realistic flood

In short: the mod makes water behave realistically, and rain can build up into a flood. It has two parts: the water physics engine (the original Realistic Water Physics) and the flood module added on top.

What happens in the game

1. Rain starts (about 15 s): puddles form in low spots around every player.
2. Heavy rain continues (about 90 s of rain; a thunderstorm counts double): the flood stage begins. Springs appear in low ground near each player, and nearby lakes and rivers rise and overflow.
3. Water spreads lowest spot first. It fills basins before rising higher, and the surface stays level. The depth limit is 10 blocks by default.
4. Rain stops for 60 s (or a manual flood runs out of time): the flood session ends. The water stays where it is, because the mod no longer removes water. It is then handled by the normal water physics.

Water physics engine

• Flowing: a source block moves toward the nearest lower edge or hole, so water behaves like a real volume instead of spreading forever.
• Leveling: connected pools slowly even out to the same height.
• Volume ledger: stops infinite-water duplication. Using a bucket shows "water in this pool: N blocks (equal to N buckets)".
• Rain refill: rain slowly tops up small pools. A thunderstorm does this twice as fast.
• Extras: water slowly evaporates and erodes. Lava moves too, but more slowly.
• Large bodies of over 400 blocks (such as the sea) are left alone.
• Performance: it measures tick time and reduces its work when the game lags, so it stays smooth on phones.

Flood module

• Weather check (every second): counts rain points, starts puddles, starts floods, and ends the session.
• Springs and lake scan: places water springs on low ground and finds nearby lakes and rivers to raise.
• Water placement: a lowest-first queue places real water blocks. It checks for ground or water underneath, enforces the depth and block caps, and registers each block so the engine does not move or delete it during the flood.
• Manual flood: starts a flood immediately with a countdown (150 s by default).
• Pause and resume: stops and restarts the timer and filling.
• Weather control: summons rain, a thunderstorm, or clear sky.

Sandbag block

• Craft: sand and string in a 2×2 pattern gives 4 sandbags.
• Effect: flood water cannot be placed within 2 blocks sideways of a sandbag, from 1 block below it to 3 blocks above it. Placed sandbags are saved with the world.

Menu and commands

• Open the menu: sneak and use a clock, or run /scriptevent flood:menu.
• Menu buttons: resume or pause, start flood now, summon thunderstorm, rain, or clear sky, flood settings, rain settings, performance mode, show status in chat, and clear the sandbag list.
• Flood settings: max height, springs per player, spread speed, spring distance limits, lake rise speed, scan radius, total block cap, and manual flood duration.
• Rain settings: rain intensity, seconds before puddles, seconds of heavy rain before flooding, puddle radius, and two toggles (auto puddles, auto flood).
• Performance: Auto, Saver, Balanced, or Full.
• Other commands: flood:start, stop, status, storm, rainfall, sunny, perf, max, springs, radius, time, clear, and rw:stats.

• WARNING: Once the mod is activated, the world cannot be restored to its original state.