Sustainable Rainwater Harvesting
|By Igin Staff|
BY FRED PAPE AND ED BEAULIEU
Located in the heart of pittsburgh, the phipps Conservatory is home to the first leedcertified building in a public garden and is broadening its sustainable reach to every corner of its campus.
In 1995, the conservatory embarked on a three-phase build-out plan to add a state-ofthe-art welcome center, production greenhouses, a tropical rainforest display, and its Center for sustainable landscapes.
The new Center for Sustainable Landscapes is one of the world’s first certified living buildings, complete with green roof, and will generate all of its own energy while capturing and treating all onsite water. Aquascape Inc. in St. Charles, Illinois, was called on to lend their stormwater management expertise and construct a viable and sustainable rainwater harvesting solution.
Phipps realized that while there are numerous green building experts available, many were not focused on the landscape. They wanted to provide a living classroom and research areas for focused work on sustainable landscapes.
When Phipps set out to design and build the Center for Sustainable Landscapes, their bold vision for the design team included achievement of the highest LEED certification level. Phipps also accepted the Living Building Challenge, which requires an even deeper level of sustainability.
Sustainable Sites certification was the final item on their checklist. The Center is designed to be a ‘net zero building,’ which means that it produces more electricity than it uses. All stormwater will be captured, filtered and reused, and all materials used in the project must pass stringent requirements. For example, PVC was not allowed in any capacity.
For the past three years, the Aquascape team worked with Phipps on the stormwater management aspects of the project. The project site sits on a terrace in the middle of a steep hill looking up at the existing conservatory campus. The steep topography coupled with a rather small site posed a significant challenge to the design team charged with handling all onsite stormwater.
Water is collected from the upper campus and off the roofs of the Center for Sustainable Landscapes and another nearby building. Collected rainwater is then directed to a stormwater lagoon, designed to fluctuate with storm events and also serve as a decorative element next to the Center.
The wetland filtration system, patented by Aquascape, cleans and polishes the stormwater through stone beds by using a multi-staged filtration approach of suspended solid removal, biological filtration, and phytoremediation using native wetland plantings. The beneficial bacteria colonizing on the stone, along with the aquatic plants, strips the water of nutrients and toxins from the environment.
Skimmers at each end of the lagoon draw water in while skimming the surface to keep debris out of the pond. The skimmer on the west side of the lagoon sends part of the water to the wetland filter and a small amount of water to a shallow reflective pool near the entrance to the Center.
The skimmer on the east side pushes water to the other half of the wetland area and also to a formal waterfall spillway. The waterfall aerates the water and disguises the pipe that carries stormwater to the lagoon. A laminar-style fountain provides visual interest for visitors.
When the lagoon overflows, water is channeled through a large concrete weir to a 65,000-gallon storage system. The system lies beneath a parking drive and contains rain tanks and a liner. Directly adjacent to that is a 23,000-gallon infiltration tank. This system is wrapped in a geotextile fabric and collects runoff from the parking area through a rain garden.
Installation for the stormwater management system was completed in two phases. In October 2011, the 65,000-gallon storage system was installed, along with the 23,000-gallon subsurface reservoir to handle overflow. The lagoon was added in April of 2012.
Both projects were constructed under the direction of Ed Beaulieu, director of contractor development and field research, and Fred Pape, specialty projects manager, both with Aquascape. Also helping out were local certified Aquascape contractors: Greg Fisher of Fisher’s Landscaping, Phil Rook of Professional Lawn and Landscape, and Kevin Soergel of Soergel’s Landscaping.
The two combined systems have the ability to capture more than 88,000 gallons of stormwater. The rain tanks were installed and are capable of handling any traffic load, such as buses, and fire or delivery trucks. These tank systems were installed with an average of eight people, working over a five-day period. An engineered piping system that plugs into the city’s storm system can handle any overflow that might occur on rare occasion.
The conservatory’s production greenhouse uses almost 20,000 gallons of water per day to irrigate the vast plant collection. To accommodate the demand, a 20,000-gallon storage system was installed on the upper campus next to the greenhouse. This tank is slowly fed from the larger tank below and is then pumped quickly into the greenhouse each morning for irrigation purposes. This system allows Phipps to drastically reduce its dependence on municipal water.
An overarching goal of the Phipps Conservatory is to connect people with nature. Perched on one of Pittsburgh’s many hillsides, Phipps showcases thousands of different plant species from around the world. Visitors can wander through a variety of gardens, from desert landscapes to Japanese bonsai, to a tropical rainforest. The ornate Victorian architecture and original glass houses add to the rich history and beauty of the entire experience.
EDITOR’S NOTE: Fred Pape is specialty projects manager, and Ed Beaulieu, director of contractor development and field research, both with Aquascape Inc.