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. Photo: Exploration Green Conservancy
The former golf-course-turned-park is being converted into a system of detention ponds to hold stormwater during major rainfall events. Photo: Stan Cook
Technical knowledge was also required from different parties. The project’s different elements, such as incorporating wetlands, has re- quired expertise from outside agencies. For example, Texas Coastal Watershed Program, an extension of Texas A&M AgriLife, is coordi- nating the wetland effort. There will be 39 acres of wetlands through- out Exploration Green, as well as more than 100 acres of upland and island areas. Phase 1 of the project was divided into three sub-phases — Phase 1A and 1B are complete, with 171,420 cubic yards excavated, while Phase 1C was 80 percent complete by mid-January, and weather-permitting, was expected to be completed in February. Phase 1C requires 177,230 cubic yards of excavation. In its entirety, Exploration Green Detention Facility will provide 38 acres of permanent water storage and addition- al storage room for water runoff. The water storage area is equivalent to 750 Olympic-sized swimming pools. The project’s first two phases were designed to contain runoff from a 100-year storm, of which there have been at least seven in the Clear Lake area in the last 40 years. “It’s worked out well that we split Phase 1 up,” Stanhouse said. “The knowledge we have gained along the way has assisted in the planning of Phase 2, and we’ll apply it to future phases as well.” She cited the challenge of using native grasses in the project as an example. While Bermuda grass is typically seen at detention basins in the area, incorporating native Texas plants and grasses was important for the client, she said. LAN collaborated with the Harris County Flood Control District to learn what types of native grasses would provide
the needed turf establishment in the ponds and be resilient enough to survive underwater after a storm event. Community centerpiece “Exploration Green really is a centerpiece to the community,” Stan- house said. The project is exceptional in that the entire Clear Lake community has been involved since the beginning. “The local community got upset (when the condominium development was proposed) and mobilized, putting up signs and having meetings and calling their local officials among other things,” Peterson said. “The community has been very supportive from the get-go.” Stanhouse also said the community aspect made a difference in how LAN designed the project. “Most of the projects we work on are un- derground pipelines. They’re not something that people are going out their backdoor every day to see,” she said, so this highly visible project required the engineering team to be more open to community input and collaboration. Peterson described the collaboration process as “organic,” saying that “people were going to town hall meetings to express their interests and what they wanted here, right in the heart of the Clear Lake area. The project has generated a lot of excitement among residents because we don’t have a lot of parks here, and here’s an opportunity to create a 200-acre nature park,” he said. Clear Lake City Water Authority is funding the excavation of the
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csengineermag.com
april 2018
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