This Plant's Landscape Replicates the Stages of Water Treatment

Community involvement helped a Connecticut water authority create a unique building and a landscape with educational and functional values.
This Plant's Landscape Replicates the Stages of Water Treatment
View from the front interior of the operations building at the Lake Whitney plant.

The story of how a community’s drinking water is collected and processed has been cleverly designed into the landscape and buildings at the award-winning Lake Whitney Water Purification Plant owned by the Southern Connecticut Regional Water Authority.

A functional landscape that replicates a watershed and the stages of water treatment, a 28,000-square-foot green roof at nearly ground level, and a uniquely designed operations building are all located on 14 acres next to a residential area in New Haven, Connecticut.

All integrated

The landscape is at the forefront of the design and includes six distinct areas, each representing a segment of the treatment process in the plant.
An elevated area behind the plant, representing a mountain as a water source, allows water to pass through each discrete landscape area. Swales and undulations direct rainwater through small meadows, fields, valleys, grassy mounds and vegetated areas, ending in a wetland for filtering, and then a holding pond before recharging the water table.

“The goal of the landscape was not only to educate but also to provide a marsh-like area that controls runoff,” says Jim Hill, operations special projects manager for the authority.

The green roof, the largest in the state, has 21 domed skylights that shed light into the plant, which is 70 percent below grade. Visitors can use the skylights to observe the treatment process. The green roof is designed for low maintenance and requires no mowing or irrigation.

Vegetation on the roof was chosen to provide year-round blooming along with the desired foliage height and texture. Nearly 900 pounds of several species of sedum cuttings cover the roof. Some 7,000 flowering perennials were planted as plugs and cover various roof areas. Together, the flowering plants, leafy succulents, creeping herbs and shrubs provide aromas typical of a mountain meadow.

Unique building

The most striking feature of the 15 mgd facility is its 360-foot-long operations building, shaped like an inverted drop of water. Clad in shingles that cover 190 tons of structural steel, the long keyhole-looking building with its dual-curved façade and abundant glass also houses the laboratory, conference room, and exhibition lobby.

The parcel of land surrounding the facility is available from dawn to dusk as an outdoor park for residents. Paved pathways meander through the park, and strategically located benches allow visitors to rest at popular observation points and watch native and migrating birds and a variety of wildlife.

The planting schemes for the park were modeled after an alpine meadow with rock outcroppings to minimize the impact of foot traffic. As with the green roof, all use native grasses and shrubs that require no fertilizers or pesticides, reducing the facility’s downstream impact. Meadow-like habitat for birds, butterflies and small mammals was created to achieve the sustainable, functional and aesthetic objectives of the design.

Eliminating discharge of stormwater into the nearby Mill River was also critical. Rather than using drains and piping, the drainage system is managed through the landscape. Runoff from the green roof and the entire park area collects in the pond for return to the water table. “Stormwater abatement on site was important to us and became a critical requirement of the landscape design,” says Hill.

Community project

The facility was completed in 2005 and was built on the site of a water plant that had been decommissioned in 1991. To be a good neighbor, the authority involved residents in setting the design objectives. The design firm of Michael Van Valkenburgh Associates received the 2010 American Society of Landscape Architects Design Honor Award, and building architect Steven Holl Architects won the 2007 Top Ten Green Projects Award from the American Institute of Architects Committee on the Environment.

Hill says the original intent was to allow students and visitors to see the water treatment process from within the plant. That plan changed after the tragedy of 9/11, and visitors now are allowed inside the facility by appointment only.

The Lake Whitney facility, one of four owned by the authority, serves nearly 430,000 people in 15 towns. Its environmentally sensitive design integrates landscape, infrastructure and striking architecture in a public park. Says Hill, “The entire site serves as a state-of-the-art model for effective water stewardship through the integration of best management practices of green roof, vegetative swales and wetlands.”   
 



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