It is more important than ever to continue efforts to help others understand the need and importance of conservation.
Without a lot of fanfare, there has been a shift in the tide. Constituents are taking a more holistic approach to water and energy-related issues. As you’ll learn, traditional methods are no longer the game plan.
This article serves as a quick-and-dirty look at water conservation. It will inform about the health of our current water supply, give a brief overview on important water legislation, review a variety of strategies and techniques for irrigation and stormwater management, and conclude with real-world applications. As a seasoned Landscape Architect, it is my job to equip readers with good information so that they can make better, more informed decisions.
At the opposite end of this discussion, however, is energy. Pulling at precious water resources is the need for more energy. Water is needed to generate energy. Energy is needed to deliver water. Getting these two limited resources to coexist without giving one up for the other is tricky. This will be discussed in a later piece.
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Photo: LPA Inc.
South Tahoe High School engages students with sustainable buildings and water-efficient landscapes, which culminate with curriculum that complements these themes. |
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Photo: LPA Inc.
This passive park doubles as a Bioswale, which collects runoff. |
Change Factors
So, what impacts our water supply? One of the main factors is climate change. Under this umbrella, one finds themes like rising water levels, the national drought, wildlife species management, and sensitive species water allotments, to name a few. Population growth is another factor that affects finite resources, migration patterns, and our infrastructure. Infrastructure built back in the 1800s and early 1900s is showing its age and inability to deal with modern-day pollution and strain induced by time and exponential growth. Keep in mind that, according to the US Census Bureau, our nation will reach the 400 million mark by 2039.
Droughts also play a key role in the state of our current water supply. It seems like every time I check the drought monitor (found at http://drought.unl.edu/DM/Monitor.html), it gets worse and worse. If one looks now, they can see the entire West Coast, with a few small exceptions, is in a drought. All of Texas, a lot of the Midwest, and even portions of the East Coast and Florida, that traditionally have never had an issue, are suffering.
In the state of California, where I live and work, a good portion of the state is in the severe drought category. We just don’t have enough water. Earlier this year, our governor, Arnold Schwarzenegger, declared a state of emergency and pleads with Californians to save water. “Even with the recent rainfall, California faces its third consecutive year of drought, and we must prepare for the worst—a fourth, fifth, or even sixth year of drought,” he says. “…This is a crisis, just as severe as an earthquake or raging wildfire, and we must treat it with the same urgency.”
In terms of cost, it’s estimated that in the next 25 years, the US and Canada will need 3.6 trillion dollars to maintain the water supply system. If you look at the stimulus package that was just passed, this is three times that amount. This only includes water the US and Canada will need to maintain and keep up with current water systems.
As expansion and development continue, and cities and states lack the resources to finance such expedient growth, others are being asked to contribute. School districts come into new areas to build and are now asked, more and more, to wear more of a “developer” hat. Meaning, they’re asked to build the sewage and water systems to supply new school sites. Times are changing and districts are reaping the costs and burdens that accompany this change.
Legislation Cliffs Notes
If one gets nothing else out of this piece, here are the two major pieces of water legislations to be familiar with, AB 325 and AB 1881.
According to Lance Sweeney, president of Sweeney and Associates, AB325 was the first attempt at establishing a scientific method for the determination of water use in landscapes. Before AB 352, most other methods were based on unscientific, knee-jerk reactions. If people are told to water only two days a week, they simply watered more on those two days. Results included over watering, which lead to excess runoff that lead to evaporation and deep percolation—when water moves down through the soil and below the root zone where it cannot be utilized by plants.
The AB 325: Model Water Efficient Landscape Ordinance established a maximum amount of water that should be applied to the landscape of any project. They did this by using evapotranspiration (ET) as the basis for their water calculations. They also made some assumptions as to how they would modify the ET to reflect the planting and irrigation aspects of the average landscape. The biggest affect that AB 325 had on landscape design was that is severely limited the amount of turf that could be used on a project. It also encouraged the use of more efficient irrigation methods such as rotors and drip irrigation.
“Where AB 325 fell short was that the majority of local agencies did not use the ordinance,” explains Sweeney. “By law, local agencies could submit their own water conservation plan and opt out of using the state’s model ordinance … local water ordinances could be anything the local agency decided on, even if it really saved no water at all.” There was no requirement for local agency regulations to conserve water as in the state’s ordinance. Enforcement was minimal or nonexistent in most cases.
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Photo: LPA Inc.
An LPA-designed green roof at Ford’s Premiere Automotive Group North American Headquarters in Irvine, CA |
Then comes AB 1881 that goes into effect January of 2010. AB 1881 is designed to improve upon AB 325 (1993), and requires local agencies to adopt water conservation plans that are either more effective, or as effective, as that of the state’s. “Local agencies have until January 31, 2010 to either tell the state if they will be using the state’s ordinance or submit their own, along with supportive documentation indicating whether their ordinance is as water conservative as the state’s,” continues Sweeney.
AB 1881 establishes a new ET adjustment factor (ETAF) of 70%, which assumes a higher irrigation efficiency of 71% versus the older measure of 62.5%. New mandatory design elements, and regulations require landscape plans to indicate hydrozones and special landscape area (SLA). SLA is defined by all edible plants, recreational turf, or areas served by recycled water. These areas may receive substantially more water and since recycled water is common in many areas, its use means that greater turf areas and higher water use plants can be employed.
“Defining turf areas as active play areas will be important for schools, since they often have higher percentages in their landscape because turf areas are essential play and assembly points,” continues Sweeney. “Landscape architects and irrigation consultants must be familiar with these developing regulations as new technologies such as smart controllers and subsurface drip irrigation will need to be incorporated into each design. Balancing the need for drip irrigation with the necessity of vandal proofing the irrigation system will be challenging.”
One final note about AB 1881, readers should know that it establishes a branding system for irrigation products that shows their water conservation status. Wasteful irrigation products will be banned from sale, and, at the time this article is written, we have not seen much of what this will look like.
Diverse Strategies
There are various strategies for coping with stormwater. The main categories comprise mechanical and natural systems.
When it comes to mechanical systems, one can basically stick a machine in the ground and have a site’s water flow through it. It’s no different than having a filter for a car or air-conditioning system. These tanks and filters mimic a natural process in a much more confined system. Drainage structure inserts are basically baskets that go into each catch basin to collect pollutants. The mechanical system one uses also depends on the pollutants; there are different filters that deal with specific pollutants, and they can be designed to catch anything from cups to oil.
For larger projects, sites, or buildings, projectwide storage treatments are used. These are large tanks—large enough for people to walk around in—mainly used for building systems. A large facility may have one or two. Maintenance issues can be a deal breaker, however, as someone must constantly change the filters, otherwise they don’t work. The frequency of cleanings could be monthly, annually, or semi-annually—end users won’t know until they occupy their site and gage the amounts and types of pollutants coming in.
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Photo: LPA Inc.
Natural systems—such as bioswales, green roofs, and innovative design ideas—slow water that leaves the site, by restoring, cleaning, and treating it. |
When you’re dealing with school sites, there’s another level of difficulty, because reduced budgets often mean one person is responsible for the maintenance of an entire site—everything from vacuuming floors, to making sure toilets flush properly, to now changing these
filters. It often doesn’t happen, the systems fail, and everything is rendered useless. There is a place and application for these, but they aren’t necessarily the best management strategy, because, again, the maintenance is a nuisance.
Better strategies are experienced with more natural systems. Natural systems mimic what nature does already. It is a cyclical cycle, so one never really runs out of water. Our goal is to slow water that leaves the site and restore, clean, and treat as much of it as possible. Natural systems used to achieve this include bioswales, paving strategies, green roofs, and innovative design ideas.
Bioswales. With a bioswale, excess water is washed into an often-depressed area and runs through plant material that removes fertilizer and other pollutants. Paving strategies include permeable pavement, precast pavers, permeable asphalt, permeable concrete, and creating soft versus hard surfaces, to name a few. Where the water hits is where we want it to go into the ground, and where we want it to restore itself.
Green Roofs. Green roofs are another natural stormwater management strategy. Believe it or not, roofs are incredibly pollutant causing, especially in large commercial developments or schools with gyms and multi-purpose rooms, or structures with huge roof spans. They generate heat and collect dust pollutants and dirt from air-conditioning systems. Roofs take all of those pollutants and flush them into the stormwater management system, usually without treatment. Green roofs provide a wonderful alternative. Benefits include a cooler roof which means reduced energy demands inside, the production of oxygen through vegetation, and, if properly done, the reuse of water for irrigation or other water-related needs.
Similar to stormwater, irrigation requires its own batch of solutions. Strategies include drip irrigation, smart controllers, recycled water, and rain harvesting.
Drip Irrigation. When one thinks of drip irrigation, they think of little tubes that run to each plant and drop little amounts of water on them. This works in many situations but it is not what we’re proposing for schools because, from a maintenance standpoint, it is a labor-intensive process. Subsurface drip irrigation proves a much better option. Systems with sub-injected tubing have emitters that are placed on or below grade, and spread water out over an area. Users experience a significant reduction in the amount of water usage—especially over a spray system. Plus, less water is lost to evaporation and even less is bounced off the hardscape.
Smart Controllers. Smart controllers are another possible option. Based on the amount of water that actually hits the ground and is usable by plant material, these controllers work off ET data downloaded daily from the Internet. Satellites communicate with smart controllers so they can automatically adjust the amount of water used in response to changing weather conditions. From a maintenance standpoint, smart controllers are great. A facilities manager can log on from home, office, or anywhere he can get on the Internet, and review all of his zones, and easily identify problems. He or she can then fix that zone and have the assurance that the rest of the system is running properly. In terms of costs, smart controllers cost a fraction of what a central control system costs, because one is not buying a weather station for
the site.
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Photo: LPA Inc.
Green roof benefits include reduced energy demands inside, the production of oxygen through vegetation, and the reuse of water for irrigation. |
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Photo: LPA Inc.
Water-efficient landscape inspires learning at a Child Development Center in Chula Vista, CA |
Recycled Water. Recycled and reclaimed water are a no brainer. Most facilities are starting to get that. Newer areas are starting to get reclaimed water; it is a matter of pushing jurisdictions to bring water to their areas. We did a park recently where, at first, there wasn’t any reclaimed water. After a little bit of research, we found a reclaimed water line nearby and between the city and the water district; we were able to extend that line to the park. Now, the park is irrigated with reclaimed water, and it would have never happened, had we not been the catalyst.
Rain Harvesting. Rain harvesting refers to the collection and storage of rain. In certain parts of the country, it is absolutely appropriate and works wonderfully. In other parts, like here in southern California, it is a little more difficult because our water is concentrated in such a short amount of time. We have three months where we get 90% of our rain, and it’s really not that much rain. Collection usually happens on the roof, and the water can be recycled to meet other needs.
Sustainable Sites. Rather than discuss each nuance behind design options or standards—whether it be the US Green Building Council’s Leadership in Energy and Environmental Design (LEED) criteria or educational standards such as CHPS—it’s fair enough to say there are two main ideas in common: control runoff and clean the water. Both basically require you to keep as much of your water onsite as you can. If you have a new development, don’t increase the amount of water flow off your site prior to and after your development. Any water that now leaves your site must also be cleaned either by a mechanical or natural system.
Snapshots of Success
To get a better sense of what water efficiency looks like in a real-world setting, I’ll share two examples both from my home state of California.
The Brea Sports Park in Brea, CA, is a 26-acre sports complex that incorporates bioswales, a low-flow bypass system, and sub-drainage systems for starters. We creatively dealt with water treatment onsite by using the athletic fields as a drainage mechanism. Each field has 6-inch sand layers and sub-drains underneath. When soil and sub-drains can no longer percolate, only then does water pass to the storm drainage system. At this point, it has been cleansed by the sand layer that naturally removes pollutants.
The existing blue stream—a dilapidated ditch with pollutants, cans, rats, etc.—designated by the Army Corps of Engineers, was surpassed for a wetlands area toward the top of the project. This passive park, used less during the winter, doubles as a bioswale. Environmental consultants helped with the selection of true, native grass species that deal with water filtration.
An additional water-related challenge presented by this site, was that water came in from several hundred acres north. A bypass in the park’s drainage system diverts the first flush of rainfall, filters and cleans it, then allows it to leave. Natural strategies like these do not require extra cost or maintenance; they’re more about smart design.
When sharing this sports park, I often get the question about synthetic turf. There are two main reasons why we did not use it on this project. First, the cost was prohibitive. Second, there can be maintenance issues when synthetic fields are open to the public; there is no control over gum, food, dogs, etc. Since fill material is derived from used tires and other recyclables, synthetic turf can be a sustainable option if designed and implemented properly. Water savings can be experienced, however this depends on how turf is managed, mowing, application of pesticides, etc.
In a separate project for a high school in South Tahoe, CA, the site calls for a mix of mechanical and natural systems. Located deep in the woods of this lake community, South Tahoe High School is home to more than 1,300 students. It is the district’s only comprehensive high school, and part of the city’s plan is to encourage students to preserve the environmental balance, scenic beauty, and recreational opportunities of the Tahoe Basin.
When the portion we have designed is built, stormwater treatment chambers and infiltration trenches will pair with onsite retention strategies and increased vegetation to manage their water efficiently and effectively.
When I work on projects like South Tahoe, where they equip and teach students about conservation of their natural resources, it fuels me. I see that gradually, as a nation, we are beginning to grasp the urgency of our situation and are moving away from the notion that water should be cheap or free. For school districts, this presents an opportunity for community outreach and education programs. Creative solutions must arise to engage students and involve them in conservation that gives rise to a more sustainable outlook for everyone.