The potential of rainwater harvesting in Tennessee
Logan, J.  2012.  Proceedings of the 2012 annual meeting., Tennessee Chapter of the American Water Resources Association, Montgomery Bell State Park, TN. April 13-15, 2012. (oral presentation).

By collecting rain from a roof during rain events and storing it in a barrel or cistern, homeowners and businesses can create an alternative supply for their home gardens, landscaping, and gray water supply that won’t overpump the groundwater or increase the water bill. The typical homeowner rain barrel is a 50-gallon heavy-duty plastic barrel with a spigot located near the bottom of the tank. Often they are installed at the bottom of a downspout, and some are used with diverters that both allow an initial flushing of the roof water away from the barrel, as well as diverting the rainwater when the barrel is full. Commercial rainwater harvesting equipment may include cisterns or plastic containers with capacities of 5000 gallons or more. The objectives of this study were 1) create a spreadsheet that will allow user input to set the parameters such as the size of catchment area (ie. roof) and container, system efficiency, watering habits, and daily rainfall data for the period 1981-2010. 2) use this spreadsheet to develop a cross-section of rainwater harvesting scenarios for 50 locations across Tennessee 3) spatially interpolate the results for the entire state and present the results in a series of maps. Results show that only very large collection systems divert enough water to make an impact on water usage or stormwater runoff. However, the educational benefits of homeowner rain barrels should also be taken into account when developing a rainwater harvesting program.