The Seattle 2030 District, a public-private collaborative working to create a groundbreaking high-performance building district in downtown Seattle, has developed guidelines to encourage developers to take action on stormwater management, which is becoming a greater issue as climate change leads to more days per year of substantial rainfall. Heavy storms overwhelm existing water-treatment systems, causing untreated water to overflow into local waterways.
District guidelines require newly constructed buildings to keep stormwater discharge 50 percent below the current district average in their designs. Existing buildings must implement retrofits to achieve the 50 percent reduction by 2030. Although the guidelines only affect buildings within the district — 11 neighborhoods in and around downtown Seattle — other communities are taking action as well and coming up with their own site-specific solutions to stormwater management.
The Sheraton Seattle downtown is finishing the design on a project that will divert rainwater from its roof to a storage tank for filtering, sanitizing and ultimate use in the hotel’s laundry operation. The Sheraton is working with Seattle-based Herrera Environmental Consultants on the filtration and pumping system design and is evaluating bids to find a certified mechanical contractor to complete the work. The goal is to install the system by this fall.
Rodney Schauf, director of engineering at the Sheraton, believes Starwood Hotels — Sheraton’s parent company — may follow suit with similar efforts to reuse stormwater in its properties nationwide. The result is attractive from financial and environmental standpoints, as it allows the hotel to buy less water from the city.
Seattle’s little wing Office Building on Sixth Avenue houses the administrative offices of the EMP Museum and demonstrates that creating a green infrastructure doesn’t necessarily cost more money than more established methods and can actually save money. Vulcan Inc., the property owner, is one local developer taking a lead in implementing environmental consideration into its designs.
The Little Wing design includes a sloping green roof that filters rainwater and also keeps the building cooler in the summer. Runoff from the roof is filtered and either stored in a 9,000-gallon tank for later use or distributed immediately into the building to supply the sewage system.
Theoretically, the system can save up to 89,000 gallons of water per year; actual data show results closer to 60,000 gallons. Installing the green roof and outdoor storage tank for about $180,000 eliminated the need for an underground detention tank and a secondary storm/sewer discharge connection below the street, which would have cost about $250,000.
The Little Wing building is also Salmon-Safe certified, which means it has met a list of performance requirements that aim to minimize the impact of urban development on the environment and enhance salmon habitat. Standards cover stormwater management, water use, water quality protection and more. Vulcan’s aim is to certify all its properties as salmon safe.
Over in north Bothell, Clearwater Commons, a small, eco-friendly residential development, has a goal of achieving zero discharge. All stormwater is infiltrated on site. The houses stand on pin foundations so rainwater that isn’t sent to cisterns flows underneath the buildings and soaks into the ground, making the houses look more like cabins in the country than suburban homes a quarter-mile from a main road.
None of the houses have basements or garages. The “road” running down the center of the development is made from drivable grass — square bricks with greenery growing between them and sand underneath — and is intended primarily as a pedestrian path with access for emergency vehicles. Residents park their cars in a lot at the front of the development, much of which is covered in permeable pavement.
Permeable pavement absorbs rainfall that would otherwise flow into storm drains, but it suffers from certain drawbacks, such as not being durable enough to be used on heavily traveled roads. Collaboration among the Boeing Company, WSU and the Washington Stormwater Center led to a pilot project using discarded carbon-fiber composites from aircraft production to develop a stronger alternative to existing permeable pavement. Initial testing suggests the material absorbs water efficiently and does a good job of filtering toxic chemicals. More research is needed before such a product reaches the market.