Another flood like 1998 'possible'
Oct. 19, 2013 at 5:19 a.m.
Updated Oct. 20, 2013 at 5:20 a.m.
It could happen again.
A flood like the one in October 1998 is possible, but forecasting methods and warning systems have improved greatly during the past 15 years, said John Metz of the National Weather Service.
"Fast-moving water is destructive and deadly. Improvements to the river forecast process will hopefully allow for much more accurate forecasts than in 1998," Metz said.
No one died because of the flood in the Crossroads.
Those improvements include a new computer system at the River Forecast Center.
The center also provides daily river forecasts for Victoria, which didn't exist in 1998, Metz said.
In addition, the weather service's hydrologic forecast system also did not exist in 1998.
It now allows for real-time river monitoring and provides a historical database and the ability to quickly issue forecasts and warnings with guidance from the River Forecast Center, said Metz.
Observations from U.S. Geological Survey river gauges were available every four hours in 1998. Now, the weather service gets updates every hour, he said.
In Cuero, City Manager Raymie Zella said warning sirens - for any inclement weather as well as a flood - have been installed, and the city has a reverse 911 system to alert residents of potential danger.
In the aftermath of the flood, the Guadalupe-Blanco River Authority worked to make some changes, too, said chief engineer Tommy Hill.
It helped install new rain gauges and river level gauges along the San Marcos and Guadalupe rivers.
It also helped secure funding for a National Oceanic and Atmospheric Administration weather radio program for a new master radio site in Gonzales County.
The GBRA and other entities established some high-water marks at various sites along the Guadalupe River and several of its tributaries, Hill said.
Ultimately, GBRA staff pushed for some federal funding, receiving some to assist with floodplain modeling primarily in Comal, Guadalupe, DeWitt and Gonzales counties. Some of the modeling effort remains in progress today, said Hill.
The 1998 flood, followed by another major flood in 2002, moved the San Antonio River Authority, too, to make some changes.
The Bexar Regional Watershed Management partnership was formed, allowing all communities and agencies to work cooperatively and pool resources and capability to tackle flood control issues, said Russell Persyn, the San Antonio River Authority's watershed engineering manager.
The authority also invested more than $14 million in improved flood mapping and modeling throughout its jurisdiction.
"SARA is working with emergency operators to develop a near real-time flood mapping and response system that can support preparation and response to flooding," Persyn said.
Metz said the Guadalupe River, however, is in the perfect place for the repeat of such an event.
"It is located near a significant moisture source, the Gulf of Mexico," he said.
"Combine this moisture, especially during the tropical season, with a slow moving frontal system, and you could have a repeat scenario or worse."
In October 1998, 30-plus inches of rain fell upriver in San Marcos and New Braunfels, propelling the swollen rivers down toward Gonzales and Cuero.
"The 1998 flood was the most devastating single rain event I've experienced during my 38 years working with GBRA," said Hill.
DeWitt County Emergency Management Coordinator David Dodge said residents are much more aware now than in 1998.
"Although it has been 15 years, this major flood is still on the minds of a lot of county residents, especially those very affected by it," Dodge said.
"Recently, during a heavy rain event, I began receiving calls inquiring about the chances of flood. I would say that we no longer have the 'It cannot happen to us' attitude."
Metz agreed that the public has become more involved.
A network of hundreds of rainfall observers that didn't exist in 1998 is now connected to the weather service
"These observations are critical in helping to validate how much rain fell in the river basin in a 24-hour period," Metz said.
Technology improvements, too, help with early warnings.
The emergency alert system is much improved and now alerts smartphones when flash flooding is expected, said Metz.
"Social media now allows for much faster dissemination of weather information to broader audience," he added.
Dodge also sees those changes in DeWitt County.
"We live in an information age, so it's not too difficult to keep up with river conditions, weather conditions and other factors that may have an impact on us and our families."
In addition to the improvements in forecasting methods and warning systems, Metz was also optimistic about the statistical probability of another 500-year flood.
"Considering the size and location of the Guadalupe River watershed, another event is certainly possible, but the probability at any given time is around 2 percent," Metz said.