Rainwater Harvesting System

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Nic Koontz, Biosystems Engineering undergraduate, worked at the Student Organic Farm for over two years. For his Senior Capstone Design class (BE 416), he decided that he wanted to build a rainwater harvesting system for the farm. He and two classmates, Hunter Hicks and Bryan Kohart, approached Dr. Geoff Zehnder, Clemson University Sustainable Agriculture Program Coordinator,with their ideas and shortly thereafter began work.

For the project, these students designed and installed a rainwater harvesting system for the CFLL building that will allow for the collection of a maximum of 1500 gallons of water at a time. The collected water is intended to be used for the produce washtable and the irrigation of the landscape around the building. Approximately 80,000 gallons of water will come through the system in an average year. The 1500 gallon tank is conservatively sized and can meet the intended irrigation needs through a three week drought when utilizing drip or point irrigation.

The system has a small pump outfitted with a pressure tank, pressure switch, and float switch to effectively and economically distribute the collected water to where it will be used/needed. The system is currently installed and functioning. This rainwater harvesting system will help to make the CFL more sustainable and demonstrate rainwater collection and utilization techniques for small farmers and homeowners.

(click the following links for further details about how the rainwater harvesting system works)

A Walk Through of Installation

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	A concrete pad form with reinforcement was laid and the flume was installed before the rainwater system installed.		Nic gluing PVC parts together for the system.
	Nic in cistern installing and setting the float switch, which will turn the pump on and off at predetermined water levels.		Critical components of the system: the centrifugal pump, manual cistern drain, overflow, blue water tank, pressure switch, and check valve.
	Blue water tank allows for storage of pressurized water to reduce pumping cycles and extend the life of the pump.		The metal flume transports the water from the roof to the system.
	The First Flush Device - Because the first water collected is usually unsuitable for the system, this device allows the first 35 gallons of water to go straight to the drain.		Side and top view of the First Flush Device.
	Side view of the 1,550 gallon polyethylene cistern.		(L to R) Pressure gauge, 3 valves for irrigation on other 3 sides of building, 1 valve for produce wash table, 1 valve for hose.
	The completed rainwater system can be seen on the left. The cooler is on the right, and the Calhoun Field Learning Lab can be seen in the background.		Rainwater system as seen from inside the Calhoun Field Learning Lab.