The city sought better ways of collecting and assessing the data and partnered with Dewberry and Civis Analytics to run predictive models of the storm to determine how it impacted communities, and which communities it impacted the most.
Dewberry and Civis took building footprints, tax assessment data from Houston counties and did analysis of how the rainfall impacted the communities. The traditional analyses are done from a fluvial, which is associated with rivers and streams, and not a pluvial [rainfall] perspective, according to Mat Mampara, associate vice president at Dewberry.
“We assessed those damages at the structural level and then our partners at Civis imputed demographics into those structures,” Mampara said. “Now we had impacts based on structural characteristics and also based on population and demographics imputations.”
The goal was to estimate the unmet needs, which Mampara said was impacts, minus federal assistance received and compared with the data.
“The difference here is having the geographic and structural-level assessment and being able to tie it together in a way that has made for compelling information to inform decision-making at the city level,” Mampara said.
One of the problems the analysis might help address in the future involves lower-income areas and renters who are under-represented when it comes to recovery funding. "Helping the most vulnerable Houstonians is our hightest priority," said Sarah Labowitz, the communications and policy director at Houston’s Housing and Community Development Department."Low-income people still living in mold or other dangerous conditions more than a year after the storm."
But the analysis also showed that some of the neighborhoods with the most unmet needs were among the wealthiest.
“One of the things that the research showed was that about 64 percent of Houston was underwater, which is a huge impact from Harvey,” Labowitz said. “In our needs assessment, we have to look honestly and totally at what was the impact across the city, and some of the very wealthy areas were hit hard and had some of the deepest flooding.
The data indicated that the $1 billion figure that was calculated originally for unmet needs was short by $2 billion. Houston received $1.15 billion as part of a $5 billion package from the U.S. Department of Housing and Urban Development, but it’s not enough to cover the damage to housing, and the city is trying to determine how to ensure funding is distributed equitably.
A fact sheet released by the city from the analysis that Dewberry and Civis collected said the old methodology only counted some of the damage from Harvey, and estimated the total residential damage at $16 billion.
Other facts from the analysis:
• About 30 percent of the 700,000 households in Houston sustained some form of damage to their home or personal property, with floodwaters coming very close to touching the building. Ten percent had floodwater inside their homes.
• Flooding from Harvey was not simply the result of rivers and bayous spilling their banks. Sustained, heavy rainfall over inadequate drainage systems caused ponding across all areas of the city. Fifty-nine percent of the damage from Harvey occurred outside the 500-year floodplain.
• Persons with disabilities were disproportionately impacted. Though persons with disabilities represent 10 percent of the Houston population, they represented 15 percent of impacted households.
• Forty-six percent of impacted households were renters. The federal disaster recovery framework limits the kinds of assistance that can be provided to renters directly.
• After six years of declining homelessness, the city has seen a 15 percent rise in homelessness after Harvey.
In the wake of the five recent federally declared disasters, Labowitz hopes this analysis can put forth some more efficient mitigation strategies.
“In the short term, it will help us design programs and target them better than we ever have before,” Labowitz said. “In the long term, Houston is a city that’s had five federally declared disasters in three years and if we’re chronically undercounted in terms of how many people were effected and how much it will cost to fix that damage, then we’re being chronically under-resourced.”
