Green Building Services

Recently the Green Building Services’ team of Ralph, Terry and I directed a week-long eco-charrette for the Oregon Sustainability Center, which is pursing the Living Building Challenge. For those not familiar, the Living Building Challenge is a standard that far exceeds current building practices and LEED criteria. Working through the concepts during the intensive eco-charrette, we looked past the steep requirements and questioned our own assumptions – and those of the Living Building Challenge – about what resource equity really means. On one question in particular, water became a focal point.

LEED encourages building owners and designers to lower potable water use and try to provide areas where rainwater is absorbed on site. LEED provides very specific, but incremental reduction requirements. The Living Building Challenge jumps over this practice with pre-requisites for net zero water (Prereq. 10: Net Zero Water) and zero storm water discharge (Prereq. 11: Sustainable Water Discharge). This means that the building and landscape will not use any water that does not fall on the site and storm water will not be drained away from the site in pipes. If a project is completed in summer months, you can fill up a cistern once to establish operations, but, in essence, the project will not be connected to the municipal water source. (There are temporary exemptions for areas where the code does not allow water reuse.)

On the surface, this pre-requisite of the Living Building Challenge would appear to be a wholly positive thing. But if we compare the natural hydrology of the site before any building exists, following the requirement without carefully considering its impacts could potentially cause harm. In theory, capturing all of the rain water that falls on the site to use on landscaping and in the building may mean that limited water is returned to the ecological surroundings. By taking this concept to a larger scale – if all the buildings in downtown Portland were to adopt this practice – there could be significant disruption of what should be the normal flow of rainfall into aquifers and rivers, which could have downstream impacts on salmon and other species. Likewise, if we jump from water to energy – if every building was designed to maximize solar collection area in site – the buildings might end up shading significant portions of adjacent sites and denying solar access to their neighbors.

This is not to suggest that the Living Building Challenge doesn’t offer an excellent framework, but we need to recognize that we cannot design in absolutes. The Living Building Challenge asks us to “account for downstream ecosystem impacts” but does not yet provide a metric to judge this by. Buildings must be considered within the context of their ecosystems, and we need to examine our right to hold onto resources.

At the Oregon Sustainability Center, the project team decided our best move would be to first use less water by reusing the rainwater in a variety of forms. We intend to take the cleanest water and cycle it down through the systems: capture it from the sinks to use in toilets, from toilets to use in irrigation. Not only does intelligent reuse of the rainfall allow the project team to minimize the size of the cistern, but fresh water still will be supplied to the aquifer.

In Portland we are fortunate to have plentiful rainfalls that make resource equity possible, but the climate in another city like Reno, Nevada, changes the playing field considerably. If the same solutions would not work on a single building basis, can we address them on a regional scale? What would happen if every building – commercial and residential – retrofitted with only low-flow fixtures? What if everyone used only native landscaping that required no irrigation? Could we achieve true resource equity by greatly reducing our water needs in the first place?

As we look at our resources – and how our claims on them impact the natural systems we rely on – perhaps a site-by-site approach is no longer feasible. The Living Building Challenge encourages scale-jumping, and in some locations this may be exactly what is required. Would a gravity-fed municipal water system, as Portland has, that introduced ecological means to purify the water without chlorine be more sustainable than many independent, building-by-building systems? Perhaps it’s time to think about how we can work collectively across a district or a city to ensure our resources serve all the components of life in the greater region.

By Alan Scott, GBS Principal, AIA, LEED Faculty