Rainwater Cistern Provides Greenhouses With Water
DuPont Pioneer installed a rainwater cistern as part of its greenhouse expansion in Johnston, Iowa. The cistern has already proven valuable through the first six months of use.
The cistern was installed as part of company Core Value initiative to advance environmental stewardship by conserving water. The greenhouses that are served by the rain cistern do not use the City of Johnston water supply, except for potable water in break rooms and restrooms. Water from the cistern is used for plant irrigation and the leftover gray water from the filtration process covers other operations such as toilet flushing and greenhouse table/floor washing.
A wet spring filled the 100,000 gallon cistern and the greenhouses began drawing water from it in March.
Spring rains gave way to another dry summer in central Iowa. Between June 22 and Sept. 11, only 0.03 inches of rainfall was received at the greenhouses. On average, central Iowa receives more than 8.5 inches of rain in July and August combined. Despite the dry conditions, the cistern was able to supply the greenhouses with water through Sept. 11. At that time, the greenhouses had to begin using city water again.
The cistern is designed to be filled when one inch of water is received. The storm on Sept. 17 dropped 0.82 inches of rain and subsequent rains have allowed the greenhouses to return to the cistern for water.
During a normal year, the cistern is expected to capture 3.3 million gallons of rainwater and provide a majority of the expanded greenhouse’s irrigation and operation needs. The tank structure is made of 100% recycled plastic and was manufactured locally in Iowa.