Coastline Retreat Research Articles

Relation between planimetric and volumetric measurements of permafrost coast erosion: a case study from Herschel Island, western Canadian Arctic

Ice-rich permafrost coasts often undergo rapid erosion, which results in land loss and release of considerable amounts of sediment, organic carbon and nutrients, impacting the near-shore ecosystems. Because of the lack of volumetric erosion data, Arctic coastal erosion studies typically report on planimetric erosion. Our aim is to explore the relationship between planimetric and volumetric coastal erosion measurements and to update the coastal erosion rates on Herschel Island in the Canadian Arctic. We used high-resolution digital elevation models to compute sediment release and compare volumetric data to planimetric estimations of coastline movements digitized from satellite imagery. Our results show that volumetric erosion is locally less variable and likely corresponds better with environmental forcing than planimetric erosion. Average sediment release volumes are in the same range as sediment release volumes calculated from coastline movements combined with cliff height. However, the differences between these estimates are significant for small coastal sections. We attribute the differences between planimetric and volumetric coastal erosion measurements to mass wasting, which is abundant along the coasts of Herschel Island. The average recorded coastline retreat on Herschel Island was 0.68 m a −1 for the period 2000–2011. Erosion rates increased by more than 50% in comparison with the period 1970–2000, which is in accordance with a recently observed increase along the Alaskan Beaufort Sea. The estimated annual sediment release was 28.2 m 3 m −1 with resulting fluxes of 590 kg C m −1 and 104 kg N m −1 . Keywords: Coastal erosion; LiDAR; carbon fluxes; mass wasting; landslides; digital elevation model. (Published: 23 September 2016) To access the supplementary material for this article, please see Supplementary files under Article Tools online. Citation: Polar Research 2016, 35 , 30313, http://dx.doi.org/10.3402/polar.v35.30313

The Impact of an Extreme Storm Event on the Barrier Beach of the Lefkada Lagoon, NE Ionian Sea (Greece)

The present investigation examines the characteristics of a high energy storm event, that took place on November 9-11, 2007 in the NE Ionian Sea (eastern Mediterranean), and its impact upon the barrier beach that separates the Lefkada lagoon from the open Ionian Sea. The storm event was caused by NW winds with speeds exceeding 20 m/s (40 knots), which have an annual frequency of occurrence less than 0.015%. This high energy event produced waves with >5 m significant offshore height and 9.5 s period; these waves developed on 10th November during the rapid rise of barometric pressure (~1.4 hPa/hr), which followed the barometric pressure drop from 1020.5 hPa at 06:00 (UTC) of 9th November to 1001.7 hPa at 06:00 h (UTC) of 10th November. Secondary breaking at the shoreline produced wave heights >1.5 m, associated with a surge of >0.4 m and a run-up capability of >2.4 m. The waves managed to overtop the barrier beach (elevations ~2.5 m), lowering the seaward side of the barrier beach by 10-30 cm and causing a coastline retreat of 0.9 to 2.2 m; these morphological changes correspond volumetrically to a sediment loss of approximately 8 m3/m of coastline length from the sub-aerial part of the beach. During the last three decades a significant change in the frequency of occurrence and direction (from S-SW-W to N-NW-NE) of severe storms with wind speeds exceeding 40 knots has been recorded, affecting the sediment transport pattern and contributing to the erosion of the north beaches of Lefkada.

The effect of coastal defense structures (mounds) on southeast coast of Buenos Aires province, Argentine

The rapid increase of tourism and urbanization in the coastline of Buenos Aires province resulted in the need of infrastructure and services development along the entire coast. However, the lack of environmental criteria of human activities altered the aero and hydrodynamic conditions and is causing important cliffs regression and beach erosion.In this scenario and to minimize such problems, since 1980's, installing coastal defense structures became a very used method. The main types used in the study area are mounds built with blocks of quartzite and set up as longitudinal defenses on the cliff base. It was seen that these structures reduced coastline retreat but caused several environmental alterations changing natural dynamic conditions. These alterations caused serious consequences in coastal configuration, local and regional hydrodynamic, morphometry of beaches, environment and ecology of the coast and obviously, in the human activities and recreation areas.This paper analyses the coastal system evolution after mounds settlement, their functions and consequences to nature (comparing altered environments with those which still preserves natural conditions) and discuses its advantages and disadvantages with the objective of establish precedent for future integrated and conscious coastal management projects.

Composite coastal protection methods used at Cijin Coast, Taiwan

Cijin Coast has suffered from severe beach erosion and a consequent coastline retreat. To analyze the trend of topographic evolution of Cijin Coast, bathymetric data from field investigation were used and both numerical simulation and physical modeling were implemented in the wave basin to obtain the corresponding parameters that replicate similar phenomena. To protect Cijin Coast, composite coastal protection methods, such as submerged detached breakwaters accompanied with artificial nourishments, were proposed. Parameters used in previous studies were employed to test the proposed protection methods, and the results showed that the methods were effective in preventing the consequent retreat of the coastline. Thus, field construction of the proposed methods was initiated and completed in August 2013. Recent aerial photographs showed that the beach erosion was eliminated, proving the validity of the composite methods.

The Quaternary coversands of southwest France

Detailed stratigraphic analysis and numerical dating (OSL, IRSL, ESR, 14C) of Pleistocene coversands in southwest France enable the construction of a renewed chronostratigraphic framework for sand deposition. The chronological data obtained from sandsheet units testify to the development of transgressive dunefields since at least the Middle Pleistocene (MIS 10). Three main phases of accumulation occurred during the Last Glacial. The oldest one (64–42 ka) is associated with wet sandsheet facies, histic horizons and zibar-type dune fields, which reflect deposition in a context strongly influenced by the groundwater table. The Late Pleniglacial (24–14 ka) corresponds to the main phase of coversand extension in a drier context. Silty gley horizons suggest, however, local interruptions of sand drifting during GS 2.1. Lateglacial stabilization of the coversands may not have occurred before GI-1c (Allerød), which was typified by the development of cumulic arenosols. These were covered by parabolic dunes during the Younger Dryas. The variations in extent of the emerged continental shelf during the glacial–interglacial cycles may explain the uneven geographical distribution of sand deposition through time. Because of coastline retreat up to 100 km north of 45°N during the LGM lowstand, the coversands were unable to reach the northern part of the basin. Comparison with other European regions highlights stronger affinities of the French record with Portugal than with the Netherlands and Great Britain, probably because of reduced influence of permafrost.

The influence of wave action on coastal erosion along Monwabisi Beach, Cape Town

The coastline to the east of the Monwabisi Beach tidal pool has been subject to substantial visible coastal erosion. Monwabisi is located near the City of Cape Town and is situated along the northern coastline of False Bay. The erosion that has occurred has raised concern as it is damaging local infrastructure. The coastline retreat to the east of Monwabisi was investigated through analysis of aerial photographs and wave data to establish whether there is a relationship between dynamic wave action that this bay is subjected to, and the observed erosion within the study area. The maximum lateral coastal erosion at the Monwabisi study area from 2003 until 2014 was approximately 30m in a landward direction. Based on the correlation of the results between the rate of coastline retreat and the wave data, the study has concluded that the extreme rates of coastline retreat experienced within the study area at Monwabisi is most likely a direct result of a combination of influences including the number and height of big wave events, waves coming from a more southerly direction, the underlying geological substrate of the study area, and the impact that the local infrastructure has had on the geological substrate. Three time periods of maximum monthly erosion rates occurred from June 2008 to November 2009, March 2010 to March 2011 and April 2011 to June 2012.

Observing Muostakh disappear: permafrost thaw subsidence and erosion of a ground-ice-rich island in response to arctic summer warming and sea ice reduction

Abstract. Observations of coastline retreat using contemporary very high resolution satellite and historical aerial imagery were compared to measurements of open water fraction, summer air temperature, and wind. We analysed seasonal and interannual variations of thawing-induced cliff top retreat (thermo-denudation) and marine abrasion (thermo-abrasion) on Muostakh Island in the southern central Laptev Sea. Geomorphometric analysis revealed that total ground ice content on Muostakh is made up of equal amounts of intrasedimentary and macro ground ice and sums up to 87%, rendering the island particularly susceptible to erosion along the coast, resulting in land loss. Based on topographic reference measurements during field campaigns, we generated digital elevation models using stereophotogrammetry, in order to block-adjust and orthorectify aerial photographs from 1951 and GeoEye, QuickBird, WorldView-1, and WorldView-2 imagery from 2010 to 2013 for change detection. Using sea ice concentration data from the Special Sensor Microwave Imager (SSM/I) and air temperature time series from nearby Tiksi, we calculated the seasonal duration available for thermo-abrasion, expressed as open water days, and for thermo-denudation, based on the number of days with positive mean daily temperatures. Seasonal dynamics of cliff top retreat revealed rapid thermo-denudation rates of −10.2 ± 4.5 m a−1 in mid-summer and thermo-abrasion rates along the coastline of −3.4 ± 2.7 m a−1 on average during the 2010–2013 observation period, currently almost twice as rapid as the mean rate of −1.8 ± 1.3 m a−1 since 1951. Our results showed a close relationship between mean summer air temperature and coastal thermo-erosion rates, in agreement with observations made for various permafrost coastlines different to the East Siberian Ice Complex coasts elsewhere in the Arctic. Seasonality of coastline retreat and interannual variations of environmental factors suggest that an increasing length of thermo-denudation and thermo-abrasion process simultaneity favours greater coastal erosion. Coastal thermo-erosion has reduced the island's area by 0.9 km2 (24%) over the past 62 years but shrank its volume by 28 x 106 m3 (40%), not least because of permafrost thaw subsidence, with the most pronounced with rates of ≥− 11 cm a−1 on yedoma uplands near the island's rapidly eroding northern cape. Recent acceleration in both will halve Muostakh Island's lifetime to less than a century.

Impacts of the Aswan High Dam After 50 Years

Perform an assessment of the environmental and health impacts of the Aswan High Dam (AHD) after nearly 50 years of operation. This paper describes the effect the AHD had on (1) the prevalence and incidence of schistosomiasis in Egypt, (2) sedimentation in the reservoir formed by the AHD (Lake Nasser in Egypt and Lake Nubia in North Sudan), (3) soil water logging and subsequent soil salinization in the Nile Delta (4) coastal retreat along the Egyptian Mediterranean Sea. • Schistosomiasis has decreased in Egypt since the AHD. • Agricultural fields in the Nile Valley and Delta tend to waterlogged and since the water is not flushed out annually, the soils are saltier and so less fertile. However, the AHD affords multi-cropping during the year and Egyptian farmers have adopted better seeds and harvesting methods. Overall, agricultural production in Egypt has increased. • Coastal erosion is severe in some areas, especially at the Rosetta and Damietta promontories. Efforts to stop the overall coastline retreat have been largely unsuccessful. Other areas of the Egyptian Mediterranean coastline are stable or have accreted. • Reservoir-induced seismicity is not an issue. • Deterioration of low-lying ancient Egyptian monuments due to seepage water from irrigation is a problem.

海平面上升对生态系统服务价值的影响及适应措施

PDF HTML阅读 XML下载 导出引用 引用提醒 海平面上升对生态系统服务价值的影响及适应措施 DOI: 10.5846/stxb201408081583 作者: 作者单位: 同济大学建筑与城市规划学院,浙江大学城乡规划设计研究院,中国科学院地理科学与资源研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 美国Florida Sea Grant College Program 2012-2013: A Spatial-Temporal Econometric Model to Estimate Costs and Benefits of Sea-Level Rise Adaptation Strategies资助 Impact of sea level rise on ecosystem services values and adaptation measures Author: Affiliation: College of Architecture and Urban Planning at Tongji University,Urban Planning and Design Institute of Zhejiang University,Institute of Geographic Sciences and Natural Resources Research,CAS Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:海平面上升导致了海岸线后退、沿海侵蚀、风暴潮加强、生物栖息地改变、湿地变迁等,引起了近海域生态系统服务价值的变化。以美国Hillsborough County为研究区域,应用SLAMM模型,模拟了海平面从2010年-2100年上升1m的情景下各类用地面积的变化,利用效益转移法评价了生态系统服务价值的变化。结果表明:①旱地面积减少3037 hm2,湿地面积增加3037 hm2,其中河口水域、滩涂、盐沼、定期洪水沼泽面积大幅度增加;季节性洪水沼泽、潮汐淡水沼泽、河流潮汐、沙滩面积大幅度减少,其它类型湿地受影响较小。②湿地总面积的增加反而导致了生态系统服务价值总量的降低,从2010年的61672万美元降低到2100年的61548万美元,这是由于净水湿地和沙滩大面积损失引起的;其中艺术娱乐、水调节、气候调节、文化精神价值将下降,水供应、栖息地保护、干扰调节和废物处理价值将上升。③防护、适应、后退3种措施分别降低、不影响、提升了生态系统服务价值,应根据其适用范围综合应用以制定应对海平面上升的适应性措施。 Abstract:Sea level rise, one of the most obvious and direct effects of climate change in coastal areas, has become an important and urgent problem. Rising sea level has brought about coastline retreat, coastal erosion, storm surge strengthening, pollutant release, habitat change, and wetlands migration. In addition, it has caused changes in the ecosystem service value of coastal areas. Five processes of coastal ecosystems that may be affected by sea level rise are inundation, erosion, overwash, saturation, and accretion. Wetlands migration is simulated by the Sea Level Affecting Marshes Model and benefit transfer method in Hillsborough County, US, where the sea level is assumed to rise 1 m from 2010 to 2100. According to the calculation results, ecosystem services values for every 10 years are evaluated using the benefit transfer method. The results showed that dry land areas will decrease by 3037 hm2, while wetlands will increase by 3037 hm2 with sea level rise. Areas of estuarine open water, beaches, salt marshes, and regularly flooded marshes will increase by 394.29%, 380.62%, 141.93%, and 121.41%, respectively. The areas of irregularly flooded marshes, tidal fresh marshes, tidal flats, estuarine beaches, and inland shores will decrease by 95.52%, 91.31%, 59.29%, 37.59%, and 21.44%, respectively. Mangroves, inland open waters, swamps, inland fresh marshes, and cypress swamps will be less affected, and will decrease by 6.67%, 4.05%, 2.35%, 0.90%, and 0.10%, respectively. Increasing the total wetland area contributes to reducing the total ecosystem service value due to the large loss of beaches and freshwater wetlands. The values of art, entertainment, water regulation, climate regulation, spirit and culture will decrease, while the values of water supply, habitat protection, disturbance regulation, and waste disposal will increase. Extensive efforts have been devoted to adaptation planning and impact analysis in the face of rising sea levels. Protection, accommodation, and retreat are the main adaptation measures that have been adopted by both state and local governments in the U.S. The analysis results showed that different measures have very different impacts on ecosystem services values. According to the comprehensive application of these measures, planners develop adaptive strategies to cope with rising sea levels. Due to global differences in sea level rise, local topography, seawater erosion degree, and the existing measures, it is difficult to judge whether the impact of sea level rise will have beneficial or detrimental effects on an ecosystem. The case study of Hillsborough County needs more discussion, such as the uncertainty of sea level rise and scenario simulation, the change and valuing of ecosystem service value per unit area for different types of wetlands, and quantitative analysis for impacts of adaptation measures on ecosystem services. In addition, the application of SLAMM in Chinese research should also be considered. 参考文献 相似文献 引证文献

Processes affecting recent and future evolution of the Xylokastro beach zone (Gulf of Corinth, Greece)

<div> <p>The aim of the present study is to investigate the morphodynamic regime of the coastal area of Xylokastro (north coast of Peloponnese), in order to identify and evaluate the processes controlling its formation and evolution. Within this concept, a number of factors have been considered and evaluated; near-shore morphometry and granulometry along shore-normal profiles, the direction and potential volumes of long- and cross-shore sediment transport the decadal and future trends of coastline displacement, the available information for terrestrial sediment influx and the geological processes operating in the broader coastal region of Xylokastro (i.e. subaqueous slides) as well as human interference. On the basis of these results, the formation and evolution of this coastal stretch seems to be governed primarily by the neotectonic activity and relative change of sea level rise, and secondarily by the wave-induced near-shore sediment transport; the role of the latter could be enhanced substantially by human intervention (i.e. construction of marina, seafront walls). Moreover, the expected eustatic increase in sea level by the year 2100, could cause a coastline retreat up to 9 m (SLR=0.38 m) or >19 m (SLR≥1 m).</p> </div> <p> </p>

Coastline retreat via progressive failure of rocky coastal cliffs

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Hydro-morphologic setting of the Samborombón Bay (Argentina) at the end of the 21st century

Abstract. We report on the hydrologic and morphologic setting of the Samborombón Bay, Argentina, which is expected at the end of the 21st century as a consequence of possible scenarios of relative sea level rise (RSLR). The geomorphological analysis of the Samborombón coastland points out only minor changes occurred over the last 40 yr. The modifications are mainly related to the construction of canals to enhance the floodplain drainage. A digital elevation model (DEM) obtained by the Shuttle Radar Topography Mission (SRTM) data archive, ad hoc calibrated/validated for the study area, highlights that about 3000 km2 of coastal plain present a morphological setting at high risk of sea flooding. The analysis of sea level and storm surge events recorded from 1905 to 2010 in Buenos Aires provides the RSLR rate and the return period of extreme floods. In addition, vertical land movements (VLM) measured by the permanent GPS stations of Buenos Aires and La Plata allow for the quantification of the eustatic component of the RSLR and estimating a plausible RSLR rate in the Samborombón Bay. Taking into account possible RSLR scenarios at the end of 2100 as resulting from the statistical analysis of (i) tide gauge and GPS time series and (ii) Intergovernmental Panel on Climate Change (IPCC) predictions, the potential effect of the increased sea level on the Samborombón coastland is simulated. The results show that the combined rise of sea levels, surficial waters and groundwater will lead to a new morpho-hydrologic setting of the coastal area, especially in the low-lying southern sector. Here, a coastline retreat up to 40 km is expected, with temporary submersion up to 4000 km2 during storm surges.

Advanced Land Observing Satellite Phased Array Type L-Band SAR (ALOS PALSAR) to Inform the Conservation of Mangroves: Sundarbans as a Case Study

Mangroves are an important bulkhead against climate change: they afford protection for coastal areas from tidal waves and cyclones, and are among the most carbon-rich forests in the tropics. As such, protection of mangroves is an urgent priority. This work provides some new information on patterns of degradation in the Sundarbans, the largest contiguous mangrove forest in the world, which are home to more than 35 reptile species, 120 commercial fish species, 300 bird species and 32 mammal species. Using radar imagery, we contrast and quantify the recent impacts of cyclone Sidr and anthropogenic degradation on this ecosystem. Our results, inferred from changes in radar backscatter, confirm already reported trends in coastline retreat for this region, with areas losing as much as 200 m of coast per year. They also suggest rapid changes in mangrove dynamics for Bangladesh and India, highlighting an overall decrease in mangrove health in the east side of the Sundarbans, and an overall increase in this parameter for the west side of the Sundarbans. As global environmental change takes its toll in this part of the world, more detailed, regular information on mangroves’ distribution and health is required: our study illustrates how different threats experienced by mangroves can be detected and mapped using radar-based information, to guide management action.

Deltaic coastline retreat due to dam construction: The case of the River Alfios mouth area (Kyparissiakos Gulf, Ionian Sea).

Ghionis, G., Poulos, S.E. and Karditsa, A., 2013. Deltaic coastline retreat due to dam presence: The case of river Alfios mouth area, Kyparissiakos Gulf, Ionian Sea.The deltaic coast of the Alfios river, and especially its mouth area, is undergoing intense erosion over the last decades. This erosion has been caused primarily by the dramatic reduction of the fluvial sediment fluxes, following the construction of two dams (in 1954 and 1967), with the second dam being located at a distance of only 6 km from the river mouth. A further decrease in sediments reaching the sea is induced by the extended (even not continuous) abstraction of sand and gravel from the river's lower route. The resulting sediment deprivation in association with the highly energetic nearshore hydrodynamic regime has caused a retreat of approximately 450 m (from 1945 to 2003) of the mouth area of the R. Alfios. The northern part of the mouth has been affected more heavily by the erosional processes (shoreline retreat between 200 and 445 m) than the southern part (100–240 m retreat), the sediment losses of which are partially replenished by the northward longshore sediment transport of Kyparissiakos Gulf. Shoreline retreat at distances >1 km on either side of the river's mouth is approximately equal, becoming minimal at distances >2 km. The erosional trend of the Alfios River deltaic coast, that has caused significant property losses and damage to coastal infrastructure, is expected to continue and may become more intense as a response to the anticipated future sea level rise.

Erosion or Coastal Variability: An Evaluation of the DSAS and the Change Polygon Methods for the Determination of Erosive Processes on Sandy Beaches

ABSTRACT Albuquerque, M., Espinoza, J., Teixeira, P., de Oliveira, A., Correa, I., Calliari, L., 2013. Erosion or Coastal Variability: an evaluation of the DSAS and the Change Polygon methods for the determination of erosive processes on sandy beaches. There has recently been growing concern about issues related to erosive processes on sandy beaches and climate change in the scientific community. Several methodologies have been proposed in the worldwide literature to quantify coastline retreat on shorelines in an accurate way. It has been questioned whether these methodologies show the erosive process or the shoreline variability in a certain area. From this perspective, this paper aims at characterizing the accuracy of the Digital Shoreline Analysis System (DSAS) and the Change Polygon Method in the studies of regression on shorelines which are prone to erosion. Data collected by a GPS-RTK along Hermenegildo Beach, located in the south of Brazil, and the geo-referencing of satellite images enabled the ou...

Probabilistic modeling of wave climate and predicting dune erosion

Li, F., van Gelder, P.H.A.J.M., Callaghan, D.P., Jongejan, R.B., den Hijer, C. and Ranasinghe, R., 2013. Probabilistic modelling of wave climate and predicting dune erosion considering sea level riseKnowledge about future oceanographic events will assist governments to better manage risk in coastal zones, a crucial task in the light of projected sea level rise, population growth and economic development. In this study, a 31-year data set of deep water wave climate parameters and bathymetry measurements (yearly cross-shore transect surveys) at Noordwijk, the Netherlands, were analyzed (1) to jointly estimate storm events variates of deep water wave conditions, and (2) to probabilistically compute dune erosion volume and the resulting coastal retreat distance with the simulated wave climate and plausible local sea level rise scenarios by 2100. The probabilistic coastline retreat models were applied and adjusted to the study site. Based on the outcomes of this application, a modeling technique can be established to propose a framework for probabilistically describing the coastal risk along the Dutch coast.

Using ArcGIS® Modelbuilder and Aerial Photographs to Measure Coastline Retreat and Advance: North of France

Abstract Chaaban, F.; Darwishe, H.; Battiau-Queney, Y.; Louche, B.; Masson, E.; El Khattabi, J., and Carlier, E., 2012. Using ArcGIS® Modelbuilder and aerial photographs to measure coastline retreat and advance: North of France. Coastal areas are naturally dynamic with changes occurring over periods of time. When the shoreline moves landward, coastal erosion becomes a serious problem, and the rate of change has to be calculated. Coastline retreat is one of the best indicators of coastal erosion. Here, the geographic information systems (GIS) platform (ArcGIS® 9.3.1; Esri software) is used to study the long-term (last 59 years) shoreline change in the area of Hardelot-Plage and Sainte Cecile–Plage (a north–south 14-km-long beach), in northern France. The primary aim of this study was to develop a methodology for calculating shoreline change using ArcGIS Modelbuilder and aerial photographs. Changes in 14 coastlines over the course of 59 years (from 1946 to 2005) were digitized and represented in ArcGIS 9.3....

Morphodynamic development and sediment budget of the Dutch Wadden Sea over the last century

AbstractThe availability of nearly 100 years of bathymetric measurements allows the analysis of the morphodynamic evolution of the Dutch Wadden Sea under rising sea level and increasing human constraint. The historically observed roll-over mechanisms of landward barrier and coastline retreat cannot be sustained naturally due to numerous erosion control measures that have fixed the tidal basin and barrier dimensions. Nevertheless, the large continuous sedimentation in the tidal basins (nearly 600 million m3), the retained inlets and the similar channel-shoal characteristics of the basins during the observation period indicate that the Wadden Sea is resilient to anthropogenic influence, and can import sediment volumes even larger than those needed to compensate the present rate of sea-level rise. The largest sedimentation occurs in the Western Wadden Sea, where the influence of human intervention is dominant. The large infilling rates in closed-off channels, and along the basin shoreline, rather than a gradual increase in channel flat heights, render it likely that this sedimentation is primarily a response to the closure of the Zuiderzee and not an adaptation to sea-level rise. Most of the sediments were supplied by the ebb-tidal deltas. It is, however, unlikely that the sediment volume needed to reach a new equilibrium morphology in the Western Wadden Sea can be delivered by the remaining ebb-tidal deltas alone.

Climate-change impact assessment for inlet-interrupted coastlines

Climate-driven sea-level rise will result in coastline retreat due to landward movement of the coastal profile. However, coastlines adjacent to tidal inlets will also be influenced by changes in the rate of basin infill and variations in rainfall. A model demonstrates that typical practice, which fails to incorporate these processes, is liable to represent only 25–50% of total coastline change.

A new process–response coastal recession model of soft rock cliffs

The development of cliff erosion predictive models is limited by the complex interactions between environmental processes and material properties over a range of temporal and spatial scales. Current models incorporate a stochastic representation of cliff behavior based on assumptions regarding the magnitude and frequency of events in a probabilistic framework. The new model presented here has been developed to incorporate the behavioral and mechanical characteristics of coastal cliffs which are dominated geologically by overconsolidated clays (tills) and an associated protective colluvial wedge. This model is capable of providing precise and stable responses to some of the inherent uncertainties in cliff recession processes including those caused by different failure mechanisms e.g. colluvium generation, groundwater and erosive tidal cycles. Material strength is incorporated using the unconfined compressive strength of the material that composes the cliff. Unlike previous models, a calibration parameter is restricted to account for uncertainties linked to marine processes. The mechanisms of cliffline retreat have been identified as slump and topple landslides. Once cliff material has fallen, colluvium formation at the cliff foot is incorporated into the model using three different procedures according to the geomechanical characteristics of the debris. The model is validated through profile evolution assessment at various locations of coastline retreat on the Holderness Coast, UK. Higher groundwater content also produces an increase in the number and size of the slope failures. The results represent an important step-forward in linking material properties to the processes of cliff recession.