“Buffalo Bayou Not a Natural River”
Supporting Costly Engineering to Slow the Flooding River. Spending Money to Stop the River Slowing For Free.
Nov. 30, 2016
Updated April 23, 2017 — The Harris County Flood Control District reports that repair costs through March 2017 are $1.25 million. Terry Hershey Park remains closed until construction work is complete.
Harris County Precinct Three Commissioner Steve Radack called to comment on our article criticizing unnecessarily costly and destructive “repairs” to the north bank of Buffalo Bayou in Terry Hershey Park. The six-mile long park is in Precinct Three in far west Houston and Commissioner Radack is the boss there.
Radack’s main point, apparently in support of needlessly spending an excessive amount of money, was that Buffalo Bayou is not a natural river. Because the bayou is not natural, it “does not naturally meander.”
For background: the naturally meandering bayou in Terry Hershey Park was stripped and straightened in the 1940s and ‘50s. Last spring high waters from record rains and extended high flows from the federal dams immediately upstream ate away at the bank in places and damaged the asphalt hike-and-bike trail on the north side. We pointed out that this had occurred where the old meanders or bends were. The bayou, we said, was seeking out its historic meanders, adjusting to the flow.
Our point was that it would make more sense, in accordance with the most advanced river management practices across the country and around the world, to move the asphalt trail slightly away from the very edge of the water and allow the river room to move and restore itself. This would be far cheaper, prettier and more natural, and healthier for the bayou, the beneficial trees and plants and creatures that grow there, and for the water flowing through it to the bay. Doing that rather than hardening the bank in an artificial straight line is also less likely to cause flooding and erosion downstream and less likely to require expensive repairs all over again. It’s also federal policy.
But according to Radack, this doesn’t matter, because Buffalo Bayou is not natural. It’s not natural because the Corps of Engineers “controls the flow.” The bayou “only has water in it,” Radack explained patiently, if the Corps opens the floodgates. “The water comes from the reservoir system.”
Therefore, according to Radack, the bayou is “not natural.”
Is that all true? Beg pardon, but no.
But here’s a puzzle: Radack supports spending tens of millions in public funds to carve up the banks and engineer some two dozen in-channel detention basins on the bayou in Terry Hershey Park. (See below.) But he opposes allowing the bayou to carve out for free its own detention by widening and restoring its old bends. Instead he approves spending taxpayer funds to keep the bayou from doing that.
Does that make sense? Seems contradictory to us.
A Natural River
Buffalo Bayou is a natural river, of course, with important biological and ecological functions, like cleansing the water. Created by nature some 18,000 years ago, the bayou has its source in the Katy Prairie west of Houston and flows through Barker Reservoir and the floodgates of Barker Dam, then for some six miles through Terry Hershey Park, a 500-acre linear forested park, and continues on for another sixteen river-miles into downtown Houston before ending up in Galveston Bay.
Barker Reservoir and, just to the north, Addicks Reservoir are both dry reservoirs, located in Buffalo Bayou’s upper watershed. Built exclusively to control flooding downstream, both federal dams drain into Buffalo Bayou and hold storm water only temporarily to prevent the river from causing or adding to dangerously high flows downstream. The floodgates are always open except when it rains at least an inch downstream–or half an inch if the Corps is already in the process of releasing impounded storm water from the reservoir pools–explains the Corps’ Galveston District Water Control Manager Charles Scheffler.
The bayou, a perennial river, meaning it flows all the time, has water in it even when the dam floodgates are closed. The bayou even floods when the floodgates are closed. This is because rain that falls in Terry Hershey Park and downstream of the dams runs off the ground (and through drainage pipes, etc.) into the bayou. (That’s unless it can soak into the ground or be absorbed by trees and plants, which helps recharge the groundwater and reduces flooding.) In addition, three ditches or sloughs that run around the outside perimeters of the dams carry rainwater from the south and north and empty a significant amount of stormwater into Buffalo Bayou even when the floodgates are closed.
Radack is surely aware of the controversy over the impact of these free-flowing ditches on Buffalo Bayou, particularly the Clodine Ditch, which brings stormwater from Fort Bend County.
Numerous tributaries and creeks, not to mention ditches, storm and wastewater drains downstream of the dams flow freely into the bayou. But the Clodine and Barker ditches and Turkey Creek empty into the bayou right below the dams. Clodine Ditch, which has its origin in the Longpoint Slough in Fort Bend County, drains an area of 10-15 square miles, runs along the east side of Barker Dam and flows into Buffalo Bayou at Highway 6 just below the dam floodgates. There it meets Barker Ditch, which drains runoff from Interstate 10 and runs along the northern outside edge of Barker Reservoir and then south into Buffalo Bayou. Turkey Creek receives water from as far north as Jersey Village, flows along the outside eastern edge of Addicks Reservoir and enters the bayou in Terry Hershey Park near N. Eldridge Parkway.
Together the uncontrolled Clodine and Barker ditches can contribute as much as 1,500 cubic feet per second (cfs) of water to the bayou when it rains and the dam gates are closed, according to Michael Huffmaster, president of the Briar Forest Super Neighborhood and a homeowner on the south bank of the bayou in Terry Hershey Park. During major storms such as the April Tax Day storm last spring, when the dam floodgates were closed, the combined flow of Clodine and Barker ditches reached nearly 5,000 cfs at Highway 6, based on the USGS gauge on Buffalo Bayou at Highway 6. The flow downstream at Beltway 8 measured nearly 6,500 cfs that day, and by the time it reached Piney Point, the bayou was flowing at at over 7,000 cfs.
People “start to get wet,” as the Corps’ Scheffler puts it, when the flow downstream goes above 4,150 cfs as measured by the USGS gauge at Piney Point, which is part of what the Corps uses to decide whether to open or close the floodgates.
However, Richard Long, the Corps’ supervisory natural resources manager of the dams on Buffalo Bayou, cautions that the gauge at Highway 6 can reflect water that has backed up from rainfall or “other discharge points” downstream. Other discharge points would include, for instance, this very big drainage pipe on the south bank of the bayou in Terry Hershey Park. Drainage aimed directly across the stream acts like a dam and causes blockage of the flow.
There are also two City of Houston wastewater treatment plants discharging treated water into the bayou in Terry Hershey Park: Turkey Creek east of North Eldridge Parkway and West District west of Beltway 8.
Residents in the Briar Forest area are opposed to Harris County Flood Control District plans, supported by Radack (see below), to remove forest and scrape out detention ponds for floodwater on the south bank of Buffalo Bayou in the park. The unpopular detention plan, known as Charting Buffalo, would carve out some two dozen detention basins overall on both sides of the bayou in the park but create only about 280 acre-feet of detention at a cost of millions of dollars.
Trees are important natural storm water detention devices, and it makes little sense to remove them to create detention ponds. Destroying forests is a violation of the flood control district’s legal obligation to conserve forests.
The Briar Forest group was successful last year in persuading the City of Houston not to build up to six large detention basins at a cost of $3.5 to $8.5 million on the south bank in the park. But the flood control district’s plan, though apparently dormant, is still alive. The Briar Forest group proposes, instead of the destructive in-channel detention basins, that Harris County work with Fort Bend County to build a regional detention basin in the Clodine area that would temporarily hold 700-1000 acre-feet of storm water, reducing the peak flow in Buffalo Bayou under Highway 6 by half, according to Huffmaster.
“Developers are buying up Clodine,” says Huffmaster. “We are losing the opportunity.”
Harris County officials have objected to the cost of buying the land to build detention. Terry Hershey Park, on the other hand, is owned by the flood control district and leased to the county. (The flood control district and the county are separate entities, but the county commissioners appoint the director and govern the agency, which is supported by a dedicated tax on property value.)
Fast Rains, Low Flows
It’s true that the flow in Buffalo Bayou is very low when it’s not raining. Called the base flow, at this time of year the median base flow is about 150 cubic feet per second, which is very leisurely. It’s been reported that much of the base flow in the bayou, normally the result of groundwater seeping into the river, is recycled wastewater, which is the case for many urban rivers, including White Oak and Brays bayous, now surrounded by so much impervious surface in the form of buildings and pavement that the rain cannot soak into the ground, or in the case of White Oak and Brays, seep into the concrete channel.
Note that there was a time in the 1940s when the Corps was releasing up to 7,900 cfs into the bayou following rains. (The dams were designed to allow a combined discharge of 15,700 cfs, but that was back when they had plans for a south canal, among other things.) But having made the bayou downstream safe for development, development on the bayou downstream forced the Corps to reduce the flow in the 1960s to 2,000 cfs to avoid flooding lawns and flower gardens, etc. (“People were getting wet,” says Scheffler, who’s been with the Corps for forty-one years.) This year development upstream and heavier, more intense rainfall pushed the Corps to double the maximum allowed discharge from the dams to 4,000 cfs. With a record amount of water impounded by the dams last spring, the Corps was forced to release as much water as quickly as possible in order to be prepared for future storms. With continuing rains, draining the reservoirs took months, and caused erosion problems up and down the river.
“It’s not a natural flow at all,” said Radack, unswayed by the observation that the bayou was a living river, with trees and plants and fish, behaving as rivers do, naturally adjusting to the high flows that it probably once had. “It’s a man-made occurrence,” he insisted, referring to the disturbed banks and broken path.
So Radack is going to forge ahead with the most expensive solution, even if it damages the natural beauty of the park of which he is so proud. “I believe that what we’ve done is an enhancement to Buffalo Bayou,” he said, referring to the creation of Terry Hershey Park in 1993. Radack has been commissioner of Precinct Three since 1989.
“We’ve built that park in a way that makes it a real asset to Harris County and the City of Houston,” he said. “And we’re going to keep it that way.”
“Maybe there will be one or two, a few places” where he would consider moving the path away from the bank. But “right now we’re putting it back together the way it was,” said Radack. “We’re going to continue and I would say there will be detention on the bayou too,” referring to the flood control district’s controversial and seemingly contradictory plans to remove trees and excavate detention basins along the bayou in the park while simultaneously “repairing” the banks where the bayou was naturally doing practically the same thing.
“Any detention in the Buffalo Bayou channel is symbolic,” says Briar Forest’s Huffmaster, referring to the costly creation of artificial detention areas by digging up the forested banks. “Approximately 1000 to 3000 acre-feet are needed to address structural flooding, and Charting Buffalo identified only 280 acre-feet from detention along the bayou channel.
“Let us not undermine those endeavoring to preserve and enhance green space along the bayou.”
For more information on the most advanced ideas in river management and working with nature to reduce the hazards of flooding, we recommend the book Floodplain Management, A New Approach for a New Era.