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SUPPLY AND DEMAND IS A concept familiar to any good businessman. The more people want something, the more they’ll pay to get it. It’s as simple as that. Nothing illustrates this more clearly than the mind-numbing high oil prices that have become a constant in this day and age.
But oil is not the only natural resource that has recently skyrocketed in value. Over the last half century, the demand for water has tripled. Explosions in population and the depletion of existing sources of the resource have created a demand for water that is proving difficult to meet. According to the American Groundwater Trust, 3.3 billion people world-wide will experience water scarcity by 2025.
Because water is becoming increasingly scarce and increasingly expensive, you would probably be pretty skeptical if someone told you that large supplies of it could be had for free. Remarkably, this is not far from the truth. Harvesting rainwater allows contractors, property owners and municipalities to literally create their own water supplies that can be used in place of potable water for irrigating landscapes, etc. Depending on the size of the system being used, gallons and gallons of rainwater can be harvested and stored. By some estimates, one inch of rain on a 2,000 square foot roof generates more than 1,000 gallons of water. Given the dire nature of the current water crisis, it is unacceptable to let this water go to waste.
Throughout the world, countries, cities and states are realizing the importance of harvesting rainwater. Australia, a country where constant droughts have become a way of life, has implemented rainwater harvesting on a large-scale as a solution to water shortages. Many state governments in Australia require new homes be designed and built with the latest energy and water-efficient products. Capturing rainwater is mandatory in some of those areas. Consequently, collecting rainwater and storing it for reuse is becoming a common practice in South Africa, Bermuda and many other parts of the world.
Rainwater harvesting is not only practical in places where there are water shortages. The trend is becoming increasingly popular in locations where there is an abundance of water. Too much water is a problem because it can overwhelm a city’s stormwater infrastructure, causing sewers and septic systems to deliver raw sewage and other pollutants into lakes, rivers and streams. Instead of spending countless dollars to upgrade antiquated systems, municipalities are providing incentives to consumers and businesses to capture water that falls on their properties. In Portland, Oregon, the Downspout Disconnect Program encourages homeowners to disconnect their downspouts from the combined sewer/stormwater system and then use roof runoff to irrigate their landscapes. The city will do the work for free, but homeowners who do it themselves can get a $53 reimbursement. More than 42,000 homeowners have participated, removing 842 million gallons of roof water per year from the combined sewer/stormwater system.
Another northwestern city that is harnessing the potential of rainwater for reuse is Seattle. Famous for a wet season that never seems to end, the city is becoming known for its cutting-edge approach to rainwater catchment systems. Many of Seattle’s newer municipal buildings were designed with measures intended to limit the use of potable water. Seattle City Hall, a 20,000 square-foot structure that was completed in 2003, includes a rainwater harvesting system for toilet flushing and on-site irrigation. Because this system is in place, peak flow from the city’s drainage system is reduced and water quality is improved because pressure on the city’s sewer system is lessened. In addition, stormwater runoff has decreased by up to 75 percent and indoor potable water use is reduced by 30 percent.
As the trend towards water sustainability continues to grow, local and state governments throughout the country are cracking down on the use of water for irrigation. Outdoor water use is estimated to account for up to 50 to 70 percent of a household’s total water consumption. Many officials find this to be an unacceptably high percentage. As a result, more and more municipalities are implementing mandates restricting or totally eliminating the use of water for irrigation. These restrictions, which are becoming increasingly common, have created a need to find ways to irrigate that don’t rely on potable water. A rainwater harvesting system is proving to be one of the most practical ways to fulfill that need and is gaining more traction. Harvesting systems used for irrigation come in a variety of shapes and sizes. They are built using a myriad of materials and can be buried underground or attached to the side of a structure. However, aside from a few minor differences, they all function in basically the same way. Typically, rain is diverted from a catchment area into a filter where the “first flush,” or the very first rain to fall into the catchment area, is filtered and diverted away from the main storage tank. After the rainwater is filtered, it is diverted into a cistern where it is housed until it is pumped into the irrigation system. Not all systems contain a pump. In more basic units, a hose can be connected directly to the tank, allowing for manual irrigation.
It’s important to remember that rainwater catchment systems used for irrigation are similar to traditional irrigation systems. The only major difference is the source of the water. “The irrigation system is basically the same, the difference is that the water source is rain. The piping, the sprinklers and the layout are all the same,” says Brian Vinchesi, president of Irrigation Consulting, Inc., Pepperell, Massachusetts. Of course, there are some things you should be aware of prior to installing a catchment system. One of the nice things about rain is that it is a relatively clean source of water. For the most part, it requires a very limited amount of filtering. However, it’s essential that the first flush does not enter the main storage area. “It’s really important that the very first water that hits your catchment area is diverted and filtered” says Mike Ray of Bushman, a manufacturer of rainwater storage tanks. “This water can contain fecal matter and other contaminants, so it’s not something you want entering your storage area.”
To ensure that the first flush water is properly handled, Ray recommends equipping harvesting systems with two items. “When you install a harvesting system, or are building one of your own, there are two things that should always be included. The first is an inlet strainer and the second is a flush diverter,” says Ray. An inlet strainer is usually the first part of a harvesting system to come into contact with the rainwater. Positioned directly beneath the rain gutter, inlet strainers prevent large contaminants, such as leaves and twigs, from entering the storage tank. Flush-diverters capture the contaminated water after it passes through the inlet strainer, allowing the clean water to travel to the main storage area. Flush diverters come in a number of forms but are usually vertical tubes with a valve at the bottom.
When the valve is released, the contaminated water is dispelled, making room for the next batch of first flush water. Before beginning installation, it is also important to determine how much storage capacity will be needed. Geography and budget will help to make this decision for you, but, according to Vinchesi, there are four things that should always be considered before you decide on the size of the storage tank. “You have to determine how much risk you’re willing to take that you may run out of water. That’s number one,” says Vinchesi. “You also need to account for evapotranspiration (ET) or the amount of water a given plant needs to survive.
The two final things to consider are the amount of rainfall the area gets and whether or not there is a back-up irrigation system in place.” Storage tanks are one of the more expensive elements of a harvesting system. Vinchesi estimates that every gallon of storage space costs roughly two dollars. Since there is no reason to spend money on space that will go unused, it’s important to determine exactly how much storage will be needed. But because there is no way to predict the weather with 100 percent accuracy, sometimes it pays to spend a few extra dollars on a tank with a larger storage capacity. This way you’ll be sure to have all the water you need. This is especially true in areas where there are restrictions on using potable water for irrigation. In these areas, if your supply of rainwater is depleted, you may be forced to let the turf go brown. When choosing a tank that is going to store water primarily for irrigation purposes, it’s probably a good idea that it is equipped with what Ron Harris, western state sales manager for Darco, Inc., Bennett, Colorado, calls a “makeup water valve.” Makeup water valves are small valves that maintain the minimum level of water in the tank. Let’s say, for example, that level is 12".
If the level of water dips below that mark, the valve, which is hooked up to a potable water system, will release more water to fill the tank. However, all of the available rainwater will be used up first. Having such a device in place eliminates the need for tank owners to constantly be monitoring water levels. “The makeup water valve basically lets a system function on auto pilot,” says Harris. “We’ve put systems in without the valves and inevitably the landscape gets burned up because no one is watching the tank or because someone forgot to fill it up. A lot of times when we sell a system without a makeup valve, the customer ends up coming back to have one retrofitted.” Ray agrees with Harris when it comes to the importance of makeup water valves, which are also commonly referred to as float valves. “One of the reasons our Signature Series tanks are so popular is because of the float valve,” Ray says. “It’s really a turn key system; you install it and that’s it. Homeowners want a system that doesn’t require constant monitoring, and because of the float valve that’s what they get.” As the demand for rainwater harvesting systems continues to grow, new products entering the marketplace are becoming more and more advanced and diverse.
The RainXchange system from Aquascape, Inc., St. Charles, Illinois, is a great example of this. This is particularly true of their RainXchange’s storage tank, which actually isn’t a tank at all. The AquaBlox Water Tank Matrix Modules are an innovative and unusual approach to rainwater storage. Foregoing the traditional cistern shape design, AquaBlox consist of a series of flat panels that snap together to form what closely resembles a milk crate. Once the AquaBlox are assembled they can be placed side by side or stacked on top of each other, creating various shapes and reservoir sizes. The panels are shipped individually in flat packages and are intended to be assembled onsite. “The great thing about the AquaBlox is their flexibility.
They’re totally custom designable,” says Greg Wittstock CEO of Aquascape. “You’re not limited to a size or a shape like you are with pre-molded cisterns. If you wanted to build a harvesting system under a sidewalk that’s 50-feet wide and 50- feet long, you could do that.” Rainwater harvesting systems that use matrixes instead of traditional cistern shaped tanks are not only innovative, they are also durable. Atlantic Water Gardens, Mantua, Ohio, manufactures EcoBlox, a 31.5 gallon storage matrix. “Our EcoBlox are load bearing,” says Jeff Weemhoff president of Atlantic Water Gardens. “This makes them a perfect match for permeable pavers or for use under patios, sidewalks and front entrances.” Systems are also becoming increasingly user-friendly. Many of Darco’s systems are pre-packaged as kits and delivered directly to the jobsite. The systems are modular and are designed to fit into most trucks and vans. Each accessory is boxed separately and labeled and comes with instructions. The modules are also labeled so contractors know where each component goes.
“Our systems are pretty much foolproof. Contractors don’t want to be making a bunch of trips to the hardware store, and we eliminate that by sending everything in one kit to the jobsite. We don’t want contractors to have to make unnecessary engineering decisions while they’re out in the field. That’s why we provide detailed instructions and take time to carefully label everything,” says Harris. There are countless benefits to becoming familiar with rainwater harvesting. Contractors located in colder climates can install rainwater systems in the winter months when construction has slowed, to supplement their incomes.
Additionally, rainwater capture systems will eventually pay for themselves, which makes them appealing to consumers. But the real draw of rainwater harvesting is its green appeal, which in today’s day and age is a powerful marketing tool. “The green movement is not going away. In fact, it will probably be stronger in five years,” says Wittstock. “People want to be seen as green. They want to be green to the point that they’re willing to spend money that they may not immediately recoup.” “In 2009, it is no longer acceptable to be in business strictly for money. The days of not having a green mission statement are no longer being tolerated by consumers.
This trend is only going to amplify,” says Wittstock. By adding rainwater system installations to their list of services, landscape contractors will be prepared to take on a future that is growing greener everyday.