Landscape Lexicon: Wetlands
- Devayani Khare
- Jul 30
- 7 min read
Dear Reader,
For a while now, I’ve had the idea of a landscape lexicon, where I can compile a list of words for a particular geographical feature. Yet I haven’t quite known how a lexicon could be more than just a list of words. What purpose would such a lexicon serve? And if we could pool together words with subtle differences in meaning, could we create a mental map to draw from whenever describing landscapes?
In this landscape lexicon, we’ll explore wetlands. In geography, we often tend to use words interchangeably — weathering and erosion, hill and mountain, pond and lake — each often has a subtly different meaning (and surely, a mountain would take offence at being called a hill?).
In this essay, we won’t explore the functions of wetlands as deeply, but we will look at the subtle difference in how we describe them. What follows are myriad words for wetlands, some familiar, some obscure, to give a sense of how they are used to describe different geographies.
What are wetlands?
Wetlands are among the planet’s most important ecosystems; as wildlife refuges, drought and flood mitigators, carbon sinks, and aquifer recharge zones. Wetlands are defined as areas where surface or groundwater accumulates for near-permanent, seasonal or ephemeral spells, which may host some biodiversity. Wetlands, shaped by natural or human forces, can have fresh, brackish or salty water, which may be static or flowing. In recent years, wetlands have also been defined as per their ecological functions, their value to people and biodiversity, and as part of natural systems and cycles. In a sense, wetlands are transition zones — fluctuating between wet and dry cycles, creating habitats that demand resilience.
In 1971, the Ramsar Convention on Wetlands established 6 broad criteria for wetlands, most of which are interesting additions to our landscape lexicon:
Marine: coastal wetlands including coastal lagoons, rocky shores, and coral reefs
Estuarine: including deltas, tidal marshes, and mangrove swamps
Lacustrine: wetlands associated with lakes
Riverine: wetlands along rivers and streams
Palustrine: “marshy” - marshes, swamps and bogs
Human-made wetlands: fish and shrimp ponds, farm ponds, irrigated agricultural land, salt pans, reservoirs, gravel pits, sewage farms and canals.
Yet, for a landscape lexicon, these classifications seem too cut-and-dry. Let’s find other ways to understand these words better.
Another way to classify wetlands is based on seasonality: perennial (characterised by all-year or long-term cycles), seasonal, episodic (periodic/intermittent), and ephemeral (short-lived). With landscapes constantly in flux due to ever-changing hydrological cycles, wetlands may transition over time.
Perennial wetlands:
Marshes occur at the edges of rivers, streams, lakes or ponds, and are permanently flooded with fresh or brackish water. They harbour herbaceous, rather than woody vegetation, such as cattails, pondweeds, water lilies, sedges, rushes, and grasses. The word "marsh" can also be used to describe any low-lying and seasonally waterlogged terrain.
Swamps are forested, or woody, wetlands often found in low-elevation floodplains along rivers or slow-moving streams, and they bear rich nutrients. The flowing water may be fresh, brackish, or salty, and this determines the vegetation and wildlife of different swamps. Swamps, more than any other wetland, have inspired dark literature and art, served as settings for horror films, and have also inspired a slew of monsters!
Peatlands, bogs, fens, or mires are all words used for wetlands where soils form due to decaying organic matter, or peat. The waterlogged landscape prevents the vegetation from completely rotting, creating a boggy wetland. Peatlands and bogs are acidic, whereas fens are alkaline, and mires are used for either acidic or alkaline terrains. When the decomposing matter dries out, these habitats are at risk of burning and can release significant amounts of greenhouse gases into the atmosphere.
During the Carboniferous period, vast swamps covered much of the Earth's surface. The remains of these swamp forests, particularly giant ferns, club mosses, and horsetails, accumulated as layers of peat. Over millions of years, these peat layers were compressed and transformed into coal seams under the weight of overlying sediments and due to heat and pressure. Our carbon-intensive industrialisation has been made possible by these ancient swamps.
Seasonal Wetlands
Springs and seeps occur where water flows from an underground aquifer to the surface. Springs have more volumes of water, and can flow for considerable distances, whereas seeps carry lesser water, and form small puddles on the surface. Springs may also travel through karst or limestone, where they create astonishing landscapes of stalactites and stalagmites. Springs may also travel close past shallow bodies of magma or circulate through faults to hot rock deep in the Earth's crust, which causes them to heat up, and erupt on the surface with telltale yellow hues of sulphur. These hotwater springs have long been used for therapeutic baths.
When vegetation patches are temporarily flooded, you get seasonal wetlands like wet meadows, wet savannahs, wet prairies, or wet grasslands. Savannahs, prairies and grasslands are prone to wildfires, and the occasional inundation is essential for the vegetation to regenerate. Riparian forests or riparian woodlands, lie adjacent to waterbodies, and also undergo frequent inundation.
Episodic or ephemeral wetlands
Episodic wetlands, also known as ephemeral wetlands, are wetlands that are wet only seasonally or during wet years, and they are characterized by the absence of a permanent surface outlet. Vernal pools are rain-fed, ephemeral systems. During rainy season, these may form a network of pools, that are connected till surface runoff flows across them, but soon become independent of each other, and hence, dry out. Centuries ago, Hyderabad and Bangalore incredible water management systems, relied on a similar system of cascading pools. As the infrastructure expanded, the hydrological network was disrupted, and many waterbodies have dried up, disappeared, or have been developed over.
Coasts and deltas connect marine, freshwater and terrestrial ecosystems, and harbour wetlands like mangrove forests or swamps, salt marshes, intertidal marshes, freshwater tidal marshes, mudflats and lagoons.
As ecological corridors, these wetlands provide breeding grounds for fish and other marine fauna, stopover sites for millions of migratory birds, and hunting and grazing grounds for visiting terrestrial and marine megafauna from tigers to sharks.
Mangrove forests or swamps, found in tropical or subtropical regions, host salt-tolerant shrubs and trees. In this brackish or saltwater environment, the vegetation has specialised, aerial root systems that can tolerate tidal fluctuations and oxygen-poor conditions.
Salt marshes or saltings are often found in sheltered coastal areas like bays and estuaries. These salt-rich wetlands are characterised by salt-tolerant plants such as grasses, sedges, and shrubs.
Both mangroves and salt marshes play a vital ecological role. By gathering layers of sediment, they protect shorelines from erosion by waves and during extreme weather events, like storms and tsunamis.
Intertidal or tidal marshes occur where the coastal vegetation of grasses and shrubs is dictated by the influence of tides, and the fluctuations in salinity, temperature, and oxygen levels.
Tidal flats or mudflats are coastal waterbodies that form in intertidal zones — an area that’s dry during low tides, and underwater during high tides — defined by heavy sediment deposits. As an interface between the land and sea, subject to frequent periods of wet and dry, the organisms that thrive here are extreme. When we imagine marine life evolving out of the sea, this is the zone they would have had to breach before crawling onto land.
Lagoons are shallow bodies of water separated from a larger body of water, typically the sea or ocean, by a barrier such as a reef, sandbar, or island. Lagoons have been used in films, as idyllic places (think, Blue Lagoon), or in books, as a metaphor for a personal journey (like in Joseph Conrad’s The Lagoon).
Our quest for a wetland lexicon would be incomplete without adding regional or local words across geographies, which have found their way into English. Here are some examples, though undoubtedly, there are so many others.
Bayou: Used by southerners in the United States to denote a flat, low-lying waterbody, such as a slow-moving stream, river, marshy lake, wetland, or creek. 70s music lovers would recall Creedence Clearwater Revival’s song, Born on the Bayou, or Tina Turner’s Bayou Song.
Billabong: This isn’t just a surf apparel brand name, billabong stems from the Australian English word for an oxbow lake. When rivers change their course, they may cut off a meander or loop, which gets isolated to form a crescent-shaped lake. Billabongs are of cultural and social significance to Aboriginal and Torres Strait Islander people, though many bear the names of colonial settlers.
Playa: a word of Spanish origin, has been used in English to mean a beach or a shore. It may also refer to a dry, flat-bottomed lake bed or playa lake, which may temporarily fill with water.
Pocossin: a word derived from the Algonquin Native American word for "swamp on a hill," pocossins are waterbodies with a shallow water table, but no standing water. These are areas of saturated soil, often hosting evergreen shrubs and trees.
Turlough (also turloch or turlach): A seasonal, periodic water body that occurs in limestone topography; the word turlough is used mainly in Ireland. However, such seasonal, ever-changing waterbodies exist in other regions too, but the word hasn’t quite caught on.
(If you know of any regional/local words from your part of the world, please add them in the comments with a description)
This last, tongue-in-cheek section is an attempt to classify you into a wetlands, kind of like those ‘which character are you?’ tests that were so popular in the early days of Facebook.
So, which wetland are you? Skim through the traits below and decide!
