Lessons Learned: One Year After Hurricane Harvey

FEATURE |By Christopher Hill –

The current gold standard for flood control employed by the federal government is the one percent risk elevation, the Base Flood Elevation or the 100-year flood elevation. These terms all refer to the elevation that predicts a one percent risk of flooding in any single year for each piece of property within a community.

When Hurricane Harvey hit in August of 2017, Fort Bend County was deluged by rainfall that exceeded the 5,000-year  event in the Missouri City area, Stafford,  Sugar Land, Mission Bend and Katy, exceeded the 1,000-year event in Needville and exceeded the 500-year event in East Bernard.  Homes were damaged, lives were complicated and our critical infrastructure was tested as it never had been before. All of that — and Fort Bend was still very fortunate. Compared to some of our neighboring counties, we handled the rainwater very well. Nevertheless, it was still an historic event, and for those whose homes were flooded, comparisons are of little comfort.

Immediately after the storm hit, 175 people sheltered at Sugar Land First United Methodist Church after being evacuated. Representative Pete and Nancy Olson, along with friends and neighbors, trudged through the flooded streets to help bring food and supplies to the shelter to care for the evacuees.

At last check, 6,824 Fort Bend County homes were flooded. When we say “flooded homes,” the image is one in which a stream is flowing through a dining room, but the technical definition of flooding is a measurable amount of water on the home’s slab. Essentially, flooding is water that consistently covers the home’s first floor. It can be 1/8” of water or even 1/16”, but if it covers the floor of the home, the home is considered to be flooded. In Fort Bend County, flooding was experienced with water levels in homes that ranged from 1/16” to five feet or more. Some 1,500 flooded homes were in areas that perennially flood. These are generally older homes built in the floodway, mostly on farmland or acreage tracts, and they are not protected by levees.

During Harvey, approximately one-half of our flooded homes were located behind the Barker Reservoir, where the U. S. Army Corp of Engineers allowed water to overflow that reservoir’s boundaries. That decision to store water on private property caused the flooding of 3,400 homes and led to multiple lawsuits by property owners and by Fort Bend County.

The Levee System

There are over one hundred total miles of levees protecting Fort Bend County. Just over the past decade and a half, fifteen additional miles have been built. Levees are designed to protect residents and keep an overflowing Brazos River out of their communities. Throughout the storm, there were rumors of levee breaches, but there were none. During Hurricane Harvey, the river did not enter any levee-protected areas. Homes were flooded in Pecan Grove MUD, but that occurred due to a construction project, not to a breach of the levee.

Sugar Creek Baptist Church responded to their neighbors’ calls for help with a multitude of volunteers, who went to work immediately mucking and gutting homes. The team was briefed at the church’s LYF Center, prayed with home owners and immediately went to work as the storm clouds cleared.

Across our county, Levee Improvement Districts, or LIDs, as they are commonly referred to, are responsible for removing rainfall within their districts. When the river is low, rainfall is removed by gravity flow through a gate structure(s), but when the river rises significantly, the gates are closed and rainwater must be pumped over the levee to the river.

The design standard for drainage is the 100-year rainfall event. In many areas of the county, this standard was overwhelmed by rainfall exceeding a 2,000-year event. Although most properties avoided flooding from the record level rainfall, some homes were flooded due to the inability of the interior drainage and pumping systems to efficiently remove the resulting runoff.

Going Forward

The question on many minds, as we passed the one-year anniversary of Hurricane Harvey, is what has been done to prevent damage from a storm like Harvey.

Many Municipal Utility Districts (MUDs), which often control and maintain the storm sewers and water connections, are making tweaks to their systems based on what Harvey has revealed. Some MUDs have done lamping projects, where cameras are sent down into the sewers to detect damage. Some have added additional water-retention capabilities. The various LIDs across the county are adding projects from developing new pumping stations to adding remote sensor equipment to increase the speed of data reporting.

What is a 100-year flood?

In a boat loaded with feed and hay for a Woods Edge Estates neighbor’s eight horses, Ross Parks, Bob Ramsey, Richard McCarter and Rick Fuqua came to the rescue. Photo by Yvonne Ramsey.

Everyone heard the term 100-year flood often during Harvey. It seemed like everyone was calling Harvey a 100- or even a 500-year flood, but no one was explaining the term. The term is a probabilistic measurement created by the Federal Emergency Management Agency (FEMA) for determining flood insurance. A slab elevation below the 100-year flood elevation must have federal flood insurance if there is a mortgage on the property. If the slab elevation is above the 100-year flood elevation, federal flood insurance is optional, but always recommended. For builders, the metrics behind this elevation determine the height requirement for the slab of a new home.

Additionally, there is 100-year rainfall event that is recognized by FEMA as the standard for the internal drainage and pumping system of certified levees. In Fort Bend County, the basic 100-year rainfall event is currently set at 12.5 inches of rain in a 24 hour period. Anything over that amount is referred to as a localized 100-year flood. All utilities in the county must be able to remove that amount of water through their drainage systems. Harvey threw everyone a curve in that the rainfall over its 96-hours of heavy rain exceeding a 2,000-year event over most of the county, with rainfall totals approaching or exceeding a 5,000-year event in Sienna Plantation, Riverstone, Missouri City, Stafford, Sugar Land, Mission Bend, Cinco Ranch and Katy.   

Later this year the National Oceanic and Atmospheric Administration (NOAA) will release a new report, Atlas 14, that will update rainfall data, including Harvey data, to establish new standards for the 100-year rain event in Fort Bend County and the Gulf Coast of Texas.

All hands were on deck at the Fort Bend County OEM including Tanka, the Fort Bend County Sheriff’s Office service dog, with Fort Bend County Judge Bob Hebert.

For the county, the answers are larger and much more complicated. In the grand scheme of things, Fort Bend County is relatively new to the cycle of high population growth and urban development, with infrastructure less than fifty years old. Its growth has been spectacular in a brief amount of time. This means the data is constantly changing. The studies that we have now rightly focus on the Brazos River but generally only extend 1,500 feet from the banks. From there the data is based on extrapolation, which is not as accurate as measurement and calculation. In addition, most of the data do not correlate the rivers, streams and other biomes that populate the interior of Fort Bend. County Judge Bob Hebert is looking to change that.  “One of the most important things we can do is to update our data to really understand all of the water flow in the county, to make sure every system is working together to keep our county as dry as possible,” said Hebert.

Micah Moore and Diego Moreno, from Lamar Consolidated ISD’s Arredondo Elementary, cooked meals and brought subs and drinks to Navarro Middle School for Hurricane Harvey evacuees.Photo by Monica Jaramillo.

To accomplish this, several studies are taking place. First is the landmark Watershed Study. Approved this past July by the Fort Bend County Commissioners Court, this study will fully analyze the river, tributaries and other biomes of the watershed. This report, which may cost $3 million, will determine what impact key drainage projects will have on the county so that the correct solutions can be implemented. Expectations are for the study to be completed in eighteen months.

“Before we ask for any bond appropriations, we need to make sure the changes we ask to fund will fix the problems shown by Harvey,” said Hebert.  “Our engineers have highlighted the issues they believe should be dealt with, but this study will also find new projects to consider. In the end, we will have a study that lays out how all of these potential adjustments will work together so we can achieve the best outcomes.

The Brandani family of Brandani’s Restaurant & Wine Bar made certain Missouri City’s finest were well-fed during the storm by providing and delivering hot meals.

“Additional studies are expected to highlight specific areas of concern. Studies of Bessie’s Creek and Jones Creek will each provide unique water flow problems to overcome. The goal is to determine means to improve the drainage in those two watersheds without just moving the water onto other properties downstream. And, an independent study of Barker Reservoir will evaluate the cost-effectiveness of building a levee between our Fort Bend County homes and the reservoir.”

This issue continues to be a priority for both the county and the judge. “The priority for all this work is to make sure we fully understand the implications of every action we can take. Without doing that, unintended consequences could make the situation worse. We know these changes will cost money, so we have to make sure the expense will make our county stronger for this generation and for future generations to come,” said Hebert.