The overall winner of Decathlon V, WaterShed is a microscale ecosystem that manages storm water, filters pollutants, harvests and recycles grey water and minimizes potable water use.
THE CHESAPEAKE BAY watershed is home to 3,600 species of plant and animal life as well as 17 million people. The University of Maryland’s WaterShed mimics and serves as a micro-ecosystem, an example to help manage the state’s larger ecosytem. For the competition, Maryland even brought its own wetlands to the National Mall.
WaterShed’s public module includes this sleek, simple kitchen, which opens onto a deck trellised with edible plants.
Water is the defining theme of WaterShed. As if perched on an alluvial island, the split-house butterfly form embraces its surrounding constructed wetlands.
The sense of water flow begins in the centerpiece courtyard rivulet, enticing visitors to enjoy the home. Trellises loaded with greenery, a green roof, lush gardens and burbling ponds both join and separate the living modules that distinguish private from public spaces.
WaterShed won the overall category (essentially grand prize) for Decathlon V, scoring 951 points from a possible 1,000. It also took top honors in the architecture category, and second place in market appeal. However, with its green roof, cistern and wetlands costs included, it scored 12th in the affordability category at about $336,000.
WaterShed is made up of two modules connected by a bathroom module, for a total of about 900 sq. ft. of living space.
Water forms an axis for the holistic split-house butterfly form. A bathroom links the two wings of the house with an open shower that looks out on installed wetlands.
Construction is described as “heavy-stick framing—triple 2” x 6” studs, joists and rafters spaced 4 ft. apart, with 1-1/2”-thick tongue-and-groove decking used as sheathing.” The two larger modules have French door entries into the courtyard. The private module serves as both bedroom and office, with a dedicated office nook, The bed folds closed into a daytime work table, and the living module houses kitchen and living areas. The kitchen is adjacent to the vegetable and herb garden.
WaterShed’s green roof slopes to feed runoff to the cistern and wetlands. The vegetation slows rainwater flow to the landscape, while simultaneously insulating the living space below and improving energy efficiency. Collected grey water from the shower, lavatory, clothes washer and dishwasher also feeds through wetlands optimized for filtration and cleansing.
Humidity is an issue in Maryland. A patent-pending liquid-desiccant waterfall serves as art and dehumifier. Maryland has displayed several versions of this feature in past decathlons. A high-saline liquid solution absorbs humidity from the air; heat from the solar panels dries the desiccant for re-use. This year, LED lights illuminate the waterfalls.
But it is the bathroom that is the centerpiece of WaterShed, connecting the two larger modules—but also showcasing the mini-ecosystem. The shower has a large window screened with vegetation, so users feel they are showering outdoors.
A 9.2 kW photovoltaic array powers the home; it is clipped to the standing seam metal roof and features micro-converters. A dedicated evacuated-tube solar-thermal system heats water. WaterShed was among the seven entries that succeeded as a net-zero home.