The Upper Colorado Regional Flood Planning Group met Thursday at San Angelo City Hall to address community outreach and flood-prevention recommendations.
Officials now say the July 4 flood levels in San Angelo qualify as a 1-in-500-year event, with an estimated two-tenths-of-one-percent chance annually.
In some locations, the event is being considered a 1-in-1000-year flood, which would represent a one-tenth-of-one-percent flood-chance annually.
“There was water in places I’ve never seen before,” said Public Works Director Shane Kelton — an observation shared by many.
Officials report high-water mark data is still missing throughout the entire region, which will be collected, in part, through the iSTAT forms.
They also said there will be a renewed push for cities and counties in the region to report their data through this group, as most received at least 3- to 4-inches of rain.
County Commissioner Rick Bacon could not attend the meeting, but sent a statement requesting that the group consider new early-flood-warning systems in Precinct 3.
There was some discussion of future infrastructure changes in the East Angelo Draw, which runs down to the Bell Street overpass, potentially including adding more channels, and constructing detention ponds between there and Loop 306.
Local hydrology expert Chuck Brown, formerly of the Upper Colorado River Authority, spoke about the flow out of North San Angelo on the morning of July 4.
Brown is now the CEO of Hydro Corporation, who operates stormwater check stations for the city.
“During an event in August 2011, we received 4 to 5 inches of rain in 4 to 6 hours, we were saying that was maybe a 50 or 25-year flood.
“Theres one station off Pruesser street that was standing in about two feet of water at that time. All the water that flows out of Lake View and East Angelo Draw goes through here.
“I went out to check this location recently, and the drift line was 3- to 4-feet over the top of this station.”
When large tracts of industrial land flood, along with junkyards and warehouses like those Northeast San Angelo, it becomes a serious groundwater-contamination problem as well.
Presence of industrial chemicals in water samples will be a main concern in the coming months.
The group voted to approve a high-water marks and flood-damage workshop to be held soon for officials and residents of the region, with details to be announced later.
Work on Report to State Water Development Board Continues
The 2024 State Flood Plan relied on detailed recommendations for the 15 floodplain regions in Texas.
The group’s normal duties of mapping and preparing their report to the board continues, with surveys of city and county governments in the region.
In 2023, the planning group recommended the following practices:
- Have developers provide a study establishing Base Flood Elevations, or the elevation of water from a 1-percent chance flood so floors can be built at least 1-foot above flood level.
- Structures also should have a finished floor 1.5 feet above street or curb, and new culverts or bridges must have 1 foot of freeboard above the BFE, which are basic requirements to minimize future damage.
According to the group, 18 of the 32 counties, and 13 of the 36 cities in the region have responded to the outreach survey providing input on floodplain management.
What They Said
- “We need more areas of the county mapped for floodplains by FEMA.” – Coke County
- “Difficult to track new construction due to lack of building regulations or zoning in the county.” – Midland County
- “We need a new flood map.” – Crockett County
- “Andrews has been trying to regulate development but it was done relative to outdated and approximate maps from 1970, and so it was not effective. Good flood risk data is not available everywhere and is a difficult concept for all to understand.” – City of Andrews
- Recommended measures include further evaluations to confirm flood risk, reducing structures in the 1 percent floodplain, and improved safety at low water crossings and dams.
- The City of Winters, and Ector County reported that they need updated floodplain mapping as well.
These comments were received by cities and counties before the flooding in July.
Representatives from outside consulting firms gave updates on the current flood zone mapping projects.
“We’ll be collecting 10-year storms data in this mapping.” Said Sam Hightower of Halff Consulting.
“Current models only account for 100-year and 500-year flood events. Closer analysis will add to the existing models to account for more minor flooding events, which can still pose serious threats to life and property.”
The group also finalized plans for a dedicated website in the same style as many of the other regions, approving the name “uppercoloradoflood.org”.
The website would make flood information more accessible and would take responsibility off city maintenance crews.
