The 2001 flood of Houston and Harris County, Texas, USA

• 13.1.

  The flood

• 13.2.

  Physiography

• 13.3.

  Flood defence

• 13.4.

  Flood policy

• 13.5.

  Summary

• References

The Tropical Storm Allison rainfall and flood event of east-central Texas affected southern and eastern regions of the USA, becoming the costliest tropical storm in US history. Unprecedented amounts of rain and record flood levels were associated with Allison, as portions of the Harris County region received the 0.2% annual-chance rainfall event. The storm cost $5 billion in damages and the lives of 22 individuals, and severely inundated downtown Houston, Texas. The Federal Flood Control Act of 1936 allows state and local governments to partner with the federal government to study, design, construct and maintain a variety of flood mitigation strategies, both structural and non-structural in nature. The Harris County Flood Control District, US Army Corps of Engineers, landowners and developers improved most of the channels and flood control systems, many of which were in place prior to the flood event. The consequences of the storm and the modern flood management practices used in the event have been reviewed to examine the success of the Allison flood response, in order to better allocate current and future resources to improve flood management policies, planning and design.