World Building: How Oceans, Seas, Lakes and Rivers Can Shape Your World

Oh, the siren’s call of the open sea. Calm and flat, a shining mirror stretching beyond the edge of the world, or surging up like Poseidon’s chariot crashing against your quaking hull. Rivers like veins spreading life across continents, and silent lakes lying in wait, hiding myths for land forged heroes to find.

Water. Lovely water. It takes up the majority of our planet and is one of the main reasons we are here at all.

Even if you write a story set in the desert without a drop of water in sight, the absence of water is one of the driving factors of your story. You can write a whole story that never sees the shore, or hoists a sail, but water and the bodies that hold it are always there, factored into the entire shape of your world and its civilisations.

Oceans, rivers, lakes, and seas aren’t just backdrops for sailing adventures or pirate lore. They are climate regulators, trade routes, natural borders, religious icons, an endless fuel for your narrative.

A river might mark the edge of an empire. A sea might divide two warring cultures. A lake might hide mythic sword… or Nessy. But what ever the role water bodies have in your narrative, they are an intrinsic part of life and should be carefully considered when world building.

In this blog, we’ll dive deep (pun fully intended) into how water can elevate your world building, not just with geography and realism, but with meaning.

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1. The Great Blue: Oceans and Seas

The scale of your oceans determines the scope of your world.

A small sea connects. A vast ocean divides. A maze of archipelagos changes how people think, move, and war.

And often, the water itself becomes the challenge.

• How big are the oceans and seas in your world?
• Are they interconnected like our own? Or isolated and separated by land masses?
• How long does it take to cross the widest area?

Consider: Does crossing this water require months of perilous travel, just a good wind and a sturdy sail… or perhaps a plane or a portal?

The size of oceans and seas and the time they take to cross really helps to establish an accurate, consistent scale to the rest of your world.

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2. Blue Veins: Lakes and Rivers

If you, like me, spent your childhood sat at the back of your Geography class trying to not fall asleep whilst some tired teacher droned on about the formation of oxbow lakes, then you probably share my instinctive affliction to all things river.

But rivers and lakes are so much more than meandering, erosion and sedimentation; they are the life blood of the world.

Rivers travel. They carry. They unite. They divide. They shape everything they pass through, including your story.

Lakes hold time still. They nourish. They Flood. They give life. They drown.

• Where are the major rivers and lakes situated, and how do they enhance the landscape and ecosystems?
• Do these rivers act as vital conduits for trade or natural dividers between regions or cultures?
• Where do the rivers start (mountains, springs, glaciers)?
• How do they interact with other features like valleys, canyons, or cities?

Rivers often define cities. Lakes often guard secrets. Think about how their placement and size dictate human settlement and political, economical or even spiritual boundaries.

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3. Weather Makers: Climate and Water

Water regulates temperature. It creates fog, wind, rain, storms. It shapes the sky as much as it shapes the land.

• How do oceans and seas affect the climate of coastal areas and islands?
• Do large lakes or rivers create distinctive microclimates in their vicinities?

A humid delta. A fog-covered lake. A cold wind rolling in off a glacial sea. These conditions don’t just affect the weather; they affect culture, diet, fashion, economy, and even superstition.

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4. Something in the Water: Composition and Depth

Not all water is made equal. Salt, acidity, density, magic. These things shape ecosystems and limit what’s possible.

• Are your world’s oceans and seas salty like those on Earth, or do they have a different makeup?
• What are the depths of these waters, and what secrets, resources or marine life do they harbour?
• Are your oceans shallow and teeming with coral?
• Are they crushingly deep, black and unknowable? Does something lurk in the depths…?
• Are you preparing to give Jason Statham a call?

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5. Blueprints of Life: Ecosystems and Biodiversity

Coastal regions, reefs, and rivers are the veins, lungs and stomachs of your world. Teeming with life…and death.

• What kinds of ecosystems thrive in and around these water bodies?
• How do they contribute to the biodiversity of your world?

A sea filled with phosphorescent jellyfish, who’s stingers are a cure for a plague. A river that is dammed stopping the sacred migratory path of a holy fish. A secret lake where only one species of super conductive algae survives: the world’s only source of power.

Every ecosystem can shape a story.

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6. Food, Faith, and Finance: Culture and Economics

Thirsty? Hydrate. Water sources dictate almost everything in life. They feed us and we need them to make a living. It is no wonder that such a fundamental force has forged so many faiths.

• How reliant are societies in your world on these water bodies for food, transportation, trade, or cultural rituals?
• Do any oceans, seas, lakes, or rivers hold historical or religious significance?
• Are there dams or water mills used to harness the energy of your rivers?

A sea goddess who demands the first fish of the season. A floating marketplace on a river that changes course. A lake that contains the only edible species of fish.

Make your water feel used, needed, respected… or feared.

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7. There’s No Place Like Home: Settlements and Water-Based Communities

Where water flows, people settle. But how they live with that water says everything about them.

• Are there communities or cities established along shores or on/in the water itself?
• How have local cultures tailored their way of life to aquatic environments?

Stilt villages. Canal cities. Entire nomadic cultures that live on barges. What architecture and technologies have developed from a life near (or on) water?

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8. Splashing Around: Recreation and Leisure

Not everything has to be survival. Sometimes water means joy. Ritual. Rest. Romance.

• How are oceans, seas, lakes, and rivers used for recreational activities?
• Are there popular leisure or tourist destinations centred around these water bodies?

Imagine an elite resort built around a lake rumoured to slow aging. A sport where players ride massive eels through river rapids. A river bed where young lovers carve their names into a great river-smooth stone.

The romantic nature of water bodies give opportunities for respite and retreat.

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9. Made in the Navy: Naval Technology and Vessels

Your boats or ships say a lot about your world: its ambitions, its fears, its reach.

• What types of watercraft are utilised, and what advancements in naval technology have been made?
• How do these vessels impact exploration, warfare, or commerce?

Think beyond Viking long ships. You can invent anything you like. Coral canoes. Glass submarines. Steam-powered juggernauts. Think of the materials available in your world, the physics (or magic), and the dangers of the water itself.

• What problems do these dangers create and how do your inhabitants design their vessels to overcome them?
• What opportunities do the natural resources create?

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10. Never Get Off the Boat: Travel, Trade, and Tension

Water ways are essential for movement in your world. It dictates trade and trade dictates power and power dictates story.

• Are oceans, seas, and rivers key routes for long-distance travel and trade?
• How long does it take to cross an ocean or reach the source of a river?
• How do they enable or restrict movement between regions?

Does your world have bottlenecks? Dangerous straits? Seasonal storms? Who controls the ports; and what does that mean for the distribution of people, wealth and power?

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11. No Equal For Power: Geopolitics and Control

Water is power.

• Do any of these water bodies act as critical geopolitical element; naval routes, contested zones, or sacred waters?
• How do these features influence diplomacy and conflict?
• Have dams been built to prevent rivers reaching neighbouring enemies or to generate hydroelectric power?

Colonial expansion. Naval dominance. Piracy. Blockades. Control of the seas can mean control of the world (just ask the British!). Control of the ports, rivers, and resources can mean control of the world. And equally a lack of control can spell disaster.

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12. Rising Sea Levels: Conservation

As in our world, climate change affects water bodies massively and in turn this will affect the lives of your inhabitants.

• What conservation measures or environmental protections are in place?
• How do societies in your world address issues like pollution, overfishing, or habitat destruction?

Glaciers melt. Sea levels rise. Rivers flood. Lakes dry out. This can lead to disaster in your world, but in your story can lead to high stakes, high tension and a compelling narrative.

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13. The Deep Unknown: Rituals and Religion, Folklore and Festivals, Magic, Myth, and Mystery

Humanity makes meaning from water. We always have done. Songs, offerings, holidays, rites, Demons and Gods.

The sea is a great container for the unknown. It’s the edge of the map. The start of the journey. The unknown depths where mystery lurks, waiting for Jason Statham to discover.

Mermaid empires. Cursed islands. Rivers that whisper your true name. Nessy. The Meg. Make the water a place of discovery and transformation physically, spiritually, narratively.

• Have any religions sprung up around water bodies?
• Are there sea gods or river sprites?
• Do any of these bodies of water harbour magical properties or mythical beings?
• Are there specific rituals, celebrations, or folkloric traditions associated with these water bodies?
• How do these traditions reflect the relationship between people and aquatic environments around them?

Festivals of light on riverbanks. Ceremonial drownings. Lake spirits demanding an annual sacrifice. Finding Nessy. Hunting The Meg. Let water shape the communities and the Jason Stathams that live around it.

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Conclusion

Water shapes more than just the land; it shapes the very soul of your world. Oceans divide or unite empires. Rivers pulse with the life of trade, travel, and myth. Lakes become mirrors of the human (or non-human) experience: calm, deep, mysterious, and often dangerous. Whether it’s the absent water that defines a desert tribe’s struggle, a coast battered by storms, a holy spring in a forgotten temple, or a bustling canal teeming with life, water carries the stories that make us and should be at the forefront of your mind when you’re building your world.

So when building your world, crafting your mountains and cities, your histories and heroes, don’t just draw a blue blob on your map and move on. Never forget that the oceans, seas, lakes and rivers are the thing that cradles and shapes it all.

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More World Building

Are you keen to dive even deeper? You can download our World Building Worksheet and World Building Document for free from our Resources store. These documents explore everything you’ve just read, and much, much, much, much more…

Other blogs in our World Building series include:

• How to Build a Map That Shapes Your World
• How to Choose the Right Genre (and Make It Your Own)
• How to Build Characters That Shape Your World

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