With its green roof and inverted raindrop-shaped building, there aren’t many water purification plants like this one – but. given its green credentials, perhaps there should be.

This might look like a rather lavish solution for a water treatment plant, but in fact the Whitney Water Purification Facility and Park in Hamden, Connecticut treads lightly on its surroundings. Although the 120 m long, curvaceous stainless steel-clad building – the work of Steven Holl Architects – is a striking structure, it is its green roof that really sets it apart.

The design team’s goal was to create a development with the same water run-off characteristics as a dense forest. In fact, the building itself sheds only 30% of the rainwater volume that would normally run off a structure of this size.

The £28m development is set in a 5.5-hectare site that has been landscaped to filter and store storm water, reduce run-off and provide a mechanism for rainwater to recharge the groundwater supply.

On the facility itself, the 3250 m2 green roof – the largest in the state of Connecticut – has a rubberised asphalt waterproofing system. A root barrier fabric was installed on top of the insulation to optimise moisture management in the green cover and protect the insulation from water infiltration. The low-maintenance planting includes native sedum plants and flowering perennials, chosen to provide some year-round interest. Together, these mimic the interception, evapo-transpiration, storage and slow release of water that occurs in more natural surroundings.

The facility purifies millions of litres of water from Lake Whitney every day. By placing the purification plant beneath the building, the treatment process is below lake level and enables the purification plant to be driven by gravity, reducing the need to run pumps.

The building above houses a range of facilities, including offices, laboratories, conference rooms and an exhibition lobby with a

long, sloping floor. Lit by domed rooflights set into the green roof above, the exhibition lobby serves as one of the public areas where visitors can learn about water management.

The facility also includes a groundwater heat pump system, providing all building’s heating and cooling needs. This comprises 88 wells and is claimed to save around 850 MWh of energy a year.

Client South Central Connecticut Regional Water Authority

Architect Steven Holl Architects

Consulting engineers CHWMHill; The Bioengineering Group;Tighe & Bond.

Source

Building Sustainable Design