Lessons From Hurricane Harvey
Academic Experts Speak on What Can and Should Be Done About Flooding In Houston
March 30, 2018
Daniel Grossman reports for Re.Think on the annual American Geophysical Union meeting in New Orleans in December 2017. He also visits Houston and gathers opinions from local academics. Buyouts, making room for the river, stopping storm runoff before it floods our streams are some of the necessary strategies recommended here and elsewhere by those who study these things.
Heavier, More Frequent Rains
At the New Orleans conference, Emanuel laid out findings he’d published a few weeks earlier in the scientific journal Proceedings of the National Academy of Sciences. Simulating mayhem in a computer program, he’d released thousands of virtual past and future “seed” storms into the Atlantic Ocean and computed their tracks. The likelihood of a storm about as rainy as Harvey has increased by a factor of six in the last 40 years, he’d found. By 2100 the chance of such a deluge will increase another threefold. Then, a Hurricane Harvey will strike Texas once every 5 years.
Buyouts and Room for the River on Buffalo and Other Bayous
Yoonjeong Lee, a researcher at the Center for Texas Beaches and Shores at Texas A&M University at Galveston, says Houston should build Dutch-style flood protection, and she knows where. “Buffalo Bayou would be a perfect place to build a ‘Room for the River’ program.” She says the city could buy up a relatively small number of plots near its banks and – after demolishing any structures on them – construct a riverfront park. The land would be engineered to capture water when the bayou rose, safeguarding remaining districts. Houston has previously installed patches of parkland along its bayous before, but she says the city has to think bigger.
Timon McPhearson, a professor in Urban Ecology at the New School in New York City, says that another way Houston should become more resilient to wetter storms is by controlling how much water rushes into bayous in the first place. He says too much of the rain that lands on the city drains quickly into waterways. “Houston is an extremely paved city,” he says. Replacing street and driveway surfaces with permeable materials will lower peak floods. He also suggests green roofs, covered with vegetation that could provide important ecosystem services that retain – and stall – some of the rainwater.
Albert Pope, an architect at Rice University, doubts that adaptation through infrastructure fixes are sufficient to keep Houston safe from serious flood damage. He says that there’s too little undeveloped land left to accommodate new reservoirs of sufficient capacity, and that further straightening, widening, and bank-hardening can’t force bayous to carry more water. “We’re at the limits to what we can do, engineering-wise,” he says. His solution is more disruptive of the status quo, and Houston’s fix-it-with-concrete ethos. He insists that Houston should do something more transformative and remove all the buildings in its flood plains – 150,000 structures, including those on three-quarters of the acreage in Meyerland – and turn the acquired land into parks.
Read the article, “Lessons From Hurricane Harvey,” published by Re.Think on March 15, 2018.
High Flows in Harris County Streams Increasing Most in Texas
Study Questions Use of Dams and Urges Focus on Causes, Not Symptoms, of Flooding
County Commissioners to Discuss Flood Strategy, Funding, Tuesday, March 27, 10 a.m.
March 26, 2018
An “incredible” 70 percent of stream gauges in Harris County show significant increases in peak flow – as much as 6,400 percent in one case — since the beginning of record keeping by the US Geological Survey.
More streams in Harris County are increasingly flowing higher than in any other part of the state, according to a study recently published in the March 2018 issue of the Texas Water Journal, a publication of the Texas Water Resources Institute.
Three stream gauges on Buffalo Bayou have shown the greatest increase in peak flows since the federal dams were built in the 1940s to reduce flooding on the bayou, according to the report.
Significantly, two major streams, Langham and Bear creeks, feeding into one of these dams — the overburdened Addicks Reservoir — showed some of the largest upward trends in peak flow. The record amount of runoff flowing into Addicks during Hurricane Harvey was a major factor in the unprecedented decision to open the floodgates on both dams during the storm in order to prevent the dams from overtopping. Thousands of homes both below and behind the dams were flooded, and three people died.
The area in western Harris County above and behind Addicks Reservoir is experiencing some of the greatest development pressure in the region, particularly since the construction of the Grand Parkway (Highway 99). Buildings, paved surface, and other hard structures, including pipes, associated with development cause more and faster and more polluted rain runoff into streams, leading to flooding.
“An Overreliance on Flood Storage Reservoirs”
The report noted “the difficulty of maintaining lower peak flows below a reservoir when the inflows to the reservoir exhibit extraordinary increases year over year.”
“It is much easier for impoundments to store flood flows when these flows are not rapidly increasing on an annual basis. Thus, relying on large impoundment projects alone likely will not achieve success and again points back to our central emphasis of identifying causes, not just symptoms [of flooding].”
The study, titled “Peak Flow Trends Highlight Emerging Urban Flooding Hotspots in Texas,” was authored by Matthew D. Berg, CEO and Principal Scientist, Simfero Consultants, in Houston.
The USGS gauge on Greens Bayou at Cutten Road in northwest Harris County experienced the greatest increase in peak flow – 6,400 percent over a period of several decades.
Other rapidly increasing stream flows are occurring in Keegans Bayou at Roark Road in southwest Houston (nearly 5,000 percent), Greens Bayou near Highway 45 in north Houston (1,200 percent), Langham Creek near Addicks Reservoir in west Houston (750 percent), and White Oak Bayou near Heights Boulevard (600 percent).
Harris County Commissioners Court will meet Tuesday, March 27, to discuss flood management strategies and a possible bond referendum to pay for them. Also on the agenda is a proposal to study the feasibility of digging massive tunnels to drain stormwater from western Harris County into Galveston Bay. The contract to be negotiated is with Fugro USA Land, Inc.
The commissioners’ meeting begins at 10 a.m. on the ninth floor of 1001 Preston in downtown Houston. Those who wish to speak can sign up before the meeting here.
Rain Watchers Needed
Be A Backyard Rain Counter. Help Science
March 19, 2018
Message from the Community Collaborative Rain, Hail, and Snow Network:
The Community Collaborative Rain, Hail & Snow Network (CoCoRaHS) is a grassroots, non-profit, community-based, high-density precipitation database network made up of volunteers who take measurements of precipitation right in their own backyards. CoCoRaHS has observers in all 50 states nationwide, the Commonwealth of Puerto Rico, the U. S. Virgin Islands, the family islands of the Bahamas, and in Canada.
Texas CoCoRaHS needs volunteers who have an interest in weather observing and who would enjoy observing and reporting daily precipitation amounts on our website. Volunteers are asked to obtain an official CoCoRaHS scientific rain gauge and place it in a strategic location. They take daily precipitation measurements at approximately the same time – usually 7 a.m. – and record those measurements. Daily reporting of data is preferred, as days without precipitation are just as important to know as days with rainfall.
Many agencies rely on precipitation data collected by CoCoRaHS during and after rainfall and flood events to determine where the most rain has fallen and where the potential for flooding is greatest. CoCoRaHS’s volunteer precipitation reports help to fill in the gaps between official rainfall data collection sites in our region, such as the Harris County Flood Control District’s Flood Warning System, the National Weather Service’s climate sites, and the Lower Colorado River Authority’s Hydromet system.
The data reported by volunteers is organized and displayed on the CoCoRaHS website for use by scientists, researchers, and emergency managers – as well as the general public. The Harris County Flood Control District, National Weather Service, U.S. Department of Agriculture, and West Gulf River Forecast Center utilize CoCoRaHS data in their work, along with engineers, meteorologists, hydrologists, climatologists, insurance adjusters, ranchers and farmers, and many more.
The Houston/Galveston region of the CoCoRaHS Network consists of volunteers in 15 counties: Austin, Brazoria, Chambers, Colorado, Fort Bend, Galveston, Harris, Jackson, Liberty, Matagorda, Montgomery, Polk, San Jacinto, Waller, and Wharton counties. The network needs many more volunteers to better measure precipitation across the region. Weather hobbyists and those citizens who measure daily rainfall totals such as Master Gardeners and Master Naturalists are strongly encouraged to join CoCoRaHS.
To join, go to the CoCoRaHS website and click on the “Join CoCoRaHS” emblem in the upper right corner of the homepage. The website also has information on the organization’s background, observer training and educational tools, where to purchase the required CoCoRaHS rain gauge, how and where to set up the gauge on your property, and much more.
Please take a moment to tell a friend or neighbor about this exciting grassroots effort of citizens measuring precipitation right in their own backyards. It’s easy to join, takes only five minutes a day, and is a fun way to learn about this wonderful natural resource that falls from the sky. Your observations continue to give scientists an ever clearer picture of where and how much precipitation falls throughout our communities.
Make sure to read our newsletter.
High Bank on Bayou Damaged by Bike Riders
Fools Dug Up Vegetation and Drove Boards Into Top of Bluff
But Boy Scouts Do More Good Deeds, Plant Vegetation
March 7, 2018
Riding a bike along the edge of a cliff above a river is bad enough. Even walking on top of a high bank can be damaging. But the high banks of Buffalo Bayou in Houston’s Memorial Park are already stressed and attempting to recover from the overbank flooding that came with Harvey last summer. Large sections of the bank slid away, taking down trees and vegetation. With time, however, the vegetation will grow back, the downed trees will collect sediment, and the banks will rebuild.
Now that recovery will be much more difficult. In the past weeks, off-road cyclists built a bike jump and wooden ramp right at the very edge of the bank near the main tributary draining the center of the park. This is very near the Bend in the River that Save Buffalo Bayou and photographer Jim Olive have been documenting through the seasons for the past four years.
The culprits apparently removed vegetation, dug holes, and drove large boards into ground. And then, of course, they’ve been pounding the edge of the bank with their bikes. They also dug up dirt to mound it into a jump further down the bank.
Representatives of the Greater Houston Off-Road Biking Association (GHORBA) condemned the construction.
“We would never approve this type of activity,” said C.J. Bernard, trails director for the biking association, in an email. “For anything we do at GHORBA related to trail development and maintenance, we follow the IMBA Sustainable Trails guidelines which highly emphasizes ways to identify potential erosion concerns and provides ways to eliminate and/or minimize.” (IMBA is the International Mountain Bicycling Association.)
“Most likely it is from a mountain biker that isn’t associated with GHORBA, as our trail stewards must approve features before they are built and this one, to my knowledge, was not,” wrote Christy Jones, president of GHORBA, in an email.
The dirt paths through the woods along Buffalo Bayou south of the Picnic Loop in Memorial Park are unofficial trails. However, they are much used by walkers and runners. Other trails in the park are officially open to bike riders as well as others. The neighboring Arboretum, however, does not allow bikers on its paths.
A representative of the Memorial Park Conservancy said the structure would be removed. “We are very grateful that you alerted us to this and will assess and remove the structure ASAP,” wrote Cara Rudelson, chief operating officer of the Memorial Park Conservancy, the private nonprofit organization running the public park. “We always have our eyes out for unauthorized use of the unofficial trails!”
Boy Scouts Plant Riparian Rebar on Bank of Buffalo Bayou
In the meantime, some more positive news: members of Boy Scout Troop 55 are doing good deeds again. This time, under the leadership of Boy Scout Austen Furse, who developed the plan for his Eagle Scout project, they planted 200 buckets of native eastern gamagrass on the upper banks of the ugly stormwater outfall, formerly a nature trail, also known as the Woodway Boat Launch, in the Old Archery Range of Memorial Park west of Loop 610. This happened Saturday morning, March 3.
Eastern gamagrass is an herbaceous stabilizer plant, described as “riparian rebar” and a “big, green leafy cousin of corn.” Though slow to establish, once established, eastern gamagrass can grow to six feet or more and has “extremely good root stability,” according to Your Remarkable Riparian, a field guide to riparian plants found in Texas.
Take note, property owners contemplating ugly and damaging concrete riprap for bayou banks.
Let’s hope the young gamagrass doesn’t get mowed down.
Austen is planning to photograph the site every week or two to document the results, says his mother, Anne Furse.