Floodlines

 Floodline

**Real flood physics by a licensed dam engineer.**

Floodline is a single-file flood-defense simulator built on a mass-conserving shallow-water cellular automaton. You have a budget, a map, and minutes before the storm hits. Place levees, channels, pumps, retention basins, and sandbags. Survive a light meadow storm — or Hurricane Helene's September 2024 orographic flash flood in the Asheville gorge.

## Why this is different

Most flood games handwave the hydrology. Floodline's water model is an 8-neighbor head-difference flux with diagonal scaling, HAZUS-style depth-damage curves, stage-discharge tailwater boundaries, Green-Ampt-like infiltration with antecedent moisture, levee overtopping stress, piping failure, and wind shear on surface flow. The rainfall profiles are scaled real events — SCS Type II distributions, NOAA Atlas 14 100-year 24-hour depths, real crest gauges from Cedar Rapids 2008, Katrina 2005, and Helene 2024.

## Features

- **3 campaigns, 11 missions, 4 difficulties.** Start on the Foothills Training ladder (flat meadows, light rain) and end on the Catastrophe finale (Katrina → Asheville/Helene → Johnstown dam burst).

- **Historical scenarios** — Johnstown 1889, Mississippi 1927, Katrina 2005, Cedar Rapids 2008, Lumberton 2016, Harvey 2017, Oroville 2017, Edenville 2020, Asheville/Helene 2024. Storm profiles and terrain derived from real gauge data.

- **Real engineering tools** — sandbags, earthen levees, spillways, retention ponds, pump stations, siphons, channels, and emergency breach cuts. Each has a realistic placement cost and failure mode.

- **Wind that matters** — 2D wind vector with shear stress on shallow water. Storm events shift the prevailing direction.

- **Persistent economy** — FEMA grants, wallet carryover, permanent upgrades, career stats, ghost-best hydrograph overlays, daily seeded challenges.

- **Isometric + top-down views.** Pixel-art buildings damage in stages. Water ripples at breaches.

- **Procedural ambient music** — nu-jazz chord pad in the SimCity 4 tradition.

- **Runs offline. No account. No telemetry. No ads.**

## About the designer

Michael Flynn is a Professional Engineer licensed in multiple states, practicing dam safety, hydrology, and hydraulic modeling for over a decade. The hydrology in Floodline is simplified for a game — it doesn't replace HEC-RAS, SWMM, or FLO-2D for real work — but every equation in here has a real-world source.

## Not for engineering design

Floodline is a simulation game. Do not use it for design decisions, permitting, construction documents, or any other professional engineering purpose.

## System requirements

- Windows 10+ / macOS 11+ / most Linux distros

- 200 MB disk, 2 GB RAM

- Integrated graphics OK — no GPU required