Avoided Damages

Harvey blasted through national and state records for rainfall over four days in August 2017. Early estimates suggest that 80,00 to 100,000 structures were flooded. 

However:

• On Sims Bayou, an estimated 70 properties sustained damage during Harvey. That number would have been more than 6,570 if not for the $395 million Sims Bayou federal project, completed in 2015, and the associated stormwater detention basins and other projects constructed with local funding. 
• On Brays Bayou, an estimated 30,000 properties sustained damage during Harvey. While quite large, an additional 10,000 properties would also have been damaged, if not for the Project Brays channel improvements and stormwater detention basins previously completed. 
• On White Oak Bayou, an estimated 3,500 structures sustained damage. That number would have been more than 9,000 without previous projects constructed in the watershed.
• In addition, 2,076 homes across Harris County would have flooded during Harvey, except that they had previously been purchased and demolished – with the homeowner relocated to higher ground – in the Flood Control District’s home buyout program. 

The devastating Tax Day Flood of April 17-18, 2016, which struck northern and western Harris County, resulted in seven fatalities and thousands of flooded homes. 

However: 

• Previously completed components of Project Brays – including channel conveyance improvements and new stormwater detention basins – prevented damages to about 2,300 homes and businesses that otherwise would have flooded. 
• Flood damage reduction work on White Oak Bayou – including channel conveyance improvements and new stormwater detention basins – prevented damages to about 1,800 homes and businesses in that watershed. 
• In addition, thanks to past voluntary home buyouts in the Greens Bayou, White Oak Bayou, Cypress Creek, San Jacinto River, Brays Bayou and other watersheds, an additional 1,500 homes did not flood during the 2016 Tax Day storm because they had previously been removed from their location in the floodplain.
•  All total, with an average flood insurance policy claim for the Tax Day Flood of $50,000, those efforts saved an estimated $280 million in avoided flood claims. 
• Other previously completed Flood Control District channel conveyance projects – either in partnership with the U.S. Army Corps of Engineers or independently – on Vogel Creek, Willow Creek, Greens Bayou and others, and stormwater detention basins on Mason Creek, Langham Creek, Horsepen Creek, Cypress Creek and Greens Bayou, also helped keep stormwater out of homes and businesses during the 2016 Tax Day floods.

During the Memorial Day Flood of May 26-27, 2016, which hit north and northwest Harris County, it is estimated that: Regional detention basins in Cypress Creek, Little Cypress Creek and Willow Creek watersheds stored stormwater that otherwise could have flooded homes and businesses. In addition, thanks to past voluntary home buyouts in the Cypress Creek, San Jacinto River, Willow Creek, Little Cypress Creek and Spring Creek watersheds, 390 homes did not flood during the Memorial Day 2016 storm because they previously had been removed from their location in the floodplain (either in partnership with FEMA or directly by the Flood Control District).  

On the evening of Memorial Day 2015, portions of southwest Harris County reported receiving 10 or more inches of rainfall in six hours, greatly exceeding the statistical 1% (100-year) rainfall totals. There were seven fatalities in Harris County, between 3,000 and 6,000 structures were flooded, and more than 7,000 motorists were stranded. 

 However: 

 Because of flood damage reduction projects completed in the past 20 years – including stormwater detention basins and channel conveyance improvements – structural flooding was avoided for:

• 7,300 homes and businesses along Brays Bayou 
• 1,700 homes and businesses along Sims Bayou 
• 1,600 homes and businesses along White Oak Bayou 

An additional 485 flood-prone homes previously removed in voluntary buyouts countywide also avoided damages. (In partnership with FEMA and also acting independently, the Flood Control District acquires flood-prone homes, moves the residents to higher ground, and demolishes the structures. The land is then left undeveloped for open space and natural floodplain functions.)

On October 30 and 31, 2015, severe flash flooding with multiple tornados resulted in one flood-related fatality and the inundation of 400 structures and several roadways in Harris County.  

However: 

• Previously completed work on the Sims Bayou and Brays Bayou federal projects prevented damages to more than 1,900 homes and businesses that otherwise would have flooded during this Halloween Storm. 
• Previously completed components of regional and federal projects on White Oak Bayou (in partnership with the U.S. Army Corps of Engineers and independently) also prevented flooding of as many as 350 structures. 
• And an estimated 155 flood-prone homes previously removed in voluntary buyouts in the Greens Bayou, Hunting Bayou and other watersheds also avoided damages.