Coastal Morphological Changes Research Articles

Benthos as a key driver of morphological change in coastal regions

Abstract. Benthos has long been recognized as an important factor influencing local sediment stability, deposition, and erosion rates. However, its role in long-term (annual to decadal scale) and large-scale coastal morphological change remains largely speculative. This study aims to derive a quantitative understanding of the importance of benthos in the morphological development of a tidal embayment (Jade Bay) as representative of tidal coastal regions. To achieve this, we first applied a machine-learning-aided species abundance model to derive a complete map of benthos (functional groups, abundance, and biomass) in the study area, based on abundance and biomass measurements. The derived data were used to parameterize the benthos effect on sediment stability, erosion rates and deposition rates, erosion and hydrodynamics in a 3-dimensional hydro-eco-morphodynamic model, which was then applied to Jade Bay to hindcast the morphological and sediment change for 2000–2009. Simulation results indicate significantly improved performance with the benthos effect included. Simulations including benthos show consistency with measurements regarding morphological and sediment changes, while abiotic drivers (tides, storm surges) alone result in a reversed pattern in terms of erosion and deposition contrary to measurement. Based on comparisons among scenarios with various combinations of abiotic and biotic factors, we further investigated the level of complexity of the hydro-eco-morphodynamic models that is needed to capture long-term and large-scale coastal morphological development. The accuracy in the parameterization data was crucial for increasing model complexity. When the parameterization uncertainties were high, the increased model complexity decreased the model performance.

On the use of satellite information to detect coastal change: Demonstration case on the coast of Spain

Recent developments in satellite processing tools allow low-cost, fast and automatic processing of a large amount of information from Earth observation, enhancing the capability of detecting coastal changes from space at different temporal scales. Some works have assessed the quality of these data and applied it to detect coastal evolution locally, most of them focusing on mid-term and long-term changes in the coastline. In this work, we evaluate the capability to monitor changes in coastal morphology at various temporal and spatial scales using 1D (coastlines) and 3D (bathymetry) satellite-derived data obtained from site-specific processing methods. Local characteristics were included in several phases of the development of the satellite products used here: i) geolocated very high resolution images from each pilot site were used in the coregistration process to enhance geolocation accuracy in images from different missions, ii) different spectral indices were tested at each pilot site to obtain more reliable detection of the coastline at all sites and iii) measured topobathymetry data were used to obtain datum-based satellite shorelines and bathymetry. The accuracy and skill of those satellite products were assessed at several pilot sites in Spain. The results indicated high horizontal accuracy (RMSE < pixel size), with errors on the order of half of the pixel size (RMSE = 5.0 m and for Sentinel-2 and 18.8 m for Landsat5). Furthermore, the coastlines used here presented errors comparable to those obtained from the widely used open-source tool CoastSat. Time-series analysis using satellite-derived shorelines showed that coastal change processes can be detected at several temporal and spatial scales, such as short-term erosion and accretion events on a small beach, seasonal beach rotation, and long-term trends at local and regional scales. However, the results from satellite-derived bathymetry indicated that the quantitative assessment of the coastal morphology with 3D products is still limited. Some in situ measurements are necessary to obtain satellite data that represent site-specific conditions. However, the quantity of this auxiliary in situ measurements required to obtain reliable time series of satellite derived shorelines and bathymetry is significantly lower than the quantity required by traditional monitoring methods. The results are discussed, highlighting the gaps that need to be filled in the future so that satellite-derived products can be used in usual coastal change monitoring practices.

Coastal morphological changes due to the Nivar cyclone on the East Coast of India

Coastal morphological changes due to the Nivar cyclone on the East Coast of India

Monitoring of coastal dynamics at Subang Regency using Landsat Collection Data and Cloud Computing Based

This study aims to better understand the coastal dynamics along the 6.89 km of Subang shoreline using Landsat data and GIS methods with cloud computing-based analysis. The data is processed using remote sensing techniques, image classification, and change detection algorithms. Furthermore, this research harnesses cloud computing to efficiently manipulate big data, enabling rapid and measurable analysis of coastline changes. Cloud computing-based platforms facilitate data storage, processing, and dissemination, enhancing accessibility for researchers and stakeholders. This study indicates that the area has experienced significant changes from 1990 to 2023, with the total length of the coastlines that have changed (positive stands for accretion and negative for erosion) being 8.21 km (-16,86 %) for 1990 to 2000, 6.52 km (16.21%) for 2000 to 2010, 8.14 km (6,66%) for 2010 to 2020, and 8.81 km (-19,16%) for 2020 to 2023. The results provide valuable information about erosion, accretion, and coastal morphological changes. The findings can help make informed decisions for sustainable coastal management. The methodology presented in this article demonstrates a solid approach to coastline monitoring that can be replicated in other areas for more efficient and effective coastal management and environmental preservation.

Study of Coastal Morphological Changes by Tsunamis in Aceh (Indonesia) Using Satellite Images

This study identified the coastal morphological changes caused by tsunamis that occurred in Banda Aceh, Lampuuk-Lhoknga, and Meulaboh. The morphology of study areas was drastic changes during the 2004 tsunami and followed by the 2005, 2010, and 2012 tsunamis. Time series of Landsat satellite images and tidal data were collected during the period 1988-2020 and analyzed using DSAS (Digital Shoreline Analysis System) analysis method. The main aim of this study is to monitor recovery, trend development, and controlling factors of the coastal morphology before and after fifteen years of the 2004 tsunami. In Banda Aceh, the shoreline shift in the 2004-2005 period shows an inland retreat trend, with an average NSM (net shoreline movement) value of -644.69 m. The EPR (end point rate) value for the 2005-2020 period reached 21.31 m/year, but the recovery of the 2020 shoreline position has not returned to the original position before the 2004 tsunami. The significant shoreline retreat and land loss with an average NSM value of -40.59 m in the period 2004-2005 occurred on the Lampuuk and Lhoknga beaches. The 2020 shoreline of Lampuuk beach underwent a recovery with accretion. Nevertheless, Lhoknga beach is still experiencing apparent erosion. The recovery of the Meulaboh east coast was fast as evidenced by the development of the annual growth of spit features. The coastal morphological changes are influenced by complex interactions between natural and anthropogenic processes. The 2004 tsunami was the major factor to change the coastal morphology in the study areas.

ADVANCES ON THE USE OF SATELLITE DERIVED PRODUCTS TO DETECT COASTAL CHANGES: DEMONSTRATION CASE ON THE COAST OF SPAIN

Regular and efficient monitoring of coastal changes is necessary to inform coastal management decisions. In this regard, recent developments based on Google Earth Engine (Gorelick et al., 2017) enable the automatic detection of coastal changes using satellite data (Turner et al., 2021) However, such tools are usually calibrated with limited information and, consequently, they may lead to significant errors when applied to beaches with different conditions than those considered in the calibration data sets. In this work, we evaluate the capability to monitor changes in coastal morphology at various temporal and spatial scales using satellite-derived data obtained from an automatic processing method that includes site-specific information. These method was developed within the framework of the Coastal Erosion from Space Project (https://coastalerosion.argans.co.uk/) that brought together experts from several countries with different backgrounds, such as Earth Observation, Geology, Engineering and Management, to develop satellite products to monitor coastal change based on end-user requirements.

PSEUDO GLOBAL WARMING EXPERIMENTS OF BEACH MORPHOLOGICAL CHANGE: CASE STUDY IN NIIGATA COAST CAUSED BY TYPHOON LUPIT (2021)

Extreme external forces such as associated with strong cyclones have often caused severe coastal erosions. Numerical simulation models have been employed for evaluating these coastal morphological changes (Roelvink et al., 2009). However, few studies focused on the morphological response caused by tropical cyclones under expected climate change. In this study, field surveys and numerical simulations were conducted to evaluate morphological changes caused by typhoon Lupit (2021) on Niigata coast. PGW (Pseudo Global Warming) methods under the SSP scenarios of IPCC AR6 were used to simulate morphological responses under expected climate change.

A 40 YEAR WAVE CLIMATOLOGY OF SOUTH EAST QUEENSLAND, USING MODELLED AND IN-SITU WAVE OBSERVATIONS

Climate change has the potential to impact weather patterns that drive the Queensland wave climate and increase the intensity of extreme events such as tropical cyclones and east coast lows, due to a widening of the tropics. This will likely result in a changing wave climate, an increase of erosion events and subsequent coastal morphological change throughout the subtropics. Thus, it is important to examine not only the modal wave climate, but also the extreme wave climate. While a number of hind-cast models have been used to assess global wave climates (Perez et al. 2017), there has been an identified lack of regional assessments. Wave climatology assessments for the SEQ region, have consisted of several point specific assessments undertaken predominantly using buoy data, hind-cast data, or visual daily observations. These studies generally agree that tropical cyclone and east coast lows are the dominant source of high energy sea states and beach erosion in SEQ. A 40 year numerical wave hind-cast has been developed using the WaveWatch III (WW3) model version 4.08 (Durrant et al. 2013a, 2013b).

Assessing the impact factors and corresponding weights affecting the coastal morphology of Hsinchu Coast, Taiwan

This study investigates the long-term morphological pattern of the Hsinchu coast in northwestern Taiwan using three different methods: long-term isobath and shoreline change analysis, bathymetric volume change analysis, and the empirical orthogonal function (EOF) method. Our objectives include analyzing and understanding the effects of anthropogenic structures, natural processes, and their combined impacts on coastal morphological change. The shoreline analysis and bathymetric volume analysis briefly reveal that the morphological pattern of Hsinchu coast. Then, EOF analysis is applied to identify the dominant impact factors affecting the coastal morphology near the harbor, determine the weights of the impact factors, and infer the impact range of anthropogenic structures. Moreover, the EOF analysis is divided into two-time segments—namely, the periods 2005–2010 and 2017–2021—based on different bathymetric surveys and the corresponding values of impact factors. The primary and secondary EOF modes are strongly linked to the “interaction between wave and structure” and “interaction between river discharges and structure”, respectively. The spatial components of the EOF modes demonstrate that the impact range influenced by river discharges was mainly located in the northern part of the harbor, while the minimum impact range of the structures on coastal morphological interaction changes under natural factors was 3.5 km south of Hsinchu Fishing Harbor.

Large eddy simulation of plunging solitary wave: Understanding the breaking and turbulent mechanisms along shoaling region

A large eddy simulation (LES) is conducted to investigate the distribution of turbulence kinetic energy (TKE) under a plunging solitary wave over a 1:15 slope. This study provides a novel contribution to the field by examining the roles of resolved and sub-grid scale TKE in plunging solitary waves at the different stages of wave breaking. Furthermore, comparing the performances of two sub-grid scale (SGS) models in simulating the distribution of TKE was carried out to identify their performances. The separate investigation of these components in the context of wave breaking and recognizing the importance of an appropriate sub-grid scale model to consider the effects of small-scale eddies provide a significant advancement in understanding coastal morphological changes and nearshore sediment transport. Both the zero-equation and one-equation SGS models demonstrated acceptable performance in simulating water surface and kinematic properties. The one-equation SGS model, however, provided more accurate results on TKE transport during the breaking process and as the wave approaches its collapsing point. The study’s results reveal that an SGS model’s inability to simulate TKE transport (such as in the zero equation model) leads to inaccurate simulations of the TKE level and breaking location in the breaking zone. Additionally, the results of the one-equation model demonstrated that the maximum horizontal fluid velocity around the wavefront surface is a better predictor of breaking wave onset than the horizontal fluid velocity at the wave crest.

Bed shear stress and sediment transport equations for predicting morphological and shoreline changes: a review

Coastal sediments can be transported as bedload and suspended-load transport by waves and currents. The waves stir up the sediments, then currents transport sediments. Waves on the bottom can generate bed-shear stress. Meanwhile, the combination of bedload and suspended-load transport is known as total sediment transport. Prediction of total sediment transport has become important related to coastal morphological change and also shoreline change. Most of the sediment transport equations and approaches are developed from the physical principles. There are so many researchers proposed some formulas and methods with some considerations and difficulties. Due to the complexity of coastal conditions, the existing sediment transport rate prediction formulas are still not finished yet. Several well-known equations of bed-shear stress, bedload-suspended transport, and cross shore-longshore sediment transport; are discussed and reviewed in the present study. Thus, an overview of approaches and formulations that are reliable and nearly accurate for calculating the total sediment transport rate based on the characteristics of each coastal waters will be obtained. Accurate estimation of sediment transport rates will provide good results for predicting and monitoring changes in coastal morphology and shoreline changes. Moreover, coastal monitoring can be used for actions related to coastal protection system and coastal management.

Low-Cost Sensors for Monitoring Coastal Climate Hazards: A Systematic Review and Meta-Analysis.

Unequivocal change in the climate system has put coastal regions around the world at increasing risk from climate-related hazards. Monitoring the coast is often difficult and expensive, resulting in sparse monitoring equipment lacking in sufficient temporal and spatial coverage. Thus, low-cost methods to monitor the coast at finer temporal and spatial resolution are imperative for climate resilience along the world's coasts. Exploiting such low-cost methods for the development of early warning support could be invaluable to coastal settlements. This paper aims to provide the most up-to-date low-cost techniques developed and used in the last decade for monitoring coastal hazards and their forcing agents via systematic review of the peer-reviewed literature in three scientific databases: Scopus, Web of Science and ScienceDirect. A total of 60 papers retrieved from these databases through the preferred reporting items for systematic reviews and meta-analyses (PRISMA) protocol were analysed in detail to yield different categories of low-cost sensors. These sensors span the entire domain for monitoring coastal hazards, as they focus on monitoring coastal zone characteristics (e.g., topography), forcing agents (e.g., water levels), and the hazards themselves (e.g., coastal flooding). It was found from the meta-analysis of the retrieved papers that terrestrial photogrammetry, followed by aerial photogrammetry, was the most widely used technique for monitoring different coastal hazards, mainly coastal erosion and shoreline change. Different monitoring techniques are available to monitor the same hazard/forcing agent, for instance, unmanned aerial vehicles (UAVs), time-lapse cameras, and wireless sensor networks (WSNs) for monitoring coastal morphological changes such as beach erosion, creating opportunities to not only select but also combine different techniques to meet specific monitoring objectives. The sensors considered in this paper are useful for monitoring the most pressing challenges in coastal zones due to the changing climate. Such a review could be extended to encompass more sensors and variables in the future due to the systematic approach of this review. This study is the first to systematically review a wide range of low-cost sensors available for the monitoring of coastal zones in the context of changing climate and is expected to benefit coastal researchers and managers to choose suitable low-cost sensors to meet their desired objectives for the regular monitoring of the coast to increase climate resilience.

A Chronology-Based Wave Input Reduction Technique for Simulations of Long-Term Coastal Morphological Changes: An Application to the Beach of Mastichari, Kos Island, Greece

The main objective of the present paper is to achieve the simulation of the long-term (e.g., annual) morphological evolution (bathymetry and shoreline) of a coastal area (Mastichari beach, Greece) due to wind-generated waves in an accurate and cost-effective way. For this purpose, wave climate schematization techniques are adopted in order to reduce the computational effort without losing or distorting the crucial information. Referring to the current practice, the wave chronology is not considered in detail in these acceleration techniques, and therefore, sea bottom and shoreline evolution are not estimated as a function of time. To fill this gap, a novel and easy-to-use chronology-based wave input reduction method is developed to produce representative wave time series of different intensities and durations. The performance of all the applied techniques in the present study is evaluated, and a comparative analysis is conducted. It is shown that the new chronology-based wave input reduction method can achieve a model run-time reduction of about 70%, while at the same time, it provides satisfactorily accurate results. In general, this research could be useful for coastal engineering studies and coastal zone monitoring, and thus, it would be a valuable tool for coastal engineers and marine scientists.

Residual Sediment Transport in the Fine-Grained Jiangsu Coast under Changing Climate: The Role of Wind-Driven Currents

Residual sediment transport, which is influenced by many factors including tide, wind, and waves, controls coastal morphological changes on different time scales. For fine-grained coasts where the wave effects are limited, it is still unclear to what extent the wind-driven current can impact the residual sediment transport. Taking the fine-grained Jiangsu Coast as an example, this study aimed to identify the contribution of wind on residual sediment transport over different time scales using a newly developed model. On a seasonal scale, wind-induced sediment transport shows strong seasonal characteristics, where the residual transport is more significant in the winter and summer. Nevertheless, the tide plays a dominant role in both residual current and sediment transport and the annual sediment budget over the coast. On the scale of tidal cycles, the extreme winds overwhelm the tides, controlling the residual sediment transport. However, the net sediment transport caused by the northerly winds (representing cold waves) is comparable to that of the southerly winds (representing typhoons). Therefore, although extreme winds can drive massive sediment transport in a short period, their contribution to annual sediment transport is limited.

A Remote Sensing-Based Approach to Identifying Spatio-Temporal Changes in Coastal Morphology in Bhola District, Bangladesh

Bhola, the largest island of Bangladesh located at the estuarine mouth bar of the Bay of Bengal is very dynamic and unique in nature due to its physiographical configurations and is experienced severe morphological i.e. erosion- accretion changes. Of late, monitoring of coastal morphology and changes in shoreline trend analysis has conveniently been done through the integration of remote sensing satellite imageries and GIS techniques. The present study is an endeavor to detect and analyze the morphological changes on Bhola Island. Multi-temporal satellite images are the main data sources to attain the objectives through the integration of RS and GIS. The study concludes from the recent 42 years (1974- 2016) satellite data that- the Island is in the losing phase since 1974. The erosion processes are still active along the eastern and northeastern parts of Bhola Island due to the direct influence of the Meghna Estuary on the land by the steep bank slope, high tidal water pressure, and loose bank materials. Erosion is the burning issue on Bhola Island and due to this a large number of people are landless every year. On another side, accretion is being operated in a large part surrounding the Island increasingly in the southern part due to backwash sediment deposition by channel and estuary with the favor of a gentle topographic slope along the bank.

Modeling of sediment transport in rapidly-varying flow for coastal morphological changes caused by tsunamis

Tsunamis can cause significant coastal erosion and harbor sedimentation that exacerbate the concomitant flood hazards and hamper recovery efforts. Coupling of the non-hydrostatic model NEOWAVE and the sediment transport model STM provides a tool to understand and predict these morphological changes. The non-hydrostatic model can describe flow fields associated with tsunami generation, wave dispersion as well as shock-related and separation-driven coastal processes. The sediment transport module includes non-equilibrium states under rapidly-varying flows with a variable exchange rate between bed and suspended loads. A previous flume experiment of solitary wave runup on a sandy beach provides measurements for a systematic evaluation of sediment transport driven by shock-related processes. The extensive impacts at Rikuzentakata, Iwate, Japan and Crescent City Harbor, California, USA from the 2011 Tohoku tsunami provide pertinent case studies for model benchmarking. We utilize a self-consistent fault-slip model to define the tsunami source mechanism and field survey data to determine the characteristic grain sizes and morphological changes. The near-field modeling at Rikuzentakata gives reasonable fits with observed large-scale erosion and sedimentation associated with transition of the incoming wave into a surge and formation of a hydraulic jump in the receding flow. The non-hydrostatic module becomes instrumental in resolving tsunami waves at the far-field shore of Crescent City. The results show good agreement with local tide-gauge records as well as observed scour around coastal structures and deposition in basins resulting from separation-driven processes. While the erosion patterns in the laboratory and field cases can be explained by suspended sediment transport in the receding flow, bed load transport can be a dominant mechanism in sediment laden flows and scour around coastal structures.

Impacts of morphological change on coastal landscape dynamics in Monpura Island in the northern Bay of Bengal, Bangladesh

Coastal morphological change and landscape dynamics have been creating a new window for taking immediate sustainable management strategies for coastal resources management. The dynamic nature of coastal morphological response includes erosion/accretion of landmass, development of an island by sedimentation, movement of the island, and change in geometry and shape. The objectives of the study illustrate morphological change, driver, and mechanism of morphological change, and the effects of morphological change on coastal landscape dynamics. The study also explores spatio-temporal landscape dynamics effects on coastal ecosystem services and livelihood pattern of the coastal community. The novelty of the present research is that how morphological change influence in response to landscape dynamics and its ecosystem services by exploring historical data including shoreline change, century scale erosion and accretion, stability of the islands since 1776 to 2021. In this study, historical maps (i.e., Rennell’s map in 1776 and Tassin map in 1840), Topographic Survey map (1943) and remotely sensed digital image (i.e., Landsat TM in 1990, 2000 and 2010, and Landsat OLI in 2021) have been used to quantify coastal geomorphological change and landscape dynamics through RS and GIS tools and techniques. The finding of the study showed remarkable change occurred in geomorphology of the Monpura Island over the period of 245 years. The spatial coverage of the island has been declined dramatically, which is quantified ∼2905 ha from 1776 to 2021. In the century scale from 1840 to 1943, erosion is observed higher than accretion, and the statistics showing that 8963.40 ha eroded along the east flank of Island. In the northern flank of the Island, Net Shoreline Movement (NSM) and the rate of shoreline movement which expressed by EPR showed highest and flowed by ∼4 km and -126.55 m/y toward landmass. During the epoch 1990–2021, because of morphological change and anthropogenic interventions, the crop land of the Island has been significantly declined by ∼38%, while the rivers and settlement spatial coverage have been increased by ∼768% and ∼153%, with an annual rate of change ∼25% and ∼5% respectively. These outcomes and prepared maps of the current research will be supportive for the local inhabitant, coastal morphologist, and environmental resources management manager, national and international policy advisor, government and non-movement stakeholder, researcher to observe coastal morpho-dynamics including shoreline dynamics, coastal erosion and accretion and its impacts on landscape and ecosystem services.

A Late-Holocene palynological record of coastal ecological change and climate variability from Apalachicola, Florida, U.S.A

This study uses radiometric dating, palynological, loss-on-ignition, and X-ray fluorescence analyses to reconstruct the vegetation history and coastal morphological changes at the boreal mangrove range limit along the Gulf of Mexico, based on three sediment cores taken from St. George Island, Apalachicola, Florida, USA. The multi-proxy record indicates that the mangrove stands in the vicinity of St. George Island were formed in the recent decades, and no signs of mangroves were found for the last 1500 years during the Late-Holocene in the sedimentary record. The current mangrove expansion at St. George Island is caused by the recent climate warming instead of a recurring phenomenon tied with cyclical global climate variability. Further analysis based on decadal-scale climatic and environmental records reveal that the accelerated sea-level rise and warmer winters, especially the decrease of winter freeze events in the 21st century, are the most plausible causes for mangrove expansion at their boreal range limit during the recent decades. Under the predicted warming trend and accelerating sea-level rise in the 21st century, it is reasonable to believe that mangrove encroachment into coastal marshes will accelerate at Apalachicola and other areas near their poleward range limits.

Assessment of Sea Level and Morphological Changes along the Eastern Coast of Bangladesh

Bangladesh is one of the climate risk-prone countries in South Asia facing tremendous challenges to combat sea-level rise and its associated coastal morphological changes. This study aimed to determine the interaction of the sea-level rise and morphological changes, particularly at Cox’s Bazar and Kutubdia Island along the eastern coast of Bangladesh. Available hourly tide gauge data, daily temperature, daily rainfall data, and 15 LANDSAT satellite images for the period of 1983–2016 were analyzed to examine the sea level shore morphological change and associated climate change phenomenon. First, we identified the historical nonlinear sea-level trend using Hilbert-Huang Transformation (HHT) based on the complete ensemble empirical mode decomposition (CEEMD) technique. We divided the study period into three distinct sea-level change periods of 1983–1993, 1993–2003, and 2003–2014 based on nonlinear sea-level trend analysis. The study revealed that the sea level on the east coast of Bangladesh had a moderate rising trend during 1983–1993, slight decrease during 1993–2003, and steep rising trend during 2003–2014. We also observed that a sea-level change within a particular period impacted the shore morphological change after approximately two years, such that the average sea-level change during the period of 1993–2003 might have affected the shore morphology for 1996–2005. Alarming shore erosion was found for the period of 2005–2016 compared to the previous periods of 1989–1996 and 1996–2005 for both Cox’s Bazar and Kutubdia Island. The shore morphology of some segments was also substantially affected due to the geometric shape of the land, significant waves, and shore protection works. This study encourages policymakers to minimize the threats of sea-level rise and ensure sustainable coastal management strategies are introduced to sustain the vital eastern coast of Bangladesh.

Study of Changes in Coastal Morphology Due to Utilization of the Surabaya City Coastal Area

Indonesia is an archipelagic country with a vast coastal area, so proper management is needed in the development of coastal areas. The city of Surabaya is one of the cities that carry out the development of coastal areas by projecting strategic areas of its coastal areas as regulated in the regional medium-term development plan 2016-2021. The strategic area of the coastal area of Surabaya city is divided into two, namely strategic areas to support economic growth and save the environment. One of the efforts to optimize the development of coastal areas is to examine changes in coastal morphology due to coastal utilization. Analysis of the study was carried out by comparing historical maps of the last 10 years with existing maps from google earth and map analysis using ArcGIS 10.8. The results show that most in the coastal area of north Surabaya there is a change in coastal morphology covering an area of 360,121 m 2 as a result of the reclamation of the construction of the Lamong bay port and 623.12 m 2 in the coastal area of east Surabaya due to the addition of mangroves. Regular monitoring and improvement efforts on the coast of Surabaya city must be carried out on an ongoing basis, so that coastal threats such as sedimentation and erosion can be minimized