In just a few hours of late April and early May, as much as 18 inches of rain fell on already saturated ground in Parker County. According to some estimates, 90% of the rain that fell ran off directly into rivers and lakes because the soils couldn't absorb more. The storms caused localized flooding and filled many reservoirs to overflowing including Lake Brownwood which crested nearly 7 feet over its spillway, surpassing records that were set 30 years ago. The rains also forced the Brazos River Authority to dramatically increase releases from area reservoirs. Releases of 38,000 cfs from Possum Kingdom Lake and 58,000 cfs from Lake Granbury were typical.
Many homes and businesses were damaged. In the Horseshoe Bend subdivision near Weatherford, 60% of the homes were under water and some residents claimed they weren't notified that large releases from the dam were coming their way. In downtown Brownwood, losses were estimated at $15 million and some called it the worst disaster to ever hit the area. To make matters worse, Brown, Comanche and Erath counties had never joined federal flood insurance programs and Parker County left the program in 1981. Consequently, many forms of federal aid were unavailable following the floods.
The Red River Overflows
On the Red River, heavy rains also created extensive flooding. Traffic backed up five miles near Dennison Dam as onlookers watched the water flow over the dam's 1,500-foot spillway for the first time since 1957. Behind the dam, Lake Texoma had grown from its normal size of roughly 90,000 acres to nearly 150,000 acres. Later, spectators viewed the flooding on the Red River as less of a spectacle and more of a crisis. When high flows on the Red River neared Texarkana, the river swelled from its normal width of a half-mile to 10 miles in places.
A key question was whether the levees could stand up to the high water or if they would collapse and cause even greater damage. To shore up the levees, 400 national guardsmen were called out to reinforce the levee with 30,000 sandbags. Some officials gave the levees only a 50% chance of surviving the floods because the constant pressure of water against them could force the levees to fail. A 60-foot section broke and floodwaters were just inches from the top of the 10-foot levees. An emergency official said that walking on the levees was like "walking on Jell-O" and reported that stepping on a vulnerable levee sent ripples across a nearby street.
Corps of Engineers officials estimated that Lake Texoma and other reservoirs reduced peak river levels by 6 to 12 feet in many places, and projected that lakes and levees along the river avoided more than billion in property damages.
Flooded Crops, Devastating Erosion
Many of the damages, particularly in losses to agriculture. The Texas Department of Agriculture estimates losses to crops and livestock at $500 to $700 million. Meanwhile, Texas A&M University Agricultural Economist Carl Anderson suggests that losses could top $1 billion when soil erosion, damage to the environment, losses to the recreation, tourism and camping industries, and property destruction are factored in.
The adverse impacts fall into two major categories - crop losses and erosion. Estimates suggest that the floods may have destroyed most of the wheat and up to half of the corn and sorghum crops in a 41-county area. Agricultural production along the Trinity River suffered severe losses and cotton and grain sorghum crops in the region were virtually destroyed.
Because the floods came after farmers had freshly plowed their fields to plant crops, erosion was especially heavy. Estimates from the U.S. Department of Agriculture's Soil Conservation Service suggest that up to 5 tons of soil per acre (roughly a dime in thickness) eroded from Texas croplands. Flooding near the Red River produced as much as 30 tons of erosion an acre and carved gullies 10 feet deep into croplands. Besides increasing siltation in area rivers and lakes, the loss of topsoil could be especially damaging in the future because it will take years to replace.
A "Huge Funnel" Pointed at Lake Livingston
The storms caused extensive damage in Dallas and Fort Worth. The Trinity River crested at 6 feet over flood stage in many areas, while the West Fork of the Trinity crested at a depth of 48 feet (its third deepest level ever). Much of the worst flooding was in south Dallas areas that were not protected by a levee where nearly 400 people were forced from their homes. After the floods, extending the levee to south Dallas has become a high priority. Floodwaters topped spillways at many dams including Eagle Mountain, Lake Worth, and Lake Bridgeport. The flooding in the Dallas area could have been much worse if flood control dams had not been built.
The upstream rainfall produced major flooding downstream. Runoff was coming of 81,000 cfs from Dallas was merging with flows of 40,000 cfs from Navarro and Henderson counties. An official with the National Weather Senvice said the river "was going crazy...it was so big it looked like a lake instead of a river." At some places, the river had swollen to 10 miles wide. The runoff converged just upstream from Lake Livingston. A Trinity River Authority (TRA) official said: "This large section of the watershed is overflowing..it's like a huge funnel pointing directly at Lake Livingston and the lower Trinity."
The crisis reached its peak in mid-May when runoff arrived from upstream areas and the Trinity reached an all-time record crest of 29 feet near Liberty (5 feet above flood stage). TRA then began releasing flows from Lake Livingston of roughly 108,000 cfs over a week-long period. The total amount of water that was released was equal to 40% of Houston's annual water supply. Only the absence of extra rain kept the situation from being even worse.
The impact of storms could be felt far downstream. Texas oystermen estimated that half the oysters in Galveston Bay could be lost because of reduced salinities.
Floodplain Development Puts People at Risk
By early May, TRA officials were warning residents that flood flows were on the way and urged them to evacuate and "head for higher ground." Unfortunately, many people had built on low-lying properties.
Why did so many people decide to build in floodplains below Livingston Dam? Properties with creeks or nearby lakes are beautiful when they aren't being flooded. Also, many people who developed property below Livingston were newcomers to the area who may not have comprehended or cared about the flood risks.
Although some people were ignorant of the risk of the area to flooding, others built in the area even though they knew TRA had the right to temporarily flood their lands. TRA bought the rights to occasionally flood lands around the lake itself (but not downstream) when the lake was too full. Some people still built homes on these areas.
Only a few people actually evacuated during the floods. Most stayed to guard their homes and possessions from looting. Others stayed in the surrounding area during the floods and said they would probably return after the floodwaters subsided. Even if they wanted to sell their homes, they couldn't find buyers who would give them the price they originally paid.
A key lesson that was reinforced from the flooding was that homes and businesses built in low-lying floodplains are more likely to be devastated when a flood occurs. Roughly 4,000 people were forced from their homes in the area immediately downstream of Lake Livingston because of the flooding. Roughly 200 homes in low-lying subdivisions were destroyed and losses were estimated at more than $11 million.
"As long as people are living in the floodplain we'll have problems," said a TRA spokesman. "Is the problem that the Trinity River floods below the dam or is the problem that people are living in the floodplain? People have to realize that the low-lying land below Livingston Dam is a floodplain. It has flooded since time immemorial and will almost certainly flood again. There's absolutely nothing TRA can do to provide flood relief to those poor, beleaguered people downstream. Many of those people simply live somewhere they probably shouldn't."
Could Prereleases Help?
One of the controversies surrounding this year's flooding was whether prereleases ought to be made from Lake Livingston. Liberty County officials and people who live near the river bottom contend that there would be little or no flooding below the dam if TRA would lower its lake levels before heavy rains hit. They want the water supply dam operated as a flood control reservoir.
TRA argued that prereleases would not have lessened the flooding because too much rain fell. The amount that could have been prereleased was only a fraction of the water that reached the lake. Prereleasing could also have caused minor flooding. Even if the floodgates had been opened earlier to allow flows of 100,000 cfs to leave the lake, it would have taken 63 days to empty the reservoir because rainfall and runoff still would have filled the lake more than 3 times, TRA said. Others say that even if the lake was drained it would have been filled to overflowing in a few days.
One reason prereleases were not made was a fear that the practice might diminish water rights in the lake that cities have paid to develop. Prereleasing water now might limit water rights in the future by setting a precedent in which TRA would be obligated to release water before every potential flood. It should be noted that only half of the water supplies in Lake Livingston are now being used by the City of Houston and TRA.
Not everyone agrees that prereleasing is impractical. A Liberty County judge argued that TRA could release floodwaters in advance of storms based on weather forecasts. No water supplies would be lost and the risk of flooding would be reduced if rains fell as predicted. If the weather forecasts were inaccurate, water supply problems could develop. Prereleasing may be a viable strategy when small amounts of water that won't cause flooding are released.
Potential solutions have been proposed. Those interested in using Livingston as a flood control dam could buy water rights in the lake and dedicate them to flood control (if there were willing sellers). The Corps is investigating whether new flood control dams could be built upstream of Fort Worth or above Lake Livingston at Tennessee Colony. The Texas Legislature has created a task force to review flood control operations in the region and to study the impact of reservoir releases during floods.
Federal Flood Relief Efforts
Many flooded residents from throughout Texas qualified for disaster relief from federal agencies. NFIP identifies communities that are vulnerable to flooding and produces maps that show the boundaries of floodplains and other areas that are likely to be flooded. NFIP then makes federal flood insurance available if communities enact floodplain management ordinances and take steps to reduce flood risks.
There may not be much sympathy for those who continually rebuild in floodplains and regularly suffer flood damages, only to be reimbursed by NFIP. An editorial In The Dallas Morning News commented on the situation this way. "It seems reasonable with all that is known about floods that no structure should be allowed in the floodplain that is below the level of the expected water rise, no matter how many years it has been there. It would be cheaper to relocate people before a flood than to handle a disaster. If people wish to continue living as they have then they should not be able to [do so] at taxpayer expense."
Banks are supposed to verify that those who borrow money for developments within designated floodplains purchase flood insurance and keep those policies active over the life of the loan. Only a small percent of banks may be requiring that people who take out loans to buy properties in floodplains actually buy flood insurance (Rose, 1988). Many borrowers are not keeping their flood insurance policies active after initially taking out loans. Another recent study (GAO, 1990) reports that nearly 80% of properties in Texas that were required to be covered by flood insurance are uninsured.
In many areas of the state, floodplain management and participation in FEMA programs is controversial. No one wants to endanger lives and property to the potential risk of flooding. However, floodplain management makes it clear that some properties are in danger from flooding and some argue this reduces their market value. Residents are often required to elevate or floodproof homes and other structures which can be expensive. In Houston, ordinances require that part of new lands being developed be set aside to control stormwater runoff (Corps of Engineers, 1988). Others don't like the idea that a federal agency can tell them where they can and can't build.
Parker County commissioners voted to leave the FEMA program a few years ago because some residents didn't want to elevate mobile homes and other structures. Parker County received limited federal aid after this year's floods and later reapplied to the FEMA program and was readmitted. Since rejoining the program, Parker County has been identifying properties that were damaged in previous floods, requiring the elevation of some buildings, and adopting maps with the 100-year floodplain.
Local reaction to the NFIP program is mixed. Following last year's and this year's floods, roughly seven counties and seven communities have joined the NFIP. Palo Pinto County was recently debating whether or not to join the program. Burnet County protested detailed maps by FEMA showing where flooding was likely.
Summary
Texas received a great deal of rainfall earlier this summer. Obviously, the amount of precipitation was going to cause flood damage in many parts of the State.
However, there are some things Texans can do to reduce the risk of flood damages. The most important measure involves planning new development so that it isn't sited in flood-prone areas. More controversial issues include what to do with existing homes and businesses located in flood-prone areas and how to avoid repetitive losses.
Historically, Texas has relied on structural flood control projects - construction of dams, levees, channels and even drainage tunnels. While these measures have merit, recent evidence is showing that flood control dams, for example, can not be justified economically if they are built and paid for by local governments.
Evidence suggests that a mix of structural and non-structural policies (including programs that discourage development of flood-prone areas, relocating or buying out vulnerable areas and creating incentives to move out of those areas) may be the best way to control flood damages.
References
Buffalo Bayou and Tributanes, Flood Damage Prevention Feasibility Report, U.S. Army Corps of Engineers, Galveston, TX, 1988.
Burby, Ray, Cities Under Water, Behaviorial Sciences Institute, University of Colorado, Boulder, CO, 1988.
Burka, Paul, "The Unholy Trinity," Texas Monthly, Austin, TX, July 1990.
Clean Water, North Central Texas Council of Governments, Arlington, TX, 1990.
Common Vision: Upper Trinity River Reconnaissance Report, U.S. Army Corps of Engineers, Ft. Worth, TX, 1990.
Community Rating System, Federal Emergency Management Agency, Washington, DC, 1990.
FEMA/ NFIP Annual Report, Texas Water Commission, Austin, TX, 1990.
Flood Insurance: Information on the Mandatory Purchase Requirement, U.S. Government Accounting Office, Washington, DC, 1990.
Flood Insurance: Statistics on the National Flood Insurance Program, U.S. Government Accounting Office, Washington, DC, 1988.
Interagency Hazard Mitigation Report in Response to the May 2, 1990 Disaster Declaration for the State of Texas, FEMA Region 6 Interagency Hazard Mitigation Team, 1990.
Milleman, Rose, and Elsie Jones, Storm on the Horizon: The National Flood Insurance Program and America's Coasts, National Wildlife Federation, Washington, DC, 1989.
National Flood Insurance Program: Major Changes Needed if It Is to Operate Without a Federal Subsidy, U.S. Government Accounting Office, Washington, DC, 1983.
Rose, James, "The Mandatory Flood Insurance Purchase Requirement," ABA Bank Compliance, Washington, DC, Autumn, 1988.
Questions and Answers on the National Flood Insurance Program, Federal Emergency Management Agency, Washington, DC, 1990
Thomas, Frank, A Status Report on the Nation's Floodplain Management Activity, Interagency Task Force on Floodplain Management, Knoxville, TN, 1989.
Wurbs, Ralph, "Economic Feasibility of Flood Control Improvements," Journal of Water Resources Planning and Management, New York, NY, January, 1988.
Jensen, Ric. "Finding Answers to Flooding Woes." Texas Water Resources. V16 N3. Fall 1990. Publication of Texas Water Resources Institute.
