Beach
Overview
Beach (海邊, beach) is a gently sloping coastal landform created by sand or gravel transported by waves, currents, and wind and deposited at the boundary between the sea and land. Beyond a simple scenic resource, it functions as a core habitat of the marine ecosystem and as an economic and cultural space where tourism, fishing, and leisure are concentrated. The world's coastline is about 1.5 million km long, and a substantial portion of it consists of beaches and sand dunes (沙丘).
Main content
Definition and scope
A beach generally includes the intertidal zone (潮間帶) between the high-tide line and the low-tide line, and the dune zone behind it. Geomorphologically, it is divided into the foreshore (前濱), where wave energy is concentrated; the backshore (後濱), the upper part of the intertidal zone; and the foredune behind it. In Korea, the term is used interchangeably with 'haesuyokjang' (beach resort/swimming beach), but academically, beach is a geomorphological and sedimentological concept, not a concept based on purpose of use.
Formation process
Beaches are formed when sediment transported by rivers and streams, erosion debris from sea cliffs (海蝕崖), shells, and coral fragments move along longshore currents and longshore drift and are deposited. When the energy of breaking waves (碎波) pushes sediment toward the land, a wide, gently sloping 'summer beach' is created in summer; when high winter wave energy pulls sediment out to sea, a narrow, steep 'winter beach' is created. This seasonal variation is called the 'breathing of the beach.'
Sediment and sorting
The character of a beach is determined by particle size and sorting (分級, sorting). The more uniform the particles, the gentler the slope and the more pleasant it is to walk on, making it preferred as a tourist destination. Most beaches consist of quartz and feldspar sand, but in volcanic regions there are various colored beaches: black basalt sand (e.g., Papakōlea in Hawaii), white and pink sand mixed with coral and foraminifera (e.g., Pink Beach in Indonesia), and black sand beaches rich in magnetite (e.g., Samcheok and Gangneung in Korea).
Types
- Sandy beach: the most common type, with particles roughly 0.06–2 mm.
- Shingle beach: develops on coasts with strong wave energy and has a steep slope.
- Rocky shore: consists mainly of wave-cut platforms and sea cliffs and forms a distinct ecosystem.
- Dune beach: coastal dunes develop behind it, where windbreak forests and halophytes grow.
Ecosystem
Unlike tidal flats, beaches have coarse particles and frequent desiccation, so biodiversity is relatively low, but benthic invertebrates, sandworms, and shellfish live within the sediment. On the dunes behind, salt- and drought-tolerant plants such as Carex kobomugi, Ixeris repens, and Vitex rotundifolia take root, and the area is also important as a nesting ground for sea turtles and a stopover for shorebirds. Beaches serve as a buffer zone connecting terrestrial and marine ecosystems.
Human life and culture
Beaches have been the basis of fishing, salt fields, and ports since the early days of human civilization, and since modern times they have been transformed into public leisure spaces centered on sea bathing. Leisure activities such as surfing, beach volleyball, paddleboarding, and beach yoga have spread, and beach festivals in various countries (e.g., Sydney Beach Culture Festival, Busan Sea Festival) have become regional brand assets. In Korea, beaches nationwide open from late June to August every year.
Economic value and threats
Beaches are high-value resources that affect tourism income, real estate values, and the foundation of fishing. However, indiscriminate development, blockage of sediment supply due to port and breakwater construction, and sea-level rise and swell waves caused by climate change accelerate coastal erosion (beach erosion). In response, projects such as beach nourishment (養浜) projects, dune restoration, and rip current (離岸流) warning systems are being introduced.
Latest trends
In 2024–2025, the biggest topics related to beaches are climate change adaptation and sustainable management. First, as cases increase in which the area of white sandy beaches retreats by several meters per year due to sea-level rise and typhoons/swell waves, countries are shortening the cycle of beach nourishment projects and shifting to 'nature-based solutions (NbS)' that restore dunes and salt marshes. Second, as the concept of blue carbon spreads, the carbon uptake function of dunes and halophyte communities is being reevaluated, and attempts to register beaches as carbon sinks continue. Third, real-time marine safety control using AI and IoT is expanding, and 'smart beaches' that provide rip current, jellyfish, and water quality information via mobile are increasing. Fourth, barrier-free beaches (wheelchair access paths and sea bathing assistive equipment) and pet-friendly zones are expanding, and discussions on accessibility and inclusiveness are active. Finally, overtourism and marine plastic and microplastic pollution have emerged as new management tasks, and policies such as reservation-based entry and garbage return deposit systems are being tested. In Korea as well, beach branding and development of four-season beach content are being promoted by local governments.
Related topics
- [[Mudflat]]
- [[Ocean]]
- [[Coastal erosion]]
- [[Beach resort]]
- [[Dune]]
- [[Climate change]]
- [[Marine ecosystem]]