Continuing Education: Water Conservation
Some have declared California’s water woes over. As of early last month, precipitation in many parts of the state was on track to make this winter one of the wettest on record. Reservoirs were filling up—so much so that one dam in Northern California seemed on the verge of collapse.
But others say not so fast. As of press time, much of the middle and southern part of California was still considered in moderate to severe drought. And, in fact, the state’s Water Resources Control Board announced an extension of its existing conservation regulations on February 8, with prohibitions against practices such as watering lawns after rainstorms and hosing down sidewalks and driveways, citing still-depleted groundwater supplies and the lingering effects of the drought on agriculture, fish, and wildlife.
Those who follow water-use issues closely, however, say that conservation is not just for drought-plagued regions or arid places. Rob McDonald, the lead scientist for the Global Cities program at the Nature Conservancy, points to the effects of climate change. Water supplies all over the world will see the effects of warming temperatures, shifting precipitation patterns, and more extreme weather.
Other sources make the case that conserving water means saving energy. They point to a relationship known as the “energywater nexus.” The term is used to describe the interdependence of the water used for energy production and the energy consumed to extract, purify, heat, or cool water, and then clean and dispose of wastewater. “Treating and moving water around has a substantial energy footprint,” says Justin Stenkamp, a senior associate in the Seattle office of engineering firm PAE. The amount of energy expended on water varies greatly by region, but nationwide it accounts for about 4 percent of electricity consumption, according to a 2002 Electric Power Research Institute Report.
Using less water also means improved water quality. Amy Vickers, an independent water planning-and-policy consultant based in Amherst, Massachusetts, cites the problem of algae growth in waterways caused by runoff from farms and yards.
But what can architects and their consultants do about these problems at the scale of individual buildings? With so much water policy set at the state and regional levels, it is only natural for design teams to assume that there is little they can do beyond selecting efficient plumbing fixtures or specifying native landscaping. However, architects can help drastically reduce water use by looking at their projects holistically. One possible road map is offered by the water-conservation ambitions of the stringent Living Building Challenge certification program (LBC), which requires “net-positive” water performance. This means, according to the International Living Future Institute (ILFI), the nonprofit organization that oversees the LBC, that a project’s water supply must come from captured precipitation or from recycled water and that stormwater and wastewater should be managed on-site through reuse, a closed-loop system, or infiltration. The idea is that a Living Building is one that “has a positive impact and restores the ecosystem around us,” says Amanda Sturgeon, ILFI CEO.
Those familiar with the standard will know that water is only one of its many aspects. Achievement of “living” status entails satisfying 20 imperatives organized into seven performance areas: place, energy, health and happiness, materials, equity, and beauty—in addition to water. Full certification has proved tough to attain, with only 12 projects, so far all in the U.S., certified as full Living Buildings since the program’s launch in 2006.
The small number of certified projects is not surprising, given that one of the aims of the LBC program is to transform the design and construction industry and challenge established practices. The net-positive water imperative is no exception: many of its recommended strategies conflict with building codes and health department regulations in some jurisdictions. In cases when these conflicts can’t be resolved, ILFI does grant exceptions, as long as a project team can demonstrate that it has been an advocate for change.
Lately, however, LBC projects have had some success implementing progressive water strategies. One such project is the Chesapeake Bay Foundation’s Brock Environmental Center in Virginia Beach, Virginia, designed by SmithGroupJJR. The 10,000-square-foot structure hosts the nonprofit’s educational and outreach programs and houses offices for its staff. Completed in late 2014 and LBC-certified in the spring of 2016, Brock is the first commercial building in the continental U.S. per- mitted to capture and treat rainfall for use as drinking water.
The toughest part of realizing this rain-topotable- water system, according to Greg Mella, SmithGroupJJR’s director of sustainable design, was devising a waterworks that would satisfy the requirements of Virginia’s Department of Health and its Office of Drinking Water, but was scaled appropriately for the building’s modest size and would be easy to maintain. In the resulting system, rainfall is captured from about half of its 10,000 square feet of arced and sloped standing-seam roofs and stored in two 1,650-gallon cisterns. The water then undergoes numerous filtering and disinfecting steps, including treatment with UV light and ozone, and—at the insistence of local authorities—chlorine, before it is supplied to the low-flow fixtures, including bathroom and kitchen sinks, water fountains, and a shower. (Instead of conventional toilets, Brock has composting ones.) Once used, the relatively clean wastewater from the plumbing fixtures, known as graywater, along with excess runoff from the roofs, is piped to rain gardens. These landscaped depressions naturally filter the water and allow it to slowly infiltrate into the ground.
The Brock project team was not the first to try to permit a potable-rainwater system in a commercial building. Several years before, the Bullitt Center in Seattle (RECORD, June 2013) covered the same ground. But the Miller Hull–designed 52,000-square-foot, sixstory office building, completed nearly four years ago, does not yet have the necessary regulatory approvals to begin using the rainfall collected from the structure’s roof and stored in a 56,000-gallon basement cistern to supply showers, sinks, and drinking fountains. In the meantime, the center has an exemption from ILFI allowing it to rely on the municipal utility for its potable water and still satisfy the certification system’s water requirements (the building received LBC certification in 2015).
The foundation has made progress toward obtaining the permissions needed to make Bullitt’s rainwater system operational, but one problem has yet to be resolved: the lack of National Sanitation Foundation (NSF) certification of the already installed rooftop photovoltaic (PV) panels as part of the drinkingwater- catchment system. Because of its commitment to the concept of rainwater reuse, the client continues to work with the PV manufacturer on a retroactive NSF designation, even though the building has already earned its LBC designation, says Jim Hanford, a Miller Hull principal. The foundation has been “pugnacious” in pursuing net zero water, he says. “It’s pretty impressive.”
Regardless of the outcome of the Bullitt’s efforts to obtain a permit for its rainwater system, the building can claim several waterrelated innovations, including the world’s first six-story composting system. The building’s overall water consumption is also remarkably low—only 1.1 gallon per square foot over the past 12 months, compared to a 14-gallon-persquare- foot average for Seattle office buildings. But more important, the project has spurred significant regulatory changes. One “triumph,” says Sturgeon, is a set of new city- and stateapproved standards for graywater established as a result of the project. These allow the water from the showers, drinking fountains, and sinks to be treated by a constructed wetland on one of the building’s terraces and then infiltrated through a street-level planting strip instead of being drained to the sewer. If widely adopted, the approach could help relieve pressure on the city’s infrastructure, in addition to helping replenish groundwater aquifers.
Some regions seem especially receptive to the LBC and its water-conservation imperative. In Western Massachusetts, there are four completed projects pursuing certification or already certified: Smith College’s off-campus Bechtel Environmental Classroom, in West Whately; the Class of 1966 Environmental Center, at Williams College in Williamstown; and the Hitchcock Center for the Environment and the R.W. Kern Center, both on the campus of Hampshire College in Amherst. Each building benefited from the regulatory successes of the previous project. “By the third one, the permitting process was almost routine,” says Christopher Chamberland, a civil engineer with the Northampton, Massachusetts–based Berkshire Design Group, which has been involved in some aspect of the water systems of all the area’s projects.
The four projects in Western Massachusetts depend on a handful of core strategies: all but Bechtel, which has a well, collect and treat precipitation for their potable-water supply; all purify graywater with devices such as constructed wetlands or rain gardens before reintroducing it into their sites’ natural hydrological system; and all have composting toilets.
In addition to being similar to each other, these projects’ water-conserving features are of course remarkably similar to those deployed at both Bullitt and Brock. But that doesn’t mean that the water systems are interchangeable. They must be tailored to the site and the climate, the program, and, especially, the architecture, says Chamberland. He points to the 17,000-square-foot Kern project, designed by Cambridge, Massachusetts–based Bruner/ Cott and dedicated in September. Almost every aspect of the concrete, stone, and timber structure, which serves as a campus social hub and houses administrative offices and classrooms, was the product of intense examination by both the architects and Berkshire Design.
Just one example of the many scrutinized elements are those relating to Kern’s roof, which is a critical part of the rainwater-harvesting system. The two firms studied details such as the optimal slope, the relationship between the overhang and the gutters, and how best to attach screens that help keep leaves and other debris out of the water. “The performance criteria can’t be separated from the architecture,” says Chamberland.
Such functional elements are important in any locale, but in dry climates, they take on heightened relevance. This was the case for Desert Rain, a recently LBC-certified singlefamily residential project in Bend, Oregon, designed by local firm Tozer Design. As the name of the compound of five wood-framed buildings with butterfly roofs implies, the project depends on precipitation for its potable supply and was one of the first in Oregon to take advantage of new state guidelines for rainwater harvesting.
Since Bend averages only 12 inches of precipitation per year, and in some years gets as little as 7, the Desert Rain team needed to capture every drop—even with a miserly water budget of 42 gallons per occupant per day, says Morgan Brown, president of Whole Water Systems, the firm responsible for design of the project’s water technology. (A typical budget is more than twice that, he says.) One innovation was the substitution of a device known as a first flush diverter, or FFD, which disposes of the initial runoff from a roof surface and any contaminants that come with it. Instead, Brown devised ground-level gravel filters positioned under each roof downspout. These remove unwanted debris while capturing up to 15 percent more water, he says.
In addition to rainwater harvesting, Desert Rain also took advantage of a rule for graywater reuse issued while the project was already under way. The system directs the water from sinks, showers, and washing machines through a constructed wetland for remediation before it is used for irrigation. Partly because of the newness of all the regulations and officials’ unfamiliarity with the proposed systems, the project took almost seven years to complete. “Normally we could have designed something like this in a few weeks,” says Brown. But he’s pleased to have been part of a project that broke new ground and takes its cues from nature’s water cycle, he says. “It’s the ultimate example of biomimicry.”
To earn one AIA learning unit (LU), including one hour of health, safety, and welfare (HSW) credit, read “A Thirst for More,” review the supplemental material listed below, and complete the online test. Upon passing the test, you will receive a certificate of completion, and your credit will be automatically reported to the AIA. Additional information regarding credit-reporting and continuing-education requirements can be found online at continuingeducation.bnpmedia.com.
Toward Net Zero Water: Best Management Practices for Decentralized Sourcing and Treatment (Executive Summary and Introduction)
By Cascadia Green Building Council
1 Explain why water conservation is important even in regions not prone to drought.
2 Describe the goals and the structure of the Living Building Challenge.
3 Identify the elements in a potable rainwater-harvesting system.
4 Discuss some of the regulatory challenges sometimes encountered by projects trying to implement ultra water-conserving strategies.
AIA/CES Course #K1703A