Environmental impacts of shore-parallel breakwaters along Nagahama and Ohgata, District of Joetsu, Japan

A combination of sedimentological analysis of beach sands, field surveys and the assessment of the empirical methods for the breakwater design is used to investigate the impacts of offshore breakwaters on beach morphology along Nagahama and Ohgata. The results indicate that the nearshore sedimentation has been substantially disrupted due to the features formed behind the breakwaters stopping littoral transport, which led to sediment accretion on the updrift side of the breakwaters, and erosion on their downdrift side. Sedimentological analysis of beach sands made it possible to recognize the dominant process at the sections considered. In fact, the occurrence of strong offshore-going currents, the removal of finer mean grain size and the predominance of high-density heavy minerals led us to deduce that the two sections undergo a natural sedimentary imbalance.     

Threats to beach resources and park boundaries caused by shoreline migration in an urban estuarine park

An evaluation of coastal processes, shoreline erosion, and shore management options for Conference House Park, New York, USA, reveals the problems associated with lack of congruence between jurisdictional boundaries and boundaries required for maintenance of beaches and shorefront park land. Rates of shoreline change are high despite low wave energies because bay beaches contain small amounts of sand. The park is so narrow in places that the shoreline will soon move out of park boundaries. This condition will eliminate natural beach resources, restrict access, and create political and administrative problems. Management strategies include revetment construction, beach nourishment, and acquisition of additional land. Obtaining the maximum length of shorefront to create a park may be less cost effective in maintaining natural beach resources than obtaining a shorter frontage and more compact shape that allows for shoreline movement. The problems of managing eroding shorelines in urban estuaries are acute because space is lacking, the cost of land is high, and the critical nature of shoreline erosion is disguised by low wave energies and lack of daily beach change.     

Post-tsunami changes in the littoral environment along the southeast coast of India

The 26th December 2004 Indian Ocean tsunami devastated coastal regions of the Indian subcontinent. Andaman and Nicobar Islands, coastal stretches of Tamil Nadu, Andhra Pradesh and Kerala were the most affected regions of India. Changes in the beach profiles, long shore currents, breaking wave characteristics in the surf zone at selected locations along the Tamil Nadu coast were studied during January, April, October 2005 and January 2006. Long shore sediment transport rates were estimated from the observed parameters. Studies were carried out earlier (1995-1996 and 1998) to understand the coastal environment over a one-year cycle in the study region. The post-tsunami observations were compared with the earlier studies to establish the variations in the littoral environment and to ascertain the normalcy of the littoral environment in the post-tsunami scenario. From the changes in the beach profiles, the shoreline was observed to recede by about 20m and built-up of backshore by about 0.5m at most locations. Observations from the field investigations and comparisons with earlier studies along this stretch of the coastline indicate that the coastline is yet to return completely to normalcy.     

威海典型海滩沉积地貌及质量评价

选择威海双岛湾附近海滩、国际海水浴场海滩、金海滩、青叽岛以西海滩、青叽岛以东海滩、天鹅湖海滩、桑沟湾海滩、楮岛海滩、南海新区海滩和乳山银滩十处代表性岸滩进行了海滩地貌和底质调查,结合沙滩表层样品分析测试数据,对研究区海滩地貌、沉积物粒度分布特征及海滩质量进行了综合评价。结果表明:威海海滩沉积物主要包括砾砂、粗砂、中砂、细砂四种类型,其中中砂分布最广,约占所有点位的35.6%,细砂、粗砂、砾砂分别占34.4%,26.7% 和3.3%。岸滩坡度一般较缓,宽度中等以上,岸滩质量整体较好,部分岸滩受沉积物粒度影响,质量稍差。     

Survival potential of Escherichia coli and Enterococci in subtropical beach sand: implications for water quality managers

Fecal bacteria have traditionally been used as indicator organisms to monitor the quality of recreational waters. Recent work has questioned the robustness of traditional indicators, particularly at seawater bathing beaches. For example, a study of Florida beaches found unexpectedly high abundances of Escherichia coli, fecal coliforms, and enterococci in beach sand. The aim of the present study was to explain these abundances by assessing the survival of E. coli and enterococci in beach sand relative to seawater. We used a combination of quantitative laboratory mesocosm experiments and field observations. Results suggested that E. coli and enterococci exhibited increased survivability and growth in sand relative to seawater. Because fecal bacteria are capable of replicating in sand, at least under controlled laboratory conditions, the results suggest that sand may be an important reservoir of metabolically active fecal organisms. Experiments with "natural" mesocosms (i.e., unsterilized sand or water rich in micropredators and native bacteria) failed to show the same increases in fecal indicators as was found in sterile sand. It is postulated that this was due to predation and competition with indigenous bacteria in these "natural" systems. Nonetheless, high populations of indicators were maintained and recovered from sand over the duration of the experiment as opposed to the die-off noted in water. Indicator bacteria may wash out of sand into shoreline waters during weather and tidal events, thereby decreasing the effectiveness of these indicators as predictors of health risk and complicating the interpretations for water quality managers.     

Assessment of Coastal Vulnerability Through the Use of GIS Tools in South Sicily (Italy)

This study assessed coastal erosion vulnerability along a 90-km sector, which included both erosional and accretionary beaches, and different levels of human occupation. Two aerial photogrammetric flights were used to reconstruct coastal evolution between 1977 and 1999. During this period, extensive accretion was recorded updrift of human structures at harbors and ports, e.g., Scoglitti (105.6 m), Donnalucata (52.8 m), and Pozzallo (94.6 m). Conversely, erosion was recorded in downdrift areas, with maximum values at Modica Stream mouth (63.8 m) and Point Castellazzo (35.2 m). Assessments were subsequently divided into four categories ranging from “high erosion” to “accretion.” Several sources were examined to assess human activities and land use. The latter was mapped and divided into four categories, ranging from “very high” to “no capital” land use. Subsequently, coastal erosion vulnerability was assessed by combining land use categories with recorded coastline behavior. Results showed “very high” to “high” vulnerability along 5.8% and 16.6%, respectively, of the littoral, while 20.9% and 56.7%, respectively, was found to exhibit “medium” and “low/very low” vulnerability. A very good agreement between predicted coastal vulnerability and coastal trend had been observed over recent years. Furthermore, several human structures and activities are located within the “imminent collapse zone (ICZ)” which reached maximum values of 17.5 m at Modica Stream and 13.5 m at Point Braccetto.     

Estuarine Shoreline Changes in Jamaica Bay, New York City: Implications for Management of an Urban National Park

The Jamaica Bay portion of Gateway National Recreation Area, located next to highly urbanized New York City, faces many challenges to preserve and protect its natural, cultural, and recreational resources. To aid in the management of the park resources, detailed estuarine shoreline analyses of Jamaica Bay were undertaken using imagery taken in 1951, 1974, and 2006. A 15-class land use/land cover (LULC) classification scheme was created after doing an initial examination of the types of LULC in the 2006 orthoimagery and then applied in the analyses of the previous years. By quantifying how and where the shoreline has changed over the past 60 years, park managers can better assess the impact of management practices by comparing LULC of the shoreline within the park boundary to the LULC of the shoreline outside the park boundary before and after the park was created in 1972. Despite the heavy development of New York City and the trend for shoreline modification, the overall shoreline of Jamaica Bay has maintained large percentages of undeveloped vegetation and sandy beaches. Much of the LULC change has occurred in the creeks as a result of dredging and shape modification for residential and commercial uses. Park management has been effective in limiting the alteration of undeveloped shoreline although there have been significant changes in the relative percentages of sand and vegetated beaches between 1974 and 2006.     

Sand Fences in the Coastal Zone: Intended and Unintended Effects

Sand-trapping fences modify the character of the coastal landscape and change its spatial structure, image, and meaning. This paper examines the relationship between these changes and fence usage at the municipal level, where most decisions about fence deployment are made. Use of fences in 29 municipalities on the developed coast of New Jersey is examined over a 6-year period. Interviews with municipal officers indicate that wooden slat sand-trapping fences are used primarily to build dunes to provide protection against wave uprush and flooding, but they are also used to control pedestrian traffic and demarcate territory. These uses result in changes in landforms and habitats. An aerial video inventory of fences taken in 2002 indicates that 82% of the shoreline had fences and 72% had dunes. Single and double straight fence rows are the most commonly used. Fences are often built to accomplish a specific primary purpose, but they can cause many different and often unanticipated changes to the landscape. The effects of a sand fence change through time as the initial structure traps sand, creates a dune that is colonized by vegetation, and becomes integrated into the environment by increasing topographic variability and aesthetic and habitat value. Sand fences can be made more compatible with natural processes by not placing them in locations where sources of wind blown sand are restricted or in unnatural shore perpendicular orientations. Symbolic fences are less expensive, are easy to replace when damaged, are less visually intrusive, and can be used for controlling pedestrian access.     

Drivers of Coastal Shoreline Change: Case Study of Hon Dat Coast,Kien Giang,Vietnam

Coastal shorelines are naturally dynamic, shifting in response to coastal geomorphological processes. Globally, land use change associated with coastal urban development and growing human population pressures is accelerating coastal shoreline change. In southern Vietnam, coastal erosion currently is posing considerable risks to shoreline land use and coastal inhabitants. The aim of this paper is to quantify historical shoreline changes along the Hon Dat coast between 1995 and 2009, and to document the relationships between coastal mangrove composition, width and density, and rates of shoreline change. The generalized linear mixed-effects models were used to quantify the major biophysical and land-use factors influencing shoreline change rates. Most significant drivers of the rates of change are cutting of mangroves, the dominant mangrove genus, changes in adjacent shoreline land use, changes of shoreline land cover, and width of fringing mangroves. We suggest that a possible and inexpensive strategy for robust mangrove shoreline defense is direct mangrove planting to promote mangrove density with the presence of breakwater structures. In the shorter term, construction of coastal barriers such as fence-structured melaleuca poles in combination with mangrove restoration schemes could help retain coastal sediments and increase the elevation of the accretion zone, thereby helping to stabilize eroding fringe shorelines. It also is recommended that implementation of a system of payments for mangrove ecosystem services and the stronger regulation of mangrove cutting and unsustainable land-use change to strengthen the effectiveness of mangrove conservation programs and coastal land-use management.     

Proposal for an Integral Quality Index for Urban and Urbanized Beaches

A composite index, based on function analysis and including thirteen sub-indices, was developed to assess the overall quality of urban and urbanized beaches in the Mediterranean area. The aggregation of components and sub-indices was based on two questionnaires completed by beach users and experts. Applying the new Beach Quality Index (BQI) demonstrated that the quality of beaches could be improved. In general, the strongest aspects of the beaches assessed were those related to short-term user demand, and the weakest were those related to the consequences of human pressure on the area, in particular, erosion problems. The composite index is intended to be used together with Environmental Management Beach Systems (EMBs) as a hierarchical management scorecard and in monitoring programs. This new tool could also make planning more proactive by synthesizing the state of the most important beach processes.     

Use and Occupation of Olinda Littoral (NE,Brazil): Guidelines for an Integrated Coastal Management

Located on the northeast Brazilian coast, Olinda is one of UNESCO’s World Heritage Sites, which is economically dependent on tourism, commerce, industry, and the informal economy. Despite its environmental and socioeconomic importance, the city of Olinda (understanding the coast as part of it) has suffered several environmental and human disturbances over the last decades. This work describes the environmental and social status of Olinda’s beaches and makes recommendations concerning the development of an Integrated Coastal Management Plan for this coastal zone of the Brazilian littoral. The methodology adopted in this study is based on field campaigns (social, physical, chemical, and biological data collection), local observations, and the collection of sea contention building project data from city hall. The results showed that along the seven studied beaches, the main problems were related to the: (i) building of coastal protections, (ii) inefficient sewage disposal systems, (iii) inefficient urban management, and (iv) natural events (equinoctial spring tides and precipitation/evaporation rates). Casa Caiada beach showed the best hydrologic conditions as a consequence of its morphology and it presents facilities that attract housing and recreation investments (by private and public sectors) valuing and improving local use conditions. The obtained data showed that the studied beaches need an urgent action plan to minimize the environmental degradation of Olinda’s littoral and to promote sustainable development of the local coastal environments.     

Microbiological Monitoring of Marine Recreational Waters in Southern California

An inventory was conducted to assess the number, type, spatial distribution, and costs of microbiological monitoring programs in southern California marine waters from Point Conception to the US/Mexico International Border. The location of each sampling site was determined using global positioning system (GPS), and estimates of geographic coverage were determined using geographic information system (GIS) techniques. Twenty-one programs conducted 87,007 tests annually at 576 sites in the study area. The largest number of sites was sampled in Orange County, whereas the largest number of analyses was performed in Los Angeles County because monitoring programs in this area focused on daily monitoring. Fifteen of the 21 programs were managed by National Pollutant Discharge Elimination System (NPDES) permitted sewage effluent dischargers who sampled both offshore and shoreline waters and typically tested for three indicator bacteria (total coliform, fecal coliform, and enterococcus). Their combined efforts comprised 82% of all of the microbiological indicator analyses conducted on an annual basis. Five of the remaining monitoring organizations were public health agencies, which typically focus their efforts on testing only total coliforms. Laboratory methodology also varied considerably, with NPDES permittees predominantly utilizing membrane filtration while public health agencies generally used multiple tube fermentation or premanufactured test kits. Nearly three quarters of all the effort expended in southern California occurred along the shoreline as opposed to offshore locations. Two thirds of this shoreline effort was focused on high-use sandy beaches and in proximity to perennial freshwater outlets (storm drains and creeks). Most sampling occurred at a set of fixed sites that were revisited frequently, but only represented about 7% of the total shoreline. We estimated that roughly $3 million is spent annually on monitoring bathing water quality in southern California, exceeding that spent in any other part of the country.     

Evaluation of beach quality as perceived by users

Recreational beaches are strategic ecosystems for tourism and should be used in a sustainable manner. We studied three beaches in the municipality of Guaymas (NW Mexico), in order to assess their beach quality and identify key management issues. The evaluation was based on the perceptions of users concerning: (1) the user profile; (2) the recreational habits of users; and (3) the biophysical characteristics, infrastructure, services, and cleanliness of each beach. The results showed that the beaches were of different quality. The key management issues identified were the need to design and apply specific management programs for each beach, specifically in regards to improving infrastructure and services, and obtaining certification as a sustainable beach. The evaluation of the beaches as perceived by users suggests that it would be useful to assess beach quality in order to support management goals and be applicable to other beaches, both nationally and internationally.     

Morphological changes at Vellar estuary, India--impact of the December 2004 tsunami

Coastal subsystems formed by interaction of various processes, impacted by natural hazards like tsunami and storms, pose irreversible morphological changes. Vellar estuary, located on the southeast coast of India, with huge sand dunes (of 3-6m height and spread to 560ha) and barrier islands, has undergone extensive morphological changes due to the giant Indian Ocean tsunami that occurred on 26th December 2004. The damage caused by the tsunami has been quantified using extensive field data collected during pre- and post-tsunami periods through Real Time Kinematic GPS (for mapping coastal features and beach profiles) and Geographic Information System (GIS) couple. The tsunami with a wave height as high as 4m not only inundated the entire coastal land up to a maximum of 2km but also eroded the sand dunes and deposited the eroded material at the inlet, which ultimately formed as a vast tidal flat spread over 31ha. The estuary has suffered immensely due to the tsunami especially in terms of (i) loss of natural protection barriers (sand dunes), which made this coastal area more vulnerable to storm attack, and (ii) shallowness of inlet creating hindrance to navigation of fishing vessels. Based on the observations made at Vellar coast and past recovery experiences of tsunami/hurricanes elsewhere in the world, we contend that the morphological loss might take at least two annual cycles to regain its original form and the rebuilding of sand dunes may even take a decade.     

Impacts of Off-Road Vehicles (ORVs) on Burrow Architecture of Ghost Crabs (Genus Ocypode) on Sandy Beaches

Recreational beach use with off-road vehicles is popular, but potentially harmful from an environmental perspective. Beaches are important habitats to invertebrates such as ghost crabs of the genus Ocyopde, which excavate extensive and elaborate burrows. Ghost crabs are sensitive to human pressures and changes in burrow architecture may thus be a consequence of disturbance by vehicles—the predictive hypothesis of this article. This was tested during the austral spring and summer by comparing 305 burrow casts between beaches open and closed to vehicles in Eastern Australia. Traffic influenced burrow architecture: there were smaller crabs on vehicle-impacted beaches, and after the peak traffic period (Christmas and New Year holidays), these crabs had tunnelled deeper into the sediment on shores rutted by cars. Crabs constructed all types of previously described burrows, but, significantly, smaller crabs from vehicle-impacted beaches simplified their shapes following heavy traffic disturbance from four (I, J, Y, M) to only two types (I, Y). These data support a model of active behavioural responses to disturbance from vehicles, extending the known effects of beach traffic to impacts on behavioural traits of the beach fauna.     

Characteristics of Coastal Dune Topography and Vegetation in Environments Recently Modified Using Beach Fill and Vegetation Plantings,Veneto, Italy

Human actions can contribute to degradation of coastal environments or they can increase the likelihood that these environments will be restored. Beach nourishment provides a basis for restoration, but ways must be found to add habitat improvement to projects designed for shore protection. This study examines how beach nourishment projects can help reinstate dune landscapes in locations where beaches and dunes had been replaced by static shore protection structures. Dune topography and vegetation on three nourished sites on the northern Adriatic Coast of Italy are compared to a reference site to evaluate changes after beach fill was emplaced. Results reveal how nourishment projects used for shore protection can restore the space available for dunes to form, increase the likelihood of sediment transfers inland and increase the diversity of topography and vegetation. Beach raking prevents formation and growth of hummocky, incipient backshore dunes that would otherwise evolve into a naturally functioning foredune. Sand-trapping fences can speed the process of foredune development but can be counterproductive if they interfere with transport to beach grass (Ammophila littoralis) planted landward of them. Shore protection structures can provide stability and more time for dune evolution on eroding shores, resulting in greater species richness and longer retention of ecological niches. These structures need not be required if re-nourishment occurs frequently enough to provide a beach wide enough to protect against storm wave uprush.     

Interaction and influence of two creeks on Escherichia coli concentrations of nearby beaches: exploration of predictability and mechanisms

The impact of river outfalls on beach water quality depends on numerous interacting factors. The delivery of contaminants by multiple creeks greatly complicates understanding of the source contributions, especially when pollution might originate up- or down-coast of beaches. We studied two beaches along Lake Michigan that are located between two creek outfalls to determine the hydrometeorologic factors influencing near-shore microbiologic water quality and the relative impact of the creeks. The creeks continuously delivered water with high concentrations of Escherichia coli to Lake Michigan, and the direction of transport of these bacteria was affected by current direction. Current direction reversals were associated with elevated E. coli concentrations at Central Avenue beach. Rainfall, barometric pressure, wave height, wave period, and creek specific conductance were significantly related to E. coli concentration at the beaches and were the parameters used in predictive models that best described E. coli variation at the two beaches. Multiple inputs to numerous beaches complicates the analysis and understanding of the relative relationship of sources but affords opportunities for showing how these complex creek inputs might interact to yield collective or individual effects on beach water quality.     

A GIS Approach to Model Sediment Reduction Susceptibility of Mixed Sand and Gravel Beaches

The morphological form of mixed sand and gravel beaches is distinct, and the process/response system and complex dynamics of these beaches are not well understood. Process response models developed for pure sand or gravel beaches cannot be directly applied to these beaches. The Canterbury Bight coastline is apparently abundantly supplied with sediments from large rivers and coastal alluvial cliffs, but a large part of this coastline is experiencing long-term erosion. Sediment budget models provide little evidence to suggest sediments are stored within this system. Current sediment budget models inadequately quantify and account for the processes responsible for the patterns of erosion and accretion of this coastline. We outline a new method to extrapolate from laboratory experiments to the field using a geographical information system approach to model sediment reduction susceptibility for the Canterbury Bight. Sediment samples from ten representative sites were tumbled in a concrete mixer for an equivalent distance of 40 km. From the textural mixture and weight loss over 40 km tumbling, we applied regression techniques to generate a predictive equation for Sediment Reduction Susceptibility (SRS). We used Inverse Distance Weighting (IDW) to extrapolate the results from fifty-five sites with data on textural sediment composition to field locations with no data along the Canterbury Bight, creating a continuous sediment reductions susceptibility surface. Isolines of regular SRS intervals were then derived from the continuous surface to create a contour map of sediment reductions susceptibility for the Canterbury Bight. Results highlighted the variability in SRS along this coastline.     

Predicting flooding probability for beach/dune systems

The determination of the risk from flooding that shorefront communities face is an important component of coastal management that has not been resolved successfully. Wave runup offers one way of quantifying the risk of coastal flooding that results from overtopping by storm waves. The calculation of runup probabilities uses wave frequency analysis and an average beach/dune profile for a given shoreline segment. The amount of risk is determined by using a runup probability curve for specific shoreline locations within the segment. The procedure is demonstrated using the New Jersey shoreline as an example, and results indicate a higher degree of risk in the southern part of the state. Although the procedure is attractive, there is a need for additional field research to test: (1) the accuracy of the calculation procedure; (2) the applicability of a design profile for a shoreline segment; and (3) whether a non-storm beach/dune profile may be used in the calculation. In terms of the broader subject of coastal hazards, these runup calculations need to be integrated with research on beach erosion to provide a comprehensive assessment of the risk at specific locations.     

Impacts of Off-Road Vehicles (ORVs) on Macrobenthic Assemblages on Sandy Beaches

Sandy beaches are the prime sites for human recreation and underpin many coastal economies and developments. In many coastal areas worldwide, beach recreation relies on the use of off-road vehicles (ORVs) driven on the shore. Yet, the use of ORVs is not universally embraced due to social conflicts with other beach user groups and putative environmental consequences of vehicle traffic on sandy shores. Such ecological impacts of ORVs are, however, poorly understood for endobenthic invertebrates of the intertidal zone seawards of the dunes. Consequently, this study quantified the degree to which assemblages of intertidal beach invertebrates are affected by traffic. The study design comprised a series of temporally replicated spatial contrasts between two reference sites (no ORVs) and two beaches with heavy ORV traffic (in excess of 250,000 vehicles per year) located in South-East Queensland, Australia. Macrobenthic assemblages on ORV-impacted beaches had significantly fewer species at substantially reduced densities, resulting in marked shifts in community composition and structure. These shifts were particularly strong on the middle and upper shore where vehicle traffic was concentrated. Strong effects of ORVs were detectable in all seasons, but increased towards the summer months as a result of heavier traffic volumes. This study provides clear evidence that ORVs can have substantial impacts on sandy beach invertebrates that are manifested throughout the whole community. Demonstrating such an ecological impact caused by a single type of human use poses a formidable challenge to management, which needs to develop multi-faceted approaches to balance environmental, social, cultural, and economic arguments in the use of sandy shores, including management of “beach traffic.”