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Wednesday, July 07, 2010
Designing a Water Efficient Community in Central Washington State
As for your request for new approaches to water efficiency, I’ve been designing a 10-home residential project near Yakima, Washington, where we are trying to address water issues in a responsible way. It’s still in the design phase, so some of the features may, by necessity, change based on the builder’s ability to keep costs down and ultimately be able to sell the homes for a certain price and with certain features. Check out the project website.
Water and Low Impact Development Strategies
The site averages about eight inches of precipitation annually, about half rain, the rest snow (note this is really a high desert location!). The area has hot summers, cold winters, and a steady (drying) wind from the west, with 300 days of sun per year. The land for this home site is not arable and most of it (40+ acres out of ~52) will remain as common open space, without fences so that wildlife can roam freely.
Constructed wetlands will naturally treat graywater waste – from bathtub, shower and sinks and toilets depending on whether or not a home has the solar composting variety – using gravel and plants to filter non-toxic impurities. We are working with a company called Whole Water Systems. The constructed treatment area will cover only 2,500 sq. ft. of the site and remain “natural” with plants.
The homes are designed to accommodate solar composting toilets; bathrooms are located at two corners of the building with southern exposure, oriented so that even where homes are facing off-south, the toilet’s collectors would be sufficiently exposed to the sun to do their work. As the solar composting toilets are a sort of unknown in the market, the builder will offer them as an option. For many months, I’ve been communicating with SWSLoo on the Eloo system which appears to be the best choice for our uses. These toilets use the sun to efficiently turn waste into compostable material, are low-maintenance and have no smell; with Yakima’s 300 days of sunshine per year it totally makes sense to adopt this technology here. It may be that the first ‘spec’ house has conventional ultra-low-flush or dual-flush toilets, but a later home will be able to act as a prototype for the solar composting toilet.
We have an appropriate, simple roof for collecting rainwater. Made of standing seam metal to keep the water cleaner, it slopes to the south and north. Rainwater and snow melt will be captured in rain ‘barrels’ to be used in raised beds or on trees. The rainwater collection tanks will be stored under the deck on the north side of the homes, out of the sunlight to keep it cooler and, we hope, freer of algae development. Annual precipitation is about eight inches, but only half that is rain. Preliminary calcs, using rainfall only, show that the roof could yield about 37,000 gallons over the course of a year. However, the rain falls in large quantities, quickly, so the storage tank needs to be fairly large in comparison with the annual rainfall. We are looking at maybe 1,000 gallon storage tanks. (Editor’s note: it’s probably better to run some of the water directly to plants than to build a very large tank that is almost never full).
Low-flow fixtures will be installed inside the homes for faucets and shower heads. Plus we’ll use Energy Star-rated appliances such dishwasher, clothes washer and dryer that conserve water.
Community rules will require all-organic site and vegetation treatments. Even though there is not much water on-site, it is important to keep that water healthy and free of toxins. In Washington State, phosphates are a typical water pollutant, often from fertilizers and detergents. Landscaping will remain native except for raised-bed gardens so that no permanent irrigation system will be in place. Watering can be very targeted and specific to the raised beds, and possibly to some added fruit trees. The rest of the land uses only what falls naturally on the site.
All homes will have solar hot water. While this is not exactly a water conservation measure, plans are to educate homeowners in their new systems so that they understand the limited water resources and how their systems use the sun passively to provide domestic hot water. The solar collectors will be located prominently on the south-facing roof, that is also the entry side and visible to the community – reminders to the residents that the water in their homes is part of a renewable energy system.
Look for more information on Rocky Top Living in the next year or two!
Posted by Jerry on 07/07/2010 at 02:58 PM
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Green Building News • Water Efficiency • PermalinkEcoBroker in Colorado spearheads MLS listing of green features of homes
About five years ago, CoStar began putting Energy Star and LEED status into listings for commercial real estate, so that brokers tasked with finding green real estate for clients could do so more easily. Now Ashby reports that she has spent that last couple of years being involved with development of a green building program and as one of my roles on that committee she took on the greening of the MLS system in the area. Now she can report that this was recently accomplished and it will now give sellers the advantage of identifying their features accurately. Buyers seeking energy efficiency and sustainable design will be able to have their agents better refine the search approach. Change is not easy but after much determination Ashby was pleasantly surprised with how it was finally implemented. There is also a glossary for those that want to learn more. Think of how the sales of green homes could accelerate if every EcoBroker made a similar effort to have the local Board of Realtors revise the MLS to include green features and attributes, along with the number of fireplaces, bathrooms and “elegant” dining rooms!
Posted by Jerry on 07/07/2010 at 02:21 PM
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Green Building News • PermalinkMonday, July 05, 2010
Omega Center for Sustainable Living: The First to Achieve Living Building Status?
The Omega Center for Sustainable Living aims at net-zero water use on an annual basis, one of the key requirements of the Living Building Challenge.Courtesy © 2009 Farshid Assassi.
The OCSL is a new 6,200-square-foot facility that serves not only as a laboratory classroom but also as a wastewater filtration facility. The heart of OCSL is a hydroponic biological wastewater treatment system, the Eco Machine, located inside the 4,500-square-foot-greenhouse. The Eco Machine consists of anoxic tanks, constructed wetlands, lagoons, sand filters and large dispersal fields that can process up to 52,000 gallons of wastewater a day. The treatment process is primarily gravity-fed and requires minimal energy to operate. Purified water output is used for irrigation and toilet flushing throughout the campus.
OCSL is aiming for both LEED Platinum certification and designation as one of the first projects to meet the Living Building Challenge (LBC). A restorative or regenerative building approach, LBC projects go “beyond LEED” and generate as much or more water and energy than they use, returning any excess back into the landscape and into the grid.
LBC has 16 prerequisites that a “living building” must meet, of which two deal with water: The first specifies that all occupant water must come from “captured precipitation or closed-loop water systems.” The second requires that all stormwater and building water discharge are managed onsite. LBC projects must demonstrate not only that they meet the rating system’s 16 design and construction criteria, but also that meet the criteria during actual operations for at least one year.
The OCSL is helping to pave the way for net-zero water and Living Buildings to enter the building stock. Let’s hope that the wisdom of what works and what doesn’t, along with the enlightened insights from these pioneering projects, will be incorporated into many more projects.
Posted by Jerry on 07/05/2010 at 03:56 PM
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Green Building News • Water Efficiency • PermalinkFinding the Payoff in Rainwater Harvesting
At the LEED Silver-certified Tacoma, WA, police vehicle maintenance facility, two 4,800-gallon culvert tanks collect rainwater and recycle it for toilet flushing. Courtesy of TCF Architecture, Tacoma.
Target Field, the new home of the Minnesota Twins, features an advanced rainwater harvesting and reuse system, the largest to date in professional
sports. Courtesy Wayne Kryduba.
The problem lies often in cost-benefit analysis of rainwater collection systems compared to most potable water prices, which are still quite cheap in the U.S. Using a ten-year cost analysis for a rainy U.S. climate, the rainwater collected over the ten years would cost approximately $4.55 per hundred cubic feet (CCF), which is higher than average water rates in most U.S. cities (but not necessarily higher than the highest-tier rates). The system wouldn’t quite pay for itself just with water savings because the added cost of extra plumbing to convey the water to the points of use hampers overall cost-effectiveness.
Although first-costs are higher than conventional systems, in new buildings rainwater collection systems could potentially eliminate expensive charges for storm-drain hookups, putting an owner “money ahead from Day One,” where the costs of savings are greater than the installation cost. In one project in which I was involved, just the cost of installing the storm drainage pipes to take water off the site and to connect to the town’s storm drains was greater than the cost of installing two 20,000-gallon tanks to hold runoff from the 100-year rainfall event and providing a treatment system that generates enough water for toilet flushing for a good part of the year. In addition, the use was for an academic building whose use pattern just about matched perfectly the annual rainfall cycle of the West Coast.
If seasonal and annual rainfall continues to be more erratic, water rationing and higher prices will be likely, making rainwater harvesting a rational economic response especially for large users. I harvest a few thousand gallons a year of rainwater at my house in southern Arizona, and I can tell you that nothing could be easier (or more sustainably satisfying) than using recycled rainwater for plant irrigation in a dry climate.
Posted by Jerry on 07/05/2010 at 03:49 PM
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