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Incorporating recreational surfing into coastal management practices is required to protect the seabed features and oceanographic processes that create surfing waves. A review of research-based surfing literature is undertaken to provide a summary of information available to assist in coastal management decision making around surfing breaks. The different categories of research-based surfing literature are identified as artificial surfing reef (ASR) design, ASR monitoring, ASR construction, ASR sediment dynamics, biomechanics, coastal management, economics and tourism, industry, numerical and physical modeling, surfers and waves, sociology, and physical processes. The majority of this research has been undertaken in the last decade, making it a relatively young research area. As a background for nonsurfing coastal researchers and managers, the characteristics of surfing waves and surfing breaks are described, referring to relevant literature. Wave height, peel angle, breaking intensity, and section length are identified as essential parameters to describe surfing waves. Existing surfer skill and maneuver categorization schemes are presented to show the relationship between surfers and surfing waves. The geomorphic categories of surfing breaks are identified as headland or point breaks, beach breaks, river or estuary entrance bars, reef breaks, and ledge breaks. The literature discusses the various scale bathymetric components that create these surfing breaks. Examples of modeling offshore wave transformations at Mount Maunganui, New Zealand, as well as the measurement microscale wave transformations at “The Ledge,” Raglan, New Zealand, are presented to demonstrate surfing wave transformations.
County Road 399 along Santa Rosa Island in northwest Florida was largely impassable following Hurricanes Ivan and Dennis, but the damage was highly variable alongshore, ranging from areas with little or no damage to areas where the road was completely breached. Damage was categorized and correspondence analysis was used to examine how the levels of damage were affected by the proximity of the road to the shoreline, the elevation and width of the island, and the offshore bathymetry. Depending on the specific combination of these variables along the island, they can have either a compounding or competing influence on the overwash penetration and the damage to the road. Sections of road with little to no damage were located close to the shoreline and associated with an above-average island elevation (large foredunes or berm). These areas tended to be located in wider sections of the island and equally distributed between areas with a steep and a gentle offshore profile. During Hurricane Ivan, sections of the road that sustained major damage or were completely destroyed tended to be in narrow sections of the island where the offshore profile was steep, while half the level of damage was associated with a more gently sloping bathymetry. In contrast, major damage during Hurricane Dennis occurred in areas where the road was located in the backbarrier, where the prestorm elevation of the island was relatively low, and half the level of damage occurred in narrow sections of the island where the offshore bathymetry was steep. Based on the observed relationships it is concluded that damage to the road is forced by the island geomorphology and that areas where the road received extensive damage will continue to be areas of concern despite changes in road design and placement.
Nutrient dynamics and its influence on the distribution of chlorophyll-a in the upwelling area of the Changjiang (Yangtze) River estuary were investigated in the spring (May) and summer (August) of 2004. In the spring, upwelling was apparent in the region of 122°20′–123°00′ E, 31°00′–32°00′ N and was associated with low temperature (16–21°C), high salinity (24–33 practical salinity units [psu]), and low dissolved oxygen (2.5–6.0 mg L−1) in the upper 10 m of the water column. The spring upwelling increased the mixed-layer phosphate, nitrate, and silicate concentrations to roughly 1, 15, and 15 μmol L−1, respectively, and improved the light transparency in the euphotic zone. This improvement in phytoplankton growing conditions was followed by an increase in chlorophyll-a concentrations. The summer upwelling was weaker and occurred over a smaller geographical area (122°20′–123°00′ E, 31°15′–31°50′ N). Strongly influenced by turbid Changjiang diluted water (CDW), it had little impact on the upper 10 m of the water column but instead increased nutrient concentrations at greater depths. The high concentration of particulates in the CDW reduced light transmission in the upper 10 m and, hence, limited phytoplankton growth throughout the water column. Chlorophyll-a concentrations in the summer upwelling area were roughly an order of magnitude lower than in the spring. Water clarity, as influenced by the CDW, appears to be the principal factor limiting the impact of upwelling on phytoplankton biomass in this area.
In Western Australia, coastal dynamics are influenced by a major ocean boundary current system, the Leeuwin Current, which is characterised by mesoscale features. To fully understand the Leeuwin Current using satellite altimeter measurements, we must have a precise (1–2 cm) and full-spatial-scale (<100 km) geoid model. This paper focuses on a comparison between two mean dynamic ocean topography models derived from independent hydrographic climatologies, and an altimeter-observed mean sea surface referenced to recently released geoid models offshore of Western Australia (20°S to 45°S, 108°E to 130°E). The geoid models used include combined global geopotential models from the GRACE satellite mission and AUSGeoid98. The estimated mean dynamic ocean topography models are compared with independent dynamic ocean topography from CSIRO's Atlas of Regional Seas (CARS) climatology. The results show that the EIGEN_GL04C and GGM02C EGM96 global geopotential models to degree and order 360 give the best comparisons against CARS in the Leeuwin Current region, suggesting that they should be used in the future for computing ocean transport, surface current velocities, and dynamic topography, and be used as a reference field for future computations of regional marine geoid models.
The Dunwich–Walberswick gravel-dominated barrier system is one of many such systems in England and Wales which have been managed over the last 40 years for the purposes of flood risk management and habitat conservation. Since the early 1990s it has become increasing difficult to repair the barrier after storms and to maintain an effective flood defence. The central part of the barrier has progressively lost sediment, leading to increased risk of wave overtopping and breaching. A significant, although not extreme, storm on 31 October–1 November 2006 flattened a 2-km section of the barrier. During the summer of 2007 insufficient sediment returned to the beach and it was not possible to rebuild the bank to its original standard. Further washover and breaching occurred during 2007. Artificial maintenance of the barrier as an effective flood defence is now considered to be unsustainable, especially when the effects of climate change are considered. Consequently there is a need to develop adaptive strategies which take account of the fact that existing habitat of high conservation value will be lost, resulting in a need to create compensatory habitat elsewhere.
The U.S. Geological Survey (USGS) recently completed an analysis of shoreline change and cliff retreat along the California coast. This is the first regional, systematic measurement of coastal change conducted for the West Coast. Long-term (∼120 y) and short-term (∼25 y) shoreline change rates were calculated for more than 750 km of coastline, and 70 year cliff-retreat rates were generated for 350 km of coast.
Results show that 40% of California's beaches were eroding in the long term. This number increased to 66% in the short term, indicating that many beaches have shifted toward a state of chronic erosion. The statewide average net shoreline change rates for the long and short term were 0.2 m/y and −0.2 m/y, respectively. The long-term accretional signal is likely related to large coastal engineering projects in some parts of the state and to large fluxes of sediment from rivers in other areas. The cliff-retreat assessment yielded a statewide average of −0.3 m/y. It was found that Northern California has the highest overall retreat rates, which are influenced by erosion hot spots associated with large coastal landslides and slumps.
The databases established as part of the shoreline change and cliff-retreat analyses were further investigated to examine the dynamics of the beach/cliff system. A correlation analysis identified a strong relationship between the geomorphology of the coast and the behavior of the beach/cliff system. Areas of high-relief coast show negative correlations, indicating that higher rates of cliff retreat correlate with lower rates of shoreline erosion. In contrast, low-to moderate-relief coasts show strong positive correlations, wherein areas of high shoreline change correspond to areas of high cliff retreat.
Although a variety of cross-shore wave transformation models have been developed during recent decades, there is a lack of suitable models that can be applied to soft mud beds offshore. To address this issue, an integrated cross-shore model is introduced. This model combines the effects of wave shoaling, energy dissipation within fluid mud, and wave breaking. The constitutive equations for a viscoelastic model are adopted for the rheological behavior of fluid mud, whereas stationary mud below fluid mud is assumed to be elastic. As part of the integrated model, submodels for mud fluidization and wave transformation are developed for regular waves and then extended to irregular waves. Application of the integrated model at selected sites using available data reveals that it can reasonably predict mud fluidization and associated wave height transformation.
To predict the effects of dredging operations in the Western Scheldt estuary, insight into the morphological behaviour of its channels is needed. The estuary features two large main channels that meander alongside each other and that are linked by smaller connecting channels. These connecting channels originate from water level differences between the two main channels. Three hydrodynamic mechanisms are investigated that are responsible for generating such water level differences: (1) differences in tidal wave propagation along two neighbouring main channels, (2) centrifugal forces, and (3) Coriolis forces.
The magnitude of the three mechanisms is analytically assessed based on channel geometry, which is derived from historical depth charts. The analysis demonstrates a large temporal variability of the water level differences due to tidal wave propagation, mainly as a function of changes in the depth ratio between the two main channels. Conversely, both the centrifugal effect and the Coriolis effect are relatively constant over time. The temporal evolution of the connecting channels can therefore primarily be attributed to the wave propagation mechanism. A correlation analysis reveals a linear relationship between connecting channel dimensions and the net water level differences produced by the three processes.
The relationship suggests that dredging operations may significantly influence the evolution of connecting channels by changing the depth ratio between the two main channels. The proposed future deepening of the navigation channel is therefore expected to induce a decline in the size, or even a total disappearance, of connecting channels in some parts of the estuary.
A detailed study of sediment components and selected metals has been carried out in two mudflat cores collected from the creeks of Kalinadi Estuary, India, in order to assess the variations in distribution of sediment components, metals, and the controlling processes, including early diagenetic movements, if any. Grain size analyses reveal the possibilities of three episodes of deposition in a highly varying depositional environment with overall fining up of the cores. Organic carbon (OC) is comparatively high in muddy Core KM, which was collected from a more sheltered creek with a narrow mouth in the estuarine interior, than sandy Core KH, which was collected from a creek with a wide mouth nearer to the sea. Geochemical data show an upper zone of marked enrichment of all trace metals, including Fe and Mn, in both the cores. The variations in sediment components as well as associated metals between the two cores reveal variations in controlling factors including the morphology setup. The distribution of trace metals in Core KH are controlled by the proportions of finer fraction of sediments, degradation of organic carbon, and redox-sensitive Fe and Mn oxides, while the distribution of trace metals in Core KM are probably controlled by the finer sediments as well as by redox-sensitive Fe and Mn oxides.
The red tide in Hongsha Bay caused by Skeletonema costatum (S. costatum) from April 27 to May 4, 2006, was monitored in this study. The dynamic variety of environmental factors, including chlorophyll a (chl a), temperature, salinity, pH, dissolved oxygen, chemical oxygen demand, nitrate, ammonium, nitrite, phosphate (PO43−), silicate, and iron (Fe), was observed and analyzed during the red tide in Hongsha Bay for the first time. The results indicated that the concentration of dissolved inorganic nitrogen was high (26.34 μmol/L) in Hongsha Bay. Because of the heavy rainfall from April 13 to 15, a large input of nutrients surged into the bay, causing an increase in the concentration of various nutrients, especially PO43−, which showed an obvious increase (from 0.72 to 1.45 μmol/L). The abundant nutrients provided fundamental nutrient supply for the rapid proliferation of S. costatum. Three critical environmental factors, including water temperature, and PO43− and Fe concentration, played an important role in this red tide. Water temperature had a significant positive correlation with chl a. The water temperature shift was one of the critical environmental factors affecting the S. costatum red tide in Hongsha Bay. With the occurrence of the red tide, the concentration of PO43− rapidly decreased. Inorganic PO43− was rapidly depleted at the blooming stage, causing the red tide to gradually dissipate. Phosphate was the limiting factor of S. costatum proliferation in this red tide. Iron was also a factor. Salinity shift had little effect on the growth of S. costatum.
Experiments were conducted in the Large-scale Sediment Transport Facility (LSTF) at the U.S. Army Engineer Research and Development Center to investigate the importance of wave height, period, and breaker type (spilling and plunging breakers) on total rate of longshore sediment transport (LST) and the cross-shore distribution of LST.
Estimates computed by the CERC formula and Kamphius were compared to the accurately measured total LST rates. Several K-values were used with the CERC formula, including the recommended value of 0.39 and calculated values by Kamphuis and Readshaw, Ozhan, Bailard, and Del Valle et al. The recommended K-value and most of the calculated K-values overpredicted the measured total LST rates, but methods that included parameters to indicate breaker type gave good estimates. The Kamphuis and Readshaw equation, in which K is a function of surf similarity parameter, gave consistent estimates with measurements. The Kamphuis equation, which includes wave period and beach slope that in turn influences wave breaking, also compared well with the measurements. Additionally, the CERC formula has been used successfully if K is calibrated, and the formula gave excellent results if K was calibrated with measured data and applied to similar breaker types. The findings indicate that total LST rate is strongly influenced by breaker type.
The cross-shore distribution of LST indicated three distinct zones of transport: the incipient breaker zone, the inner surf zone, and the swash zone. Transport in the incipient breaker zone was influenced by breaker type. Transport in the inner surf zone indicated that wave height was the dominating factor and independent of wave period. Swash zone transport, which accounted for a significant percentage of the total transport, showed a dependence on wave height, period, and beach slope.
Despite their large numbers worldwide, surfers as a coastal interest group have largely been ignored during coastal management decision making. Surfers are, however, increasingly being considered in coastal management decisions as the social, economic, and environmental benefits of high-quality surfing breaks are realized. Examples of surfing breaks that have been improved or compromised by coastal engineering are presented here to demonstrate the fragility of surfing breaks. Integrated coastal zone management techniques are suggested as an approach to sustain recreational amenities associated with surfing breaks. Surfers can benefit from integrated coastal zone management practices that balance the coastal space requirements of various coastal user groups. This paper advocates detailed and standardized assessments of the environmental impacts that coastal activities can have on the quality of surfing waves as part of modern integrated coastal zone management practices. Baseline information must also be collected to develop an understanding of the physical processes around a surfing break. To facilitate baseline studies, and ongoing monitoring of surfing breaks, this paper identifies the types of surfing and oceanographic factors that need to be considered. The need for regional and central governments to strategically protect surfing breaks using legislation, reserves, and coastal management plans is explored. It is recommended that further surfing research investigate ideal coastal management techniques for different resource management frameworks.
A new method of splitting regular or irregular waves into reflected and transmitted waves using a single moving wave gauge was developed. Water surface elevations at several locations and times were measured with one wave gauge, and the incident and reflected wave heights were obtained using the fast Fourier transformation and the least-square method. The accuracy and efficiency of the proposed method were validated using numerical tests for regular and irregular waves. Good agreement was observed between the target and the prediction values.
Reef islands of Palmyra Atoll in the northern Line Islands, equatorial Pacific Ocean, underwent mainly minor natural changes in shape and size between 1874 and 1940. Many major changes occurred between 1940 and 1945 when military construction created a dredged channel into the lagoon, enlarged several islands, joined most islands around the lagoon system into a continuous roadway, constructed a causeway separating two lagoons, and created several new islands. Overall, land area approximately doubled and land volume approximately trebled during this period, and the construction affected water circulation between reef flats and lagoons. Since 1945, the atoll has been largely uninhabited, construction and most maintenance of the newly-created shoreline has ceased, and coastlines of larger islands have simplified by infilling of bays and erosion of promontories, at net rates of up to 1.8 m/y. Narrower land masses have been broken into multiple smaller arcuate islands with intervening shallow channels. Sediment moves mainly westward along ocean coasts, into lagoons on lagoon coasts, and via tidal currents where causeways have been breached. In the east, Barren Island appeared and began growing from natural causes well before military construction. After purchase by The Nature Conservancy, the atoll was designated a U.S. National Wildlife Refuge in 2001. This protection offers the opportunity to observe coastal processes operating in the absence of the efforts to protect infrastructure typically associated with inhabited atolls.
Using mooring hydrodynamic observation, cross-shore profiles, and topographic-map and satellite-image comparisons, this study shows dramatic coastal erosion on the Qinhuangdao coast (northeast Bohai Sea, China) between 1986 and 2000, with an average retreat rate of 3.7 m/y. While the retreat rate during 1996–2003 decreased to 1.5 m/y, serious coastal erosion was found around river mouths, such as the Tang, Dai, Yang, Dapu, and Renzaohe Rivers, as well as Qilihai Lagoon, with the maximum of >7.0 m/y.
Sediment starvation induced by dams mainly caused this fast coastal retreat. Sediment flux of the Luan River, the dominant fluvial sediment source in the study area, declined to only 9.0% of the levels before the impoundment of two large dams in 1979. Sharply reduced sediment supply disrupted the stability of sediment transport as well as the beaches' self-recovery processes after storm surges. Coastal erosion was further intensified by coastal engineering and tourism activities.
Wave run-up along the north shore of Oahu has an annual cycle with a maximum centered on boreal winter. An understanding of the variability of high wave wash is important for coastal planning, transportation, safety, and property protection. Wave run-up increases with increasing surf size and tidal height. This study analyzed hourly historic wave data and predicted tides from 1981 to 2007 to better understand wave run-up potential based on the frequency and duration (in hours) that high surf and tides coincided as categorized by thresholds of surf and tidal height.
The Waimea buoy, located just 5 km offshore, was the primary source for deep-water wave height and period. However, this series only began in 2001. The National Data Buoy Center platform 51001 extends back to 1981. Its location is sufficiently remote from Oahu to warrant a correction in significant wave height. The correction was made based on a regression analysis between daily mean wave heights from these two buoys. From the final, deep-water, nearshore Oahu, hourly series of swell height and period, surf heights were calculated using an empirical transformation scheme.
Thresholds were defined for four surf heights and three tidal elevations. Recurrence was calculated for each of the 12 categories. Duration was computed by summing consecutive hours for each event above each threshold. Historical evidence of sand wash onto select portions of the coastal highway was used to qualitatively rank the 12 categories as marginal, significant, or extreme. One important application of these results would be improvement to surf-related coastal flood forecasts by the National Weather Service in pursuit of protection of life and property. For future design considerations, a joint probability model was constructed to better understand the annual average number of hours exceeding any given paired surf and tidal height.
Low-cost, handheld, L1 (1575.42 MHz) global positioning systems (GPSs) provide scientists with the opportunity to acquire position and velocity estimates at reduced expense (order of [O]$100), size (∼cell phone), weight (O[70 g]), and engineering time. Two different low-cost, handheld GPS units and four different position-correcting configurations are evaluated here to determine their practicality in measuring surf-zone currents. Three of the simpler configurations result in relative position and velocity errors of O(2 m) and O(0.5 m s−1) for stationary tests. Surf-zone position and velocity signal-to-noise spectral ratios for the three configurations suggest that only motions <0.01 Hz can be confidently estimated for these surf-zone systems. For the fourth configuration, a GPS handheld unit that internally records GPS carrier phase is postprocessed using more sophisticated software for position corrections to obtain absolute position and velocity estimates. Simple modifications are required to improve the position accuracy by reducing patch antenna signal multipathing. For this configuration, the absolute position error for dynamic surveys was ∼0.40 m, and the velocity error on land relative to a survey-grade GPS system was 0.01 m s−1. The handheld GPS was attached to a surf-zone drifter and evaluated in the field. The flow field of a rip-current system was obtained with 24 surf-zone drifters. The drifters tracked simultaneous dye releases well, verifying that the observations are valid Lagrangian estimates. Owing to the low cost and small size of the handheld GPS, a large number of drifter systems can be deployed for absolute position tracking and velocity estimates of surf-zone currents.
Studies and evaluations were carried out for the purpose of analyzing satellite measured data, or carrying out preliminary evaluations for the study area, near Port Said. In this study waves were transformed from the offshore area to the nearshore area, and longshore sediment transport quantities and rates were evaluated by applying and adjusting some of the available modern formulae. This was done by calibrating with the available reference data, as given in the literature. Thus, the applicability of such formulae for that area can be checked. Offshore significant wave heights from altimeter measurements, which can be downloaded at www.waveclimate.com, are used in this research for 2003 through 2005. The study domain dimensions are 50 km long offshore and 25 km wide alongshore. Wave nearshore transformation is carried out by using the mathematical Simulating WAves Nearshore model (SWAN) based on seasonal/directional bases. Four seasons are considered, winter, spring, summer, and autumn, representing the whole year.
Three bulk-type modern formulae, Coastal Engineering Research Center, U.S. Army Corps of Engineers (CERC), Kamphuis, and Van Rijn, for longshore transport evaluation are applied in the study area. The reference targets used for comparison are based on the literature. Through calibration with the reference targets and among themselves, the study comes up with some correction factors for both CERC and Van Rijn formulae to give quite realistic evaluations for that area. These extended/corrected formulae can also be applied in places with similar conditions to the Egyptian coast.
The objective of this work is to determine the relative importance of different processes (swash, overwash, aeolian, and lagoon) affecting sediment dynamics in barriers with frequent overwash. Aerial photographs, topographic surveys (with real-time kinematic global positional system), and sample collection were undertaken on Barreta Island (Ria Formosa barrier islands, Portugal). Wave and tidal data were also analysed during a 3-year monitoring period (2001–2004). This 3-year period represents the typical wave conditions of this region. Historical barrier evolution was characterised for the 1947–2001 period. Up until 1996, the supratidal barrier changed from barred sand to fully developed dunes. In 2001, a wide washover plain had developed and an updrift tidal inlet (Ancão Inlet) was migrating toward the study area. Between 2001 and 2004, the study area had three geomorphological sectors. Sector A (westernmost) showed the widest beach berms that developed because of welding of swash bars of Ancão Inlet. Sector B had the widest washover and developed embryonic dunes with well-sorted medium sands. In sector C (easternmost), overwash was more frequent, and induced the deposition of 57 m3/m of sediments (the coarsest of the barrier). Globally, barrier volume variation was mostly due to swash (83%); however, net barrier accretion was 88% induced by overwash. Barrier volume variation was more related to Ancão Inlet evolution than to the seasonality of wave climate. A four-stage conceptual model of barrier evolution under frequent overwash is presented: beach erosion; dune destruction, and formation of washover plain; frequent overwash; and dune development.
Wetlands are ecosystems where a high level of biodiversity is found. Being a suitable medium for the nourishment, reproduction, and accommodation of many species of living creatures, wetlands are museums of natural riches, not only of the country where they are located but also of the whole world.
Kavak Delta, one of the most important wetlands of Turkey, with coastal dunes and halophilic vegetation as well as being on the north–south bird migration route, provides not only opportunities for coastal tourism but also offers substantial potential for ecotourism. During observations, bird species, especially of the orders Anseriformes, Falconiformes, and Charadriiformes, were identified. Some 14 orders, 39 families, and 124 bird species were spotted in the delta. Also, dune and halophilic plants constitute a rich flora in the delta.
In this study, the potential for ecotourism and opportunities for coastal tourism in the area are outlined. Within this context, besides ecotourism activities, such as bird observation, botanic tourism, and angling, the use of beaches for coastal tourism is determined. Various recommendations are made for the optimal use of all tourism opportunities detected in the delta and for enabling sustainable coastal use and management.
Photo-Electronic Erosion Pins (PEEPs) can be used to measure short-term fluctuations in swash zone (foreshore) profiles. Because the sensors depend upon ambient light for the detection of bed elevation change, their signal indicates false changes during swash inundation. A method is presented to mitigate this source of noise and to allow a reconstruction of bed changes at swash frequencies. The protocol is illustrated with a sample data set.
Dauphin Island is a segmented, microtidal barrier island, located in the northern Gulf of Mexico, approximately 8.0 km offshore from southwestern Alabama (United States). It was first mapped by Spanish explorers in 1519 but was not settled until 1699 after being claimed as a French possession. In 1707, the French officially named it Isle Dauphine. Maps of the island from this French colonial period reveal a different morphology than subsequent maps. The first American maps of Dauphin Island and Mobile Bay show two small islands (i.e., Pelican and Sand islands) offshore from the southeastern end of Dauphin Island. Passing storms have moved and reshaped both of these delta margin islands around the south-southwestern periphery of the submerged Mobile Bay ebb-tidal delta. Only in the past 25 years have the two islands combined to slowly move in a northwesterly arc toward Dauphin Island. In early 2008, continued longshore drift and strong tides have combined Pelican-Sand Island and Dauphin Island forming an island similar in morphology to that previously documented by French geographers in 1717.
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