy used to rebuild eroding beaches with sand dredged from other locations. Previous studies indicate that beach width positively affects coastal property values, but these studies ignore the dynamic features of beaches and the feedback that nourishment has on shoreline retreat. We correct for the resulting attenuation and endogeneity bias in a hedonic property value model by instrumenting for beach width using spatially varying coastal geological features. We find that the beach width coefficient is nearly five times larger than the OLS estimate, suggesting that beach width is a much larger portion of property value than previously thought. We use the empirical results to parameterize a dynamic optimization model of beach nourishment decisions and show that the predicted interval between nourishment projects is closer to what we observe in the data when we use the estimate from the instrumental variables model rather than OLS. As coastal communities adapt to climate change, we find that the long-term net value of coastal residential property can fall by as much as 52% when erosion rate triples and cost of nourishment sand quadruples.  相似文献   

4.
The Coastal Vulnerability and Exposure Degree (CVED) of the Gran Canaria Island and the coastal risk of Playa de Las Canteras (Las Palmas de G.C.) have been assessed by means of a GIS analysis. The evaluation of coastal vulnerability (H) has been performed by using two different levels of analysis: the first one regarding the entire Island (Coastal Vulnerability Index method - CVI), the second one regarding specifically Las Canteras Beach, selected for its socio-economic importance (Coastal Vulnerability Assessment method - CVA). The application of the CVI method, based on geologic-geomorphologic and meteomarine data easily available, has allowed the regional scale assessment of coastal vulnerability (H) along the Gran Canaria coastline and, therefore, the individuation of more critical coast stretches deserving further analysis. The application of the CVA method, based on more specific morphologic-sedimentary beach features that allow to consider both the beach retreat due to storm surge and the coastal inundation due to run-up on the beach, has provided a large scale detail on the coastal vulnerability of Las Canteras Beach. Socio-economic and damage indexes have been determined for the 15 coastal municipalities included in the study area and, by means of the resulting matrix product, the degree of exposure (Ex) along the Gran Canaria coast has been assessed. Finally, the combination of coastal vulnerability and exposure levels has allowed to obtain the Coastal Vulnerability and Exposure Degree (CVED) for the entire Island and the risk levels that characterize specifically Las Canteras Beach. Major results in terms of CVED highlight prevailing low vulnerability and exposure levels along the western coast, and overall high vulnerability and exposure levels along the eastern coast, from Las Palmas de G.C. to San Bartolomé de Tirajana. The focus made on Playa de Las Canteras has allowed to identify the areas characterized by medium and high risk levels that represent approximately one third (940 m) of the entire beach and are located in its central part. The used two-level analysis approach has proved its efficiency by highlighting the degree of coastal vulnerability along the study coast and, especially, more critical coast stretches (CVI method) such as the Playa de Las Canteras that can be successfully analysed with the CVA approach allowing for a large-scale assessment of risk aspects, essential for a correct definition of priority management strategies. Results obtained with the present study, along with the awareness of the increasing phenomena of coastal erosion and marine flooding arising on the mid-long term due to the effects of global climate change, highlight the need for the competent public administrations of Gran Canaria to develop a strategic approach to coastal management and sustainable development that considers as a whole socio-economic values and natural resources, coastal vulnerability and exposure degree, and risk aspects.  相似文献   

5.
The Chennai coast, an integral part of the east coast of India, extends over ca. 35 km. Over the past 120 yr the coastline has witnessed both man-made and natural disturbances which led to the destruction of the beach front. The construction of Madras harbour in 1876, was the prime cause of the degradation of this very sensitive coastal region. Continued growth of Madras harbour has helped in the natural formation of the wide ‘Marina Beach’, south of the harbour. But the shoreline north of the harbour suffered the consequences of harbour development activities. The north shore receded by ca. 500 m over the past 120 yr and received attention from the authorities in the past few decades because of the growing awareness of the conservation value of the coast. This paper highlights the effects of Madras harbour development on the adjoining coast and on the shortterm mitigation measures planned and executed by the Government agencies to protect the fragile coastline. In spite of sincere efforts to protect the coastline, the destruction continues unabated due to various reasons. This paper analyses the facts and suggests a long-term solution to protect the coastline and to regain the past glory. Feasible and cost effective permanent measures are identified, construction methods suggested and the advantages that the community can derive from the longterm solutions are discussed.  相似文献   

6.
A detailed and multidisciplinary study of physical and biotic factors of a coastal sector of southern Italy, the Pineta della foce del Garigliano SCI (Site of Community Importance) area, has been carried out in the frame of the European research project LIFE + Nature & Biodiversity PROVIDUNE. We evaluated the degree of dunes vulnerability (Dune Vulnerability Index, DVI) and sustainable anthropogenic load (carrying capacity) of the emerged beach of the study area, which is largely affected by shoreline retreat and degradation of dune habitat. The values of about 0.6 of the DVI in the two key sectors of the study area suggest a high level of vulnerability of beach/dune system due to both natural and human factors. The partial vulnerability index related to the geomorphological condition exhibits the highest values, as a consequence of a coastal system largely affected by recent and present-day beach erosion and severe hydrodynamics processes. Several inadequate human practises have been recognized in the study area whose impact appears to be an important factor in controlling the reduction of the beach-dune system resilience. Integrated analysis of DVI and carrying capacity suggests that the northern and central sectors of the study area have a high level of dune vulnerability due to hydrodynamic and geomorphological factors whereas the human impact can be considered relatively less important. The southern sector of the study area is featured by a well-developed infrastructure system, which is able to assure a sustainable beach occupation. Nevertheless, significant interventions such as dune replacement by permanent or ephemeral infrastructures, uncontrolled pedestrian or vehicular access and inappropriate use of mechanical beach cleaning have been recognized in this sector of the beach. These long-lasting impacts have promoted the dismantling of large sector of the dune habitats. Obtained results allowed identifying the critical area where appropriate actions can be performed for the mitigation of impacts, the conservation of dune habitats and their sustainable use.  相似文献   

7.
In 1990, the Government and Parliament of the Netherlands decided on a new national policy for coastal defence. To ensure the enduring safety of the low-lying polders as well as the sustainable preservation of the coastal dunes, it was decided to maintain the coastline in its 1990 position. The main method for coastline preservation in the Netherlands is beach nourishment. Since 1991, approximately 7 million m3 of sand is added to the Dutch beaches annually. From an evaluation study of sand nourishment projects it is concluded that nourishment is an effective and efficient method to preserve the coastline. The evaluation study also proves that nourishment projects should be ‘tailor-made’, taking the local morphological and hydraulic conditions into account. The first results of an experimental shoreface nourishment are discussed. The choice for nourishment as the principal method to combat erosion is well in line with the intention to restore the natural dynamics of the dune-coast in the Netherlands. The key probably is a less strict policy with regard to the maintenance of the foredunes. Plans for the development of typical coastal features such as slufters*, wash-overs, blow-outs and mobile dunes are currently under discussion. A slufter is a breakthrough in the first dune-ridge whereby the sea invades former dune slacks or beach plains situated behind the duneridge. In this way a tidal marsh is formed within the dune zone.  相似文献   

8.
The main aim of this paper is to present a new methodology to determine coastal susceptibility to erosion and flooding processes by means of an index-based method. The proposed indices take into account physical parameters, such as dune and beach geomorphologic characteristics, shoreline evolution, local significant wave height and relative run-up. The coastal susceptibility has been estimated by elaboration of spatial input data into a GIS environment. The method has been tested in Valdelagrana area, a sandy spit located in SW Spain. The spit includes several morpho-sedimentary environments: sandy beach, discontinuous embryo dunes and foredunes, mud flats and wide areas of vegetated salt marshes. The Northernmost sector is densely urbanized whilst the rest is part of a natural protected area belonging to the Bahía de Cádiz Natural Park. The results obtained showed how the Southern part of the spit presented a high susceptibility due to an elevated erosion rate and the presence of low and discontinuous dune ridges.  相似文献   

9.
The case described in this article regards 4.7 km of beach in Ferring, situated approx. 5 km south to the mouth of the Limfjord strait on the west coast of Denmark. In 2005, this section of the beach was nourished with 721,000 m3 of material in order to protect backshore properties, natural heritages and the recreational value of the beach. After the nourishment, the beach was monitored by levelling profiles on four dates to monitor and track the evolution of the nourished material. Furthermore, laboratory tests involving different gradations of nourishment material are shown which indicate solutions to different kinds of coastal protection strategies, estimate the time in between two nourishments and evaluate the cost of maintaining a beach with a high recreational value for the public.  相似文献   

10.
Sandy beaches represent typical venues for recreation and tourism worldwide, as well as part of the lifestyle and identity of coastal communities. Their overexploitation, however, threatens their survival. Especially in urban areas, beach management requires balancing needs by different users and obligations to protect beach functions, including conservation. In light of this, research about the human dimension of beach ecosystems has been advanced as a way to assist planning and decision making in beach management. This study assessed beachgoers' perceptions of sandy beach conditions in South Africa, by means of a questionnaire survey. The effects of demographic profile, travelling habits, motivations to visit, and recreational preferences on beachgoers' perceptions of beach conditions were tested. Beachgoers shared a general concern for the wellbeing of sandy beaches, with particular reference to the state of biodiversity and conservation. They also gave great importance to the values underlying beach ecosystems. Three motivations to visit groups and four recreational preferences types were identified. Demography, travelling habits, motivations to visit, and recreational preferences all influenced perceptions of beach conditions. The results from this study were used to draw management recommendations, with particular attention towards the promotion of conservation while also maintaining the recreational quality of urban sandy beaches. The results also highlighted the relevance of considering users' views as a tool in decision-making processes in Integrated Coastal Zone Management.  相似文献   

11.
In The Netherlands shoreline retreat is actively counteracted, mostly by means of beach nourishment in which some allowance is made for natural fluctuations. For some parts of the coast, however, a more active socalled ‘seaward coastal defence strategy’ might be more profitable. This applies to coasts with a small dune ridge subject to severe erosion. According to this strategy the morphological system is influenced in such a way that erosion is prevented, which will result in a stable or even an accretion coastline. The effectiveness of the seaward coastal defence strategy has to be compared with maintenance by beach nourishment. The effects on the morphological system, the environment and other interests must also be analysed. Several seaward solutions are possible. In order to gain more insight into the behaviour of these solutions, comparative pilot studies have been executed for the most vulnerable locations. This paper gives an overview of the main conclusions of the pilot studies in comparison with sand nourishment, the main coastal defence measure.  相似文献   

12.
Phenotypic sex in sea turtles is determined by nest incubation temperatures, with warmer temperatures producing females and cooler temperatures producing males. The common finding of highly skewed female-biased hatchling sex ratios in sea turtle populations could have serious repercussions for the long-term survival of these species and prompted us to examine the thermal profile of a relatively pristine hawksbill nesting beach in Guadeloupe, French West Indies. Data loggers placed at nest depth revealed that temperatures in the forested areas were significantly cooler than temperatures in the more open, deforested areas. Using these temperatures as a predictor of sex ratio, we were able to assess the relative contributions of the different beach zones to the primary sex ratio: significantly more males were likely to be produced in the forested areas. Coastal forests are therefore important male-producing areas for the hawksbill sea turtle, and this has urgent conservation implications. On Guadeloupe, as on many Caribbean islands, deforestation rates are high and show few signs of slowing, as there is continual pressure to develop beachfront areas. The destruction of coastal forest could have serious consequences both in terms of local nesting behavior and of regional demography through the effects on population sex ratios. Human alterations to nesting habitat in other reptile taxa have been shown to modify the thermal properties of nest sites in ways that can disrupt their ecology by allowing parasite transmission, increasing vulnerability to climate change, or rendering existing habitat unsuitable.  相似文献   

13.
Phosphate chemistry at the sediment-water interface could play a key role in the periodic eutrophication events characteristic of a N-W Adriatic coastal area. In order to establish a general knowledge of phosphate speciation in the sediments, we chose the sequential extraction procedure which gave most reproducible results as an analytical method. Comparison of data from the sequential procedure with that obtained with different methods using a single extraction step, indicates some inconsistencies due to the effects of chemical reagents on the sedimentary mineral composition.  相似文献   

14.
Coastal dunes are an essential part of beach-dune systems. Dunes systems have their own intrinsic values and provide a range of goods and services, including the protection of tangible goods located on the shoreline affected by waves, storms, and sea erosion. Dunes also act as repositories of biodiversity that have their exclusive habitat in dune communities, and the aesthetic value of dune landscapes derived from unique plant communities and landforms is also of great importance. Nevertheless, dune systems on developed coasts suffered a drastic decline in geomorphological and ecological quality throughout the last century. Catalonia (Spain, NW Mediterranean Sea) is no exception, and the coastal dune systems which were present in the early 20th century have now disappeared due to urbanization. The regeneration of dune systems is of crucial importance in this context. The aim of this study is to assess the current status of dune systems in Catalonia in order to determine their future prospects based on beach characteristics, those beaches likely to host dunes being determined according to their width and sediment type. The results of our study show that nowadays most dune systems in Catalonia are not developed due to human pressure on the beaches. Only those beaches located in the natural protected areas in Roses Bay, Baix Ter Bay, the Llobregat Delta, and especially the Ebro Delta, have the right characteristics to host well-developed dune systems. That said, 30% of sandy beaches in Catalonia have a width of over 35 metres; wide enough to host well-developed dune systems if appropriate integrated beach management is applied. The methodology used in this research also provide a tool to assess which are the beaches that can host dunes on other developed shores in the Mediterranean area.  相似文献   

15.
In many coastal resort areas of the world, it is likely that optimal climatic conditions for beach use might occur outside the peak of the tourist season. Investigation of this issue together with associated publicity might help to spread the tourism load and hence reduce undesirable social and environmental effects of extreme seasonality in tourist demand. For this to take place, better knowledge of beach user preferences in terms of climate and bathing water temperature is required. Questionnaire surveys were carried out in Wales, Malta and Turkey to establish the preferences of north European beach users for thermal sensation and bathing water temperature, plus priority levels for other climatic attributes. A user-based beach climate index based on these preferences and priorities was formulated. Linkage was made between the user-generated ratings for various climatic conditions and published climate data to evaluate most major Euro-Mediterranean/Black Sea and a range of other beach tourism areas on a month-by-month basis. Results showed excessively hot thermal sensation in many southern and eastern Mediterranean coastal destinations during July and August, the present peak of the beach tourism season. Highest preference was given to water temperatures rather lower than those found in these areas during late summer. Many long haul coastal destinations popular with north European visitors had similar unpleasant thermal sensations over several months. Uncertainties and deficiencies still exist with the system, but from the point of view of north European beach users the final scores generated in this study may be regarded as good approximations of the quality of resort area climates for sedentary beach use.  相似文献   

16.
Wave hydrodynamics around a multi-functional artificial reef at Leirosa   总被引:1,自引:0,他引:1  
This paper describes an application of the Boussinesq-type COULWAVE model to study the wave hydrodynamics in the vicinity of a multi-functional artificial reef (MFAR). This reef is under investigation and consists of a supplementary protection solution for the Leirosa sand dune system located at South of Figueira da Foz, on the Portuguese West coast. Such installation near the coastline is expected to contribute to enhance the surfing conditions in the area, protect the sand dune system in the surroundings of Leirosa beach, and increase its environmental value. Numerical calculations with the COULWAVE model were performed for four test cases, considering two reef geometries (differing in the reef angle) and two incident wave conditions (storm condition and a common wave condition). Comparisons between the results obtained, in terms of wave heights and breaking line positions allow us to assess the influence of the reef on the hydrodynamics near the beach and around the reef. Moreover, the reef performance was analysed in terms of surfability and coastal protection. The surfability parameters (breaker height, Iribarren number and peel angle) were calculated for each test case using the numerical wave heights, wave directions and wave breaking positions. Comparisons of parameters allow characterizing the most appropriate configuration of the reef to improve the surfing conditions in the study area. A methodology based on numerical free surface elevations and horizontal velocity components was developed to calculate wave directions, since this is not a direct output of the COULWAVE model. Concerning coastal protection, analyses of the mean currents around the reef were used together with observations of the velocity cells near the shoreline as an indication of the sediment transport.  相似文献   

17.
Beach conservation and management on the high-value French Riviera in southeastern France have had mixed fortunes in shoreline economic development strategies over the past half century. Prior to 1965, socio-economic growth related to immigration and tourism resulted in considerable pressure on the coastal zone, leading in particular to beach erosion and degradation of beach environmental quality. Between 1965 and 1980, over 20% of the 132 km-long French Riviera was permanently altered through the implantation of yachting harbours and reclamation fill structures, while beach-based recreation had a rather low ranking as a development choice, except in the two major resorts of Cannes and Nice which exhibit a densely urbanized seafront. On this preponderantly bold rocky coast, the mediocre recreational value inherited by many of the beaches from the regional geologic setting, and from development pressures and earlier errors in coastal management, left them vulnerable to appropriation and so-called ‘valorization’ by yachting harbour and estate developers. Over the last decade, artificial shoreline development has virtually ceased, in response to several more or less interrelated factors. These include relative stagnation of socio-economic growth, increasing development and maintenance costs of yachting harbours, saturation of the yachting harbour market as a result of the burgeoning of new, often cheaper, resorts and of reconversion of commercial and shipbuilding ports to leisure ports in the Mediterranean, more stringent legislation, since 1986, on the implantation of residential and major engineering structures on the coastline, pressure for conservation of the cultural and environmental heritage, and greater demand for beach recreational space. This situation has forced a diversification of shore-based activities, as it has been realised that better managed beaches may balance economic aspirations while contributing to enhanced environmental quality and sensible shoreline conservation. This change in strategy has entailed considerable efforts and money on the improvement of coastal water quality, the provision of amenities for beach-goers, and especially the nourishment of eroding beaches and the creation of several artificial beaches. The extent to which beaches will continue to play a role in the sustainable development of French Riviera resorts will depend largely on the capacity of local authorities to maintain environmental quality in the face of inherited and persistent handicaps such as beach erosion.  相似文献   

18.
The article presents the main ancient marine sites of the Holy Land, points the endangered sites and the needed preservation activities. The ancient cultural heritage existing on the Mediterranean shores reflect important events in the history of humanity. It represents numerous important cultures, religions and traditions. This coastal and underwater heritage is rapidly eroded due to sea level rise, global changes and rapid coastal development. Actions taken by the state of Israel to rescue, protect and preserve the marine cultural heritage include: underwater rescue surveys, coastal erosion monitoring, risk assessment surveys and pilot projects for protecting and preserving the sea front of the antique sites at Akko, Apollonia and Ashkelon. Israel proposes that the Mediterranean and European countries will establish a collaborative project aimed at mapping the cultural recourses and establishing master plans for the protection and preservation of the marine and coastal cultural heritage of the Mediterranean.  相似文献   

19.
Beach conservation and management on the high-value French Riviera in southeastern France have had mixed fortunes in shoreline economic development strategies over the past half century. Prior to 1965, socio-economic growth related to immigration and tourism resulted in considerable pressure on the coastal zone, leading in particular to beach erosion and degradation of beach environmental quality. Between 1965 and 1980, over 20% of the 132 km-long French Riviera was permanently altered through the implantation of yachting harbours and reclamation fill structures, while beach-based recreation had a rather low ranking as a development choice, except in the two major resorts of Cannes and Nice which exhibit a densely urbanized seafront. On this preponderantly boldrocky coast, the mediocre recreational value inherited by many of the beaches from the regional geologic setting, and from development pressures and earlier errors in coastal management, left them vulnerable to appropriation and so-called ‘valorization’ by yachting harbour and estate developers. Over the last decade, artificial shoreline development has virtually ceased, in response to several more or less interrelated factors. These include relative stagnation of socio-economic growth, increasing development and maintenance costs of yachting harbours, saturation of the yachting harbour market as a result of the burgeoning of new, often cheaper, resorts and of reconversion of commercial and shipbuilding ports to leisure ports in the Mediterranean, more stringent legislation, since 1986, on the implantation of residential and major engineering structures on the coastline, pressure for conservation of the cultural and environmental heritage, and greater demand for beach recreational space. This situation has forced a diversification of shore-based activities, as it has been realised that better managed beaches may balance economic aspirations while contributing to enhanced environmental quality and sensible shoreline conservation. This change in strategy has entailed considerable efforts and money on the improvement of coastal water quality, the provision of amenities for beach-goers, and especially the nourishment of eroding beaches and the creation of several artificial beaches. The extent to which beaches will continue to play a role in the sustainable development of French Riviera resorts will depend largely on the capacity of local authorities to maintain environmental quality in the face of inherited and persistent handicaps such as beach erosion.  相似文献   

20.
A comparison of current techniques for measuring elevations in the beach and near-shore zones is presented. Techniques considered include traditional methods such as ground survey along transects and airborne stereophotogrammetry, and also newer methods based on remote sensing such as airborne scanning laser altimetry (LiDAR). The approach taken was to identify a representative group of users of beach elevation data, elicit their requirements regarding these data, then assess how well the different methods met these requirements on both technical and financial grounds. Potential users of beach height measurements include those concerned with coastal defence, coastal environmental management economic exploitation of the intertidal zone, and coastal flood forecasting. Three test areas in the UK were identified covering a range of such users and also different beach types. A total of 17 basic user requirements were elicited. For each requirement each method was scored according to the degree to which it could meet the requirement. Total scores were calculated and each method ranked. This was undertaken for all the requirements together, for a subset relating to survey of narrow beaches, and for a subset relating to survey of wide beaches. Approximate costs were also established for the top six methods. Airborne stereophotogrammetry proved to be the best method technically, but was also the most expensive. Ground survey provides very good technical performance on narrower beaches at moderate cost. Airborne LiDAR can achieve good technical performance on both narrow and wide beaches at lower cost than ground survey. The satellite-based waterline method was also inexpensive and gave good results on wide beaches. An overall conclusion is that, while the traditional methods of ground survey and airborne stereophotogrammetry remain the best for engineering-related surveys requiring high levels of accuracy, airborne LiDAR in particular looks set to have a significant impact on beach survey for applications for which a vertical accuracy of 20 cm is acceptable, provided that its technology evolves satisfactorily.  相似文献   

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