Category Archives: Emergency Operations

The flowing evolution of water control

By Miles Brown

The laws of physics and fluid dynamics have not changed over the millenniums. Water still looks for the path of least resistance flowing from higher elevations toward sea level. But how engineers manage the U.S. Army Corps of Engineer reservoirs across the Little Rock District continues to evolve with every major high-water event. One person who has seen that evolution first hand for more than 28 years is Janis Jones, a hydraulic engineer with the Little Rock District’s Reservoir Control Section. “When I started in the Little Rock District, we used dial-up modems to download water level data every four hours and that data was loaded into our system via very cumbersome “automated” processes,” recalls Jones. “Now data is collected in almost real time, processed, and loaded into our file systems with more modern network technology and truly automated processes which allows our engineers more time to focus on the most important task – the operation of our reservoirs.”

1992
1992

 

Every day, the Little Rock water control professionals manage 12 reservoirs from southern Missouri to southwest Arkansas ensuring the congressionally authorized purposes of each lake are maximized. All Corps lakes within the Little Rock District have one purpose in common – to reduce the risk of down-stream flooding. Some have hydropower requirements and others supply drinking water to thousands of Arkansans. Two lakes have minimum flow requirements, and there are provisions for recreation at most of the District’s lakes. With all of these interests vying for the water stored behind Corps dams, the engineers managing the releases have their hands full. The water control mission really reaches a fever pitch during high-water years. This year levels in all 12 Little Rock District reservoirs rose rapidly in the late spring and early summer as three waves of storms dumped record rains across the region in a matter of just a few weeks. The upper White River lakes experienced major rises due to the runoff, and crested at levels that represented 83 percent of the available system flood storage in mid-June.  Peak river levels in the downstream White River valley were greatly reduced as the runoff was stored in the lakes. Unfortunately this was only the most recent flood event in the White River basin. “In 2011, major flooding occurred on the White River and the problems were made worse by the very high levels on the Mississippi River,” said Jones. “The water we had to release from reservoirs upstream had nowhere to go at the confluence of the White and Mississippi rivers.” In the Little River system in southwest Arkansas, DeQueen Lake, which discharges into Millwood Lake, set a new pool of record this year cresting at 472.8 on June 3. In addition, Millwood Lake, which feeds the Little River, and eventually the Red River, set a new pool of record cresting June 14 at 282.9 feet. That is 24 feet above the top of its conservation pool. “This year, we held back as much water as possible at Millwood because the Red River was above flood stage for weeks. We worked with two sister Corps districts to coordinate our releases and minimize the risk of floods for communities along the Red River.” Reservoir control professionals have been managing water levels at District lakes for more than 60 years, but several of the flood events over the last quarter century have approached record levels.

Jan Jones - mid to early 90's
Jan Jones – mid to early 90’s

 

“Every high water event is different to manage as we implement the water control plans and use our engineering judgment to adjust operations at each of the projects to hold flood waters back and then release the stored water as channel capacity allows,” explained Jones. “The heavy rains across Oklahoma, Arkansas and Missouri created some of the highest flows we have experienced on the MKARNS (McClellan-Kerr Arkansas River Navigation System),” said Jones. “We had not seen a flood event this late in the year in my 28 years.” Arkansas River flows peaked at more than 370,000 cubic feet per second and sustained high flows continued for almost three months because of the large volumes of flood storage being released from reservoirs in Oklahoma and the uncontrolled runoff in the river basin. The volume of water that flowed down the river during this historic flood event was the largest since the navigation channel was completed in 1971. One of the essential missions for the Corps is keeping key stakeholders and the public informed about lake levels, river flows and dam releases. To help emergency responders and community planners prepare for possible future flood events, the District Reservoir Control team members conduct what they like to call “Water Management 101” sessions. “We started Water Management 101 events back in 2008 just before one of the major flood events on the White River,” recounts Jones. “Now we conduct these events each year and try to visit all the major river communities across the District.” Now that Jan Jones is winding down her decades-long tenure as a key team member managing the water storage and flows of the District, she has taken a little time to look back at the years and the major high-water events. “My hope is that we have documented these historical events and lessons learned well enough so our experiences can be passed on to the less seasoned engineers just starting their careers in Reservoir Control,” said Jones. “It is cool to see the smart, young professionals eagerly soaking-up the knowledge. It is very rewarding to realize that they are eager, anxious to use the available cutting-edge technology, and more than capable to take over the reins and keep the mission of water control and protecting people, communities and our infrastructure on track.”

2015
2015

Army Corps of Engineers awards $71.9 million contract to rehabilitate Addicks, Barker Dams

Construction to begin in September 2015

GALVESTON, Texas (Aug. 31, 2015) – The U.S.

Addicks and Barker Dams
The U.S. Army Corps of Engineers, Galveston District, awarded a contract in the amount of $71,902,340 to Granite Construction Company for construction of new outlet structures at the Addicks and Barker Dams in west Houston. Work will consist of construction of new intake towers, steel-lined conduits, parabolic chute slabs, stilling basins, cutoff walls and downstream filters, in addition to the grouting and decommissioning of the existing outlet structures in place at both dams. There will also be an additional seepage cutoff element for Barker Dam at Noble Road located south of Briar Forest Drive.

Army Corps of Engineers, Galveston District, awarded a contract in the amount of $71,902,340 to Granite Construction Company for construction of new outlet structures at the Addicks and Barker Dams in west Houston.

Work will consist of construction of new intake towers, steel-lined conduits, parabolic chute slabs, stilling basins, cutoff walls and downstream filters, in addition to the grouting and decommissioning of the existing outlet structures in place at both dams. There will also be an additional seepage cutoff element for Barker Dam at Noble Road located south of Briar Forest Drive.

“The Corps’ primary objective is to maintain public safety by ensuring the dams we own and operate are safe and the risks to the public are minimized,” said Col. Richard P. Pannell, USACE Galveston District commander. “With interim risk reduction measures already implemented and long-term measures to be undertaken with this contract, it is expected that the dams and reservoirs will continue to serve the City of Houston for another 50 years.”

The 70-year-old structures were designated as extremely high risk in 2009 based on technical issues concerning the safety of the dams and the potential consequences to the City of Houston should the outlet structures fail.

“Partly because of this risk classification, the dams received the attention and funding to complete several interim risk reduction measures while USACE has been working on a long term fix,” said Enrique Villagomez, mechanical engineer and Addicks and Barker project manager with the USACE Galveston District. “The interim risk reduction measures implemented included filling the voids along the conduits and beneath the parabolic chutes caused by the seepage from the reservoirs, constructing a granular filter around the ends of the outlet structure  conduits to prevent voids from forming in the future, installing additional lighting to aid in increased inspection and monitoring, the addition of emergency generators to ensure uninterrupted power to the outlet  structures and the installation of steel plates to stabilize the concrete parabolic  chute slabs.”

According to Villagomez, while construction should have little impact on the operations of the reservoirs, there will be unavoidable impacts to the hike and bike trails located in the vicinity of the existing outlet structures and the adjacent construction area for the new outlet structures, as well as the parking lot and hike and bike trail in the Briar Forest area of Barker Dam.

“We will be working with the contractor and Harris County to minimize these impacts,” said Villagomez.

Residents will be able to track construction schedules, detours and upcoming events related to the Addicks and Barker Dams’ safety modification project thanks to story map technology located online at http://geospatial.swf.usace.army.mil/AddicksBarker2/index.html.

“It’s the first time we’ve used this type of interactive web application to inform residents and recreational users about our construction plans,” said Villagomez. “The story map combines the location of the dams and recreational facilities with multimedia content to make it easy for viewers to find information while allowing us to post updates to keep viewers apprised of our construction progress.”

Work is expected to begin in September 2015 with an estimated completion date of summer 2019.

According to Villagomez, the U.S. Army Corps of Engineers continually inspects all of its dams nationwide under its Dam Safety Program – a program that shows our commitment to protecting lives, property and the environment by ensuring that all dams are designed, constructed, operated and maintained as safely and effectively as possible. The Corps’ Dam Safety Program provides a framework to ensure that both short and long term solutions are studied and applied, and helps to ensure public safety for our local communities.

The Addicks and Barker dams and reservoirs have protected the Houston metropolitan area for more than 70 years. Since their construction, the dams have prevented more than $8 billion in potential flood damages. It is estimated that more than $2 billion in potential flood damages were prevented during the May 2015 flood event alone.

When a rain event occurs that may result in flooding downstream of the dams, the outlet structure gates are closed in order to reduce the potential for flooding below the reservoirs along Buffalo Bayou. When the downstream flows along Buffalo Bayou have receded to non-damaging levels, reservoir operations resume, the gates are opened, and water is released from the reservoirs at a non-damaging rate until the reservoirs are empty.

Learn more about the Addicks and Barker facilities at www.addicksandbarker.info. For more news and information, visit www.swg.usace.army.mil. Find us on Facebook, www.facebook.com/GalvestonDistrict or follow us on Twitter, www.twitter.com/USACEgalveston or Flickr athttps://www.flickr.com/photos/98857835@N08/sets/72157644293522432/.