Lines in the Sand on Buffalo Bayou
Nov. 19, 2017
Yes, we have alligators.
Reader Richard Lynn sent in these photos of alligator tracks on Buffalo Bayou. These photographs were taken recently on the north bank of what we called the middle meander. This is the big bend in the bayou at the eastern or downstream edge of Memorial Park. The indefinitely delayed “restoration” project proposed by the Harris County Flood Control District would fill in this meander, level the high cliffs, and reroute the bayou channel further south across the sandy point on the south side.
Lynn, a runner in the park, says the footprints were about six inches long. A reader on our Facebook page familiar with alligators estimated this one was probably six feet long.
Note that Parks and Wildlife says that alligators are generally afraid of humans and would rather just stay out of the way.
Lynn later sent in some photos of tracks that are a little more mysterious. One of the pleasures of walking or paddling on Buffalo Bayou is the beauty of the patterns of tracks in the sand.
The big drag track, however, is obviously a turtle.
On a recent float trip down the bayou with geologist Tom Helm, we saw these strangely beautiful tracks of something that waddled, sidled, or slithered up or down the bank.
County Commissioners Vote Yay
Approval to Go Forward with Contracts to Destroy Riparian Forest for Bayou Detention
Nov. 14, 2017
On the Radio
Excellent commentary from environmental lawyer Jim Blackburn on the vote by Harris County Commissioners today (Tuesday, Nov. 14, 2017) to go forward with contracts for detention basins in public forest alongside the channel of Buffalo Bayou. Save Buffalo Bayou is quoted also.
Note that the KUHF reporter describes the issue as Not in My Backyard. No one on the Save Buffalo Bayou board or advisory board lives anywhere near this proposed project. This series of detention basins (not just one) will be built in a public park, public forest, riparian forest in west Houston. Creating only a modest amount of holding capacity (280 acre feet), they will not hold back water flowing into the bayou but will temporarily peel off water that is already in the bayou, and will have to be continually maintained and scraped of sediment.
Detention is important and vital. Bigger, wider floodplains are important. That means buyouts.
New motto: Stop Raindrops Where They Fall!
Public tax dollars should be spent where they will create the most benefit. Flood management policy should be focused on detaining stormwater before it enters our streams. The flood control district had the choice years ago of building bigger, more useful detention basins elsewhere. They chose not to do that.
And On the Tee Vee
KHOU reporter Adam Bennett’s report on the flood control proposal to remove trees on the forested public banks of Buffalo Bayou in Terry Hershey Park. The controversial plan, long in the works, is to create a series of basins to temporarily hold water overflowing from the bayou. Save Buffalo Bayou thinks the time to stop stormwater is before it gets into our streams. Forest provides valuable detention. Removing it makes no sense.
What would Terry do?
And In The Houston Chronicle
Flood control “improvements” will definitely destroy public forest along Buffalo Bayou in Terry Hershey Park. They’ve pulled an existing, long-opposed plan off the shelf to look like they are doing something, anything, about reducing flood damages. This won’t help. We are not in favor of trees because they look pretty. We’re in favor of trees because they help reduce flooding.
The Chronicle’s Mihir Zaveri’s report on the issue and the vote:
Commissioners Court on Tuesday voted unanimously to let the Harris County Flood Control District sketch out what exactly a study of that segment of the bayou would examine.
The Court would have to vote again to green light the actual study, which could recommend flood reduction measures, such as clearing trees and installing detention ponds.
Susan Chadwick, executive director of the nonprofit Save Buffalo Bayou, opposed the flood control district’s study, stating that residents in the area had been fighting for years to keep the forests’ natural aesthetic.
Removing Trees for Detention on Buffalo Bayou
Commissioners Court to Vote Tuesday on Trees, Stormwater Detention on Buffalo Bayou
Nov. 13, 2017
Harris County commissioners will vote Tuesday, Nov. 14, 2017, on whether to authorize the negotiation of contracts for removal of trees and excavation of detention basins in Terry Hershey Park on Buffalo Bayou.
The controversial detention project has long been opposed by homeowners near the forest on the bank of the bayou, many of them recently flooded out of their homes during Hurricane Harvey. Under pressure from their group, Save Our Forest, the City of Houston in September 2015 withdrew a plan to build a large detention basin on the bayou in the park. However, the vote Tuesday includes negotiating with the City for detention on the bayou along the length of the park.
“It makes me mad,” said one displaced and distracted homeowner active with Save Our Forest. “They’re taking advantage of the flood to ram things through.”
The plan in 2013 was to destroy forest in order to create 280 acre-feet of stormwater detention in a series of basins on the banks of Buffalo Bayou between Highway 6 below Barker Dam and Beltway 8.
Removing trees and vegetation for stormwater detention makes little scientific sense. Trees and vegetation are powerful natural devices for slowing and holding rainwater runoff, not to mention their role in cleansing our polluted urban runoff and other valuable ecological services. A study by American Forests found that a single front-yard tree can intercept 760 gallons of rainwater in its crown. Vegetation can reduce runoff from a site by as much as 90 percent, according to a study by the University of Arkansas. While it would take a whole lot of trees to store as much water as even a small detention pond, it still seems like a better idea to create artificial detention where there are no trees.
Save Our Forest, the Briar Forest Super Neighborhood, and other neighborhood groups supported an alternative plan to create larger regional detention basins, in particular the Clodine Ditch Detention Basin, which would have created some 1,600-acre feet of detention.
The Harris County Flood Control District last year spent over $1.25 million to fill and “repair” parts of the north bank in the park where the bayou was attempting to recover its former meanders. The US Army Corps of Engineers stripped and straightened the 6.2 mile stretch of the bayou in the park and directed the flow into an artificial channel, cutting off the meanders in the 1940s.
The flood control district is legally bound by its 1937 charter to conserve forests. (p. 6)
The five county commissioners will vote at a session that begins at 10 a.m. in the commissioners’ courtroom, 1001 Preston Street., Suite 934. The long agenda includes consideration of whether to approve negotiating contracts with:
R.G. Miller Engineers, Inc., for design, bidding, and construction phase engineering services for construction of linear detention on Unit W100-00-00 in the Buffalo Bayou Watershed in Precinct 3.
The City of Houston for additional linear stormwater detention along Buffalo Bayou between SH-6 and Beltway 8 on Unit W100-00-00 in the Buffalo Bayou Watershed in Precinct 3.
Buffalo Bayou is Unit W100-00-00.
The public can sign up to speak during the meeting for up to three minutes.
The Problem with Dams
If You Build Them, They Will Come
Nov. 9, 2017
Some two months after the flood, neighborhoods on upper Buffalo Bayou were still haunted. A moldy, gray pall hung in the air like the Spanish moss draped in the trees. Houses were empty, their windows dark, walls stained where the dark floodwaters rose. Lawns and gardens were ruined, muddy and brown. Scattered piles of debris, broken mirrors and plasterboard, lined the nearly lifeless streets. The air, even out of doors, smelled of mildew.
“They’re having a hard time being more …. positive,” said resident Michelle Foss, her voice trailing off, looking towards a house where a family with children had to be rescued by helicopter from the roof.
Foss’s neighborhood is Briargrove Park. Like most of the subdivisions along Buffalo Bayou, it was developed in the decades after the federal government built two earthen dams west of Houston on what was then, in the late 1940s, mostly prairie—ranch and farmland. But the land next to the ancient meandering river, in the natural floodplain, was graced with forests of tall oaks and other trees—ideal for upscale residential development. With the construction of the dams, the floodplains were now considered safe. During heavy rains, the reservoirs behind the dams, Addicks and Barker, would hold back the waters of Buffalo Bayou, Houston’s main river, its Mother Bayou, and several creeks flowing into it, until the rain runoff collected in the bayou below the dams could empty into Galveston Bay.
It was a classic case of moral hazard, a situation identified by the late renowned geographer Gilbert White as early as 1942 in a paper titled, “Human Adjustment to Floods.” Government sponsorship of structural solutions like levees and dams that protect floodplains encourage development in those floodplains, which leads to damages that are often worse than what would have happened prior to construction of the levees and dams. (pp. 17-18) (See also p. 2.)
In the wake of Hurricane Harvey, the calls for a new or third reservoir in west Houston are virtually unanimous. It’s worth considering whether that might be a mistake.
On Mud, Dust, and Rain
And Letting the Bayou Heal
Sept. 19, 2017
Rain at last! Monday morning the sky is grumbling with thunder, even as the sun shines. A sprinkle of rain will wash the pavement covered with mud from the overflowing polluted bayou waters, dried mud that billows in thick choking clouds when cars and buses drive down the streets. A light, sparkling rain will wash the leaves and plants and sidewalks in our yards and parks.
The sky had been quiet for so long, empty for a while even of the roaring of low-flying planes. But later in the afternoon the sky turns somber. The rain grows heavier. And now we all feel the nervousness of those who have been flooded and watch the sky with anxiety. We who have grown up with mighty thunderstorms, fearlessly playing in the rain, splashing through flooded streets. Now we are all afraid of what the rain might bring.
It’s been nearly three weeks without rain since the historic deluge of Harvey sent flood waters and rain runoff through sewage treatment plants, sewage pumping stations, sewer lines, chemical storage facilities, service stations, toxic waste sites, half a million vehicles (not including smaller machinery), homes, offices, parking lots, shopping malls, and more.
The Rain Went Away
The absence of rain was a blessing. We could dry out and recover. The beleaguered Corps of Engineers could attempt to empty the reservoirs on Addicks and Barker dams in west Houston on Buffalo Bayou upstream. For the first time ever the engineers had been forced to open the floodgates of the seventy-year-old dams during a heavy storm. They knew that they would flood people downstream, that the already flooding river would rise even higher. But the water was rising quickly behind the earthen dams and would soon be flowing over the low spillways at the ends for the first time. At least two people died in their homes on Buffalo Bayou; a third in the basement ceiling of a luxury hotel on the banks near Woodway.
We don’t really know what the peak high flow was in the bayou during the storm. The gauges were overwhelmed. Maybe 15,000-16,000 cfs on around Aug. 31. Maybe more. (For comparison, the flow in the West Fork of the San Jacinto River was a record 80,000 cfs when authorities there opened the dam on Lake Conroe Aug. 28.) Since the rains stopped on Aug. 30, the flow in the bayou has been dropping slowly by several hundred to nearly a thousand cubic feet per second a day. (On Tuesday morning the floodgates were closed, and the flow had dropped to below 1,000 cfs. Base flow with no rain is about 150 cfs.) But on Monday evening the floodgates on the dams were still open, and the water was still draining. And there was still some 36 billion gallons of storm water remaining in the reservoirs, down from about 129 billion at their apparent peak on Aug. 29. The two reservoirs are normally dry parks with flowing streams (including Buffalo Bayou), filled with trees, trails, and recreational facilities now covered with sediment. A spokesman for the Corps, citing pending lawsuits, declined to comment Tuesday afternoon on the unusual shutting of the floodgates while storm water remained in the reservoirs.
We have been waiting for the waters to recede, to see what was revealed, the changes wrought to the banks. A flood in a natural setting is an awesome thing. We do not mourn the process of nature. But a flood where people live and work is tragic.
Houston Lashed by Critics Over Harvey
A Roundup of Harvey Flood Reporting and Commentary
Sept. 18, 2017
Not since the Enron scandal in 2001 has Houston faced such a deluge of criticism and bad publicity. Abundant praise, yes, for the generous and courageous response of neighbors helping neighbors and strangers. But according to our critics, flaws in the civic character—greed, incompetence, short-term thinking, a disrespect for nature—created an urban landscape that allowed maybe the worst storm ever to hit a metropolitan area to become a catastrophic flood, damaging or destroying some 136,000 homes, businesses, and other structures, maybe a half a million cars and trucks, taking fifty lives, damaging and disrupting the lives of many thousands more.
Here are links to some of the more thoughtful and informative articles published.
On Flooding Causes and Solutions and Working with Nature
Development, Drainage, and Destruction of Wetlands
The Atlantic, Aug. 28
Debo advocates that urban design mimic rural hydrology as much as possible. Reducing impervious surface and improving water conveyance has a role to play, but the most important step in sparing cities from flooding is to reduce the velocity of water when it is channelized, so that it doesn’t deluge other sites. And then to stop moving water away from buildings and structures entirely, and to start finding new uses for it in place.
Quartz, Aug. 29
The Harvey-wrought devastation is just the latest example of the consequences of Houston’s gung-ho approach to development. The city, the largest in the US with no zoning laws, is a case study in limiting government regulations and favoring growth—often at the expense of the environment. As water swamps many of its neighborhoods, it’s now also a cautionary tale of sidelining science and plain common sense. Given the Trump administration’s assault on environmental protections, it’s one that Americans elsewhere should pay attention to.
How the city’s development may have contributed to devastating flooding
Washington Post, Aug. 29
AP, Aug. 29
Experts blame too many people, too much concrete, insufficient upstream storage, not enough green space for water drainage and, especially, too little regulation.
“Houston is the most flood-prone city in the United States,” said Rice University environmental engineering professor Phil Bedient. “No one is even a close second — not even New Orleans, because at least they have pumps there.”
The entire system is designed to clear out only 12 to 13 inches of rain per 24-hour period, said Jim Blackburn, an environmental law professor at Rice University. “That’s so obsolete it’s just unbelievable.”
Also, Houston’s Harris County has the loosest, least-regulated drainage policy and system in the entire country, Bedient said.
New York Daily News, Aug. 30
Know How High The River Flows
Get Alerts on Bayou Rise and Decline
Sept. 4, 2017
Updated Sept. 6, 2017, with a new tool from the Corps of Engineers for projecting inundation levels on Buffalo Bayou going forward.
Updated Sept. 7, 2017
Update Sept. 14, 2017: The Harris County Flood Control District has reported that at least eighteen gauges were damaged by extreme high waters from Harvey. As of Sept. 11, the district had repaired twelve of them. The Corps of Engineers also reported that the US Geological Survey gauge on Buffalo Bayou at Piney Point was temporarily knocked out of commission by high waters.
As of this writing a great many people living along Buffalo Bayou have been forced out of their homes by the flooding river. On Friday, Sept. 1, those who remained in their flooded homes below Addicks and Barker dams in west Houston were asked to leave by the mayor, a request that became mandatory the next day. Offices, apartments, hotels, parking lots, parks, country clubs, and sewage treatment plants built next to the bayou also have been flooded.
Many people were taken by surprise, it seems. Knowing when and how fast the bayou was rising might have helped more people prepare. Knowing when the waters might recede might also help people plan.
Here is how people living and working along Buffalo Bayou below Addicks and Barker dams can receive real time alerts about a dangerous rise in the flow of the bayou. This is for the gauge at Piney Point, which is the gauge the Corps of Engineers uses to monitor the flow in the bayou and regulate storm water releases from the reservoirs behind those two federal dams in west Houston.
And here is a link to the interactive inundation map, just released to the public by the Corps of Engineers, that can help people see when and where the bayou might go down.
$12 Million Bayou Project Based on a Mistake
A Fundamental Error
August 17, 2017
The instability of riverbanks is generally divided into two types: banks that collapse vertically and banks that are worn away laterally or horizontally by the erosive force of the water flowing downstream.
Vertical collapse is called slumping or sloughing. The face of the bank slides or rotates away, often leaving a concave scar or scarp in the bank and a clump of sediment at the base. Sometimes the slump takes trees and vegetation with it. The vegetation can continue to grow in the collapsed sediment, which creates a sort of terrace or beach at the foot of the high bank.
According to a lengthy analysis by geologists working with Save Buffalo Bayou, slumping is the primary type of bank collapse on Buffalo Bayou in the stretch targeted for a $12 million “stabilization” and “restoration” project by the Harris County Flood Control District.
Engineers Mistake Slumping for Erosion
But the engineering consultant working for the flood control district describes what is happening to the high banks of the bayou in the project area as “shear stress,” which is the lateral or parallel drag of the water flowing past the banks and down the channel.
The district’s permit application to the Corps of Engineers repeatedly refers to shear stress and shear stress only, specifically ruling out vertical instability. (“Vertical stability not an issue.” P. 39.) The Corps’ Environmental Assessment, released in May in conjunction with the granting of a permit for the project, also refers exclusively to shear stress.
“The assessments conducted by HCFCD’s design team indicated that due to the erosive nature of high flows in the bayou … hydraulic energy dissipation measures (bankfull benches, pool and riffle reestablishment, channel pattern adjustments, and in-stream structures) were necessary in the design to relieve shear stress on the streambanks of the bayou, and ultimately stabilize the channel system,” stated the Corps on page 21 of the Environmental Assessment.
The Corps’ Environmental Assessment found that the proposed project, which would use heavy equipment to raze most of the trees and vegetation and dredge, fill, reroute, and reconfigure the channel, historic high banks and meanders of more than a mile of forested Buffalo Bayou flowing past Memorial Park, would have no significant impact on the environment.
Remedy Decided Before Problem Was Analyzed
But Flood Control’s project, known as the Memorial Park Demonstration Project, is based on an error. Shear stress—lateral erosion—isn’t the primary problem in this stretch of Buffalo Bayou. Slumping—vertical instability—is what naturally happens on our 18,000-year-old bayou. (And it’s only a “problem” if you, say, unwisely took down the trees and built your house or your mowed golf course on or near the edge of a bank.) The project will do nothing for slumping, for which there is little remedy anyway.
Even worse, the proposed “in-stream structures”—wads of tree roots to be installed to “stabilize” the toe or bottom of the banks to protect them from shear stress—will likely also slide away.
The controversial project, not yet under construction, is based on a mistake. And it probably will fail, leaving behind a wasteland of denuded and weakened banks. That has happened elsewhere with these controversial Natural Channel Design methods. (See also here.)
The promoters of the project, who include the Bayou Preservation Association and the Memorial Park Conservancy, decided years ago to use Natural Channel Design to “fix” the bayou and demonstrate what they believed to be a superior method of erosion control.
The remedy was decided before the engineering consultant, Kellogg Brown and Root (KBR), or apparently anyone else, had done an analysis of the problem. Except that the same engineering firm, or its predecessor, Brown and Root (BR), had done a study in 1995, almost twenty years earlier. That study came to somewhat different conclusions: vertical stability was an issue.
On the Radio
Talking About Buffalo Bayou on KPFT
July 21, 2017
Susan Chadwick, executive director of Save Buffalo Bayou, was on KPFT’s Open Journal Thursday, July 20, talking with Duane Bradley and Marlo Blue about the organization’s campaign to stop a flood control project that would destroy one of the last natural stretches of Buffalo Bayou for no good reason.
Here’s a link to the show. The discussion about Buffalo Bayou doesn’t come on until about thirty minutes into the hour-long show.
Summer on Buffalo Bayou
That Bend in the River
July 11, 2017
We waited several days for just the right opportunity, checking the water flow at dawn. Even though there were loud, thunderous storms with angry winds and throwdown rain with cars alarmed in the afternoon, the gauge measuring the current at Piney Point, used by paddlers as well as the Corps of Engineers to track the volume of flow in Buffalo Bayou, barely popped up. And by early morning the bayou was down again to base flow, a very slow and shallow 150 cubic feet per second. For our summer 2017 photograph of the Bend in the River, we wanted a little more water in the stream. We have been documenting this same spot through the changing seasons since the summer of 2014.
But late Monday Jim Olive called and said a rainstorm was predicted during the night. And sure enough after nightfall the oak trees began wrestling with the wind. Lightning exploded overhead and a drenching rain shot out of the sky. At 5:45 a.m. the Piney Point gauge indicated a flow of some 500 cubic feet per second. We met in Memorial Park, at the parking lot for the South Picnic Loop. Jim looked at the sky skeptically. Gray clouds had drifted in. But we were there, so we walked towards the woods across the boggy picnic area, stepping around puddles, dodging the early morning cyclists whizzing around the loop road.
Here Comes the Sun
The Memorial Park Conservancy still hasn’t done anything about diverting the rainwater runoff from the park and parking lot that’s eating away at the ravines in the woods. But someone has pruned and slightly opened up the narrow dirt trail leading around the ravaged ravines, now decorated with summer greenery, and past the clay and concrete remnants of the drainage pipes from Camp Logan, the World War I military training camp and hospital located in the park before it was a park.
Our shady spot on the high bank overlooking the bend of the river has changed over the years. During the great rains of 2015-2016, high waters caused sections of the bank to slide down, taking trees and vegetation with it. But the living trees and plants and even some of the soil remain at the foot of the bank, collecting more sediment, and the vegetation continues to grow. The bank here and elsewhere was healing nicely.
Jim set up his tripod and waited for the sun to arrive. The sunlight had to be just perfect. This takes time and patience. So the photographer’s assistant had plenty of opportunity to roam through the woods looking for mushrooms. No luck. Too hot maybe. But a frog hopped on the trail, maybe a departing member of the hidden chorus of Mr. Froggies singing love songs late into the morning. A pair of nervous turtles swam in the clear, shallow stream that drains the center of the park and empties into the bayou nearby. The Harris County Flood Control District plans to dam this lovely stream for some reason as part of its $12 million restoration/erosion control/conveyance project.
A great blue heron flew slowly back and forth across the bayou, trying to get into the picture. Eventually the sun did arrive and struck the leaves and water just right. Jim got his beautiful photo.