Image representing the contrast between mangrove forest preservation and coastal erosion.

Coastal Erosion Unveiled: How Shoreline Changes Impact East Java

Avery Sinclair in Climate & Environment December 2025 • 4 min read.

"A deep dive into the factors driving coastal erosion in East Java and what it means for the future."

Coastal zone management hinges on understanding how shorelines evolve. While predicting the future is complex, analyzing past trends provides essential knowledge for developing effective strategies and prediction models. East Java, an area in Indonesia with an extensive coastline of 81,000 km spread across 17,508 islands, stands as a critical region for studying coastal development and disaster risk reduction.

Focusing on the East Java coast, specifically the Pamurbaya and Sidoarjo districts, this study examines shoreline changes by comparing data from 2006 and 2015. These districts are geographically positioned between 7°24' South Latitude - 112° 80' East Longitude and 7°48' South Latitude - 112°83' East Longitude. The region is well known for its unique mangrove forests that form a key distinction between land and sea.

These mangrove ecosystems provide vital habitats for marine species, function as breeding and nursery grounds, and support local economies through traditional fishing and aquaculture. To analyze shoreline changes, digital shoreline analysis system (DSAS) techniques were applied to measure erosion (shoreline retreat) and accretion (shoreline advance).

What Factors Drive Shoreline Change?

Image representing the contrast between mangrove forest preservation and coastal erosion.

Shoreline dynamics result from a complex interaction of physical processes. These processes significantly influence coastal morphology, determining how the coastline evolves over time:

Waves: Initiated by wind action, waves transform as they approach the shore, altering in height, speed, and direction. Their impact on coastal forms depends on the angle at which they strike the shore, influencing whether changes lead to seaward or landward movement.

Currents: Large water masses moving in specific directions due to density, temperature, and salinity variations. They play a role in coastal morphology by transporting warmer or colder waters, influencing ecological conditions and shore dynamics.
Tides: Periodic rises and falls of water levels caused by gravitational forces. Rising tides disperse sediments, while falling tides can erode sediments from the shore.
Anthropogenic Processes: Human activities, such as the overexploitation of mangrove forests for charcoal, fuelwood, and shrimp farms, can significantly impact coastal stability, increasing vulnerability to erosion.
Abrasion and Accretion: The balance between erosion (abrasion) and sedimentation (accretion) shapes the coastline, influenced by nearshore processes, wave climate, geology, and human interventions. Accretion refers to the gradual increase of land area due to sedimentation, while erosion involves the removal of debris or rock material.

Sea level rise is a critical factor, as global climate change forecasts predict rising sea levels, threatening mangrove forests worldwide. The ability of these ecosystems to adapt depends on sediment supply and their overall resilience. When accretion and erosion reach a state of equilibrium the coastal dynamic remain relatively stable [11].

Key Findings

This study highlights the dynamic nature of East Java's coastline and the interplay of natural and human factors driving shoreline change. By understanding these processes and utilizing analytical tools, we can better manage and protect coastal regions facing increasing environmental pressures.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1051/matecconf/201817701022, Alternate LINK

Title: Determination Of Shoreline Change Along The East-Java Coast, Using Digital Shoreline Analysis System

Subject: General Medicine

Journal: MATEC Web of Conferences

Publisher: EDP Sciences

Authors: Eva Louise Den Boer, Suntoyo, A C Oele

Published: 2018-01-01

Everything You Need To Know

What are the key factors contributing to shoreline changes along the East Java coast, specifically in the Pamurbaya and Sidoarjo districts?

Shoreline changes in East Java, particularly in Pamurbaya and Sidoarjo, are driven by a combination of natural and anthropogenic processes. Natural factors include the impact of Waves, which alter coastal forms based on their angle of approach; Currents, which influence ecological conditions and shore dynamics; and Tides, where rising tides disperse sediments and falling tides erode them. Anthropogenic Processes, such as the overexploitation of mangrove forests for various uses, also play a significant role by destabilizing the coastline. Furthermore, the balance between Abrasion and Accretion determines the overall shape and stability of the coast.

How do mangrove forests contribute to coastal stability in East Java, and what are the potential consequences of their overexploitation?

Mangrove forests in East Java play a crucial role in maintaining coastal stability by providing vital habitats for marine species, serving as breeding and nursery grounds, and supporting local economies through fishing and aquaculture. Overexploitation of these mangrove forests for activities like charcoal production, fuelwood, and shrimp farming disrupts this natural protection, increasing the coastline's vulnerability to erosion. The loss of mangroves reduces the natural buffer against wave action and tidal forces, leading to increased shoreline retreat and potential damage to coastal communities and ecosystems. Rising Sea levels further exacerbate this issue.

What analytical techniques are employed to assess shoreline changes in regions like Pamurbaya and Sidoarjo, East Java, and how do these methods aid in coastal zone management?

To assess shoreline changes in areas such as Pamurbaya and Sidoarjo in East Java, digital shoreline analysis system (DSAS) techniques are utilized. These methods allow for the measurement of erosion (shoreline retreat) and accretion (shoreline advance) by comparing shoreline data from different time periods, such as the comparison of data from 2006 and 2015. By quantifying these changes, coastal zone management can be improved through the development of effective strategies and prediction models. Analyzing past trends provides essential insights into shoreline dynamics, facilitating informed decision-making for protecting coastal regions.

Why is understanding the dynamics between abrasion and accretion important for coastal management in areas like East Java?

Understanding the dynamics between abrasion and accretion is crucial for coastal management in East Java because the balance between these two processes determines the stability and shape of the coastline. Accretion, the gradual increase of land area due to sedimentation, can help build up and protect coastal areas. Conversely, abrasion, or erosion, involves the removal of debris or rock material, leading to shoreline retreat. When accretion and erosion reach a state of equilibrium, the coastal dynamic remains relatively stable. Sea level rise can destabilize the equilibrium. By monitoring and understanding these dynamics, coastal managers can implement strategies to promote accretion where needed or mitigate the effects of abrasion in vulnerable areas, ensuring the long-term resilience of coastal communities and ecosystems.

Considering the complex interplay of factors affecting East Java's coastline, what are the long-term implications for coastal communities and ecosystems if shoreline erosion continues unchecked?

If shoreline erosion continues unchecked in East Java, the long-term implications for coastal communities and ecosystems are significant. Continued erosion threatens the loss of valuable mangrove ecosystems, which are crucial for biodiversity and coastal protection. Coastal communities may face displacement as land erodes and infrastructure is damaged by increased wave action and flooding. Economic activities such as traditional fishing and aquaculture, which rely on healthy coastal ecosystems, could decline, leading to economic hardship. The resilience of East Java's coastline depends on implementing effective coastal zone management strategies that address both natural processes and human activities to mitigate erosion and protect vulnerable areas. This requires a holistic approach that considers the complex interplay of Waves, Currents, Tides, Anthropogenic Processes, Abrasion, and Accretion.