Communities: Know the Risk

Harris County

What's Next on the Path?

  • Public Appeal and Comment Period

In Harris County, only the areas impacted by coastal flooding are being updated under TXCHART. The riverine flood hazard data was updated on the effective Harris County FIRMs in 2007. Several flood studies are currently ongoing in Harris County.

Harris County was founded in December 1836 as Harrisburg County. The name was changed to Harris County in December 1839.

In 2010, Harris County has a population of 4,092,459, making it the most populous county in Texas, and the third most populous county in the United States.

The region in Harris County receives annual rainfall averages of 48 to 52 inches. Several historic storms affected the area, including Hurricane Ike in September 2008, and Tropical Storm Allison in June 2001. Tropical Storm Allison was especially destructive and caused significant flooding even outside the designated Special Flood Hazard Areas. To mitigate this, the Tropical Storm Allison Recovery Project (TSARP) was established, culminating in new Special Flood Hazard Area (SFHA) maps in June 2007.

Harris County entered the regular National Flood Insurance Program (NFIP) in May 1970. Many cities in Harris County also joined the regular NFIP during the 1970s and 1980s.

Harris County and several other communities within the county participate in the Community Rating System (CRS) and enjoy a five to 20 percent discount on flood insurance premiums as of June 2010.

For flood insurance questions, call the NFIP Hotline - 1-800-621-3362.(press 2 for insurance)

Addicks Reservoir - Physical Map Revision

The Addicks Reservoir watershed is located in western Harris County with a small portion crossing into eastern Waller County. Rainfall within the 138 square miles of the Addicks Reservoir watershed drains to the watershed’s primary waterway, Langham Creek (U100-00-00). The Addicks Reservoir watershed occasionally receives a significant amount of natural stormwater overflow from the Cypress Creek watershed during heavy rainfall events. Stormwater runoff from this watershed drains through the Addicks Reservoir and eventually into Buffalo Bayou. Rural and agricultural uses have historically dominated the upstream regions of the watershed, but residential and commercial developments are rapidly growing. There are 159 miles of open waterways in the Addicks Reservoir watershed, including Langham Creek and its major tributaries, such as South Mayde Creek (U101-00-00), Bear Creek (U102-00-00) and Horsepen Creek (U106-00-00). Based on the 2010 U.S. Census, the estimated population of the Addicks Reservoir watershed is 295,694. 

Together with Barker Reservoir, Addicks Reservoir was built in the 1940s as part of a federal project to reduce flooding risks along Buffalo Bayou, which runs west to east through downtown Houston. The U.S. Army Corps of Engineers (the Corps) completed construction of Addicks Dam and the outlet facility in 1948. The Corps owns, operates and maintains the reservoir, including leases or permits for some compatible recreational uses within the basin. Operation of the outlet facilities controls discharges from the reservoir into Langham Creek, then into Buffalo Bayou. Environmentally-sensitive areas and a wide range of wildlife habitats exist within the reservoir boundaries and along the upper tributary reaches that extend into the Katy Prairie.