Residential Rain Harvesting Systems
You may be amazed at how much rain runs through your gutter downspouts in a year’s time. You probably will be surprised at how much water your irrigation system uses in just one cycle. Why not use one to reduce the other? A home in Asheville, NC with a 2500 square foot roof can potentially harvest a total of approximately 55,000 gallons per year. This water can be harvested in cisterns and reused to irrigate landscapes, wash vehicles, and even be recycled into the home for flushing toilets. Another potential use of the water is for supplement fire protection, as many of us live in rural areas that are hard to reach in times of emergency. This, in turn, reduces the amount of potable water that is wasted. When you factor in the droughts of the last several years, recycling rain water can do a lot to help reduce the stress on municipal water supplies and local wells
Several local developments now require the installation of rain harvesting systems, and we expect it to become common practice within a few years.
There are several different types of systems used to harvest rainwater. Above ground cisterns have a lower initial investment, and are most suitable in areas that will not obscure the aesthetic values of the home. These cisterns can range from 55 gallon rain barrels to 5,000 gallon plus containers.
Below ground cisterns require a higher initial investment, but are able to be placed in almost any area around the home. Ranging in size from 325 gallons to 2500 gallons, these systems are the most versatile for long term water supplement. These cisterns can be plumbed together to create more storage capacity, which extends the period of use in drought conditions. Another system that has been developed is a group of load bearing containers that are sealed in a waterproof membrane. This system allows for the cistern to be located under driveways or drive courts, which reduces the amount of site disturbance. On steep slopes, this type of system can be especially helpful. These systems can range from 2000 gallons up to 50,000 gallons plus. All of these systems are eligible for LEED certification points, and can be a sustainable element in any construction project.
Depending on the intended use of the captured water, several different methods of conveyance are employed. A simple system may use gravity alone to water landscape plantings through drip irrigation. Submersible pumps are typically used if the cistern is located below the areas of use, or if the water is to be used in a traditional irrigation system with spray heads. A simple system to consider is to have several yard hydrants located throughout the property in areas that may require irrigation. These on-demand systems are easily maintained and winterized, and provide the most flexibility in use.
A properly designed rain harvesting system starts by assessing the amount of water required for the various uses of the homeowner. By totaling these amounts and working backwards, the required capacity of the system can be determined. Another important factor in system design is the average monthly rainfall. When you include this data into the design process, you can determine whether or not the supply will meet the demands throughout the year.
No matter how large or small the roof area of a home is, a rain harvesting system can dramatically reduce our dependence on the potable water supply. Whether you are planning to build a new home, or want to add a system to an existing home, rainwater catchment is an easy way to reuse a resource that we all have access to. In many cases, these systems can pay for themselves in less than 10 years. Snow Creek offers system design, consultation, feasibility studies, and installation for all of your water harvesting needs. Give us a call today to discuss your specific needs or schedule a site visit.
Rob Dull, Landscape Designer
Snow Creek Landscaping, LLC
rjdull@snowcreekinc.com