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A Little Perspective on the Ups and Downs of Water in Houston
San Jacinto River Flooding
During Memorial Day weekend 2015, Houston went through one of its feast moments in the water supply. Massive rains that stretched from April to this week had already saturated the ground. Actually, the public was happy to see all the rain after almost five years of drought, until the deluge. Despite all the national attention and headlines calling this a historic flood, it was much lighter in total damage and flooding than say Allison or Hurricane Ike. It wasn't even as bad as the 1994 floods that flowed over the West Lake Houston Bridge, seen in the above photograph.
FEMA reported that Allison had dumped 32 trillion gallons of water in 2001. Early estimates for this week's storm show only about 162 billion gallons. That hardly matters to some residents as they watched the water climb toward their front doors and into their homes. Yet, old-timer residents will tell you these things come and go, so what did you expect when you moved to a place called the Bayou City?
Since Houston was first developed in 1836, it has constantly battled these periods of flooding. We live in a confluence of Buffalo and White Oak Bayous, “or precisely where cars Tuesday were buried in water on an entrance to Interstate 45,” as an associated press story mentioned. To the north we have the San Jacinto River and Spring Creek and to the southeast Sims Bayou meanders southwest below 610 loop to a point south of South Post Oak Road. That doesn’t include all the other waterways that weave through Harris County shown on the below map of flood plains.
Harris County's Current Floodplains Map
Our waterways work from high points of 125 feet in the northwest to 50 feet above sea level in the downtown areas. That elevation remains fairly constant from downtown to the south toward Pearland and Alvin. In other words, the county is mostly flat. Add the City of Houston’s urban sprawl to the mix and you get a guarantee of flooding. This next map shows our various bayous broken down into individual floodplains. Seen beside the map showing flooding hot spots this Spring, you can understand that we have an ongoing issue that isn’t going away.
Floodplains and High Water Spots
Water for Texas
Reasons for Flooding Issues
Water for Texas by Jim Norwine, John R. Giardino, and Sushma Krishnamurthy is a book written four years after Tropical Storm Allison and three years before Hurricane Ike. It offers some clear history and information on our flooding issues. It is worth a look for anyone wanting to know more about water issues. It lays out several reasons for our flooding issues.
- The number one reason for the regular flooding is the natural composition of the land. Our clay soils compact, not allowing rains to filter down easily, so it becomes runoff. All the concrete we have laid makes a bad situation worse. Flowing water seeks a downstream path, but our very flat topography hinders that movement. What we get are massive puddles waiting for the long process required to soak into the clay. How long does that take? “Clay soils only allow .01 to 0.1 inches of filtration per hour,” according to page 117.
- A second reason has to do with building a city on a floodplain. “The primary source of damaging floods along Cypress Creek is increased development of the floodplain,” the Higher Ground Report written by the National Wildlife Federation states. That can be said of just about anywhere else in the county as well.
The fact that our wonderful city was built on silt and clay can be lamented, but the time to move the city to higher ground with better soils has long since passed us by. As major expansions to the city in the 1970s built on top of watersheds, we have developed ourselves into a reoccurring nightmare of continuous flooding events. What water control plans had been set up to handle 100 year flood events now can’t hold even 10 year flood events. Channelization projects have proven costly and magnets for further development, which defeats the purpose.
"Bottom line is, we live on the Texas Gulf Coast and we have a lot of low-lying area, and we have to deal with that," said Harris County Judge Ed Emmett, Harris County’s chief executive officer.
This quote may seem unhelpful, but it gets down to the essence of the problem. Efforts to change what nature intended have a high probability of failing, as we saw when water, one of the strongest forces of nature, washed away bridges, covered roads and flooded cars, homes and destroyed property in the cities large institutions during Tropical Storm Allison illustrated by the photograph below. What we experienced over the Memorial Day weekend wasn’t even .5% of the water that storm dropped.
Houston Flooding in 2001
How to "Deal with That"
In the last 100 years of the Corps of Engineers attempting to build structures that control floods, they have come to the conclusion that, “. . . individuals and society as a whole cannot have it both ways; i.e., (insisting) that development in floodplains is economically viable in a variety of ways and locations and yet seeking outside financial assistance when the extreme flood event strikes,” as stated the Higher Ground Report on page 11.
The report also says we have to start treating flood plains as what they are, places for floodwater to collect, not for people to live on. The main recommendation is to increase re-locations away from flood plains and to stop inappropriate land development. “Human activity in the floodplain will continue, but with the clear understanding that any activity is subject to the residual risk of flooding and that the costs of this risk are to be borne by the sponsors of the activity ....” They suggest that the areas people are relocated from can be converted into river-focused parks and recreation areas.
Houston and Harris County have already started that process. After our most recent hurricanes and severe tropical storms, buyouts were offered to many as seen in the Home Buyout Map below. The Federal Flood Insurance Program can help many get back on their feet after a flood, but repetitive claims need to be reduced. It is much wiser to buy and remove the structures seeing constant flooding than to continue fighting a vicious circle of rebuild and redamage with no end. Read more about Voluntary Home Buyouts.
Home Buyouts in Harris County
Protecting a flood plain area from development was not the main goal of connecting park trails that make up the Spring Creek Greenway, but in protecting the untouched wild areas, we have closed these flood prone areas from further development. The final product will be a string of reserves and parks for eco-tourism. You may have seen reports of the flooding in Jesse Jones Park and other parts of the greenway last week. The good news is that these areas are meant to flood. Think about what reports would have looked like if those areas had been allowed to be developed into riverside homes rather than nature trails. Trails are much easier to repair than homes and businesses. The below video gives an overview of the project and its benefits.
The Spring Creek Greenway
It may be a blow to our collective egos that nature can’t be bent to our will, but really, we have been relearning that lesson for centuries. It is far better that we accept gracefully and get out of Lady Nature’s way by relocating people and converting flooding hot spots into green spaces than to continue to suffer property damage and loss of lives.
© 2015 Sherry Thornburg