Grass paver, Grasspave2, installed at the Westfarms Mall

The Westfarms Mall parking lot with Grasspave2 porous grass paver. Since this photo was taken, Westfarms Mall has installed Gravelpave2 as well.

Porous pavement, Grasspave2, being plowed

Snow plowing is easily accomplished when raising the blade or using skids on grass pavers such as Grasspave2 at the Westfarms Mall.

Porous pavement Grasspave2
Grasspave2 porous turf paver meets curbing at the Westfarms Mall.

Porous grass paver parking lot
Westfarms Mall's large grass parking lot has added Gravelpave2 Permeable Paver system to some of the drive aisles.

32 12 43 Flexible Permeable Paver

Grasspave2 is listed in the Construction Specifiers Master Spec Format in Section 32 12 43. You may also place it in the 1995 Master Format Version in section 02795.

Grasspave2 | permeable/porous/pervious paver logo

A Whole Lot of Turf
Permeable paving permits mall expansion in Connecticut
by Patrick White
Turf Magazine - FEBRUARY 1996


You can see it on the faces of the folks who drive slowly by, their necks straining first forward, then sideways and finally back. It is a look of puzzlement and awe, the type of reaction normally reserved for some sort of alien sighting, and rarely produced by merely gazing at a parking lot.

But this is no ordinary parking lot - no pavement wasteland of dirty tar. The Westfarms Mall in Farmington, Conn., has destroyed the notion that the parking lot has already fully evolved by introducing a parking lot all their own, one paved with grass.

It happens, every so often, that a flash of creative energy brings about the resolution to a seemingly unsolvable puzzle. Many times it is ingenuity, rather than invention, which strikes the minds of those involved as they employ old ideas in new ways. Such was the case in Connecticut, but the road leading to the creation of an athletic field-like, lawn parking lot was slow and winding.

Westfarms Mall is a regional shopping center just west of Hartford with one million square feet of retail space. Large by anyone's standard, a 310,000-square-foot expansion was planned to stimulate the economy of central Connecticut.

Despite the potential creation of 700 permanent new jobs, more than 1,000 temporary construction jobs, a projected contribution of $8 million in new sales tax revenue, and $600,000 annually in new, local property taxes, the local Farmington and West Hartford zoning boards originally withheld their approval on environmental grounds.

Permeable Surfaces vs. Impervious Development

"When we looked at the redevelopment of the property, the greenspace ratios had been dramatically strengthened since it was first developed 20 years ago," recalls Dianne Noth, Westfarms general manager, "and we not only had the issue of finding greenspace ratio to accommodate the additional 311,000 square feet of expansion, but we also had to come up to par with what the current formulas were."

Local regulations dictating the rations of permeable surfaces to impervious development were not only sticking points of the project. The volume and quality of water run-off created by the development was also at issue.

"We looked first at sizing the detention basin larger, and improving the volume of water we discharge," explains Noth, "and what we found out was that none of these were very palatable to the community." Unlike many shopping centers that are located in more commercial areas, Westfarms is wedged between two residential neighborhoods, a factor that added to the rejection of several expansion plans.

"We were in a situation of trying to find something very innovative and creative that would accommodate the greenspace ratios, no increase in the storm water run-off volumes, and would still ensure that the water that was going into the water table had gone through some sort of filtering system," said Noth, summarizing the demands placed upon the project.

The Plan

When a sister mall in Denver observed a business across the street employing a turf parking application, and the storm water engineers on the Westfarms project read of some European applications of reinforced turf systems, a plan began to form.

A reinforced turf application would provide support for vehicle weight, and further, by using a tank submerged below a natural turf parking lot it would be possible to store storm water and bring it back into use for turf irrigation.

In addition, the volume of storm water run-off would be improved, and water quality would be strengthened as the water filtered through the turf system and soil. Most importantly, the permeable greenspace requirements would be met by way of the four-acre turf parking lot.

The biggest bonus would be improved aesthetics. "It would allow us not to turn ourselves into an asphalt jungle," translates Noth.

With strong ammunition in hand, the Westfarms team went again before the Farmington zoning board. Proposing the construction of a grass parking lot raised some eyebrows, but the ramifications were easily understood and fully supported.

"Their first reaction was puzzlement, and then after that it was enthusiasm," recalls Noth. The nearly two-year process of earning approval neared an end as the town of Farmington agreed to consider the novel idea placed before them.

Noth then turned her attention to the town of West Hartford, located downstream from the mall. "We asked them if this were something they could live with, and they came back with a resounding approval from their wetlands commission."

Formal approval followed quickly from the Farmington, and the task force accessed the green industry to select materials and turf.

Reinforced Turf

The cornerstone of this unique project, the reinforcing system used to support the turf under the weight of heavy traffic, was chosen carefully. Grasspave2, a patented system by Invisible Structures, Inc. of Aurora, Colo., was selected both because of its ability to bear the load of constant use and an environmental edge.

Grasspave2 is a series of interlocking grids with small rings to hold the sand and topsoil which fill in the unit below the turf. The system is injection molded, and produced from recycled products that will not dissolve into the soil over time; benefits that could not be matched by competitors.

Invisible Structures was founded in 1982 by Vicki Bohnhoff, president, and her husband Bill who oversees the research and development of the products, the company began producing injection molded, recycled support systems in 1988.

In addition to Grasspave2, Invisible Structures produces Gravelpave2, a system designed to be filled with decorative stones and left uncovered in high-wear areas, or used in conjunction with its grassy relative.

"We intended it to be used in large parking areas, wherever people are driving a lot looking for a parking space. We felt the combination of gravel in the aisle, and turf in the parking lot would be a strong benefit while still keeping the same porous area," explains Vicki Bohnhoff.

While Westfarms elected to go with a straight turf application, the mall has made plans for the maintenance of turf in the highest wear areas. Sod can be replaced without the reinforcing systems below, and regular turf maintenance will also be practiced, according to Noth.

A view of the Westfarms lot reveals a large quantity of tree islands dispersed in rows throughout the entire area. This is a direct benefit of grass paving, rather than a traditional asphalt application which does not allow water and nutrients to reach roots which stretch far from the tree below the impervious surface.

Recycled Water and Bluegrass Blends

There were two unusual aspects of the Grasspave2 application at the Connecticut mall project. "The Westfarms project did not fill the rings with sand on this project because they needed to get the sod established quickly, and it was going to be so thick," explains Bohnhoff.

The use of sod in he first place was caused by a freak rainstorm. The parking lot was originally hydroseeded and topdressed, but when those efforts were lost to the weather, sod became the only option to get the parking lot in use by the end of the growing season, and the beginning of the holiday shopping season.

"We had every intention of parking vehicles on it for the holiday season, but it got late in the season and the hydroseed washed off in a tremendous rainstorm," said Noth. She explains that the 12- to 16-week grow-in time required with hydroseeding ruled out the possibility of another attempt in that venue, and the decision was made to sod.

Winding Brook Turf Farm of Wethersfield, Conn., was recommend to the construction company and took on the job of supplying approximately 135,000 square feet of sod in three days. "They only requested sod, and we chose bluegrass because it is the most recoverable of grasses, and would hold up better than the ryes and the fescues," explains Doug Morgan, president of Winding Brook.

The straight bluegrass blend was composed of Adelphi, Glade, Ram, Eclipse and Touchstone, and an irrigation system with a 5,000-gallon tank underground to the side of the turf installation; and we designed a system that we can actually tap into the detention pond, rather than take water from the domestic water supply," Noth explains.

Testing the Future

The winter season has been the first real test of the turf, which has responded well to the challenge. "We are parking on it," emphasized Noth. "We have had storms of 25 inches of snow and we are still parking on it."

The Westfarms maintenance staff custom fit a roller onto the bottom of the snow plow blade to keep it about 1/2 inch off the turf. It is important to have the lot open for winter use because Westfarms expects the majority of use around the busy holiday season.

The mall has taken steps to ensure minimal damage in high-wear areas. "We are alternating the driveways into the lot every day; but we are going to have traffic on and off of it all day long, and that is a different application than I have heard of anywhere else," reports Noth.

The mall has made good use of their environmentally friendly parking lot, both in the local press and inside the mall with descriptive design and photograph displays touting the benefits of such a project. The publicity has led other turf users in the area to contact Westfarms, curious of the concept, but hesitant of the results.

"We have gotten queries from the Greater Hartford Open, several other golf courses and the Connecticut Department of Transportation; my sense is that they will be watching us for the next year or two to see how it goes," predicts Noth.

Passersby find the peculiar parking lot a source of wonder, but the green industry should observe with the same attention. Bohnhoff feels that the grass paving industry is moving forward because of the environmental and aesthetic benefits that are so obvious, and also cost considerations that are, like the structures themselves, hidden below the surface.

She reports that her unofficial studies show the costs between grass paving and asphalt to be even at five years, with a decided turf advantage after that.

The advancement of turf reinforcement technology, and a more widespread usage in the future will provide on more open door for the turf industry; and soon people may drive right by without a second glance.

 

Sizes

Manufactured in 1 square meter units (3.3' x 3.3') or quarter-meter units (1.65 feet x 1.65 feet) and assembled into rolls. Please view our Roll Chart for dimensions. Some curves can be achieved without cutting.

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