Keep eye on flood threat
Harris County looks to install gauges in adjoining areas to monitor rainfall
Earlier this year, a wave of water washed into Harris County from neighboring Waller County, spilling into the creeks and rivers and flooding hundreds of homes.
The invisible line dividing the two counties means nothing to the Houston region’s perennial rains. But it has meant the data that public officials use to coordinate a response is a patchwork that depends on who is gathering it.
That might change as the Harris County Flood Control District seeks to go beyond the county’s borders and install rain gauges in several surrounding counties to get a better idea of when potentially deadly flooding is coming — and from where.
The Harris County Flood Control District is looking to add at least eight “rain gauges” in Waller, Montgomery and possibly Grimes counties, where watersheds for Spring Creek and Barker Reservoir cross county lines, said Jeff Lindner, a meteorologist who is director of the district’s hydrologic operation division.
The gauges can accurately measure rainfall as well as the water level in a creek.
That would allow county officials and emergency responders to better tailor warnings, provide estimates of how long people might be trapped in their homes and decide where to place high-
“Even if you can have one to two hours of advanced warning, that’s saving infrastructure, lives.” Tom Ballestero, director of the University of New Hampshire’s Stormwater Center
water vehicles or boats.
“We just want to make sure that we are getting a full picture of how much water is coming into our watersheds that are on our county borders,” Lindner said.
The gauge initiative, still tentative, is one of several steps the flood control district is undertaking after last spring’s storms. The first, dubbed the “Tax Day floods,” struck on the night of April 17 and continued into the following day, the deadline for filing federal income taxes. The second hit Memorial Day weekend. Torrential downpours swelled creeks and bayous across the county, flooding more than 7,000 homes and killing more than a dozen people.
These storms followed two significant disasters the year be- fore, on Halloween and Memorial Day 2015, raising concerns and demands for action from weary flood victims across the county. Studies underway
The flood control district has contributed $200,000 to a federal study of past rainfall totals across Texas, which could help local officials better predict the size and frequency of rainstorms. And the district has commissioned a third party to evaluate its detention requirements, which force developers to offset the impact new subdivisions and strip malls can have on downstream flooding.
Tom Ballestero, director of the University of New Hampshire’s Stormwater Center, said that when it comes to flood response, weather forecasts are the most important tool because they can predict rainfall — and inform re- sponse — days in advance.
But he said gauges also can make a difference by giving realtime updates of where the water is moving.
“Even if you can have one to two hours of advanced warning, that’s saving infrastructure, lives,” Ballestero said.
He said working across jurisdictions has become the “state of the art,” with effective models in the Northeast and in California. He said Harris County’s effort builds on that.
The gauges would have benefits in predicting rainfall, too. Much of what many jurisdictions across the country know about rainfall comes from data gathered over a few decades in the 20th century, Ballestero said.
Lindner said the flood control district’s current network of 144 gauges across Harris County is one of the densest in the nation. It began in 1983, with around 15 gauges, and slowly expanded over time after major storms flooded different areas.
The county has several gauges on Clear Creek in Galveston County. Lindner said the county also gets information from gauges maintained by other entities in other counties, but the expansion would provide better and more reliable data — for example, there is only one gauge in Waller County from which the flood control district gets information. All information useful
The latest plan would cost roughly $6,300 per gauge for the installation — and roughly $500 to $700 per year, per gauge, for maintenance. The expansion ideally would be completed in the spring, though Lindner said the district was negotiating placement with the neighboring counties.
He said the gauges also would provide rain- and water-level information to those counties.
Lindner did not think the county would have necessarily reacted any differently to the spring storms had the gauges been in place then, though he said the information would have helped.
“We would have had a better idea of exactly how much water is coming down into Harris County and probably a better idea of the timing, how quickly it’s going to reach us and how long it’s going to last,” he said.
Lindner encourages county residents to follow gauge data at near-real time at www.harriscountyfws.org.