Institutional controls in an area of subsidence induced flooding

摘要

This paper is a summary of the institutional controls enacted after a catastrophic flood in a major metropolitan area. The percentage of property inundated by Tropical Storm Allison (2001) in Harris County, Texas, United Sates of America, was much greater than anticipated. Two thirds of the areas flooded were outside of the 1% (100 year) flood plain. Excessive insurance and property damage claims caused the Federal Emergency Management Agency (FEMA) to underwrite a LiDAR survey of the county to develop a better topographic base for flood plain mapping. New flood plain maps were created and presented at public forums. Areas not thought to be seriously affected by subsidence were better mapped, showing greater areal subsidence and flooding potential. Additional flood insurance, certificates of elevation, and property construction standards were required for lending loan applications. Structures in the areas now realized as prone to flooding were purchased by the government to reduce the economic impact of future floods.