Waterworks: Flow Lab
A water-routing puzzle on a 3D basin. Dig, build and open gates, press Simulate, and watch the water find its way - or not.
About Waterworks: Flow Lab
Waterworks: Flow Lab is an original puzzle sandbox. Each map is a small terraced landscape with a spring or rain, one or more gold target basins to fill and coral keep-dry areas to protect. You change the ground with a limited set of tools, then run the water and watch it move cell by cell.
Five Learn Flow lessons introduce volume, gradient, bottlenecks, spillways and reservoirs. Twenty missions across Dry Basin, Rain Garden, Coastal Cut and Glassworks then add one constraint at a time: limited digging, low dams, spillways, split targets, rain bursts and pumps with a fixed capacity. Every mission has a stored solution that the game's own solver completes in automated tests, and the same mission with no edits does not.
The water is a simple cell-based game simulation: each cell holds a depth, water moves to lower neighbours by the difference in surface height, soaks into soil, dries slowly and leaves through open or drain edges. The game keeps a running water budget, so the panel shows how much water is on the map, how much soaked away or left, and how much it cannot account for (it stays far below 1%). It is a game simulation for entertainment and learning - not for real-world engineering, drainage or flood design.
How to play
- Read the brief at the top left: which gold target to fill, and which coral areas must stay dry.
- Pick a tool from the palette at the bottom of the view and drag or tap on the ground. The cost of your plan is shown next to the tool budget and par.
- Press Simulate. Pause, step one tick, or scrub back along the bar to see how the water moved. Gates can be opened and closed during a run.
- If it fails, press Reset (or Edit plan), adjust and run again. Your edits and your selected tool are kept.
Controls
- Mouse: click or drag to use a tool, wheel to zoom, right-drag to pan, middle-drag or Shift-drag to turn the view. Click a gate during a run to open or close it.
- Keyboard: Space simulate or pause, N step, R reset the run, Ctrl+Z undo, Ctrl+Y redo, WASD pan, Q and E turn, + and - zoom, C camera view, [ and ] brush size, F flow arrows, H hint, Esc menu. Tool keys: 1 Dig, 2 Raise, 3 Channel, 4 Dam, 5 Gate, 6 Sluice, 7 Spillway, 8 Culvert, 9 Pump, X Remove.
- Keyboard-only editing: the arrow keys move a cell cursor, Enter uses the selected tool there and G toggles a gate under it.
- Touch: one finger paints or places; two fingers pinch to zoom, drag to pan and twist to turn. Zoom, turn and camera buttons, the tool palette and Simulate / Pause / Step all sit inside the view.
The rules
- A target is filled when its average depth reaches its gold line and no cell in it is below half of that line.
- A keep-dry area overflows when any of its cells holds more than 0.05 du of water for a total of one second.
- A mission is complete when every target stays filled together for 3 seconds, with nothing overflowed, before the time limit.
- Each tool costs points (dig and raise 1 per cell, channel 1 per 4 cells, dam 1 per 3 cells, gate, sluice, spillway and culvert 1, pump 2). A mission sets a budget, per-tool limits and a par.
- Units are game units: du for height and depth, vu for volume (one cell times one du).
Scoring, saving and limits
Missions award up to three stars - target reached, kept dry the whole run, and tool cost within par - plus a storm star on storm maps for holding the fill after the rain burst. Finishing missions unlocks water colour themes. The Daily Basin keeps your best result for each day and gives you a short result card to copy.
Progress, mission drafts, your sandbox basin and settings are saved in this browser on this device only. Nothing is uploaded and there is no account. Sandbox basins can be exported and imported as small .zflow files. The Clear data button in Settings removes only this game's data.
Needs a browser with WebGL 2. Maps are at most 48 by 32 cells. The water model is a simplified game simulation, not an engineering or hydrology tool. There is no online leaderboard.
Accessibility
Depth is never shown by colour alone: every target gauge shows numbers, a numbered depth key sits beside the map, and the inspector reads out exact ground and water heights. Everything can be played with the keyboard, including placing tools with the cell cursor. Settings include reduced motion (no ripples or moving rain), graphics quality and sound (off until you turn it on); Display has a left-handed layout, flow arrows and camera views. Status updates are announced to screen readers.
Questions
- Is every mission solvable?
- Yes. Each mission has a stored solution that the game's own solver runs to completion in automated tests, and each Daily Basin is solved by a short search before it is offered. If a day's basin cannot be solved, a fixed template basin is used instead and labelled as such.
- Is this how real water behaves?
- Only loosely. It is a cell-based game simulation tuned to be readable and fair. It is for entertainment and learning, not for real-world engineering, drainage or flood design.
- What is the Storm Scenario?
- Pick any mission you have finished, set the strength and length of a rain pulse and how much the drain edges can take, and see if your plan still holds the targets 3 seconds after the storm, within a visible 120 second limit.
- Can I share a basin I made?
- Yes. In the Sandbox, open Basin settings and export a .zflow file. A friend can import it in their Sandbox. Imported files are checked strictly and a bad file never replaces your basin.