Shoreline Damage Research Articles

Ecological risk assessment under the PSR framework and its application to shallow urban lakes.

Shallow urban lakes are naturally vulnerable to ecosystem degradation. Rapid urbanization in recent decades has led to a variety of aquatic problems such as eutrophication, algal blooms, and biodiversity loss, increasing the risk to lake-wide ecological sustainability. Instead of a simple binary assessment of ecological risk, holistic evaluation frameworks that consider multiple stressors and receptors can provide a more comprehensive assessment of overall ecological risk. In this study, we analyzed a combined dataset of government statistics, remote sensing images, and 1year of field measurements to develop an index system for urban lake ecological risk assessment based on the pressure-state-response (PSR) framework. We used the developed ecological safety index (ESI) system to evaluate the ecological risk for three urban lakes in Jiangsu Province, China: Lake Yangcheng-LYC, Lake Changdang-LCD, and Lake Tashan-LTS. LYC and LTS were classified as "mostly safe" and "generally recognized as safe," respectively, while LCD was assessed as having "potential ecological risk." Our data suggest that socioeconomic pressure and aquatic health are the two main factors affecting the ecological risk in both LYC and LCD. The ecological risk of LTS could be improved more effectively if regional management plans are well implemented. Our study highlights the pressure of external wastewater loading, low forest-grassland coverage, and lake shoreline damage on the three selected urban lakes. The findings of this study can inform watershed management for lake ecosystem restoration and environmental sustainability.

Beach rebuilding period buffers Indiana beach erosion in Lake Michigan

Recent high-water levels in the Laurentian Great Lakes caused widespread shoreline damage to beaches, homes, and coastal infrastructure. To quantify these shoreline changes and place them in historical context, shoreline imagery was analyzed to determine the magnitude, rates, and spatial variability of shoreline changes along the Indiana shoreline of Lake Michigan. The analysis shows that over the recent period of water level increase from 2013 to 2020, during which the water level rose nearly 2 m, the median shoreline recession along the Indiana coastline was 58 m and the median recession slope was 35:1 (shoreline recession : water level change). This magnitude of shoreline change is comparable to that experienced in other water level increase periods, 1965–1973 and 1990–1998. This recent shoreline recession was highly variable spatially, but not strongly correlated with shoreline type or position relative to littoral barriers. In spite of the widespread recent shoreline changes, the 2020 shoreline was generally more lakeward than previous high-water shorelines examined, with the exception of historical erosion zones downdrift of littoral barriers. Analysis of water level records and available wave hindcasts for the coastline suggest that while large, the erosion associated with the recent water level increase was tempered by a prolonged beach rebuilding period of low water levels and waves that resulted in an accreted shoreline that largely buffered the erosion associated with the water level increase. These results suggest that recent Indiana erosion could have been substantially worse had it not been preceded by the beach rebuilding period.

How monster storms shape fringing reefs: Observations from the 2020 Middle East Cyclone

AbstractIn March 2020, an unusually intense storm system struck the Gulf of Aqaba‐Eilat, resulting in severe shoreline damage. This brief account examines post‐storm observations of inconsistent damage patterns and structural changes along a specific coastal stretch located at the south beach of Eilat. Certain sections of the coastline experienced direct impact from extreme waves on the south‐southeast‐facing shallow reef, resulting in areas where rocks were completely stripped of corals due to sediment backwash. Conversely, areas characterized by ridges and deep troughs saw the loss of branching corals and some massive colonies, while many small corals survived. A neighboring area with a well‐developed fringing reef suffered lesser damage. Between the severely affected shallow reef and the robust fringing reef lies an unconsolidated slope that migrated eastward by at least 2 m following the storm, incorporating numerous coral colonies dislodged by the event. We propose that this slope advances with each major storm occurrence, influencing the characteristics of nearby shores and coral reefs. This case demonstrates how storm events, in conjunction with geomorphology, have a cumulative and significant impact not only on the structure of coral communities but also on the fundamental shape of coral reefs themselves. As climate change amplifies the range, intensity, and frequency of storms, comprehending these processes becomes increasingly crucial.

Dampak Gelombang Kapal Cepat Pada Wilayah Pesisir Pantai Yang Mengakibatkan Abrasi

Introduction: Seacoast areas and small islands have strategic meaning in building the nation and prospering its people. This is because of the wealth of natural resources contained in this region, both biological and non-biological. However, this wealth of natural resources has not been utilized optimally, which is partly due to sectoral egos between government agencies.Purposes of the Research: To determine the impact of abrasion from the activities of fast boats with great power that cause large waves and result in an abrasion on the coast.Methods of the Research: The method used in this study is normative-juridical, which focuses on the main law by examining theories, concepts, legal principles, and laws and regulations related to this research.Results of the Research: Abrasion is the process of releasing the energy behind the waves towards the land, hitting the coastal areas, then washing away "soil debris" along the coastal slopes, and finally being deposited in the sea. The greater the wave strength, the more abrasion occurs and the more "soil debris" is washed away. The process of eroding the beach caused by the destructive power of sea waves and ocean currents is known as abrasion. Beach erosion is another term for abrasion. Shoreline damage due to abrasion is influenced by natural phenomena and human actions. Human actions that encourage abrasion include taking stones or sand from the coast or rivers as building materials. In addition, the felling of trees in coastal forests or mangrove forests spurs faster coastal abrasion. However, the process of erosion due to the waves of fast boats is also very much felt in coastal communities.

Resident Perceptions and Parcel-Level Performance Outcomes of Mangroves, Beaches, and Hardened Shorelines After Hurricane Irma in the Lower Florida Keys

Hurricanes have large and lasting effects along coastlines, representing one of the deadliest and costliest natural hazards. Among the rapidly growing literature on the impacts of hurricanes, an increasing topic of interest is the potential role of mangroves, and other coastal habitats, as nature-based strategies (NBS) for coastal defense. In addition to coastal protection, NBS have been shown to provide many ecological, economic, and social co-benefits. However, few studies have assessed coastal resident perceptions or residential-scale performance of NBS, particularly in the wake of major hurricanes. Through a survey of 288 residents of the Lower Florida Keys 1 year after Hurricane Irma, this paper describes hurricane impacts on mangroves, beaches, and hardened shorelines. Specifically, we measured perceptions of shoreline damage and shoreline effectiveness for coastal protection at the community- and parcel-levels. At the parcel scale, we also measured performance outcomes through the cost to repair or replace residential shorelines. At both community- and parcel-levels, beaches were perceived as the most damaged shoreline type, followed by mangroves, and then hardened shorelines as the least damaged. Specifically at the parcel-level, repair actions were not taken by many residents with a hardened shoreline (43.2%) due to their shoreline receiving no damage. However, when repair actions were taken, the average cost to repair or replace parcel-level mangroves ($64.33 (USD) ± SE 58.08 per meter) was less than hardened shorelines ($105.14 (USD) ± SE 38.57 per meter). Additionally, 44% of residents reported that no repair or recovery actions were needed after the storm for damaged mangroves, whereas when hardened structures were damaged, many required at least minor repairs (29.5%). Mangroves were also perceived as the most effective shoreline for storm protection (54% very to extremely effective) at the community-level. Our findings indicate local community-level awareness of the storm protective properties mangroves provide but also display a disconnect between perceptions and performance outcomes at parcel scales. Although mangroves cost less to repair and are perceived as the most effective at storm protection, the majority of Florida Keys residents own hardened shorelines. Considering the diverse co-benefits mangroves provide and the local support mangroves have, their conservation and restoration could be well-supported for coastal adaptation.

An ASBPA White Paper: Human and ecosystem health in coastal systems

U.S. coastal economies and communities are facing an unprec¬edented and growing number of impacts to coastal ecosystems including beach and fishery closures, harmful algal blooms, loss of critical habitat, as well as shoreline damage. This paper synthesizes our present understanding of the dynamics of human and ecosystem health in coastal systems with a focus on the need to better understand nearshore physical process interactions with coastal pollutants and ecosystems (e.g. fate and transport, circulation, depositional environment, climate change). It is organized around two major topical areas and six subtopic areas: 1) Identifying and mitigating coastal pollutants, including fecal pollution, nutrients and harmful algal blooms, and microplastics; and 2) Resilient coastal ecosystems, which focuses on coastal fisheries, shellfish and natural and nature-based features (NNBF). Societal needs and the tools and tech¬nologies needed to address them are discussed for each subtopic. Recommendations for scientific research, observations, com¬munity engagement, and policies aim to help prioritize future research and investments. A better understanding of coastal physical processes and interactions with coastal pollutants and resilient ecosystems (e.g. fate and transport, circulation, depositional environment, climate change) is a critical need. Other research recommendations include the need to quantify potential threats to human and ecosystem health through ac¬curate risk assessments and to quantify the resulting hazard risk reduction of natural and nature-based features; improve pollut¬ant and ecosystem impacts forecasting by integrating frequent and new data points into existing and novel models; collect environmental data to calibrate and validate models to predict future impacts on coastal ecosystems and their evolution due to anthropogenic stressors (land-based pollution, overfishing, coastal development), climate change, and sea level rise; and develop lower cost and rapid response tools to help coastal managers better respond to pollutant and ecosystem threats.

Rapid impact assessment of extremely severe cyclonic storm Fani on morpho-dynamics & ecology of Chilika Lake, Odisha, India

This article evaluates the impacts of ‘Fani’, a category four cyclone on the shoreline and ecology of the largest brackish water lagoon of Asia, Chilika, on the East Coast of India. The cyclone forced open two New Tidal Inlets (NTI) along the northern shore of the lagoon’s outer channel leading to erosion of the embankments and spits. The average rate of change due to cyclonic storm ‘Fani’ was – 6.12 m while 66.03% of the total transects registered symbol of erosion along the shoreline of Chilika lagoon. Post Fani the information made available on its impact on Chilika was minimal which made us to look into published news articles, online news channels,past published scientific literature to corroborate the likely impact of such erosion and new tidal inlets on the lake ecosystem. Experts differed on their opinions on how the plankton, fish, seagrass and critically endangered Irrawaddy Dolphin would respond to the salinity changes in the lake aftermath of the cyclone. Some of the impacts of ‘Fani’ on the lake shoreline and ecosystem were imminent, such as the opening of tidal inlets and spot death of three Irrawaddy dolphins; whereas, long-term impacts such as changes in the biomass and composition of plankton communities, fish and bird population in the lake are primarily unknown and warrants further detailed investigation. Nevertheless, the study asserts that cyclone driven shoreline damage can impact lagoon ecosystem by bringing in a rapid change in the salinity field

Past hurricane damage and flood zone outweigh shoreline hardening for predicting residential-scale impacts of Hurricane Matthew

Hurricanes and tropical storms are among the most frequent and costly natural disasters in the United States, and their impacts are expected to intensify in the future. Understanding the best predictors of hurricane damage in coastal areas is of paramount importance for reducing recovery costs and protecting coastal infrastructure and human lives. This project used surveys of 295 homeowners in coastal North Carolina to evaluate damage to estuarine shorelines and homes caused by Hurricane Matthew in 2016. Specifically, we were interested in the following questions: 1) did homes with hardened shorelines (e.g. bulkheads and riprap revetments) experience more or less damage than homes with natural shorelines during the storm; and, 2) what were the strongest predictors of hurricane damage to shorelines and homes. Overall, we found that past hurricane damage to shorelines was the strongest predictor of shoreline damage during Hurricane Matthew and that flood zone and past hurricane damage to homes were the strongest predictors of home damage. However, homes with bulkheads also sustained more hurricane damage than homes with natural shorelines, perhaps because homes with bulkheads were on average 2 times closer to the shoreline than homes with natural shorelines. Our results show patterns of repeated shoreline and home damage during hurricanes and indicate that environmental context and vulnerability can outweigh individual residents’ shoreline management decisions.

Hurricane damage along natural and hardened estuarine shorelines: Using homeowner experiences to promote nature-based coastal protection

Growing coastal populations, rising sea levels, and likely increases in the frequency of major storm events will intensify coastal vulnerability in coming decades. Decisions regarding how and when to fortify estuarine shorelines against coastal hazards, such as erosion, flooding, and attendant property damages, rest largely in the hands of waterfront-property owners. Traditionally, hard engineered structures (e.g. bulkheads, revetments, seawalls) have been used to protect coastal properties, based on the assumption that these structures are durable and effective at preventing erosion. This study evaluates the validity of these assumptions by merging results from 689 surveys of waterfront-property owners in NC with empirical shoreline damage data collected along estuarine shorelines after Hurricanes Irene (2011) and Arthur (2014). The data show: 1) homeowners perceive bulkheads to be the most durable and effective at preventing erosion, but also the most costly; 2) compared to residents with revetments and natural shorelines, property owners with bulkheads reported double the price to repair hurricane damage to their property and four times the cost for annual shoreline maintenance; 3) 93% of evident post-hurricane shoreline damage was attributable to bulkheads or bulkhead hybrids and a higher proportion of surveyed homeowners with bulkheads reported having property damage from hurricanes; and, 4) shoreline hardening increased by 3.5% from 2011 to 2016 along 39km of the Outer Banks. These results suggest that bulkheads are not meeting waterfront property-owner expectations despite continued use, and that nature-based coastal protection schemes may be able to more effectively align with homeowner needs.

Analysis of Packery Channel Public Access Boat Ramp Shoreline Failure

The shoreline stabilization adjacent to the public access boat ramp in the Packery Channel basin has been damaged in two separate events. For the shoreline damage at the boat ramp bulkhead, toe scour is the likely mechanism for failure. Typical sources of hydrodynamic forcing that can lead to toe erosion include storm currents, locally generated storm waves, and offshore storm waves propagating into the basin through Packery Channel. Quantitative analysis of storm induced wind generated waves and currents eliminated them as possible causes of the damage. However, photographic and movie evidence indicate the presence of low-frequency low-amplitude waves propagated into the basin and impacted the boat ramp. The Coastal System Model (CMS) was used to simulate a range of these low-frequency low-amplitude waves and the results demonstrated that these waves could produce sufficient flows in the vicinity of the boat ramp shoreline to cause the damage. Subsequent modeling was used to develop design criteria for additional shoreline stabilization.

Rapid changes on the coast of Lake Peipsi and their environmental consequences

Lake Peipsi has a surface area of 3,555 km2 and is the fourth largest inland body of water in Europe and one of the best-stocked for fish. Its complex geological history was controlled by the retreat of the Late Pleistocene ice, and more recently by climatic fluctuations and neotectonic movements. The northern part of the N–S elongated basin is now rising, the central part is stable, and the southern part is sinking, but in the past, the differences in elevations were much greater. These processes are still causing the water to spread from north to south, where flooding of large areas poses many social problems. Because of the considerable water-level fluctuations, exceeding 3 m, both the surface area and the volume of the lake vary greatly. High water levels cause marked shoreline damage and pose a serious threat to the buildings and roads in the immediate vicinity. Extensive changes on the coast are also due to the action of hummocky lake ice.

The Relationship between Great Lakes Water Levels, Wave Energies, and Shoreline Damage

The latter half of the twentieth century can be characterized as a period of rising water levels on the Great Lakes, with record high levels in 1974 and 1986. Concurrent with these periods of high water level are reported periods of high shoreline damage and property loss. Water levels of the Great Lakes are determined by precipitation, evaporation, river outflow, and groundwater inflow, while wave energy is primarily a function of wind speed, duration, and fetch. A comparison between a recently completed long-term (1956–87) wave climate hindcast and historical lake levels for the Great Lakes shows a strong correlation between periods of high wave energy and high lake levels. Statistical comparison of these two time series indicates an approximately constant correlation from +24 months to −6 months, around a zero lag/lead. The causational link between increasing lake levels and more intense wind-generated waves appears to be related to significant changes in the climatology of Great Lake's basin cyclones....

LAKE LEVELS AND SHORE DAMAGES

Extensive shoreline damage was caused by storm action superimposed upon record high water levels during 1972 and 1973. A federal-provincial agreement undertook to survey the nature and extent of the damages and to recommend appropriate management strategies. Data collection included land use, value, ownership, shoreline physical characteristics, damage, and existing protection. Structural damage due to erosion and inundation was estimated at over $28 million, potential damage an additional $19 million. Designated hazard lands amounted to 30% of the shoreline surveyed. Three alternatives considered to reduce further damages were structural protection, water levels regulation, and shoreline management. The first two alternatives were found to be prohibitively expensive.