Paleoshoreline to Anthropocene Coast: Assessing Coastal Stability and Vulnerability in Response to Sea Level Changes

Paleoshoreline to Anthropocene Coast: Assessing Coastal Stability and Vulnerability in Response to Sea Level Changes | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Paleoshoreline to Anthropocene Coast: Assessing Coastal Stability and Vulnerability in Response to Sea Level Changes MK Rafeeque, Ashutosh Bharadwaj, Mintu E George, DS Sureshbabu, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6159107/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 5 You are reading this latest preprint version Abstract The densely populated Kozhikode coastal belt in southwest India is increasingly vulnerable to coastal hazards, exacerbated by coastal protection measures that disrupt natural dynamics. This study contrasts shoreline processes over recent geological history with current dynamics, focusing on a high-energy, micro-tidal coastline characterized by distinct paleo-shoreline features and young coastal plains from the Holocene epoch. Temporal morphological changes were assessed using various satellite products, ranging from Landsat imagery to Very High-Resolution Worldview-3 datasets. The integration of vulnerability assessments of coastal ecosystems and landform features reveals significant coastal dynamism. This study highlights critical shifts in coastal dynamics and emphasizes the urgent need for sustainable coastal management strategies to mitigate escalating vulnerabilities. Understanding these changes is essential for informed policymaking and effective climate adaptation strategies, ensuring the resilience and preservation of these vital coastal ecosystems. Analysis of shorelines from the Holocene to the present indicates a historical accretion trend until the 1960s; however, recent decades have seen a concerning reversal, resulting in coastal erosion and flooding. This paper elucidates the influences of extreme events and anthropogenic factors on coastal stability, supported by analyses of paleo-shoreline changes and contemporary disturbances linked to climate change and sea-level fluctuations. Geological and climatic events, particularly sea-level changes, are evident in paleochannels associated with the Chaliyar and Korapuzha river basins. Lithological studies from boreholes provide compelling evidence of shoreline variations, indicating that the paleo-shoreline now varies significantly from the modern shoreline across different regions. The once-accruing Holocene coast now experiences erosion along 40% of its length, with accretion rates plummeting from 100% to just 11% in recent decades, likely due to unsustainable coastal zone exploitation since the 1980s. Coastal Erosion Shoreline management Coastal Vulnerability Sea Level Rise Coastal Structures Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 1. Introduction The Quaternary period is marked by the appearance of the human race and the evolution of various cultures, particularly during the Late Pleistocene and Holocene epochs. Marine transgressions and regressions were common during this time, shifting the world's coastlines. Furthermore, these oscillations have led to geomorphological changes such as the development of backwaters, estuaries, marine terraces, spits, barriers, beach ridges, and shifts in river courses (Ahmad, 1972 ). Various natural and anthropogenic forcing factors influenced the highly dynamic coastal zones throughout this geological period, including sea-level rise, extreme events, local oceanic and atmospheric processes, and ground subsidence (Benveniste et al., 2019 ). Coastal zones are the cradles of world civilization and human development. According to the fact sheet published by the United Nations (UN) in 2017, nearly 10 percent of the world's population lives in coastal areas with elevations less than 10 meters above Mean Sea Level (United Nations, 2017 ). Despite constituting only a tenth of the global landmass, two-thirds of the world's mega-cities are situated along coastal zones worldwide (Burt et al., 2019 ; CIESIN, 2005 ; Duarte et al., 2008 ; UNEP, 2007 ). Kozhikode is one of the rapidly growing urban centers on this coast and holds the status of being one of the ancient coastal cities of peninsular India. The sea pier along this coast was constructed during the colonial era, making it the region's first artificial coastal structure. Its development was primarily for military purposes and to facilitate foreign trade for the dynasty. The headlands and promontories of Kadalur, Palakkulam, Parappalli, Thoovappara, and Elathur are natural coastal structures that play a crucial role in modifying the Kozhikode coast. The soil composition in Kozhikode can be categorized into four major types: coastal alluvial soil in the coastal plain and low-lying areas, riverine alluvial soil along the riverbanks, red loam soil, and brown hydromorphic soil (Aboo Ishaque P K, 2012 ). Cenozoic alluvium sediments of recent age cover the coastal zone at a few places; the crystalline rocks are cross-cutter by basic dykes, comprised mainly of charnockites with enclaves of mafic granulites belonging to the Lower Precambrian age. In the midlands, these rocks are, in some places, covered by laterites. The surficial geological features of the coastal belt mainly comprise sand-dunes, occasionally interspersed with sandstones and clays. Kozhikode was the capital of the well-known kingdom of the 'Zamorins' for many years and later became the capital of the Malabar district during the British rule. Arab-Persian traders arrived here before the 6th century, and Vasco De Gama landed here during his ocean exploration, marking the beginning of trade between South India and Europe. The North Kerala coast (also known as the Malabar coast) is recognized as the most stable and rapidly developing coastal zone along the west coast of India. This coastal plain was formed during the Holocene through fluvio-tidal processes. Numerous scholars have extensively studied the evolution of coastal landforms in the region and have affirmed that the Kerala coastal belt is a young coastal plain, with Holocene-Pleistocene sedimentation supported by various researchers (Alappat et al., 2015 ; Nair N J K et al., 1989a ; Narayana A C & Priju C P, 2006; Padmalal et al., 2014 ; Samsuddin M et al., 2008a ). Several scholarly works and research groups have addressed the shoreline trend along the Kerala coast, including studies by (CWC, 2017 ; Ramesh R et al., 2013a ; Ramesh R & Bhatt J R, 2018; Selvan et al., 2020 ; Sheela Nair et al., 2018a ). These studies have collectively concluded that the Kerala coast has been experiencing an erosive trend over the last few decades. The changes in shoreline associated with coastal protection measures constructed along the Kerala coast were thoroughly investigated by (Murthy C S et al., 1980 ). However, these studies often considered the coast at a smaller scale. This study focuses on the densely populated 50 km long Kozhikode city coastline, characterized by a high-energy, micro-tidal nature. Our examination indicates that the Kozhikode coast experienced accretion from the Holocene to recent years; however, this accreting trend has reversed in the last few decades. We closely examine this reversal of shoreline dynamics from the Holocene to the present and associated coastal vulnerability, shedding light on the high-energy coastal paradigm of the region. 2. Study Area The Kozhikode coast is situated at the heart of the Malabar coast, encompassing the northern coastal plain of Kerala. The specific stretch of coastline under investigation spans from Kadalur headland in the north to the Kadalundi estuary in the south, covering a shoreline length of 50 km (Fig. 1 ). This coastal zone comprises four estuaries: Korapuzha, Kallayi, Beypur, and Kadalundi, numerous small creeks, and three harbors: Koyilandi, Puthiyappa, and Vellayil. The drainage network of this coastal zone, along with associated water bodies, is formed by three river systems (Agalapuzha, Kallai, and Chaliyar) and one canal (TS Canal). The two principal harbors, Koyilandi and Puthiyappa, significantly influence the fishing activity of the region, in conjunction with the significant estuaries, which also impact the micro-geomorphology of the area. The exposed promontories and headlands at frequent intervals, coupled with sediment discharges from the estuaries, shape the characteristics of this coastal plain. The geomorphological signatures of the area reflect the physical processes it has undergone and their relationship to local geological structures. Notable landforms of the Malabar coast or north Kerala coast encompass the coastal morphological features of the Holocene period, including coastal plains of recent alluvium, barrier reefs, coast-parallel lagoons, and lateritic hills, as well as hard rock exposures from the tertiary period or even earlier. Ezhimala, Kannur, and Kadalur headlands represent significant rock exposures along this coast. Valiyaparamba, Kuppam, and Agalapuzha are vital lagoons off the coast that run parallel to the beach. Additionally, sediment-discharging estuaries such as Chandragiri, Azhithala, Valapattanam, Dharmadam, Kolavi, Korapuzha, Chaliyar, and Bharathapuzha contribute to the coastal dynamics of the Malabar coast. Unique for their short length and higher elevation gradient, the rivers in the area transport a considerable amount of coarse sediments, which are then deposited in the nearshore area. The paleochannels in the region have changed their course multiple times over its geological history. 3. Methodology To delineate the Holocene landforms, we assessed geomorphic signatures and geological footprints using information from published literature and ground truthing. Additionally, we analyzed three borehole datasets to understand lithological structure and geological sedimentation processes. 'ESlog,' a web-based software for borehole logging presentation, was utilized to plot graphical representations of borehole samples. The geological history of the Kozhikode coastal zone was referenced from the "Natural Resources and Environmental Atlas of Kerala: Kozhikode district" published by CESS in 2008 (Samsuddin M et al., 2008b ). Parameters such as geological structure, lineaments, tectonics, and landform shape and structure were demarcated. Each geomorphic feature's spatial extension was plotted with accompanying explanations in this atlas. The boundary line separating the young coastal plain and coastal features of Holocene origin from the midland of lateritic origin was considered the Holocene shoreline for this study. To understand the present shoreline trend of the Kozhikode coast, 'Digital Shoreline Analysis System' (DSAS) (Version v5.1), an 'ArcGIS' extension tool developed by the ‘United States Geological Survey’ for analyzing various shoreline statistics over time such as End Point Rate (EPR), Linear Regression Rate (LRR), and Weighted Linear Regression Rate (WLR) was utilized (Himmelstoss et al., 2021 ). The statistical values obtained were used to depict shoreline movements, including erosion and accretion, and the response of the coastline to specific coastal/marine events compared to its pre and post-dynamics. Considering the long-term changing scenario of the seacoast, the high water line (high tide line) was demarcated as a shoreline for different time periods (Dolan et al., 1980 ; Ramesh R et al., 2013a ; Sheela Nair et al., 2018a ). Twelve shorelines from different periods, spanning from 1968 to 2024, were demarcated using various raster datasets. The choice of temporal data points was critical for capturing both long-term and recent shoreline dynamics, which is in line with the study’s objective of assessing coastal changes over varying timescales. The temporal points were chosen based on the availability of key historical and satellite datasets, as well as significant geomorphological and anthropogenic events that shaped the Kozhikode coast. Data for the Holocene period were taken from the NCESS Atlas, as it provides detailed insights into the geological history of the region, which is essential for understanding long-term coastal evolution. The 1968 and 1979 topographical maps from the Survey of India (SoI) provided crucial baseline information, as they represent the pre-satellite imagery era, allowing for the earliest possible assessment of shoreline position. Google imagery from 1984 and Landsat TM mosaic (30m resolution) from 1990 were selected to understand the transitional phase of coastal dynamics as human interventions, such as coastal development and infrastructure projects, began to influence the shoreline. The availability of consistent medium-resolution Landsat imagery enabled the assessment of shoreline trends at a global standard. High-resolution data from CARTOSAT-1 (2.5m resolution) and WorldView-2 (0.5m resolution) datasets were utilized to capture more recent (2000–2014), finer-scale changes in shoreline position. These datasets provide detailed observations of smaller geomorphological processes such as localized erosion or accretion events. The very recent datasets from ArcGIS World Imagery and Google Imagery (< 1m resolution) were employed to analyze the most up-to-date shoreline positions, allowing for comparisons with historical datasets to determine ongoing trends of erosion and accretion. The choice of these temporal data points reflects the study’s objective to combine long-term and fine-scale temporal observations, providing a comprehensive understanding of shoreline dynamics on the Kozhikode coast. These datasets had varying scales/resolutions, including World View-2 images of very high resolution (0.5 m), Landsat images of medium resolution (30 m), and 1:50,000 Survey of India (SoI) topographical maps of course resolution. Appropriate uncertainty values were assigned for each data type to address the scale/resolution differences when integrating data from various sources on the ArcGIS platform. The downloaded and/or procured satellite imageries were re-registered with common precise Ground Control Points (GCPs) to the WGS 84 datum and 43 N zone of UTM projection. ArcGIS 10.6.1 is used to integrate and analyze data sets further. The details of datasets used to interpret the shoreline trend of the current situation are presented in Table 1 . Table 1 Details of Datasets used as the source for Different Temporal Shorelines Sl. No. Year Data Source Publisher Year Survey/ Acquisition Scale/ Resolution 1 Holocene NCESS Atlas CESS 2007 2000–2004 1:50000 2 1968 Toposheet SOI 1967 − 168 1963–1965 1:50000 3 1979 Toposheet SOI 1979 1977–1978 1:25000 4 1984 Google Imagery Google 1984 - 5 1990 Landsat TM mosaic GLCF 2002 1990 30 m 6 2000 Landsat 7 GLCF 1999 15m 7 2007 CARTOSAT-1 NRSC 2007 2007 2.5 m 8 2010 CARTOSAT-1 NRSC 2010 2010 2.5 m 9 2011 World View − 2 Digital Globe 2012 2011 0.5 m 10 2014 CARTOSAT-1 NRSC 2014 2014 2.5 m 11 2018 ArcGIS World Imagery ESRI 2018 2017–2018 < 1 m 12 2021 Google Imagery Google 2021 < 1 m 13 2024 Google Imagery Google 2024 < 1 m Rates of change are expressed in terms of the distance of change per year. All methods used for calculating shoreline rate-of-change involve measuring the distances between different shoreline positions over time (Dolan et al., 1991 ; Prévost & Robert, 2016 ). The simplest method, the End Point Rate (EPR), uses only two shoreline positions, while the other method, Linear Regression Rate (LRR), utilizes more or all of the shorelines by considering respective time and location. The recent shoreline trend was interpreted based on the statistical values of the calculated LRR and EPR for the respective coastline. Shoreline change values were categorized into seven groups to indicate the intensity of change: Very High - High - Moderate Accretion or Erosion, and Stable Coast. This classification standard for shoreline changes was initially introduced by NCSCM (Ramesh R et al., 2013b ) and NCESS (Sheela Nair et al., 2018b ). A negative value of shoreline statistics indicates coastal erosion, whereas a positive value indicates an accretion trend of the coastline. Sea-level changes in the Kozhikode coast were studied by comparing it to the nearby well-analyzed coastal zone of Ernakulum. Tide gauge data with longer periods and a minimum null value in data frequency were considered for the study. Long-term tidal and Mean Sea Level (MSL) data for Ernakulum, provided by the Permanent Service for Mean Sea Level (PSMSL), were referenced to understand the sea level status of Kozhikode (Dinesh Kumar, 2001 )(Chowdhury & Behera, 2015 ). Predicted Sea Level Rise (SLR) changes were plotted on the district map by simulating sea level increases of one meter and two meters (Mani Murali & Dinesh Kumar, 2015 ). Land use and land cover maps were overlaid on the inundation map to understand the categories of land loss. 4. Results and Discussion Understanding the geomorphology of any coastal zone is crucial for implementing appropriate land and risk management strategies to achieve the sustainable development goals (SDGs) set by the United Nations Development Programme (UNDP). Geomorphological databases and an understanding of landform dynamics also aid various applied sectors of environmental research. The coastal zone of western India, particularly northern Kerala, is relatively more stable than the east coast, despite being a high-energy coast. Numerous scholars have attempted to study the evolution of landforms and coastal features of Kerala from diverse perspectives. For example, (Suchindan G K et al., 1987 ) conducted one of the initial studies exploring the coastal geomorphology of Kerala, focusing on aspects like strand plains and cliffed shorelines in northern Kerala. 4.1. Geomorphic Appreciation of the Kozhikode Coast: The prominent geomorphic processes active in the Kozhikode coastal zone include marine, estuarine, fluvial, and paleo-tidal processes(Nair N J K et al., 1989b ). The urbanized coastal area of Kozhikode in northern Kerala is characterized by the presence of lagoons, backwaters, and estuaries. Log data from three boreholes, representing the north, central, and south sectors of the plain, were interpreted to understand the lithological structures of the Kozhikode coastal plain (Fig. 2 ). These boreholes revealed fluvio-marine sediments in their upper layers. The analysis of borehole data logs strongly confirmed the existence of a marine ecosystem at deeper depths and the gradual deposition of fluvio-marine sediments in these locations. The deposition of quaternary formations describes the accretion trend of the Kozhikode coastal plain during the Holocene – Pleistocene period. For example, the Vengalam borehole represents the Northern Sector of the Koyilandi region and indicates a significant presence of fluvio-marine deposits. Tertiary rock formations were not found up to the termination point of 36 m. Notably, there is an in-situ lateritic soil at a depth of 19 to 23 m, and clay-mixed sandy soils of estuarine deposits were reported to be up to 36 m. In the central sector, represented by the borehole in Vellayil of the Kozhikode city region, the thickness of quaternary sediments was reported to be 20 m in depth. Moving to the southern sector, the borehole in the Beypur region represents the coastal floodplains of the Kallayi – Chaliyar river basin. This borehole illustrates a young coastal plain with abundant signatures of paleochannels. For instance, the Nallalam borehole, located 2.8 km eastward of the south Marad beach, exhibited deposits of clay sand from the Quaternary period up to a depth of 10 m. The borehole was positioned at the southward bank of paleochannels of the Chaliyar River and at the northward slope of the Cheruvannur denudational hill, which later caused the diversion of the Chaliyar River. These borehole data logs provide strong evidence of a marine ecosystem at deeper depths, with gradual deposition of fluvio-marine sediments at these locations. The depositions of quaternary formations describe the accretion trend of the Kozhikode coastal plain during the Holocene – Pleistocene period. Historically, during his sea route exploration, the eminent Portuguese explorer Vasco da Gama anchored at Kappad beach just north of Kozhikode city on 20th May 1498, opening a trade route between Europe and Malabar. His first footstep on the Malabar coast is commemorated on land, marked by a government-developed monument (Fig. 3 ). This monument, which is presently located 100 meters inland from the shoreline, supports the accretion trend of this coast over the past few centuries along with other geological setting. Coastal landforms such as ridges, swales, sand dunes, and coastal alluvium deposits distributed along the coastal plain of Koylandi, Kappad, Kozhikode, and Beypur indicate the relation of the geomorphic evolution of this coast with fluvio-marine processes. Previous studies by (Vaidyanadhan, 1981 ) and (Merh, 1992 ) have described that the Kerala coast signifies the filling up of a series of bays during the Holocene with mud and later sands, dating back to 4460 years before the present. 4.2. Shoreline at Holocene Epoch: As per the CESS atlas titled 'Natural Resources and Environmental Atlas of Kerala: Kozhikode district' (Samsuddin M et al., 2008b ), the paleo shoreline during the Holocene period is demarcated at varying distances from the present shoreline across different sectors of the study area. The ground truthing surveys were conducted to eliminate the scale error of the atlas by identifying the geomorphological features (Fig. 4 ). In the Kadalur – Korapuzha sector, the paleo shoreline is located just 500 meters to 3.7 kilometers eastward from the current shoreline. In the Korapuzha – Kallayi sector, it extends from 700 meters to 3.3 kilometers from the present shoreline. Moving to the Kallayi – Beypur sector, the paleo shoreline is situated 2.4 to 4.7 kilometers away from the current shoreline. Lastly, in the Beypur–Kadalundi sector, the distance ranges from 200 to 800 meters from the present coastline. Identifying paleochannels using satellite imagery and observing young coastal features during field investigations substantiate these findings. 4.2.1. Kadalur – Korapuzha Sector : In this northern portion of the study area, the paleo shoreline is supported by paleochannels and evidence of various stages of landform development. Kadalur headland, in the north of this sector, is a rock exposure that indicates the past tidal action of this coast and its interaction with the west-flowing river system in the area (Nair N J K et al., 1989b). The Agalapuzha-Korapuzha river system debouches into the Lakshadweep Sea through the northern side of the Elathur headland. There are young coastal landforms such as ridges, swales, and coastal plains West of the Agalapuzha–Korapuzha river system, parallel to the present coastline. The paleo shoreline starts about 500 meters south of Kadalur headland in the Thikkodi region, gradually increasing its distance from the current shoreline in a southeast direction, reaching a maximum spread of 3.7 km at Kappad, and then moving southward up to the Korapuzha estuary. 4.2.2. Korapuzha – Kallayi Sector : In this sector, the Elathur headland is a key feature influencing the tidal and paleo activities of the coast. The paleo shoreline doesn't follow paleochannels south of Agalapuzha waterbodies. Instead, this area has been accreted by sediments trapped by denudational hills and headlands. The Holocene shoreline in this sector starts from Korapuzha and runs southward at a distance of 1.5 km from the present shoreline up to Purakkattiri Kadavu. It then follows the Poonoor Puzha channel and reaches Mokavoor, which is 3.7 km away from the present coastline. The paleo shoreline takes a parabolic structure, reaching almost 750 meters near the present coast at the crest of the parabola around the West Hill of Kozhikode city. It then follows an irregular straight line in a southeast direction, reaching the Kallayi River. 4.2.3. Kallayi – Beypur Sector : This sector features the broadest young coastal plain among the Kozhikode coastal plains. The Holocene shoreline starts from the Kallayi River in the southeast direction, approximately 2.3 km from the present shoreline. It follows the river channel up to the starting point of the Nallalam canal at Mankavu, then changes direction eastward along with the channel and reaches Nallalam, situated 4.8 km away from the current shoreline in a south direction. At Nallalam, it diverts from the canal and reaches the Chaliyar River through the western side of the Cheruvannur plateau in the same southward direction. 4.2.4. Beypur – Kadalundi Sector : In this southernmost area, the old shoreline runs almost parallel to the present coast with some variations. The paleo shoreline in the north half of this sector is very narrow, with an average distance of 200 to 300 meters from the present coast. In the southern half, the old shoreline maintains a distance of 800 meters from the coast over a 700-meter length, nearing the Kadalundi River. Moreover, studies on past sea-level changes suggest a history of accretion along the Kozhikode coast during the Holocene period. The width of the young coastal plain varies across the study area, and the evolution of this coastal plain is attributed to river discharges, tidal transgressions, and regressions. 4.3. Present shoreline Trend: The present study reveals the state of the Kozhikode coast in terms of shoreline erosion and accretion trends. Even with extensive artificial coastal protection measures covering 90 percent of the shoreline, the analysis indicates that 39.12 percent of the total shoreline is recorded for moderate erosion and 48.67 percent is reported as stable. Even though only 0.92 percent of the total coastline is affected by high coastal erosion, without any report of very high erosion, the accreting trend is found only for 11.27 percent of the total coastline, while the entire coast was reported as accreting up to the recent period. Table 2 gives a detailed idea of this coastline's erosion and accretion trend and compares EPR and LRR values for the shoreline statistics. Table 2 Shoreline Change Statistics of Kozhikode Coast Sl. No. Shoreline Change Respective Change in m/y Coastline Length as per EPR (%) LRR (%) 1 Very High Erosion < -5 0 0 2 High Erosion -5 to -2.5 0.805 0.920 3 Moderate Erosion -2.5 to -0.5 34.983 39.125 4 Stable -0.5 to 0.5 48.216 48.677 5 Moderate Accretion 0.5 to 2.5 14.845 10.126 6 High Accretion 2.5 to 5 0.805 0.690 7 Very High Accretion > 5 0.345 0.460 The analysis reveals that the north sector of the Kadalur – Korapuzha region is relatively stable, with exceptions near headlands/promontories and seawall end erosion points (Fig. 5). A notable accretion is reported along this sector at the south of Kadalur headland and Thoovappara promontory. The Korapuzha – Kallayi sector shows a high accretion trend to the south of Puthiyappa harbor due to sediment trapping by the breakwater (Fig. 6.). The southern portion of this coast was recorded as moderate erosion. The Kallayi – Beypur sector is significantly impacted by moderate coastal erosion, making it the most eroded coast in the region. Conversely, the southern part of the Beypur – Kadalundi sector displays a very high accretion trend due to the impact of breakwaters constructed at the river mouths. The paleo shoreline analysis reveals a historical accretion trend up to the 20th century, corroborated by borehole data and the monument at Vasco De Gama's first landing at Kappad beach. However, recent trends (1968–2024) demonstrate a reversal in shoreline dynamism due to human interventions, such as harbors, coastal protection measures, and alterations in sediment sources and movements. The construction of artificial structures, particularly seawalls, has significantly impacted the natural beach-gaining processes along the coast. Nearly 90 percent of this coast is regulated by artificial structures like seawalls, groins, tourism facilities, breakwaters, etc. Seawall itself was constructed at 67 percent length along this coast (Table 3). The density of the coastal population along the Kerala coastal plain necessitates extensive coastal protection measures. The end/side erosion of already constructed seawalls or other coastal structures will frequently demand the construction of new structures or extend the existing ones towards further extremes (Rafeeque & Thomas, 2022; Sheela Nair et al., 2018a). The study identifies that nearly 90% of the coast is regulated by artificial structures, primarily seawalls, and emphasizes the need for sustainable coastal management to balance development and natural processes. The impact of these coastal protection measures on shoreline changes has been previously studied in the context of the Kerala coast (Murthy C S et al., 1980). Table 3 Artificial structures along Kozhikode coast. Sl.No Structure Quantity Percentage 1. Seawall 31.45 km 66.91 2. Tourism Structures 2.70 km 5.74 3. Groins 18 Nos - 4. Breakwater 10 Nos - 5. Harbour 3 Nos - 6. Port 1 (Estuary) - 7. Sea Pier 2 Nos - The shoreline change analysis along the Kozhikode coast reveals significant trends influenced by geological and anthropogenic factors. The statistical evaluation of the shoreline dynamics, including the End Point Rate (EPR) and Long-Term Rate of Change (LRR), indicates a troubling erosion pattern. The calculated EPR and LRR suggest that the coastline is retreating, a phenomenon commonly observed in coastal regions affected by similar challenges, including sea-level rise and human activities. The regions along the eastern coast of the United States and parts of Bangladesh have documented comparable rates of erosion driven by similar factors, including increased storm intensity and anthropogenic alterations to the coastal environment (Griggs & Reguero, 2021; Roy et al., 2022). These comparisons illustrate that the challenges faced by the Kozhikode coast are part of a broader global issue concerning coastal vulnerability and the need for effective management strategies. The long-term consequences of artificial structures on coastal ecosystems are profound. Although they may provide immediate protection to certain areas, the disruption of sediment transport can lead to habitat degradation, loss of biodiversity, and diminished ecological functions of coastal environments. This situation calls for a comprehensive understanding of the ecological impacts of these interventions and the necessity for more sustainable approaches. To address the challenges posed by both geological and anthropogenic factors, it is imperative to adopt sustainable coastal management strategies, like Soft Engineering Solutions, Nature-Based Solutions (NbS), and Integrated Coastal Zone Management (ICZM). By emphasizing these strategies, we can enhance the resilience of the Kozhikode coast and similar regions, ensuring that coastal management practices align with ecological preservation and sustainability goals. In summary, the Kozhikode coastal area, characterized by a young coastal plain, has experienced a reversal in shoreline dynamism from the Holocene trend to the present due to human interventions and artificial coastal measures. Accretion trends that were prevalent up to the last century have reduced, and coastal dynamics are shifting due to these influences. The southern coastline is severely affected by coastal erosion, highlighting the need for effective coastal management strategies. 4.4. Sea Level Rise and Future Concerns: Understanding the current and projected sea level rise (SLR) along the Kozhikode coastline is crucial for comprehending future challenges for this coastal plain. The nearest long-term tidal/SLR observations are from Ernakulam (130 km southward) and Mangalore (180 km northward). Ernakulam provides a continuous dataset and is the closest station to the Kozhikode coast. Tidal datasets from 1939 to 2013 recorded by the PSMSL (NOC, n.d.) station at Ernakulam show a linear trend in mean sea level, indicating an increase from 6750 mm in 1940 (lowest MSL year) to 6998 mm in 2013 (Fig. 7). The sea level changes can be identified in three periods with different trends: a steady increase from 1939 to 1959, ups and downs from 1959 to 1986, and a further steady increase from 1986 to 2013. The Sea Level of the Ernakulum coast has risen, particularly since 1989, and this rise has become more consistent since 2004, as seen in the anomalies (Fig. 7). Studies by(Dwivedi & Sharma, 2005) predicted an SLR of 125 mm at Cochin by 2100 after assessing 58 years of observations. Another study by(Sreekesh et al., 2018) analyzed tide gauge data from Kochi (1971 to 2007) and estimated a sea level rise of 0.0018 m/year (1.8 mm/yr) along the Ernakulam district of Kerala's coast. The observed sea level changes are influenced by various processes of global warming and potential vertical land movements near the measuring instrument (Unnikrishnan et al., 2006). However, past research suggests that significant vertical land movement is not notable along the southwest coast of India (Kailasam, 1975), supporting the conclusion that observed sea level rise is primarily due to climatic changes and associated processes. Studies by(Samsuddin et al., 1992)(Suchindan et al., 1996), and(Haneeshkumar et al., 1998) traced out the sea-level rise and fall along the Kerala coastline of the SE Arabian Sea, providing valuable insights into coastal morphological features. Additionally, studies on the Maharashtra coast of the NE Arabian Sea by(Agrawal & Roy, 1978) and(Kale & Rajaguru, 1985) provided crucial information on transgression and regression phenomena since 35,000 BP based on radiocarbon dating. The study conducted a thorough analysis of the potential impact of sea-level rise on various land use and land cover (LU/LC) classes in Kozhikode district (Table 4). The impact on various environmentally sensitive areas, such as wetlands and mangroves, was also taken into consideration, and the probable areas to be affected due to the projected sea-level rise were also quantified. It was found that if the sea level rises by 1 meter, an 11.251 sq. km area will be submerged underwater. The analysis identified that 28% of the total area of Kozhikode district is vulnerable to projected sea-level rise scenarios (Fig. 8). Considering the projected sea-level rise scenarios, it is imperative to develop sustainable coastal management plans to mitigate potential adverse effects on coastal landforms, ecosystems, and human settlements. The analysis provides valuable information to guide proactive measures and policy decisions for the preservation and sustainable development of the Kozhikode coastline in the face of future sea-level rise. Table 4 Land use Land Cover Statistics – Kozhikode District Land Class Area (km 2 ) 1m SLR (km 2 ) 2m SLR (km 2 ) Residential (Converted from paddy) 0.7 0 0.05 Perennial 45.2 42.312 42.31 Mixed crop 103 8.43 11.74 Mixed built-up 48.93 8.64 8.64 Marshy 3.45 1.31 1.34 Land without scrub 1.28 0.4 0.64 Land with scrub 14.35 14.35 14.35 Current fallow 1.406 1.1 1.1 Commercial 4.12 0.02 0.68 Coconut-dominant mixed crop 1194.13 570.15 587.01 Coconut 15.13 0.95 1.22 Cashew 1.5 0.13 0.23 Beaches 6.23 2.63 4.85 Banana 3.82 0.41 0.41 4.5. Comparative Analysis of Geological and Anthropogenic Influences on Coastal Change Understanding the dynamics of the Kozhikode coast necessitates a nuanced exploration of both geological and anthropogenic factors that contribute to shoreline changes. Like many coastal regions globally, the Kozhikode coast is experiencing the impacts of sea-level rise (SLR). As detailed in Section 1.4, the long-term tidal observations from nearby Ernakulam suggest a consistent increase in mean sea level, primarily attributed to global warming. Natural processes, including seawater thermal expansion and polar ice melting, exacerbate this trend. The projected impacts of a 1-meter rise could inundate approximately 11.251 km² of coastal land, indicating that geological factors significantly shape the coastal landscape. The natural sediment supply along the Kozhikode coast, influenced by riverine inputs from the Kallayi and Chaliyar rivers, contributes to the coastal morphology. Historical data suggest that sediment accretion has characterized the region during the Holocene, driven by fluvio-marine processes and the deposition of quaternary sediments. Such geological processes inherently dictate landforms' spatial distribution and stability along the coast. The extensive installation of artificial coastal protection measures - covering approximately 90% of the shoreline - significantly alters the natural dynamics of sediment movement and shoreline stability. As indicated in Table 3, structures such as seawalls, groins, and breakwaters have been erected to combat erosion and protect urban development. However, these interventions can disrupt sediment transport, leading to localized erosion at the ends of seawalls and increased stability in other areas, which may contribute to a net loss of coastal resilience. The urbanization of the Kozhikode coastal zone has intensified pressure on coastal ecosystems. Land use changes, particularly the conversion of wetlands and agricultural lands into residential and commercial spaces, can exacerbate vulnerability to flooding and erosion. The study indicates that areas converted from paddy fields to residential zones are particularly susceptible to inundation under projected sea-level rise scenarios, demonstrating the interplay between human activities and natural vulnerabilities. While geological factors such as natural sea-level rise and sediment dynamics are crucial in shaping the coastal landscape, the extent of anthropogenic impacts cannot be overstated. Human interventions have significantly altered the historical accretion trends that characterized the Kozhikode coast. Coastal protection structures, while designed to mitigate erosion, can lead to unintended consequences, such as enhanced erosion in adjacent areas and changes to sediment supply. The comparative analysis underscores the importance of a balanced coastal management approach, recognizing that natural processes and human activities influence coastal dynamics. Sustainable management strategies should aim to integrate natural and engineered solutions, considering the cumulative effects of geological and anthropogenic factors on the coastal environment. 5. CONCLUSION The Kozhikode coastal plain, shaped during the Holocene epoch, has predominantly been characterized by accretion. The lithological and geomorphological features strongly affirm its depositional nature. Borehole data vividly portray extensive unconfined fluvio-marine sediment deposits that span the coastal plain. Notably, marine-derived sands and clays were observed at deeper depths, succeeded by the deposition of fluvio-marine sediments. The geological disposition and patterns of geomorphological features offer compelling evidence of the regression and transgression phases that mark the sea level changes during geological history. Beyond the macro analysis of shoreline changes over geological time scales, a microanalysis of the last 50 years reveals a pressing concern: over 40 percent of the analyzed coastline is grappling with coastal erosion. Astonishingly, despite the safeguard provided by various artificial coastal structures covering 90 percent of the coast, only 48 percent remains stable, experiencing a shoreline change rate of less than ± 0.5 meters per year. Concurrently, 11 percent of the shoreline is identified as accreting during the last half-century. It is hypothesized that the construction of diverse coastal structures has disrupted the natural sediment dynamics of the coast. Moreover, climatic factors such as extreme ocean currents, high waves, sea level rise, cyclones, and thunderstorms have likely influenced coastal stability over the past fifty years. The inundation analysis, a critical facet in the face of climate change, forewarns that with a one-meter rise in sea level, an expanse of 11.251 sq. km in Kozhikode would be submerged. Should sea levels rise by two meters, the total affected area would escalate to 14.675 sq. km, underscoring the urgency of proactive measures and sustainable coastal management. In this dynamic interplay between geological epochs and contemporary coastal challenges, awareness stands as our beacon, and sustainability our lodestar. To effectively address the challenges identified, specific policy recommendations include implementing a balanced approach that harmonizes development needs with the preservation of natural coastal processes. This could involve: Enhancing Natural Buffer Zones: Establishing and maintaining natural habitats such as mangroves and wetlands, which can act as effective buffers against coastal erosion and flooding. Promoting Sustainable Coastal Structures: Encouraging the design and construction of eco-friendly coastal protection measures that work with natural sediment dynamics rather than against them. Implementing Comprehensive Coastal Zone Management: Developing a holistic coastal management framework that integrates environmental, economic, and social considerations, allowing for adaptive responses to changing conditions. Conducting Ongoing Monitoring and Research: Establishing long-term monitoring programs to assess the effectiveness of coastal management strategies and adapt them based on emerging data. Our collective aspiration should be to harmonize the wisdom of the past with the foresight of the future, ensuring that the Kozhikode coastal plain endures as a thriving, resilient landscape for generations to come. The echoes of the past and the whispers of the future reverberate across the sands of Kozhikode, beckoning us to tread wisely and leave an indelible mark of responsible custodianship on this coastal wonder. As we conclude this exploration, we are reminded that the dynamic saga of the Kozhikode coast is not only a geological marvel but a call to action—a call to honor, protect, and sustain the delicate dance between land and sea. Declarations Acknowledgments The authors would like to thank the Director of the National Centre for Earth Science Studies (NCESS), Thiruvananthapuram, for the esteemed support provided during the study period. The first author is also thankful to Dr. L. Sheela Nair (Head, Marine Geoscience group, NCESS) for her heartful guidance and inspiration during the entire study. The authors gratefully acknowledge the great effort and support of Mr. Sreeraj MK, Akhil T, and Tiju I Vargese during the field data collection and lab analysis. The authors are also thankful to all staff of Marine Geoscience Group and Mrs. Reshma K of NCESS for their enormous support and inspiration for this study. Ethical Approval Not Applicable Funding The authors declare that this research work did not receive funding from any source. Availability of data and materials The datasets and research materials used in this study are available from the corresponding author upon reasonable request. References Aboo Ishaque P K. (2012). Urban Environment and Social Well being in Calicut City . Aligarh Muslim University. Agrawal, D. P., & Roy, B. (1978). Miliolite problem SEM and other analytical data. Ecology and Archaeology of Western India. C RM Seminar , 218–223. Ahmad, E. (1972). Coastal Geomorphology of India . Orient Longman. Alappat, L., Frechen, M., Sree Kumar, S., Suresh Babu, D. S., Ravur, R., & Tsukamoto, S. (2015). 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OCEANS 2022 - Chennai , 1–11. https://doi.org/10.1109/OCEANSChennai45887.2022.9775358 Ramesh R, & Bhatt J R. (2018). Climate change and the vulnerable Indian coast . Ramesh R, Purvaja R, & Senthil V A. (2013a). Shoreline Change Assessment for Kerala Coast . https://doi.org/10.1007/s12594-018-1072-x Ramesh R, Purvaja R, & Senthil V A. (2013b). Shoreline Change Assessment for Kerala Coast . https://doi.org/10.1007/s12594-018-1072-x Roy, B., Penha-Lopes, G. P., Uddin, M. S., Kabir, M. H., Lourenço, T. C., & Torrejano, A. (2022). Sea level rise induced impacts on coastal areas of Bangladesh and local-led community-based adaptation. International Journal of Disaster Risk Reduction , 73 , 102905. https://doi.org/10.1016/j.ijdrr.2022.102905 Samsuddin, M., Ramachandran, K. K., & Dora, Y. L. (1992). Quartz Grain Surface Textures as Indicators of Depositional History of Beach And Strand Plain Sedinlents Along the North Kerala Coast. Journal Geological Soaety of India , 40 , 501–508. Samsuddin M, Ramachandran K K, John Mathai, Jayaprasad B K, & Neelakandan V N. (2008a). Natural Resources and Environmental Atlas of Kerala; Kozhikode District (1st ed.). Centre for Earth Science Studies. Samsuddin M, Ramachandran K K, John Mathai, Jayaprasad B K, & Neelakandan V N. (2008b). Natural Resources and Environmental Atlas of Kerala; Kozhikode District (1st ed.). Centre for Earth Science Studies. Selvan, S. C., Kankara, R. S., Prabhu, K., & Rajan, B. (2020). Shoreline change along Kerala, south-west coast of India, using geo-spatial techniques and field measurement. Natural Hazards , 100 (1), 17–38. https://doi.org/10.1007/s11069-019-03790-2 Sheela Nair, L., Prasad, R., Rafeeque, M. K., & Prakash, T. N. (2018a). Coastal Morphology and Long-term Shoreline Changes along the Southwest Coast of India. Journal of the Geological Society of India , 92 (5), 588–595. https://doi.org/10.1007/s12594-018-1072-x Sheela Nair, L., Prasad, R., Rafeeque, M. K., & Prakash, T. N. (2018b). Coastal Morphology and Long-term Shoreline Changes along the Southwest Coast of India. Journal of the Geological Society of India , 92 (5), 588–595. https://doi.org/10.1007/s12594-018-1072-x Sreekesh, S., Sreerama Naik, S. R., & Rani, S. (2018). Effect of Sea Level Changes on the Groundwater Quality along the Coast of Ernakulam District, Kerala. Journal of Climate Change , 4 (2), 51–65. https://doi.org/10.3233/jcc-1800013 Suchindan G K, Samsuddin M, & Thrivikramji K P. (1987). Coastal Geomorphology and Beach Erosion and Accretion in the Northern Kerala Coast. Journal of the Geological Society of India , 29 , 379–389. Suchindan, Samsuddin, Ramachandran, K., & Haneeshkumar, V. (1996). Holocene coastal landforms along the northern Kerala coast and their implications on sea level changes. International Seminar on Quaternary Sea Level Variations, Shore Line Displacement and Coastal Environment . UNEP. (2007). Percentage of Total Population Living in Coastal Areas . United Nations. (2017, June). People and Oceans. The Ocean Conference . Unnikrishnan, A. S., Rupa Kumar, K., Sharon, E. F., Michael, G. S., & Patwardhan, S. K. (2006). Sea level changes along the Indian coast: Observations and projections. Current Science , 90 (3), 362–368. Vaidyanadhan, R. (1981). Sea Level. In M. J. Tooley (Ed.), Int. Bull IGCP Project No. 61 . Univ. Durham. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 06 May, 2025 Reviewers agreed at journal 25 Apr, 2025 Reviewers invited by journal 08 Apr, 2025 Submission checks completed at journal 28 Mar, 2025 First submitted to journal 28 Mar, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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11:50:51","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":193664,"visible":true,"origin":"","legend":"\u003cp\u003eGraphical representation of borehole data logs of selected locations\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-6159107/v1/254f7a6f750ae86b634510a3.png"},{"id":80313701,"identity":"4eed3951-d654-45ef-bd1b-0921d21c2719","added_by":"auto","created_at":"2025-04-10 11:58:51","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1390325,"visible":true,"origin":"","legend":"\u003cp\u003eThe monument shows the beach position during the landing of Vasco De Gama, a Portuguese explorer\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-6159107/v1/ecd1c9a22fe4b393d547e85a.png"},{"id":80312955,"identity":"8c55f47b-ecd6-4ac3-bb08-62c2f28f521e","added_by":"auto","created_at":"2025-04-10 11:50:51","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":176533,"visible":true,"origin":"","legend":"\u003cp\u003eHolocene Shoreline and Coastal Morphology of Kozhikode\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-6159107/v1/f74e0aef6e1ade49339386ca.png"},{"id":80312953,"identity":"c588c74c-8edd-437b-8f08-5a0ffd0931c2","added_by":"auto","created_at":"2025-04-10 11:50:51","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":240771,"visible":true,"origin":"","legend":"\u003cp\u003ePresent Shoreline Trend along Kozhikode Coast\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-6159107/v1/7dba54349c7e14dd2950131a.png"},{"id":80314124,"identity":"ccae8916-7e3b-4183-a204-d73500c97b17","added_by":"auto","created_at":"2025-04-10 12:06:51","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":153742,"visible":true,"origin":"","legend":"\u003cp\u003eComputed EPR and LRR for the Kozhikode Coast\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-6159107/v1/42c681b9be3f32b87dd31f2a.png"},{"id":80312956,"identity":"7ca3f3db-e035-45db-aa56-8391653d21c6","added_by":"auto","created_at":"2025-04-10 11:50:51","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":158713,"visible":true,"origin":"","legend":"\u003cp\u003eMeasured MSLs during 1939 – 2013 for Ernakulum Station. (Data source: PSMSL)\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-6159107/v1/4400fb5c9d29479f4a5678ec.png"},{"id":80312963,"identity":"8a45f5ab-ce16-4d6c-a727-55d00d8b11c2","added_by":"auto","created_at":"2025-04-10 11:50:51","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":3490605,"visible":true,"origin":"","legend":"\u003cp\u003eInundated Wetland for 1 m for Kozhikode District.\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-6159107/v1/5858cef3c788c4def8eb6552.png"},{"id":80315486,"identity":"5b20a939-495e-4444-a539-d08029505e11","added_by":"auto","created_at":"2025-04-10 12:22:54","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":7986832,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6159107/v1/282313c3-51ae-4f12-9f8c-2b35f34b8d20.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Paleoshoreline to Anthropocene Coast: Assessing Coastal Stability and Vulnerability in Response to Sea Level Changes","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eThe Quaternary period is marked by the appearance of the human race and the evolution of various cultures, particularly during the Late Pleistocene and Holocene epochs. Marine transgressions and regressions were common during this time, shifting the world's coastlines. Furthermore, these oscillations have led to geomorphological changes such as the development of backwaters, estuaries, marine terraces, spits, barriers, beach ridges, and shifts in river courses (Ahmad, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e1972\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eVarious natural and anthropogenic forcing factors influenced the highly dynamic coastal zones throughout this geological period, including sea-level rise, extreme events, local oceanic and atmospheric processes, and ground subsidence (Benveniste et al., \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Coastal zones are the cradles of world civilization and human development. According to the fact sheet published by the United Nations (UN) in 2017, nearly 10 percent of the world's population lives in coastal areas with elevations less than 10 meters above Mean Sea Level (United Nations, \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Despite constituting only a tenth of the global landmass, two-thirds of the world's mega-cities are situated along coastal zones worldwide (Burt et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; CIESIN, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Duarte et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; UNEP, \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2007\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eKozhikode is one of the rapidly growing urban centers on this coast and holds the status of being one of the ancient coastal cities of peninsular India. The sea pier along this coast was constructed during the colonial era, making it the region's first artificial coastal structure. Its development was primarily for military purposes and to facilitate foreign trade for the dynasty. The headlands and promontories of Kadalur, Palakkulam, Parappalli, Thoovappara, and Elathur are natural coastal structures that play a crucial role in modifying the Kozhikode coast. The soil composition in Kozhikode can be categorized into four major types: coastal alluvial soil in the coastal plain and low-lying areas, riverine alluvial soil along the riverbanks, red loam soil, and brown hydromorphic soil (Aboo Ishaque P K, \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Cenozoic alluvium sediments of recent age cover the coastal zone at a few places; the crystalline rocks are cross-cutter by basic dykes, comprised mainly of charnockites with enclaves of mafic granulites belonging to the Lower Precambrian age. In the midlands, these rocks are, in some places, covered by laterites. The surficial geological features of the coastal belt mainly comprise sand-dunes, occasionally interspersed with sandstones and clays. Kozhikode was the capital of the well-known kingdom of the 'Zamorins' for many years and later became the capital of the Malabar district during the British rule. Arab-Persian traders arrived here before the 6th century, and Vasco De Gama landed here during his ocean exploration, marking the beginning of trade between South India and Europe.\u003c/p\u003e \u003cp\u003eThe North Kerala coast (also known as the Malabar coast) is recognized as the most stable and rapidly developing coastal zone along the west coast of India. This coastal plain was formed during the Holocene through fluvio-tidal processes. Numerous scholars have extensively studied the evolution of coastal landforms in the region and have affirmed that the Kerala coastal belt is a young coastal plain, with Holocene-Pleistocene sedimentation supported by various researchers (Alappat et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Nair N J K et al., \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e1989a\u003c/span\u003e; Narayana A C \u0026amp; Priju C P, 2006; Padmalal et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Samsuddin M et al., \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2008a\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSeveral scholarly works and research groups have addressed the shoreline trend along the Kerala coast, including studies by (CWC, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Ramesh R et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2013a\u003c/span\u003e; Ramesh R \u0026amp; Bhatt J R, 2018; Selvan et al., \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Sheela Nair et al., \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2018a\u003c/span\u003e). These studies have collectively concluded that the Kerala coast has been experiencing an erosive trend over the last few decades. The changes in shoreline associated with coastal protection measures constructed along the Kerala coast were thoroughly investigated by (Murthy C S et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e1980\u003c/span\u003e). However, these studies often considered the coast at a smaller scale.\u003c/p\u003e \u003cp\u003eThis study focuses on the densely populated 50 km long Kozhikode city coastline, characterized by a high-energy, micro-tidal nature. Our examination indicates that the Kozhikode coast experienced accretion from the Holocene to recent years; however, this accreting trend has reversed in the last few decades. We closely examine this reversal of shoreline dynamics from the Holocene to the present and associated coastal vulnerability, shedding light on the high-energy coastal paradigm of the region.\u003c/p\u003e"},{"header":"2. Study Area","content":"\u003cp\u003eThe Kozhikode coast is situated at the heart of the Malabar coast, encompassing the northern coastal plain of Kerala. The specific stretch of coastline under investigation spans from Kadalur headland in the north to the Kadalundi estuary in the south, covering a shoreline length of 50 km (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). This coastal zone comprises four estuaries: Korapuzha, Kallayi, Beypur, and Kadalundi, numerous small creeks, and three harbors: Koyilandi, Puthiyappa, and Vellayil. The drainage network of this coastal zone, along with associated water bodies, is formed by three river systems (Agalapuzha, Kallai, and Chaliyar) and one canal (TS Canal). The two principal harbors, Koyilandi and Puthiyappa, significantly influence the fishing activity of the region, in conjunction with the significant estuaries, which also impact the micro-geomorphology of the area.\u003c/p\u003e \u003cp\u003eThe exposed promontories and headlands at frequent intervals, coupled with sediment discharges from the estuaries, shape the characteristics of this coastal plain. The geomorphological signatures of the area reflect the physical processes it has undergone and their relationship to local geological structures. Notable landforms of the Malabar coast or north Kerala coast encompass the coastal morphological features of the Holocene period, including coastal plains of recent alluvium, barrier reefs, coast-parallel lagoons, and lateritic hills, as well as hard rock exposures from the tertiary period or even earlier. Ezhimala, Kannur, and Kadalur headlands represent significant rock exposures along this coast. Valiyaparamba, Kuppam, and Agalapuzha are vital lagoons off the coast that run parallel to the beach. Additionally, sediment-discharging estuaries such as Chandragiri, Azhithala, Valapattanam, Dharmadam, Kolavi, Korapuzha, Chaliyar, and Bharathapuzha contribute to the coastal dynamics of the Malabar coast. Unique for their short length and higher elevation gradient, the rivers in the area transport a considerable amount of coarse sediments, which are then deposited in the nearshore area. The paleochannels in the region have changed their course multiple times over its geological history.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"3. Methodology","content":"\u003cp\u003eTo delineate the Holocene landforms, we assessed geomorphic signatures and geological footprints using information from published literature and ground truthing. Additionally, we analyzed three borehole datasets to understand lithological structure and geological sedimentation processes. 'ESlog,' a web-based software for borehole logging presentation, was utilized to plot graphical representations of borehole samples. The geological history of the Kozhikode coastal zone was referenced from the \"Natural Resources and Environmental Atlas of Kerala: Kozhikode district\" published by CESS in 2008 (Samsuddin M et al., \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2008b\u003c/span\u003e). Parameters such as geological structure, lineaments, tectonics, and landform shape and structure were demarcated. Each geomorphic feature's spatial extension was plotted with accompanying explanations in this atlas. The boundary line separating the young coastal plain and coastal features of Holocene origin from the midland of lateritic origin was considered the Holocene shoreline for this study.\u003c/p\u003e \u003cp\u003eTo understand the present shoreline trend of the Kozhikode coast, 'Digital Shoreline Analysis System' (DSAS) (Version v5.1), an 'ArcGIS' extension tool developed by the \u0026lsquo;United States Geological Survey\u0026rsquo; for analyzing various shoreline statistics over time such as End Point Rate (EPR), Linear Regression Rate (LRR), and Weighted Linear Regression Rate (WLR) was utilized (Himmelstoss et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). The statistical values obtained were used to depict shoreline movements, including erosion and accretion, and the response of the coastline to specific coastal/marine events compared to its pre and post-dynamics. Considering the long-term changing scenario of the seacoast, the high water line (high tide line) was demarcated as a shoreline for different time periods (Dolan et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1980\u003c/span\u003e; Ramesh R et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2013a\u003c/span\u003e; Sheela Nair et al., \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2018a\u003c/span\u003e). Twelve shorelines from different periods, spanning from 1968 to 2024, were demarcated using various raster datasets.\u003c/p\u003e \u003cp\u003eThe choice of temporal data points was critical for capturing both long-term and recent shoreline dynamics, which is in line with the study\u0026rsquo;s objective of assessing coastal changes over varying timescales. The temporal points were chosen based on the availability of key historical and satellite datasets, as well as significant geomorphological and anthropogenic events that shaped the Kozhikode coast. Data for the Holocene period were taken from the NCESS Atlas, as it provides detailed insights into the geological history of the region, which is essential for understanding long-term coastal evolution. The 1968 and 1979 topographical maps from the Survey of India (SoI) provided crucial baseline information, as they represent the pre-satellite imagery era, allowing for the earliest possible assessment of shoreline position. Google imagery from 1984 and Landsat TM mosaic (30m resolution) from 1990 were selected to understand the transitional phase of coastal dynamics as human interventions, such as coastal development and infrastructure projects, began to influence the shoreline. The availability of consistent medium-resolution Landsat imagery enabled the assessment of shoreline trends at a global standard. High-resolution data from CARTOSAT-1 (2.5m resolution) and WorldView-2 (0.5m resolution) datasets were utilized to capture more recent (2000\u0026ndash;2014), finer-scale changes in shoreline position. These datasets provide detailed observations of smaller geomorphological processes such as localized erosion or accretion events. The very recent datasets from ArcGIS World Imagery and Google Imagery (\u0026lt;\u0026thinsp;1m resolution) were employed to analyze the most up-to-date shoreline positions, allowing for comparisons with historical datasets to determine ongoing trends of erosion and accretion.\u003c/p\u003e \u003cp\u003eThe choice of these temporal data points reflects the study\u0026rsquo;s objective to combine long-term and fine-scale temporal observations, providing a comprehensive understanding of shoreline dynamics on the Kozhikode coast. These datasets had varying scales/resolutions, including World View-2 images of very high resolution (0.5 m), Landsat images of medium resolution (30 m), and 1:50,000 Survey of India (SoI) topographical maps of course resolution. Appropriate uncertainty values were assigned for each data type to address the scale/resolution differences when integrating data from various sources on the ArcGIS platform. The downloaded and/or procured satellite imageries were re-registered with common precise Ground Control Points (GCPs) to the WGS 84 datum and 43 N zone of UTM projection. ArcGIS 10.6.1 is used to integrate and analyze data sets further. The details of datasets used to interpret the shoreline trend of the current situation are presented in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDetails of Datasets used as the source for Different Temporal Shorelines\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSl. No.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eYear\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eData Source\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePublisher\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eYear\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSurvey/ Acquisition\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eScale/ Resolution\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHolocene\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNCESS Atlas\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCESS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2000\u0026ndash;2004\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1:50000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1968\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eToposheet\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSOI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1967\u0026thinsp;\u0026minus;\u0026thinsp;168\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1963\u0026ndash;1965\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1:50000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1979\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eToposheet\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSOI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1979\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1977\u0026ndash;1978\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1:25000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1984\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGoogle Imagery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGoogle\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1984\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1990\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLandsat TM mosaic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGLCF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2002\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1990\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e30 m\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLandsat 7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGLCF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1999\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e15m\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCARTOSAT-1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNRSC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.5 m\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCARTOSAT-1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNRSC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.5 m\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2011\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eWorld View \u0026minus;\u0026thinsp;2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eDigital Globe\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2012\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2011\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.5 m\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2014\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCARTOSAT-1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNRSC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2014\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2014\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.5 m\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2018\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eArcGIS World Imagery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eESRI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2018\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2017\u0026ndash;2018\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;1 m\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGoogle Imagery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGoogle\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;1 m\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2024\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGoogle Imagery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGoogle\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2024\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;1 m\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eRates of change are expressed in terms of the distance of change per year. All methods used for calculating shoreline rate-of-change involve measuring the distances between different shoreline positions over time (Dolan et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e1991\u003c/span\u003e; Pr\u0026eacute;vost \u0026amp; Robert, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). The simplest method, the End Point Rate (EPR), uses only two shoreline positions, while the other method, Linear Regression Rate (LRR), utilizes more or all of the shorelines by considering respective time and location. The recent shoreline trend was interpreted based on the statistical values of the calculated LRR and EPR for the respective coastline. Shoreline change values were categorized into seven groups to indicate the intensity of change: Very High - High - Moderate Accretion or Erosion, and Stable Coast. This classification standard for shoreline changes was initially introduced by NCSCM (Ramesh R et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2013b\u003c/span\u003e) and NCESS (Sheela Nair et al., \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2018b\u003c/span\u003e). A negative value of shoreline statistics indicates coastal erosion, whereas a positive value indicates an accretion trend of the coastline.\u003c/p\u003e \u003cp\u003eSea-level changes in the Kozhikode coast were studied by comparing it to the nearby well-analyzed coastal zone of Ernakulum. Tide gauge data with longer periods and a minimum null value in data frequency were considered for the study. Long-term tidal and Mean Sea Level (MSL) data for Ernakulum, provided by the Permanent Service for Mean Sea Level (PSMSL), were referenced to understand the sea level status of Kozhikode (Dinesh Kumar, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2001\u003c/span\u003e)(Chowdhury \u0026amp; Behera, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). Predicted Sea Level Rise (SLR) changes were plotted on the district map by simulating sea level increases of one meter and two meters (Mani Murali \u0026amp; Dinesh Kumar, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). Land use and land cover maps were overlaid on the inundation map to understand the categories of land loss.\u003c/p\u003e"},{"header":"4. Results and Discussion","content":"\u003cp\u003eUnderstanding the geomorphology of any coastal zone is crucial for implementing appropriate land and risk management strategies to achieve the sustainable development goals (SDGs) set by the United Nations Development Programme (UNDP). Geomorphological databases and an understanding of landform dynamics also aid various applied sectors of environmental research. The coastal zone of western India, particularly northern Kerala, is relatively more stable than the east coast, despite being a high-energy coast. Numerous scholars have attempted to study the evolution of landforms and coastal features of Kerala from diverse perspectives. For example, (Suchindan G K et al., \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e1987\u003c/span\u003e) conducted one of the initial studies exploring the coastal geomorphology of Kerala, focusing on aspects like strand plains and cliffed shorelines in northern Kerala.\u003c/p\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e4.1. Geomorphic Appreciation of the Kozhikode Coast:\u003c/h2\u003e \u003cp\u003eThe prominent geomorphic processes active in the Kozhikode coastal zone include marine, estuarine, fluvial, and paleo-tidal processes(Nair N J K et al., \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e1989b\u003c/span\u003e). The urbanized coastal area of Kozhikode in northern Kerala is characterized by the presence of lagoons, backwaters, and estuaries. Log data from three boreholes, representing the north, central, and south sectors of the plain, were interpreted to understand the lithological structures of the Kozhikode coastal plain (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). These boreholes revealed fluvio-marine sediments in their upper layers. The analysis of borehole data logs strongly confirmed the existence of a marine ecosystem at deeper depths and the gradual deposition of fluvio-marine sediments in these locations. The deposition of quaternary formations describes the accretion trend of the Kozhikode coastal plain during the Holocene \u0026ndash; Pleistocene period.\u003c/p\u003e \u003cp\u003eFor example, the Vengalam borehole represents the Northern Sector of the Koyilandi region and indicates a significant presence of fluvio-marine deposits. Tertiary rock formations were not found up to the termination point of 36 m. Notably, there is an in-situ lateritic soil at a depth of 19 to 23 m, and clay-mixed sandy soils of estuarine deposits were reported to be up to 36 m. In the central sector, represented by the borehole in Vellayil of the Kozhikode city region, the thickness of quaternary sediments was reported to be 20 m in depth. Moving to the southern sector, the borehole in the Beypur region represents the coastal floodplains of the Kallayi \u0026ndash; Chaliyar river basin. This borehole illustrates a young coastal plain with abundant signatures of paleochannels. For instance, the Nallalam borehole, located 2.8 km eastward of the south Marad beach, exhibited deposits of clay sand from the Quaternary period up to a depth of 10 m. The borehole was positioned at the southward bank of paleochannels of the Chaliyar River and at the northward slope of the Cheruvannur denudational hill, which later caused the diversion of the Chaliyar River. These borehole data logs provide strong evidence of a marine ecosystem at deeper depths, with gradual deposition of fluvio-marine sediments at these locations. The depositions of quaternary formations describe the accretion trend of the Kozhikode coastal plain during the Holocene \u0026ndash; Pleistocene period.\u003c/p\u003e \u003cp\u003eHistorically, during his sea route exploration, the eminent Portuguese explorer Vasco da Gama anchored at Kappad beach just north of Kozhikode city on 20th May 1498, opening a trade route between Europe and Malabar. His first footstep on the Malabar coast is commemorated on land, marked by a government-developed monument (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). This monument, which is presently located 100 meters inland from the shoreline, supports the accretion trend of this coast over the past few centuries along with other geological setting. Coastal landforms such as ridges, swales, sand dunes, and coastal alluvium deposits distributed along the coastal plain of Koylandi, Kappad, Kozhikode, and Beypur indicate the relation of the geomorphic evolution of this coast with fluvio-marine processes. Previous studies by (Vaidyanadhan, \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e1981\u003c/span\u003e) and (Merh, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e1992\u003c/span\u003e) have described that the Kerala coast signifies the filling up of a series of bays during the Holocene with mud and later sands, dating back to 4460 years before the present.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e4.2. Shoreline at Holocene Epoch:\u003c/h2\u003e \u003cp\u003eAs per the CESS atlas titled 'Natural Resources and Environmental Atlas of Kerala: Kozhikode district' (Samsuddin M et al., \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2008b\u003c/span\u003e), the paleo shoreline during the Holocene period is demarcated at varying distances from the present shoreline across different sectors of the study area. The ground truthing surveys were conducted to eliminate the scale error of the atlas by identifying the geomorphological features (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). In the Kadalur \u0026ndash; Korapuzha sector, the paleo shoreline is located just 500 meters to 3.7 kilometers eastward from the current shoreline. In the Korapuzha \u0026ndash; Kallayi sector, it extends from 700 meters to 3.3 kilometers from the present shoreline. Moving to the Kallayi \u0026ndash; Beypur sector, the paleo shoreline is situated 2.4 to 4.7 kilometers away from the current shoreline. Lastly, in the Beypur\u0026ndash;Kadalundi sector, the distance ranges from 200 to 800 meters from the present coastline. Identifying paleochannels using satellite imagery and observing young coastal features during field investigations substantiate these findings.\u003c/p\u003e \u003cp\u003e\u003cstrong\u003e\u003cstrong\u003e\u003cem\u003e4.2.1.\u0026nbsp;\u003c/em\u003e\u003c/strong\u003eKadalur \u0026ndash; Korapuzha Sector\u003c/strong\u003e: In this northern portion of the study area, the paleo shoreline is supported by paleochannels and evidence of various stages of landform development. Kadalur headland, in the north of this sector, is a rock exposure that indicates the past tidal action of this coast and its interaction with the west-flowing river system in the area (Nair N J K et al.,\u0026nbsp;1989b). The Agalapuzha-Korapuzha river system debouches into the Lakshadweep Sea through the northern side of the Elathur headland. There are young coastal landforms such as ridges, swales, and coastal plains West of the Agalapuzha\u0026ndash;Korapuzha river system, parallel to the present coastline. The paleo shoreline starts about 500 meters south of Kadalur headland in the Thikkodi region, gradually increasing its distance from the current shoreline in a southeast direction, reaching a maximum spread of 3.7 km at Kappad, and then moving southward up to the Korapuzha estuary.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cstrong\u003e\u003cem\u003e4.2.2.\u0026nbsp;\u003c/em\u003e\u003c/strong\u003eKorapuzha \u0026ndash; Kallayi Sector\u003c/strong\u003e: In this sector, the Elathur headland is a key feature influencing the tidal and paleo activities of the coast. The paleo shoreline doesn\u0026apos;t follow paleochannels south of Agalapuzha waterbodies. Instead, this area has been accreted by sediments trapped by denudational hills and headlands. The Holocene shoreline in this sector starts from Korapuzha and runs southward at a distance of 1.5 km from the present shoreline up to Purakkattiri Kadavu. It then follows the Poonoor Puzha channel and reaches Mokavoor, which is 3.7 km away from the present coastline. The paleo shoreline takes a parabolic structure, reaching almost 750 meters near the present coast at the crest of the parabola around the West Hill of Kozhikode city. It then follows an irregular straight line in a southeast direction, reaching the Kallayi River.\u003cbr\u003e\u003cstrong\u003e\u003cstrong\u003e\u003cem\u003e4.2.3.\u0026nbsp;\u003c/em\u003e\u003c/strong\u003eKallayi \u0026ndash; Beypur Sector\u003c/strong\u003e: This sector features the broadest young coastal plain among the Kozhikode coastal plains. The Holocene shoreline starts from the Kallayi River in the southeast direction, approximately 2.3 km from the present shoreline. It follows the river channel up to the starting point of the Nallalam canal at Mankavu, then changes direction eastward along with the channel and reaches Nallalam, situated 4.8 km away from the current shoreline in a south direction. At Nallalam, it diverts from the canal and reaches the Chaliyar River through the western side of the Cheruvannur plateau in the same southward direction.\u003cbr\u003e\u003cstrong\u003e\u003cstrong\u003e\u003cem\u003e4.2.4.\u0026nbsp;\u003c/em\u003e\u003c/strong\u003eBeypur \u0026ndash; Kadalundi Sector\u003c/strong\u003e: In this southernmost area, the old shoreline runs almost parallel to the present coast with some variations. The paleo shoreline in the north half of this sector is very narrow, with an average distance of 200 to 300 meters from the present coast. In the southern half, the old shoreline maintains a distance of 800 meters from the coast over a 700-meter length, nearing the Kadalundi River.\u003c/p\u003e\n\u003cp\u003eMoreover, studies on past sea-level changes suggest a history of accretion along the Kozhikode coast during the Holocene period. The width of the young coastal plain varies across the study area, and the evolution of this coastal plain is attributed to river discharges, tidal transgressions, and regressions.\u003c/p\u003e\n\u003cdiv id=\"Sec7\"\u003e\n \u003ch2\u003e4.3. Present shoreline Trend:\u003c/h2\u003e\n \u003cp\u003eThe present study reveals the state of the Kozhikode coast in terms of shoreline erosion and accretion trends. Even with extensive artificial coastal protection measures covering 90 percent of the shoreline, the analysis indicates that 39.12 percent of the total shoreline is recorded for moderate erosion and 48.67 percent is reported as stable. Even though only 0.92 percent of the total coastline is affected by high coastal erosion, without any report of very high erosion, the accreting trend is found only for 11.27 percent of the total coastline, while the entire coast was reported as accreting up to the recent period. Table 2 gives a detailed idea of this coastline\u0026apos;s erosion and accretion trend and compares EPR and LRR values for the shoreline statistics.\u0026nbsp;\u003c/p\u003e\n \u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 2\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eShoreline Change Statistics of Kozhikode Coast\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003eSl. No.\u003cbr\u003e\u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003eShoreline Change\u003cbr\u003e\u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003eRespective Change in m/y\u003cbr\u003e\u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003eCoastline Length as per\u003cbr\u003e\u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003eEPR (%)\u003cbr\u003e\u003c/th\u003e\n \u003cth align=\"left\"\u003eLRR (%)\u003cbr\u003e\u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003eVery High Erosion\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026lt; -5\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e0\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e0\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003eHigh Erosion\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e-5 to -2.5\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e0.805\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e0.920\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003eModerate Erosion\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e-2.5 to -0.5\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e34.983\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e39.125\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u003cstrong\u003e4\u003c/strong\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003eStable\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e-0.5 to 0.5\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e48.216\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e48.677\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u003cstrong\u003e5\u003c/strong\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003eModerate Accretion\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e0.5 to 2.5\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e14.845\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e10.126\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u003cstrong\u003e6\u003c/strong\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003eHigh Accretion\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e2.5 to 5\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e0.805\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e0.690\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u003cstrong\u003e7\u003c/strong\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003eVery High Accretion\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026gt;\u0026thinsp;5\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e0.345\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e0.460\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003eThe analysis reveals that the north sector of the Kadalur \u0026ndash; Korapuzha region is relatively stable, with exceptions near headlands/promontories and seawall end erosion points (Fig. 5). A notable accretion is reported along this sector at the south of \u003cem\u003eKadalur\u003c/em\u003e headland and \u003cem\u003eThoovappara\u003c/em\u003e promontory. The Korapuzha \u0026ndash; Kallayi sector shows a high accretion trend to the south of Puthiyappa harbor due to sediment trapping by the breakwater (Fig. 6.). The southern portion of this coast was recorded as moderate erosion. The Kallayi \u0026ndash; Beypur sector is significantly impacted by moderate coastal erosion, making it the most eroded coast in the region. Conversely, the southern part of the Beypur \u0026ndash; Kadalundi sector displays a very high accretion trend due to the impact of breakwaters constructed at the river mouths.\u003c/p\u003eThe paleo shoreline analysis reveals a historical accretion trend up to the 20th century, corroborated by borehole data and the monument at Vasco De Gama\u0026apos;s first landing at Kappad beach. However, recent trends (1968\u0026ndash;2024) demonstrate a reversal in shoreline dynamism due to human interventions, such as harbors, coastal protection measures, and alterations in sediment sources and movements. The construction of artificial structures, particularly seawalls, has significantly impacted the natural beach-gaining processes along the coast. Nearly 90 percent of this coast is regulated by artificial structures like seawalls, groins, tourism facilities, breakwaters, etc. Seawall itself was constructed at 67 percent length along this coast (Table 3).\u003cp\u003eThe density of the coastal population along the Kerala coastal plain necessitates extensive coastal protection measures. The end/side erosion of already constructed seawalls or other coastal structures will frequently demand the construction of new structures or extend the existing ones towards further extremes (Rafeeque \u0026amp; Thomas, 2022; Sheela Nair et al., 2018a). The study identifies that nearly 90% of the coast is regulated by artificial structures, primarily seawalls, and emphasizes the need for sustainable coastal management to balance development and natural processes. The impact of these coastal protection measures on shoreline changes has been previously studied in the context of the Kerala coast (Murthy C S et al., 1980).\u003c/p\u003e\n \u003cdiv\u003e\u0026nbsp;\u003ctable id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 3\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eArtificial structures along Kozhikode coast.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003eSl.No\u003cbr\u003e\u003c/th\u003e\n \u003cth align=\"left\"\u003eStructure\u003cbr\u003e\u003c/th\u003e\n \u003cth align=\"left\"\u003eQuantity\u003cbr\u003e\u003c/th\u003e\n \u003cth align=\"left\"\u003ePercentage\u003cbr\u003e\u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e1.\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003eSeawall\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e31.45 km\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e66.91\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e2.\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003eTourism Structures\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e2.70 km\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e5.74\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e3.\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003eGroins\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e18 Nos\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e-\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e4.\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003eBreakwater\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e10 Nos\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e-\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e5.\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003eHarbour\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e3 Nos\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e-\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e6.\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003ePort\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e1 (Estuary)\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e-\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e7.\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003eSea Pier\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e2 Nos\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e-\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003eThe shoreline change analysis along the Kozhikode coast reveals significant trends influenced by geological and anthropogenic factors. The statistical evaluation of the shoreline dynamics, including the End Point Rate (EPR) and Long-Term Rate of Change (LRR), indicates a troubling erosion pattern. The calculated EPR and LRR suggest that the coastline is retreating, a phenomenon commonly observed in coastal regions affected by similar challenges, including sea-level rise and human activities. The regions along the eastern coast of the United States and parts of Bangladesh have documented comparable rates of erosion driven by similar factors, including increased storm intensity and anthropogenic alterations to the coastal environment (Griggs \u0026amp; Reguero, 2021; Roy et al., 2022). These comparisons illustrate that the challenges faced by the Kozhikode coast are part of a broader global issue concerning coastal vulnerability and the need for effective management strategies.\u003c/p\u003e\n \u003cp\u003eThe long-term consequences of artificial structures on coastal ecosystems are profound. Although they may provide immediate protection to certain areas, the disruption of sediment transport can lead to habitat degradation, loss of biodiversity, and diminished ecological functions of coastal environments. This situation calls for a comprehensive understanding of the ecological impacts of these interventions and the necessity for more sustainable approaches. To address the challenges posed by both geological and anthropogenic factors, it is imperative to adopt sustainable coastal management strategies, like Soft Engineering Solutions, Nature-Based Solutions (NbS), and Integrated Coastal Zone Management (ICZM). By emphasizing these strategies, we can enhance the resilience of the Kozhikode coast and similar regions, ensuring that coastal management practices align with ecological preservation and sustainability goals.\u003c/p\u003e\n \u003cp\u003eIn summary, the Kozhikode coastal area, characterized by a young coastal plain, has experienced a reversal in shoreline dynamism from the Holocene trend to the present due to human interventions and artificial coastal measures. Accretion trends that were prevalent up to the last century have reduced, and coastal dynamics are shifting due to these influences. The southern coastline is severely affected by coastal erosion, highlighting the need for effective coastal management strategies.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec8\"\u003e\n \u003ch2\u003e4.4. Sea Level Rise and Future Concerns:\u003c/h2\u003e\n \u003cp\u003eUnderstanding the current and projected sea level rise (SLR) along the Kozhikode coastline is crucial for comprehending future challenges for this coastal plain. The nearest long-term tidal/SLR observations are from Ernakulam (130 km southward) and Mangalore (180 km northward). Ernakulam provides a continuous dataset and is the closest station to the Kozhikode coast.\u003c/p\u003e\n \u003cp\u003eTidal datasets from 1939 to 2013 recorded by the PSMSL (NOC, n.d.) station at Ernakulam show a linear trend in mean sea level, indicating an increase from 6750 mm in 1940 (lowest MSL year) to 6998 mm in 2013 (Fig. 7). The sea level changes can be identified in three periods with different trends: a steady increase from 1939 to 1959, ups and downs from 1959 to 1986, and a further steady increase from 1986 to 2013. The Sea Level of the \u003cem\u003eErnakulum\u003c/em\u003e coast has risen, particularly since 1989, and this rise has become more consistent since 2004, as seen in the anomalies (Fig. 7).\u003c/p\u003eStudies by(Dwivedi \u0026amp; Sharma, 2005) predicted an SLR of 125 mm at Cochin by 2100 after assessing 58 years of observations. Another study by(Sreekesh et al., 2018) analyzed tide gauge data from Kochi (1971 to 2007) and estimated a sea level rise of 0.0018 m/year (1.8 mm/yr) along the Ernakulam district of Kerala\u0026apos;s coast. The observed sea level changes are influenced by various processes of global warming and potential vertical land movements near the measuring instrument (Unnikrishnan et al., 2006). However, past research suggests that significant vertical land movement is not notable along the southwest coast of India (Kailasam, 1975), supporting the conclusion that observed sea level rise is primarily due to climatic changes and associated processes. Studies by(Samsuddin et al., 1992)(Suchindan et al., 1996), and(Haneeshkumar et al., 1998) traced out the sea-level rise and fall along the Kerala coastline of the SE Arabian Sea, providing valuable insights into coastal morphological features. Additionally, studies on the Maharashtra coast of the NE Arabian Sea by(Agrawal \u0026amp; Roy, 1978) and(Kale \u0026amp; Rajaguru, 1985) provided crucial information on transgression and regression phenomena since 35,000 BP based on radiocarbon dating.\u003cp\u003eThe study conducted a thorough analysis of the potential impact of sea-level rise on various land use and land cover (LU/LC) classes in Kozhikode district (Table\u0026nbsp;4). The impact on various environmentally sensitive areas, such as wetlands and mangroves, was also taken into consideration, and the probable areas to be affected due to the projected sea-level rise were also quantified. It was found that if the sea level rises by 1 meter, an 11.251 sq. km area will be submerged underwater. The analysis identified that 28% of the total area of Kozhikode district is vulnerable to projected sea-level rise scenarios (Fig.\u0026nbsp;8).\u003c/p\u003e\n \u003cp\u003eConsidering the projected sea-level rise scenarios, it is imperative to develop sustainable coastal management plans to mitigate potential adverse effects on coastal landforms, ecosystems, and human settlements. The analysis provides valuable information to guide proactive measures and policy decisions for the preservation and sustainable development of the Kozhikode coastline in the face of future sea-level rise.\u003c/p\u003e\n \u003cdiv\u003e\u0026nbsp;\u003ctable id=\"Tab4\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 4\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eLand use Land Cover Statistics \u0026ndash; Kozhikode District\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003eLand Class\u003cbr\u003e\u003c/th\u003e\n \u003cth align=\"left\"\u003eArea (km\u003csup\u003e2\u003c/sup\u003e)\u003cbr\u003e\u003c/th\u003e\n \u003cth align=\"left\"\u003e1m SLR (km\u003csup\u003e2\u003c/sup\u003e)\u003cbr\u003e\u003c/th\u003e\n \u003cth align=\"left\"\u003e2m SLR (km\u003csup\u003e2\u003c/sup\u003e)\u003cbr\u003e\u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003eResidential (Converted from paddy)\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e0.7\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e0\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"char\"\u003e0.05\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003ePerennial\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e45.2\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e42.312\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"char\"\u003e42.31\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003eMixed crop\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e103\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e8.43\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"char\"\u003e11.74\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003eMixed built-up\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e48.93\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e8.64\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"char\"\u003e8.64\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003eMarshy\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e3.45\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e1.31\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"char\"\u003e1.34\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003eLand without scrub\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e1.28\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e0.4\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"char\"\u003e0.64\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003eLand with scrub\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e14.35\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e14.35\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"char\"\u003e14.35\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003eCurrent fallow\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e1.406\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e1.1\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"char\"\u003e1.1\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003eCommercial\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e4.12\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e0.02\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"char\"\u003e0.68\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003eCoconut-dominant mixed crop\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e1194.13\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e570.15\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"char\"\u003e587.01\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003eCoconut\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e15.13\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e0.95\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"char\"\u003e1.22\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003eCashew\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e1.5\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e0.13\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"char\"\u003e0.23\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003eBeaches\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e6.23\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e2.63\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"char\"\u003e4.85\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003eBanana\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e3.82\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"left\"\u003e0.41\u003cbr\u003e\u003c/td\u003e\n \u003ctd align=\"char\"\u003e0.41\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\u003cbr\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec9\"\u003e\n \u003ch2\u003e4.5. Comparative Analysis of Geological and Anthropogenic Influences on Coastal Change\u003c/h2\u003e\n \u003cp\u003eUnderstanding the dynamics of the Kozhikode coast necessitates a nuanced exploration of both geological and anthropogenic factors that contribute to shoreline changes. Like many coastal regions globally, the Kozhikode coast is experiencing the impacts of sea-level rise (SLR). As detailed in Section 1.4, the long-term tidal observations from nearby Ernakulam suggest a consistent increase in mean sea level, primarily attributed to global warming. Natural processes, including seawater thermal expansion and polar ice melting, exacerbate this trend. The projected impacts of a 1-meter rise could inundate approximately 11.251 km\u0026sup2; of coastal land, indicating that geological factors significantly shape the coastal landscape.\u003c/p\u003e\n \u003cp\u003eThe natural sediment supply along the Kozhikode coast, influenced by riverine inputs from the Kallayi and Chaliyar rivers, contributes to the coastal morphology. Historical data suggest that sediment accretion has characterized the region during the Holocene, driven by fluvio-marine processes and the deposition of quaternary sediments. Such geological processes inherently dictate landforms\u0026apos; spatial distribution and stability along the coast.\u003c/p\u003e\n \u003cp\u003eThe extensive installation of artificial coastal protection measures - covering approximately 90% of the shoreline - significantly alters the natural dynamics of sediment movement and shoreline stability. As indicated in Table\u0026nbsp;3, structures such as seawalls, groins, and breakwaters have been erected to combat erosion and protect urban development. However, these interventions can disrupt sediment transport, leading to localized erosion at the ends of seawalls and increased stability in other areas, which may contribute to a net loss of coastal resilience. The urbanization of the Kozhikode coastal zone has intensified pressure on coastal ecosystems. Land use changes, particularly the conversion of wetlands and agricultural lands into residential and commercial spaces, can exacerbate vulnerability to flooding and erosion. The study indicates that areas converted from paddy fields to residential zones are particularly susceptible to inundation under projected sea-level rise scenarios, demonstrating the interplay between human activities and natural vulnerabilities.\u003c/p\u003e\n \u003cp\u003eWhile geological factors such as natural sea-level rise and sediment dynamics are crucial in shaping the coastal landscape, the extent of anthropogenic impacts cannot be overstated. Human interventions have significantly altered the historical accretion trends that characterized the Kozhikode coast. Coastal protection structures, while designed to mitigate erosion, can lead to unintended consequences, such as enhanced erosion in adjacent areas and changes to sediment supply. The comparative analysis underscores the importance of a balanced coastal management approach, recognizing that natural processes and human activities influence coastal dynamics. Sustainable management strategies should aim to integrate natural and engineered solutions, considering the cumulative effects of geological and anthropogenic factors on the coastal environment.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"5. CONCLUSION","content":"\u003cp\u003eThe Kozhikode coastal plain, shaped during the Holocene epoch, has predominantly been characterized by accretion. The lithological and geomorphological features strongly affirm its depositional nature. Borehole data vividly portray extensive unconfined fluvio-marine sediment deposits that span the coastal plain. Notably, marine-derived sands and clays were observed at deeper depths, succeeded by the deposition of fluvio-marine sediments. The geological disposition and patterns of geomorphological features offer compelling evidence of the regression and transgression phases that mark the sea level changes during geological history.\u003c/p\u003e \u003cp\u003eBeyond the macro analysis of shoreline changes over geological time scales, a microanalysis of the last 50 years reveals a pressing concern: over 40 percent of the analyzed coastline is grappling with coastal erosion. Astonishingly, despite the safeguard provided by various artificial coastal structures covering 90 percent of the coast, only 48 percent remains stable, experiencing a shoreline change rate of less than \u0026plusmn;\u0026thinsp;0.5 meters per year. Concurrently, 11 percent of the shoreline is identified as accreting during the last half-century.\u003c/p\u003e \u003cp\u003eIt is hypothesized that the construction of diverse coastal structures has disrupted the natural sediment dynamics of the coast. Moreover, climatic factors such as extreme ocean currents, high waves, sea level rise, cyclones, and thunderstorms have likely influenced coastal stability over the past fifty years. The inundation analysis, a critical facet in the face of climate change, forewarns that with a one-meter rise in sea level, an expanse of 11.251 sq. km in Kozhikode would be submerged. Should sea levels rise by two meters, the total affected area would escalate to 14.675 sq. km, underscoring the urgency of proactive measures and sustainable coastal management.\u003c/p\u003e \u003cp\u003eIn this dynamic interplay between geological epochs and contemporary coastal challenges, awareness stands as our beacon, and sustainability our lodestar. To effectively address the challenges identified, specific policy recommendations include implementing a balanced approach that harmonizes development needs with the preservation of natural coastal processes. This could involve:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eEnhancing Natural Buffer Zones: Establishing and maintaining natural habitats such as mangroves and wetlands, which can act as effective buffers against coastal erosion and flooding.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003ePromoting Sustainable Coastal Structures: Encouraging the design and construction of eco-friendly coastal protection measures that work with natural sediment dynamics rather than against them.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eImplementing Comprehensive Coastal Zone Management: Developing a holistic coastal management framework that integrates environmental, economic, and social considerations, allowing for adaptive responses to changing conditions.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eConducting Ongoing Monitoring and Research: Establishing long-term monitoring programs to assess the effectiveness of coastal management strategies and adapt them based on emerging data.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003eOur collective aspiration should be to harmonize the wisdom of the past with the foresight of the future, ensuring that the Kozhikode coastal plain endures as a thriving, resilient landscape for generations to come. The echoes of the past and the whispers of the future reverberate across the sands of Kozhikode, beckoning us to tread wisely and leave an indelible mark of responsible custodianship on this coastal wonder. As we conclude this exploration, we are reminded that the dynamic saga of the Kozhikode coast is not only a geological marvel but a call to action\u0026mdash;a call to honor, protect, and sustain the delicate dance between land and sea.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003e\u003cem\u003eAcknowledgments\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors would like to thank the Director of the National Centre for Earth Science Studies (NCESS), Thiruvananthapuram, for the esteemed support provided during the study period. The first author is also thankful to Dr. L. Sheela Nair (Head, Marine Geoscience group, NCESS) for her heartful guidance and inspiration during the entire study. The authors gratefully acknowledge the great effort and support of Mr. Sreeraj MK, Akhil T, and Tiju I Vargese during the field data collection and lab analysis. The authors are also thankful to all staff of Marine Geoscience Group and Mrs. Reshma K of NCESS for their enormous support and inspiration for this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eEthical Approval\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot Applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eFunding\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that this research work did not receive funding from any source.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eAvailability of data and materials\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets and research materials used in this study are available from the corresponding author upon reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAboo Ishaque P K. 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(1992). Quartz Grain Surface Textures as Indicators of Depositional History of Beach And Strand Plain Sedinlents Along the North Kerala Coast. \u003cem\u003eJournal Geological Soaety of India\u003c/em\u003e, \u003cem\u003e40\u003c/em\u003e, 501\u0026ndash;508.\u003c/li\u003e\n\u003cli\u003eSamsuddin M, Ramachandran K K, John Mathai, Jayaprasad B K, \u0026amp; Neelakandan V N. (2008a). \u003cem\u003eNatural Resources and Environmental Atlas of Kerala; Kozhikode District\u003c/em\u003e (1st ed.). Centre for Earth Science Studies.\u003c/li\u003e\n\u003cli\u003eSamsuddin M, Ramachandran K K, John Mathai, Jayaprasad B K, \u0026amp; Neelakandan V N. (2008b). \u003cem\u003eNatural Resources and Environmental Atlas of Kerala; Kozhikode District\u003c/em\u003e (1st ed.). Centre for Earth Science Studies.\u003c/li\u003e\n\u003cli\u003eSelvan, S. C., Kankara, R. S., Prabhu, K., \u0026amp; Rajan, B. (2020). 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Sea level changes along the Indian coast: Observations and projections. \u003cem\u003eCurrent Science\u003c/em\u003e, \u003cem\u003e90\u003c/em\u003e(3), 362\u0026ndash;368.\u003c/li\u003e\n\u003cli\u003eVaidyanadhan, R. (1981). Sea Level. In M. J. Tooley (Ed.), \u003cem\u003eInt. Bull IGCP Project No. 61\u003c/em\u003e. Univ. Durham.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-disaster-science-and-management","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"44367","submissionUrl":"https://submission.springernature.com/new-submission/44367/3","title":"Journal of Disaster Science and Management","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Open","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Coastal Erosion, Shoreline management, Coastal Vulnerability, Sea Level Rise, Coastal Structures","lastPublishedDoi":"10.21203/rs.3.rs-6159107/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6159107/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe densely populated Kozhikode coastal belt in southwest India is increasingly vulnerable to coastal hazards, exacerbated by coastal protection measures that disrupt natural dynamics. This study contrasts shoreline processes over recent geological history with current dynamics, focusing on a high-energy, micro-tidal coastline characterized by distinct paleo-shoreline features and young coastal plains from the Holocene epoch. Temporal morphological changes were assessed using various satellite products, ranging from Landsat imagery to Very High-Resolution Worldview-3 datasets. The integration of vulnerability assessments of coastal ecosystems and landform features reveals significant coastal dynamism. This study highlights critical shifts in coastal dynamics and emphasizes the urgent need for sustainable coastal management strategies to mitigate escalating vulnerabilities. Understanding these changes is essential for informed policymaking and effective climate adaptation strategies, ensuring the resilience and preservation of these vital coastal ecosystems. Analysis of shorelines from the Holocene to the present indicates a historical accretion trend until the 1960s; however, recent decades have seen a concerning reversal, resulting in coastal erosion and flooding. This paper elucidates the influences of extreme events and anthropogenic factors on coastal stability, supported by analyses of paleo-shoreline changes and contemporary disturbances linked to climate change and sea-level fluctuations. Geological and climatic events, particularly sea-level changes, are evident in paleochannels associated with the Chaliyar and Korapuzha river basins. Lithological studies from boreholes provide compelling evidence of shoreline variations, indicating that the paleo-shoreline now varies significantly from the modern shoreline across different regions. The once-accruing Holocene coast now experiences erosion along 40% of its length, with accretion rates plummeting from 100% to just 11% in recent decades, likely due to unsustainable coastal zone exploitation since the 1980s.\u003c/p\u003e","manuscriptTitle":"Paleoshoreline to Anthropocene Coast: Assessing Coastal Stability and Vulnerability in Response to Sea Level Changes","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-10 11:50:46","doi":"10.21203/rs.3.rs-6159107/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2025-05-06T18:42:16+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"244830091673640620430039496366458127735","date":"2025-04-25T17:23:47+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-04-09T00:53:57+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-03-28T07:06:37+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Disaster Science and Management","date":"2025-03-28T05:33:37+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-disaster-science-and-management","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"44367","submissionUrl":"https://submission.springernature.com/new-submission/44367/3","title":"Journal of Disaster Science and Management","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Open","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"c4e34ea4-7171-4eb6-9de0-9a2eff4913a1","owner":[],"postedDate":"April 10th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-05-28T01:23:15+00:00","versionOfRecord":[],"versionCreatedAt":"2025-04-10 11:50:46","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6159107","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6159107","identity":"rs-6159107","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}