May 2015 Houston flood

I’m posting to share a hydrograph from a channel in Houston to show how fast this flood happened, and why I think it may have left so many drivers stranded in the roads. Below is a hydrograph and rain data from Buffalo Bayou in Houston, from before the major rain to this evening (the day after). Buffalo Bayou is a largely engineered channel which means it conveys water much faster than a natural channel — this explains the really abrupt rise in the hydrograph. But why did it leave so many drivers stranded? Simple!

The Rockets Conference finals game began at 8:00pm, just before the rain started. Everyone ignored warnings to stay home and watched the game (I don’t blame them) and then when the game ended ~11:30pm, all the rain had flooded the streets (not yet into the bayou) and stranded drivers. The bayou overtopped its banks at about 2:00am this morning, and continued to rise through the morning. This led to vehicles remaining stuck and becoming even deeper submerged. Luckily, the water has began to recede.


Flood hydrograph and precipitation plot. Note that the x-axes do not line up.