When golfers lost interest in playing the greens and fairways of Clear Lake (Texas) Golf Course in the early 2000s, its owner looked to sell the Houston-area property for redevelopment. That would have been par for a course, but the Clear Lake City Water Authority had other plans.

After area residents appealed to the City Water Authority to somehow preserve the green space, a movement began to transform the old golf acreage into an eco-friendly public park. Seventeen years later, a facility dubbed “Exploration Green” is in the final stages of creation. What once was a duffer’s delight with a water hazard or two is now a nearly 180-acre stormwater detention facility featuring five ponds, islands of bird habitat, water-filtering wetlands, athletic fields and miles of walking/biking trails.

What Clear Lake residents don’t see as much these days is flooding. Exploration Green is doing its job.

Form and function

The name “Exploration Green” alludes to space exploration missions controlled at nearby Johnson Space Center and oil exploration in the region. The facility is first and last a heavy-duty stormwater detention facility. It was precisely engineered as such by personnel of Lockwood, Andrews & Newnam — known by the acronym LAN — with Kelly Shipley as its project engineer.

However, the dual nature of the project as a stormwater control area and a public park was apparent from the beginning. “Our assumption was that the water authority wanted to develop as much water detention capacity as possible,” Shipley says. “That was our assumption going in. But the board members made it clear they really wanted it to be a dual-purpose facility.”

Consequently, the fairly uniform depth of 6 feet for each of the five ponds was calculated to be deep enough to retain a large volume of water — 100 million gallons in each pond, to be precise — yet not so shallow as to encourage weed growth in the bottom of the lakes and mar the setting’s natural beauty. Function and form. Capacity and charm.

The focus on controlling flooding was not lost as the project developed. After Hurricane Harvey struck in 2017, the focus became even more sharply defined. Phase 1 of the project — comprising 15 acres of natural habitat and wetlands and a 24-acre pond — was only partly complete when the hurricane hit, yet the facility’s existence made a difference in weathering the storm.

“There are houses right on the edge of Exploration Green’s phase one that are repeatedly flooded, over and over,” says the water authority’s general manager, Jennifer Morrow. “During Harvey, only two or three of them were flooded compared to 15 or 20 in earlier storms, and they were only under 2 or 3 inches of water instead of 1 or 2 feet. And phase 1 was only 80% done at the time. We realized it would have an even larger impact on flooding when it was completed.”

Such clear-cut evidence of flood mitigation converted any project doubters among Clear Lake residents. The authority board also was impressed. The board had paid some $6 million for the old golf course in 2011. Over the next 20 years, engineers estimated that construction of the facility would require another $38 million in bond money.

But after Harvey, the board opted to move more quickly and compressed the project’s timetable. It scheduled development of one pond area after another after another. The project’s completion now is scheduled for 2023. The more urgent schedule tacked another $10 million onto project costs. “We weren’t expecting to move quite that fast,” Morrow says.

A measure of the project’s popularity is the community support it has attracted both in terms of donations and volunteer time. Commercial entities like Texas grocery chain HEB have donated to the project. A local ecology group, Trees for Houston, donated 800-1,000 trees for each of the pond areas. Texas Parks and Wildlife has granted sums of up to a million dollars. And project volunteers number in the hundreds.

While bond money covers the project’s engineering and construction costs, contributions and grants have paid for all the amenities, including benches and sidewalks, grasses and trees. A nonprofit organization, Exploration Green Conservancy, manages these ecology aspects of the project in partnership with the water authority.

Learning together

Constructing a stormwater detention facility in the middle of a settled residential community is not the best way to win friends and influence people. All the equipment moving all that earth, loading it onto on-road tractor-trailers and carefully shaping the carved out banks of the pond — all that heavy equipment meant many hours of bellowing diesel engines.

“These used to be quiet neighborhoods. The amount of construction activity residents have seen and heard is the most they have ever seen and heard,” says Shipley. “Plus trucks pulling through neighborhood streets every few hours. The noise and disruption was one of the biggest issues we faced, but it has gotten better. Residents are more used to it now.”

In all, some 200,000 truckloads of soil have been carted away — an estimated 2.4 million cubic feet of earth. Phase 1 dirt was trucked to a developer’s job site relatively close by, but some of the soil has been relocated 20 miles away. “We try to dump the removed soil as close by as possible,” Shipley says.

The soil is mainly a clay compound and easily handled. Bore samples are taken so excavating contractors know what to expect when their blades and shovels dig in, but there have been surprises. The phase four project area contained the golf course’s water hazard. “The soil was a mucky mix of clay and nonclay. It was so wet, they had to turn and spread it and dry it out so they could work with it.” Different contractors have worked the phases of the project, with each pond area contracted separately.

Each pond was created with curving natural contours, rather than uniform oval-shaped depressions, for eye-appeal. Gentle slopes on the banks of the ponds function as wetlands, with planted grasses filtering runoff from nearby paved areas. Four of the ponds are interconnected by a stream. The phase 3 pond is a standalone facility because of elevation issues, according to Shipley.

The ponds receive runoff, but also are fed by stormwater pipes ranging from 2 to 5 feet in diameter, with a few box culverts as large as 8 feet by 4 feet. To maintain the 6-foot depth of the ponds between storms, treated water from the authority’s wastewater treatment plant sometimes is shunted to the linked lakes via a 12-inch line.

All that water is detained in the five ponds, but not forever impounded. Flow from the ponds when their capacity is reached follows natural contours, emptying into ditches that eventually deposit the water in Horsepen Bayou. Runoff at the golf course also emptied into ditches leading to Horsepen.

Because the creation of a stormwater detention facility in the middle of a residential area was a novel approach to regulating flooding, the authority and its engineering partner learned together how to do it. The authority’s general manager says they sort of tiptoed into the project when construction began in 2017.

“There was a learning curve,” Morrow says. “We didn’t know quite what to expect. We hadn’t seen any other project quite like this. The first phase was divided into three smaller sections to make it easier for us so we could learn how to work the next phase.”

Moving the thousands of truckloads of excavated soil through school zones and local traffic was an ongoing challenge. However, before the first dirt was moved, the Clean Water Authority had established goodwill with the community and forewarned residents of disruptions associated with construction. The community embraced the project.

“When we had town hall meetings, the conservancy was formed,” Morrow says. “Someone would say, ‘I have an interest in trees,’ or ‘I’m a naturalist’ and we would tap such people as resources. Groups formed to plant and maintain wetlands and trees and grasses, some from colleges and high schools. It has been an amazing community effort.”

Not every stormwater detention project is as celebrated as Exploration Green. But then not every detention pond is encircled by walking and biking trails or bordered by athletic practice fields. Most don’t have well-maintained wetlands and islands for bird life. Swimming and boating in the ponds is not allowed. One reason is the treated wastewater emptied into the pond. Another reason is the occasional alligator seen lounging on a bank.

Work in progress

The stormwater facility is not the only focus of the Clear Lake City Water Authority’s work these days. For instance, it has a $138 million bond issue on the ballot in May to fund, among other things, an upgrade of its wastewater treatment plant.

But Exploration Green still is a priority. Technically, some work remains on phases 3 and 4 of the project and the final phase five has just begun with expected completion a year from now. It is still a work in progress, albeit a heralded work. Organization representatives have visited Clear Lake from places as distant as Great Britain to see for themselves how the green infrastructure does its work. The project was singled out for recognition most recently by the Association of Water Board Directors. Other awards include a Gold Medal Engineering Excellence Award by the American Council of Engineering Cos.

The awards remind anyone paying attention that Exploration Green was not a beautification project, its attractiveness notwithstanding. Shipley says ruefully that a storm of one kind or another coincided with each year of construction of the ponds, “which reminded everyone that this is not a game. The end goal is to have protections against flooding.”

She says the project continues to bring satisfaction.

“From an engineering point of view, this has been a very interesting way to give back to the community. I love that about the project. I love what we have been able to accomplish.”