Green Stormwater

March 17, 2000

In Charlotte, NC, the Sanctuary–a development built by Crescent Communities of Raleigh, NC–is racking up awards for its environmentally sensitive features. The community features 187 homes on 1,300 acres bordering Lake Wylie in Charlotte.

The Sanctuary’s lodge was the first recreational facility in Charlotte and Mecklenburg County, NC, to be certified by the US Green Building Council’s Leadership in Energy and Environmental Design (LEED).

Additionally, the Sanctuary was the first residential community in the world to receive Audubon International’s Three Diamond designation, the highest level of certification in its Gold Signature Program. The honor is based on wildlife protection measures, efforts to ensure water quality, and use of native flora and fauna, as well as green building practices and site design.

In addition to instituting initiatives that conserve energy and water, Crescent Communities has also developedthe Sanctuary with a focus on green stormwater treatment measures, such as bioretention gardens and rain barrels.

Crescent Communities had owned the property on which the Sanctuary is being developed for a long time and originally had plans to use it for a hotel, a commercial marina, and golf courses. Those plans were bagged after the company considered the area’s topography and tree cover.

“We’d have to “˜grade the world,'” says James Martin, a senior project manager for residential land development with Crescent Communities, who has been involved with the project. Instead, the company noted a shift in the market for a demand for larger home sites.”There also was a growing demand in the market–how large it is is arguable–of folks who are more interested in green building concepts,” says Martin.

Crescent Communities turned to a plan whereby 1,350 of the 1,850 acres of the land would be divided into 187 home sites, with the average acreage per property at 5.4.

“With that, we wanted to incorporate green development and then start the process of educating our builders and property owners about green building techniques they could use,” Martin says.

Crescent Communities has a featured builder program in all of its communities. The Sanctuary has 20 companies that are permitted to build at the site. While anyone can buy a lot there, he or she must use one of the featured builders.”

We had 20 participants we wanted to educate first and then start the educational process with our property owners,” Martin says.

In order to educate others on green building techniques, Crescent Communities started the process in-house. So when it built its sales center for the Sanctuary, it did so with an eye to showcasing green building techniques.

In doing so, the company didn’t deliberately seek out any type of environmentally friendly designations; instead, company officials pored through information from publications, programs, and green building initiatives to seek ideas for the sales center “so we could show it off and educate people when they come in,” Martin notes.

The company prefers to lead by example through its sales center and amenities center, says Martin. “The idea is to try to show off certain things so perhaps people would say, “˜I’d like to incorporate this into my home when I build it,'” he adds.

The stormwater runoff design is focused on all of the acreage on which the Sanctuary is developed.

Crescent Communities’ LEED-certified amenities center–the John James Audubon Lodge at the Sanctuary–features an 8,000-square-foot building divided into 4,000 heated square feet and another 4,000 unheated square feet with porches and covered areas and three pools.

“At the lodge, the amenities site is 17 acres, but not all of that is developed,” Martin says. “There has to be a certain number of parking spaces. By the time you put in six tennis courts, the pool decking, and the building and the parking, you end up having a good bit of impervious surface.”

An area stormwater utility charges fees based on the amount of impervious surface. Among the sales center’s green features: a pervious concrete driveway.

Crescent Communities designed the parking lot to slope inward on itself and drain to a large bioretention pond. An attractive bridge connects both sides of the parking lot and traverses the large bioretention pond. Water passes through the pond, as well as two others, in a sort of treatment train fashion before ending up at Lake Wylie.

“Since Lake Wylie is a drainage basin of sorts, all of the rainwater that falls goes back into the lake,” says Martin.

Red clay is the predominant soil. “You could make pottery out of it,” Martin notes. “It’s not like sandy soil, where the water can filter through. The clay is just like pavement; it all runs off. When it does, it takes up sediment out of that clay and dumps it into the drainageways.”

Crescent Communities mucked out the red clay and put amended soil into the area with organic material and sand.

“You can plant in that soil,” says Martin. “We’ve put in water-loving plants. The idea is that it all drains to that pond and is filtered slowly.”

A bioretention garden is located in the front of the sales center and receives all of the water coming from the roof and the gutters. Rather than stormwater being released into waterways through impervious pipes at a high velocity, it instead is directed into a vegetative grass swale and at some point it goes into the bioretention garden, where it is filtered before it’s released into the lake, says Martin.

Crescent Communities also installed rain barrels that are connected to gutters in the back of the sales center. Rainwater fills up the barrels. A spigot on the outside of the barrel enables water to be drawn and used to irrigate planting beds in an effort to reduce water consumption in irrigation.

“If you want to fill up a watering can, you can do that at the rain barrel, but instead of turning on water you’re paying for, you’re using the rainwater,” Martin says.

The acreage encompassing the home sites also features green stormwater treatment measures. Crescent Communities was required to have a 50-foot buffer from Lake Wylie when developing the Sanctuary. The lake has about 7 miles of shoreline, of which 6.5 miles have a 200-foot buffer.

Additionally, Crescent Communities limited the amount of clearing property owners can perform on their lots in order to reduce the impervious surface.

For example, in a typical Charlotte subdivision, sidewalks would be constructed on both sides of the street with curbs and gutters and impervious pipe, Martin points out. “The stormwater gets in that pipe and gains velocity, and then when it’s released, it’s released quickly, which causes erosion,” he adds. “It’s not filtered. That has its place in development, but we wanted to try something different here at the Sanctuary.

“We’ve reduced the impervious piping by going to a ditch section roadway, so it runs off,” says Martin. “By the time it gets into drainageways and into the streams and leads to the lake, it’s been more than filtered.”

The Sanctuary is not one of those developments that people will pass by and remark on the well-manicured landscaping, Martin notes. “There are country clubs for that sort of thing. There is a time of the year with the rain and cooler weather where the grass is wonderful,” he says. “Come July and August, there’s going to be some brown.

“The seeded areas will grow every year and spread and develop a deeper root system from the rain that falls from the sky, not from what we throw on it.”
Like most green land developers, Crescent Communities has found itself in the position of educating homebuyers on the benefits of LEED-approved practices. After all, it will be the responsibility of the homeowners’ association to maintain some of the features, such as the bioretention gardens.

“We think a lot of people who have bought here and are interested in the Sanctuary and our builders are willing to try some things,” says Martin. “They want to see the benefit of it, and at the end of the day, they want it to look good. They want it to make sense.”

The biggest learning curve is “that you don’t have to live in an adobe hut and have wild things growing all over your house to be green,” says Martin. “There are little things you can do. If everybody does these little things, look at the difference you can make. We’re careful not to cram something down someone’s throat, because that’s the quickest way to get them to run away from you.”

In some cases, it costs more to build green at the onset. With the lodge, there was a 5% increase on the $4.5 million facility to become LEED-certified. The other measures, such as the bioretention ponds, added about 25% more to the cost of development. However, a cost savings on that investment also is expected down the road.

“We knew there was going to be some savings on that, but we also did it to complement our overall scene,” says Martin.

Martin says Crescent Community opted not to pursue a higher level of LEED certification. “It would have been a good bit more expensive than 5%, but we decided to go with things we thought were very reasonable so we could prove the point that you can build a green facility and still make it look good,” he says.

Martin says such cost increases are not much of a concern with those who are buying houses at a certain price point. “An extra thousand here or there for an initiative they really believe in won’t have as much impact as if you were trying to incorporate that into a $150,000 house,” he says. “Just the economics of it makes it an easier pill to swallow.

“But at the end of the day, it’s either important to the buyer and they want to incorporate it or it’s not. I don’t know how you overcome that when it’s not. You have to constantly plug it.”

While Crescent Communities enjoys the LEED designation and other honors, the company has created its own program to promote green building, with a green leaf as a logo. A single leaf represents a certain measure of green building practices, while three symbolize the ultimate.

“We have a couple of homes that have been “˜three leaves’ and a number that have been “˜two leaves,'” says Martin. “The builders have seen the value and have used that to differentiate one builder’s house from another house.”

Martin says the company took a chance when it pursued green building techniques.
“We did not know what the take would be on marketing the Sanctuary with the efforts we’ve done, because we’re used to developing luxury, high-end communities,” says Martin. “It is a good-looking subdivision, but it is not manicured like you would see in a country club. We wondered if it was going to be a turnoff to folks.

“We didn’t know what the interest would be, and when we had the first-year sales, out of 81 private preserves, we sold more than 50 to the builders on one day and then we sold more than 20 on a retail draw. We did really well that first year and in years after that. We were pleasantly surprised.”
About the Author

Carol Brzozowski

Carol Brzozowski specializes in topics related to resource management and technology.

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From left: Matt Hacker, Metropolitan Water District of Southern California; Marco Tule, Inland Empire Utilities Agency Board President; Gil Aldaco, Chino Basin Water Conservation District Board Treasurer; Curt Hagman, San Bernardino County Supervisor; Elizabeth Skrzat, CBWCD General Manager; Mark Ligtenberg, CBWCD Board President; Kati Parker, CBWCD Board Vice President; Teri Layton, CBWCD Board member; Amanda Coker, CBWCD Board member.