environment + Sustainability
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Clear Lake community uses novel approach for stormwater mitigation. By Kelly Shipley, P.E. Exploration Green
In the Houston suburb of Clear Lake, an almost 200-acre nature park called Exploration Green is underway, complete with wetland preserves and at least six miles of hike-and- bike trails. But what makes it special is the park’s primary function of mitigating flooding for the community through its five detention basins. The recreation and detention site, once the Clear Lake City Golf Course, has been part of the community for more than 50 years. With increased development in the surrounding area in recent years, the old methods of managing runoff — outdated drainage channels — didn’t hold up. Residents several years ago took steps along with the lo- cal water agency, Clear Lake City Water Authority, as the community realized more drainage was needed. In 2005, when the golf course’s owner decided to sell it to residential and commercial developers, the Water Authority had heard enough concerns from residents and witnessed plenty of flooding in the area. The Water Authority began to consider the potential impact of converting the golf course into condos and townhouses. After two hydrologists determined that the development would dramatically increase flooding in the area, the Water Authority purchased the land for $6.2 million in 2011 with the idea to convert the property into detention. The result is Exploration Green, a former golf-course-turned-park now being converted into a system of detention ponds to hold stormwater during major rainfall events. The need for this kind of project became clear last August during Hurricane Harvey, which brought unprecedented rain- fall to the Houston area. The neighborhoods around Explora- tion Green were inundated with 45 inches of rain. Harvey’s extensive flooding has resulted in city leaders and agencies around Houston searching for solutions. Doug Peterson, the vice president of nonprofit Exploration Green Conservancy,
Exploration Green, an almost 200-acre nature park, includes wetland preserves and at least six miles of hike-and-bike trails. The park’s primary function is mitigating flooding for the Clear Lake, Texas, community through its five detention basins. Image: SWA
believes that projects like Exploration Green provide the answer. Founded by residents, Exploration Green Conservancy is a nonprofit that helps plan the rec- reational area and raise funds for conservation, recreation, and amenities for the park. “Exploration Green can and should be replicated all across Houston,” Peterson said. “It’s a good approach for having flood and stormwater countermeasures that are more than just levees and are focused on green spaces and amenities that people appreciate in addition to flood protection.” Each of the five detention ponds can store as much as 100 million gallons of water. Although the first detention pond was only 80 percent completed at the time Harvey made landfall, it protected 150 to 200 homes from flooding. Engineering challenges The 178-acre project will ultimately protect several thousand homes in the Clear Lake area from flooding during a storm event. The detention ponds will be excavated by 2021, according to Abigail Stanhouse, P.E., a project engineer at Lockwood, Andrews and Newnam, Inc. (LAN), the planning, engineering, and program management firm that prepared the plans and construction documents and is overseeing construction of Phase 1. “Due to the nature of the project, a lot of input and expertise is required from different groups, which in turn, requires iterations and modifications to the de- sign,” Stanhouse said. “Typically, we’ll do our designs and they’re set, the work gets done, and we’re finished.” This project required a lot of coordination from everyone involved, she said.
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csengineermag.com
april 2018
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