Article from Cincinnati.metromix.com:
The Cincinnati Symphony Orchestra partnered with The Motz Group and Sportworks Design to convert Riverbend Music Center into the world’s first concert venue of its size to cover its lawn – all 2.75 acres – with synthetic turf. The facility’s elaborate $750,000 system of turf, rock and drains has been in the planning stages for five years. At the opening show of the season, concertgoers will encounter a lawn consisting of five layers: 120,000 square feet of non-flammable plastic turf; 660,000 pounds of non-toxic, acrylic-coated, round-grained, bacteria-resistant sand; two layers of crushed limestone; and 1.04 miles of drainage pipe.
The reasons behind the groundbreaking move:
1. Reduce Riverbend’s carbon footprint. It eliminates the need for fertilizers, pesticides, weed-killers and gas-powered lawn mowers, and the synthetic lawn system is completely recyclable.
2. Save money. The lawn’s grass surface annually consumed 600,000 gallons of water for irrigation and $90,000 for replacement rolls of sod.
3. Extend the amphitheater’s brand. Riverbend plans to market the system to outdoor concert venues around the world.
4. Sell more tickets. Projections call for a 10 percent jump in lawn ticket sales.
“People are finally going to be able to enjoy a sold-out show on the lawn, without worrying about it turning to mud if it rains,” said Mike Smith, Riverbend’s longtime general manager and a vice president with the Cincinnati Symphony Orchestra, the amphitheater’s owner.
The top layer is made up of densely packed, 2-inch-tall blades of non-flammable plastic grass. The blades are shorter than lawn grass blades. They are close to the height of the frog-hair turf surrounding golf putting greens. Sections of the grass carpet are sewn together and held down by spikes. Round, green, acrylic-coated grains of sand mined in Texas and called Envirofill are placed on the grass, as infill. There are 5.5 pounds of sand per square foot of synthetic turf. The sand’s coating is bacteria-, mildew- and mold-resistant. The grains’ round structure keeps the blades of turf standing at attention. The roundness also acts as a cushion, preventing the sand from compacting. The base of the turf has millions of holes to let moisture drain, first through a 2-inch-thick layer of finely crushed Georgia limestone, then a 4-inch-thick layer of coarsely crushed limestone leading to a network of 10-inch drainpipes.