Water and Sustainable Design - GreenBeams



Whitepaper:

Water Conservation Best Management Practices

By Amy Cornelius

Within the next 100 years…“Water will shape the full spectrum of economic, political and social trends, as well as how we make decisions. We will all begin to view water more as a precious resource rather than a free commodity to be exploited and wasted.” Steve Maxwell, The Future of Water: A Startling Look Ahead

ABSTRACT

Freshwater, a critical resource that is necessary to support life on the planet, is facing a crisis that has far reaching implications for human health, productivity and peaceful existence. The design community has significant responsibility and opportunity to influence the management of both potable, freshwater and rainwater in buildings and their surrounding landscapes. Through design, conservation measures that dramatically reduce consumption can be introduced with little to no difference in occupant comfort and through the introduction of ‘new’ technologies such as graywater recycling and onsite infiltration of stormwater, water consumption and its treatment can be further reduced. The Best Practices detailed in the article provide a guide for designers.

Water Conservation Best Management Practices

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Imagine you have a glass that is full of water. In that glass is all the water in, on and around the world, all 1.4 billion km³ of it. Only 2.5% of that water is considered freshwater. Of the 35 million km³ of freshwater:

• 70% is trapped in ice or snow

• 0.3% is in rivers and lakes

• .05% is in the atmosphere

• About 1% is usable fresh water – 350 thousand km³ or 0.03% of all the water in, on and around the world.

That is a limited resource!

Unlike oil, water isn’t finite. It replenishes itself through the earth’s climate cycle. Because of this it is often taken for granted. Also unlike oil, water is something all of nature needs to survive and something which we all have a very intimate relationship. We drink, bathe, swim in and enjoy water. The problem is that, given business as usual, in the next 20 years, world demand for fresh water will outpace supply by 40%. [i]

Also unlike oil, water is seen as a local resource and is consumed and conserved based upon the perceptions of its availability in a particular area. It is not valued as a resource shared with other geographic locations let alone with the whole world. In the US this leads to unbalanced approaches in code development for water management, classification and treatment. The Water Footprint Network is attempting to change people’s and industry’s valuation of water and to highlight its value as a resource in the hopes of developing balanced policy. That, together with education, may provide incentives to conserve in the future. Designer’s have the ability to immediately influence consumption.

Right now the world’s 6.8 billion people use 54% of the usable fresh water. But, according to the UN, even without outpacing supply, distribution of freshwater around the world is unequal to the point that many have no access to water: 1.5 million people die every year because of lack of access to clean, potable freshwater and/or poor sanitation. 1.6 billion people have no access to sanitation. Half of the people in the world who suffer from malnutrition, suffer because of water borne and sanitation related issues[ii] These are startling numbers. For Americans though they seem like far off statistics - problems in another place. Americans need to wake up.

In October 2010 Wall Street 24/7 reported [iii] the ten largest US cities (by population) that have the greatest chance of running out of water in the near future (less than 50 and in some cases 2-3 years): Orlando, Atlanta, Tucson, Las Vegas, Fort Worth, the San Francisco Bay Area, San Antonio, Phoenix, Houston and Los Angeles. These areas represent 6% of the US population. [iv] This is in an era where we are working mightily to reduce sprawl by providing incentives to induce people to move to the cities.

According to the World Business Council for Sustainable Development, “If a supply-oriented approach is taken to meeting the coming (potable water availability) gap, up to US$ 200 billion in investments per year will be required up to 2030. However, focusing on demand-side measures can achieve the same effect for US$ 50 to US$ 60 billion per year. This approach obviously leads to cost savings.”[v] Demand-side approaches are often times in the designer’s control. Given some simple design strategies, architects and designers have a tremendous opportunity to reduce water consumption and design ways for those in need to capture, store, clean and dispose of water in a safe manner.

According to the United States Geological Service, Americans use about 408 billion gallons of freshwater a day. [vi] The Environmental Protection Agency calculates that average per household consumption of an existing house is 190 gallons per day (gphd). [vii]

The residential water consumption patterns within the EPA’s 190 gphd estimate suggest a guide for architects and designers to focus on when making design decisions and setting water strategies for new construction and for renovation. Following are some recommended Best Practices that architects and designers can employ in residential construction and renovation. Based on an extensive review of conservation strategies developed and recommended by: certification organizations, water conservation groups, worldwide social organizations, trade groups and incorporated into municipal codes and policies, these Best Practices represent simple to specify and implement design elements that make major impacts. Labeled Residential Strategies (RS), the strategies can reduce water consumption and have the secondary impact of reducing household and utility electrical use. [viii]

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BEST PRACTICES – RESIDENTIAL

Minimum = should be considered building standard. No added cost or short payback.

Medium = not normal practice but easily part of a building system. Some added cost.

High = not currently normal practice. Code allowed. Added cost ranges upon type of system.

RS 1: Minimum - Specify Water Sense Construction Methodologies and Appliances

The EPA recently funded a study [x] which shows that significant inroads – a 42% decrease in consumption - can be made by specifying Water Sense standards (Appendix A – 2009 WaterSense Single-Family New Home Specification; EPA) for the whole house:

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The Water Sense standard includes:

• Construction pipe leakage testing

• Maximum service pressure of 60 pounds per square inch

• Hot water delivery that reduces wait time for delivery to tap

• 1.28gpf toilets

o LEED Homes - High-Efficiency is ................
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