Rainwater Collection from the Greenhouse at CEET

CEET's greenhouse uses several downspouts to disperse water away from the building.	Each downspout sheds water from 1,500-3,000 square feet of roof.	The rainwater is collected in two 1,000 gallon storage tanks.

Collecting rainwater for use during dry periods is a traditional practice that dates back to Thailand, nearly 2000 years ago. Currently, many people are using barrels to collect rain for personal uses. This is a simple way of reducing their water bills, and it is environmentally friendly. In most cases, the rainwater is used to water gardens and landscapes. Rainwater is a naturally soft water without any minerals, chlorine, fluoride, and other chemicals. Plants thrive on rainwater, so watering with collected rain is beneficial to the plant. Rainwater can also be filtered, by a certified water filtration system, and used for human consumption.

Rainwater can easily be collected from gutters and downspouts and stored in large water barrels. The amount of water that can be collected is based on the size of the storage barrel, the area of the roof, and the amount of rainfall. An estimation of rainwater collection is 0.6 gallons per square foot of roof per inch of rainfall. For example, a 1,000 sq ft roof that received 0.5 inches of rain would provide approximately 300 gallons of rainwater. The same roof receiving 1 inch of rain could provide 600 gallons. With annual rainfall in Acadiana of about 60 inches, an average sized roof (1,500 square feet) could provide 54,000 gallons of water.

CEET has a large greenhouse with over 30,000 square feet of roof with gutters and downspouts. This is a substantial amount of surface area to collect rainwater. Half an inch of rain can provide CEET with about 9,000 gallons of water. Over a one year period, CEET could collect over 1,000,000 gallons of rainwater with average rainfall. However, storing this large amount of water at CEET is not feasible. Limited rainwater storage is available (currently 2,000 gallons), so only one downspout from the greenhouse will be used to collect water. This gutter collects water from roughly 1,500 square feet of roof space. With this setup, one inch of rain provides about 900 gallons of water.