FLOODLINE

Design & Engineering

Michael Flynn, PE
Professional Engineer · Dam safety, hydrology, and hydraulic modeling

Hydrology grounded in real methods

• SCS Type II rainfall distribution (NRCS TR-55)
• SCS triangular unit hydrograph for upstream routing
• HAZUS-MH-style stage-damage curves for buildings
• 100-year 24-hour rainfall depths from NOAA Atlas 14 (US) and approximate sources globally
• Shallow-water cellular automaton with 8-neighbor gradient flux
• Levee overtopping & piping-failure stress model
• Stage-discharge rating curve at the tailwater boundary
• Green-Ampt-like infiltration with antecedent moisture

Historical scenarios

Johnstown (1889) · Mississippi (1927) · Katrina (2005) · Cedar Rapids (2008) · Lumberton (2016) · Harvey (2017) · Oroville (2017) · Edenville (2020). Storm profiles, terrain, and outcomes derived from real engineering and historical records.

Tech

Single-file HTML / Canvas 2D / Web Audio API. No external libraries, no images, no audio files. All graphics and sound are procedurally generated at runtime.

Thanks

To the engineers maintaining NC's dam safety program, the hydrologists at ASDSO and USSD, and the researchers whose work on post-Katrina levee forensics and post-Oroville spillway investigation made each of those scenarios possible to model.

This is a simulation game, not an engineering tool. Do not use for design decisions.

Career Statistics

Floodline

A flood engineering simulator. Build levees, channels, and pumps against real hydrology. Levees breach under load. Infiltration matters. The hydrograph tells the truth — read it, and pre-position.

Free Play — Scenario Select

Historical scenarios use simplified but faithful parameters — river inflow, rainfall depth, breach risk, and terrain are derived from real events. This is a game, not an engineering tool.

Permanent Upgrades

Spend wallet money on perks that carry across every scenario. Purchases are permanent.

How to Play

Core loop

A storm is coming. Place levees, channels, pumps, and retention ponds to keep town damage below the threshold. Wallet money carries across scenarios; spend it on upgrades or let it fund bigger storms later.

Physics you can manipulate

• Head gradient drives water — place levees to force detours; channels cut elevation and drain faster.
• Tailwater backs up water when downstream discharge is high. Hospital may flood from the outlet, not from rain.
• Antecedent moisture (AMC) — pre-wet soil infiltrates less. Historical events start with high AMC.
• Breach — levees fail when overtopped; stress builds with head differential. Reinforce to raise threshold.
• Soil type — sand drains fast, clay slow. Visible as subtle tint on grass cells.

Hotkeys

Campaign

Scenario Complete