Bats, Bayous, and Halloween

Reasons to Love Bats

Oct. 31, 2019


Today is All Hallows Eve, which is, believe it or not, associated with the coming of winter, which is associated with death. In other places where they have seasons, that means trees, for instance, lose their leaves and appear to die. Scary and strange. But they come back! That’s one reason Easter happens in the spring.

Halloween is also associated with bats. And today is the last day of Bat Week. And since bats are also associated with rivers, and we have many bats here in Houston on our bayous, we thought we’d talk about bats.

A Bat Rap

Bats are extremely beneficial for insect control (most importantly eating tons of mosquitoes here in Houston) as well as for pollination, like bees and hummingbirds. In the tropics they carry fruit and nut seeds. We need bats.

Bats are associated with Halloween because they are nocturnal, because of vampires and Dracula. But there are over a thousand species of bats and only a few of them actually feed primarily on blood. We have eleven species of bats in Houston (thirty-one in the entire state) and none of them are so-called vampire bats. Also, almost none of them have rabies (less than estimated one percent), though it’s always best not to try to touch wild animals.

Bats on the Bayou

The Mexican free-tailed bat can fly almost 100 miles per hour. Photo by Ron Groves

Bats generally roost near sources of water, like a stream or river, which is why we have bats on the bayou hanging out under bridges, as well as under roofs, in trees, and other places nearby.

As Houston Audubon points out, the best known bat in Texas is the Mexican/Brazilian free-tailed bat, which is officially our state flying mammal. This is the bat that lives under the Waugh Street Bridge near Allen Parkway, attracting crowds of people to watch the colony emerge at dusk in search of moths, mosquitoes and other insects to eat, flying as fast as 100 miles per hour and as high as a 1,000 feet in the air to gobble up tons of insects. Hawks and falcons, too, circle overhead, diving into the colony to capture a meal.

More Information

Save Buffalo Bayou board member and canoe guide Tom Helm offers a sunset float trip on Buffalo Bayou to view the bats.

How to build your own bat house or encourage bats for natural mosquito control.





Raising Bridges, Building Meander Bypasses on Buffalo Bayou Doesn’t Reduce Flooding, Study Says

New Idea is to Strip and Widen Bayou Channel in Terry Hershey Park Above Beltway 8

New Problem: Increased Flooding Downstream


Oct. 20. 2019

A study commissioned by the Harris County Flood Control District has found negligible flood-reduction benefits to building bypass channels through meanders or raising bridges on Buffalo Bayou.

But the District is instead contemplating stripping the trees and vegetation and digging out the engineered banks of Terry Hershey Park to widen the channel by fifty feet on both sides for some six miles below the dams in west Houston. The District is still in the process of scraping out new overflow basins on the south bank in the park.

These findings were presented at a packed public meeting Thursday, Oct. 17, in the Memorial area of west Houston. The study, the result of public pressure from property owners who flooded in neighborhoods adjacent to Terry Hershey Park, was conducted by the engineering firm Huitt-Zollars and funded with $350,000 in Harris County flood bond funds.

Buffalo Bayou originates in the prairie near Katy, Texas, and flows for some fifty-three miles through the center of Houston, emptying into the San Jacinto River and Galveston Bay. It is the main river flowing through the city and a central part of the region’s natural drainage system. Below Beltway 8 to Shepherd Drive just east of downtown, Buffalo Bayou remains a mostly winding, wooded stream, and it was these many meanders that some residents upstream of the beltway blamed for flooding their homes when the floodgates on the dams were opened during Harvey.


Graphic courtesy of the Biomimicry Institute


The Meeting and The Findings: Is Nature a Better Engineer?

Alan Black, director of operations for the Flood Control District, opened the meeting by explaining what the district does and why the region floods (reasons which did not include the fact that so much of the city is covered in impervious surface). The first priority for the district is still “deepening and widening bayous,” said Black. Unfortunately that is a futile, never-ending pursuit, like building bigger freeways. It also leads to bank collapse, lifeless streams filling with silt and polluted water, a barren landscape, and continuous costly maintenance.

Modern flood management, rather than collecting and moving as much water as fast as possible, focuses on stopping stormwater before it floods a stream and on managing flooding in place. For instance, “lag time” is the amount of time it takes for rain to fall on the ground and enter a stream. The shorter (faster) the lag time, the higher the peak flow (flooding) in the stream. Trees, deep-rooted vegetation, detention basins, rain gardens and more can help increase the lag time and reduce flooding. There are many ways that neighborhoods and individuals can take responsibility for slowing, spreading out, and soaking in stormwater. (See also here.)

The district, which has limited legal tools dating from 1937 when it was founded, does focus also on building detention basins to temporarily hold stormwater, as well as on moving people out of harm’s way through buyouts.



Michael Tehrani, vice-president of Huitt-Zollars, explained the study findings, which were “not that promising,” he told the large crowd, which included politicians and representatives of the Corps of Engineers. Buffalo Bayou is relatively flat, a “lower velocity channel” with a lot of trees; the channel itself “controlling the water and determining the Water Surface Elevation, not the bridges.”

Read the rest of this post.

Public Meeting: Bridges and Meander Bypasses on Buffalo Bayou

Date is Oct. 17 to Find Out Study Results

And More

Oct. 13, 2019


In the wake of disastrous flooding along Buffalo Bayou during and after Harvey in 2017, particularly on upper Buffalo Bayou after the opening of the floodgates on the federal dams, some west Houston residents urged the Harris County Flood Control District to look into whether meanders downstream and bridges across the bayou had blocked the flow, causing them to flood.

In response, using up to $350,000 in public funding from the 2018 Flood Bond election, the District in November of 2018 hired the engineering firm Huitt-Zollars to study the thirty-three bridges and four pipelines that cross the bayou between Highway 6 at Barker Dam and Congress Street some twenty-six miles downstream in downtown Houston.

More controversially, the study also examined the possibility of constructing bypass channels or culverts in thirteen locations, cutting through natural bends in the river. This would be below Beltway 8 where the bayou twists and turns, as rivers naturally do, for good reason. (p. 36) Meandering streams are longer and carry more water. Meanders also help dissipate the force of the stream during floods. Such is the power of the underlying geology that even if altered or straightened, rivers will seek to return to their natural channel, breaking through concrete if necessary. (See Tropical Storm Allison, Tranquility Garage, 2001.)

In the 1960s, environmentally-minded property owners on the bayou, including Terry Hershey and Save Buffalo Bayou’s founding president, Frank Smith, joined forces to stop the Corps of Engineers from stripping, straightening and covering in concrete this winding, wooded stretch of the bayou—as the Corps had done earlier, destroying White Oak and Brays bayous.

The Flood Control District is holding a public meeting to discuss the results of the meanders and bridges study on Thursday, Oct. 17, from 6 to 8 p.m. at the Memorial Drive Presbyterian Church, 11612 Memorial Drive, in Houston 77024.


Comparison of Buffalo Bayou at Beltway 8 in 1944 and during Harvey in 2017. Note the engineered channel bypassing the original meander and flooding along the oxbow remnant. Graphic by Diane Masterson


Maligning Meanders

In the early morning of Aug. 28, 2017, after the peak of the flooding from Harvey had passed downstream on Buffalo Bayou, the Corps of Engineers made the unprecedented decision to open the floodgates on Barker and Addicks dams in far west Houston. Rising water flowing from the rapidly developing north and west of the city threatened to overwhelm the earthen dams. When the gates were opened, residents living along the six-mile plus channelized stretch of the bayou just below the dams were badly flooded. This stretch of the river had been narrowed and straightened by the Corps in the Fifties, essentially reducing its capacity.

But a popular belief continues that the meanders below Beltway 8 caused the bayou to backup and flood homes upstream adjacent to what is now Terry Hershey Park, hence the push to construct channels to bypass or cut through meanders. (Another popular belief, which also persists, is that the “rich people downstream” did not flood. There was, of course, massive flooding along Buffalo Bayou all the way through downtown Houston during Harvey. But that flooding, fed by the rapid accumulation of rain runoff from the city and suburbs below the dams, occurred before the floodgates were opened.)

In October of 2018 Save Buffalo Bayou published a report in response to this widespread mistaken belief about meanders downstream. The report explained why people flooded upstream and how meanders are beneficial and actually reduce flooding. You can read the full report here.

Read the rest of this post.

That Bend in the River, Fall 2019

Oct. 13, 2019


For a brief moment it was cool, which should have been a relief. But there we were staring dispiritedly at the mound of dirt piled up on the opposite bank of the bayou. Jim was back in town, and we were taking our fall shot of that Bend in the River from the same high bank in Memorial Park. Well, not really the same bank: nature changes, the river changes, the bank slumps and comes back again.

But these changes were most unwelcome. For the past six months or so, the River Oaks Country Club has been cutting down trees, grinding up, digging, scraping, pounding the bank, hammering large sections of heavy sheet pile into the bank, dumping  massive amounts of concrete riprap onto the bank and using a backhoe to pound it into place.

Instead of the soothing sounds of nature, the awful sounds of growling machinery and clanging metal shook the woods, accompanied by the occasional splash of blocks of sediment calving off the inside bend of the meander, collected there on the opposite bank during Imelda, no doubt having washed down and out from the dirt mound and from the stripped and graded bare bank upstream.

Fall 2019 on that bend in the bayou with heavy equipment and a mound of dirt dug up from the country club bank upstream. Photo by Jim Olive on Oct. 12, 2019

The country club’s “bank repair” project, said to cost some $18-24 million, has been spearheaded by club member Steven J. Lindley, who was also responsible for the renovation of the club’s golf course. The bank project has three parts totaling some 1,700 linear feet opposite Memorial Park, private residences, and parts of the Hogg Bank Sanctuary.

Save Buffalo Bayou has filed a complaint with the US Army Corps of Engineers about the irregularities and deficiencies in the club’s application for a special federal permit to “restore uplands” lost to Harvey. Among other problems, the permit application contained none of the required documentation of the alleged uplands lost to Harvey. And in fact, it would have been difficult to document the minor, if any, loss of upper bank in Area 1 upstream from where we stood. The steep high bank there has been standing in virtually the same place for at least a hundred years, which is why the bayou makes a sharp turn there.

Area 1 of the River Oaks Country Club slope repair project on April 7, 2017, before Harvey. Photo by Jim Olive

Area 1 in August 2018, one year after Harvey. Photo by George Parker











The application also misrepresented the length of the project, claiming it was only 1,499 feet. Documents presented to the City of Houston and the Harris County Flood Control District showed it was much longer.

But Jim took a lovely photo of the crime scene.

See the entire series documenting this same bend in the bayou throughout the seasons since 2014.



Looking upstream towards Area 1 of the country club’s “slope repair” project. Photo by Jim Olive on Oct. 12, 2019