Water: An Underutilized Resource
Sometimes scarce, rainwater could be–and should be–managed more efficiently.
When it rains, our natural instinct is to take cover. We find a place to shield ourselves from getting wet, or if we planned ahead, we pull out an umbrella and keep moving ahead to get to our destination. It’s in our nature to avoid the rain, when really we should be seeking measures to capture it.
The Expo Line Phase 2 project’s landscaping design uses native drought-tolerant plant species and recycled water supplemented for irrigation to conserve potable water consumption, reduce stormwater runoff and promote a more natural state of biodiversity.nsert text here
We take for granted the free resource that is rainwater, which at times in the U.S. is scarce, and around the world is rapidly becoming a scarcity crisis.
If you live in California, Nevada or Oregon, for example, you know drought all too well. Even water-surrounded Florida has suffered from drought in the last decade. Here and in developed nations abroad, as the world population charges toward 9 billion, water represents a significant problem because of supply shortages, poor quality, or inadequate distribution and disposal systems.
Rainwater is a valuable resource that we should be trying to not only harvest, but seek to manage during times of heavy rainfall. Using strategies such as incorporating cisterns and bioswales into projects from the onset is environmentally responsible and can lead to cost savings if used in a holistic approach in building a sustainable structure.
The Cistern: A Water Steward
You have probably seen these barrels connected to downspouts in residential backyards. They collect rainwater runoff from the roof, which channels into the barrel and is stored for future use to water lawns and gardens, clean off gardening tools and wash cars. Cisterns help lower water bills, particularly in the summer months, by collecting a free resource. They are also important for our environment, helping to reduce water pollution by decreasing the amount of runoff contaminated by fertilizer and other surface chemicals that wash into streams and rivers. It’s a small and simple way to make a big impact for the environment and for cost savings. Using cisterns is a great way to become a good steward of your local community.
Rain cisterns are becoming more prevalent on construction jobsites too, and for various uses. For example, it is good conservation practice, and saves cost to use water runoff to clean equipment. Systems can be designed to capture rainwater for use in nearly any non-potable need within a building, ranging from the water to flush toilets to providing HVAC systems with water for cooling towers.
At the leading edge, district-scale solutions mean the water collected by a group of buildings can be redistributed throughout a community, and even treated locally. An elegant example of this is the Omega Center for Sustainable Living in Rhinebeck, N.Y. Moreover, every gallon of rainwater collected and put to use is one less hitting utility bills.
The construction industry has made great strides in building sustainable structures. It is simply the smart thing to do, for the environment and permanency of the building, as well as delivering long-term cost savings to owners.
Incorporating a rain cistern often can help a project on its way to LEED certification. It’s also an important strategy in the Living Building Challenge, the industry’s most rigorous performance standard, which requires net-zero environmental impact.
Chesapeake Bay Foundation’s Brock Environmental Center in Virginia Beach, Va., is one of the world’s greenest buildings. The 10,500-square-foot building is Living Building and LEED platinum certified and features solar panels, wind turbines, geothermal wells, composting toilets and rain cisterns, which capture water that is then treated for all potable uses. It is the first and only Living Building to date that has been approved by governing health officials for drinking.
The Bioswale: More in the Trenches
Rain cisterns at Chesapeake Bay Foundation’s Brock Environmental Center capture water that is then treated for all potable uses. It is the only building thus far approved by governing health officials for drinking.
Bioswales, which are most often seen in large parking lots and major roadways, are designed to manage rainwater runoff. These linear trenches, which are vegetated with plants that can withstand heavy watering and drought, allow for the collection, filtration and infiltration of storm water. They also help prevent overwhelmed sewers from discharging waste into streets and waterways during storms.
In practice, these systems can be incorporated into building and infrastructure designs to lower the need for irrigation and, in rain-prone areas, potentially eliminate the need for irrigation systems. Of course, it comes with the added benefit of easing erosion and even property damage from flowing stormwater and flooding.
The Expo Line Phase 2 project in California, which is the extension of the light rail service from the current terminus in Culver City to Santa Monica, has incorporated a bio-filtration system, which has similarities to a bioswale. The landscaping design was installed along the alignment and adjacent to the Expo Line bike bath. The project, which received Envision Platinum certification from the Institute for Sustainable Infrastructure (ISI) and is the first transit project to receive the certification, had a calculated potable water savings of 27 percent below industry standard.
Rain gardens, a concept that is sometimes used interchangeably with bioswales, are seen in urban and residential settings. These are similar, but smaller systems for intercepting storm water that would otherwise flow onto city streets, again managing and making use of a free resource.
In buildings, this can go beyond solutions on the ground level. Green roofs have a number of benefits, but one of the most obvious is catching and retaining rainwater like their bioswale counterparts, slowing discharge so that stormwater systems aren’t overwhelmed during major storm events. In cities like Washington, D.C., that have combined storm and sewer systems, slowing down the flow keeps sewage from overflowing into waterways. As the built environment grows, permeable surfaces are needed to collect and manage rainwater. Green roofs are a great way to do just that.
These strategies to harvest and manage rainwater runoff share two common elements: They are cost effective and environmentally beneficial. Rainwater is a free resource that we take for granted, but that needs to change. We need to be advocates in our local communities. The buck stops here.
Elizabeth Heider is chief sustainability officer for Skanska, U.S.A. The company specializes in construction, civil infrastructure, public-private partnerships and commercial development initiatives.