Giant Rain Barrel Watches The Weather At Longwood

Published 2:14 pm Thursday, June 25, 2015

Have you ever considered connecting your gutter downspout to a rain barrel?  The rainwater captured in a typical 55-gallon rain barrel could be used instead of well or town water to help fill your pond or water the garden.  Now multiply that rain barrel by 60 and you have an idea how much water the new 3,000 gallon rain barrel, or above-ground cistern, at Longwood University can hold.  The cistern is one element of a “smart” rainwater harvesting system that was recently installed at the University’s Environmental Education Center.

Rain barrels, cisterns and other rainwater harvesting systems capture and store rain and this reduces the amount of storm water making its way to a stream.  If too much storm water traveling at a high speed reaches the stream it can cause stream banks to collapse, sending large amounts of dirt into the stream, and that causes problems for downstream water treatment plants and aquatic life. Capturing rain water and releasing it back into the environment after the peak storm event reduces flooding, reduces the amount of pollution carried into streams by runoff, and allows water to filter back into the ground where it increases groundwater supplies needed for wells.

Dr. Kathy Gee, of the Longwood University Biological & Environmental Science Department, teamed up with Dr. Robert Marmorstein to develop the rainwater harvesting system for Longwood’s Environmental Education Center.   

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“We call it a smart system because it uses real-time weather forecast data from the National Weather Service to ‘instruct’ the cistern to release the precise amount of stored water that would be expected to be replaced by the forecasted amount of rainfall,” Dr. Gee explained in a recent interview.

The stored water is automatically released 12 hours in advance of the expected rainfall.

“We didn’t invent the concept of forecast-based control, but we designed this system to help us identify system parameters that allow us to get the most out of the stored water, while reducing the amount of storm water entering the Appomattox River during peak rain events.”

When the “smart” system releases stored water to make room for the anticipated rainfall, the stored water is automatically released from the bottom of the cistern via a pipe where it is gravity fed into a rain garden. A rain garden is a concave landscaped holding area, with an earthen berm or other border to retain water for immediate use by plants. The rain garden has a soil mixture that drains easily, as well as a layer of mulch on top.  Native plants that can tolerate extreme moisture conditions are planted in rain gardens.

During extreme rain events the cistern might not be able to handle all of the rainwater entering the system.  In that case, there is an overflow pipe located near the top of the cistern that will gravity feed the overflow into the rain garden.  Before reaching the rain garden the overflow will pass through a weir designed to record exactly how much overflow is released so that Dr. Gee can use this information in her research.

“All incoming and outgoing water data is fed into a central computer – I call it the brain.  We will use the data to study how weather predictions and actual rainfall amounts differ, how much stored water is needed for the Environmental Education Center uses, and other research projects led by myself and students” Dr. Gee said.

Longwood University Junior Rachel Lombardi is currently working with Dr. Gee on the rainwater harvesting system through the school’s Perspectives on Research in Science and Mathematics, or LU-PRISM program. This eight-week, summer research program for Longwood science, technology, engineering, and mathematics students is modeled after the extremely successful Research Experiences of Undergraduates (REU) program sponsored by the National Science Foundation.

The harvested rainwater in the Longwood cistern will be used year-round for flushing toilets and cleaning boots and field equipment at the Environmental Education Center. There are also hose outlets making it possible to water landscaping.

“The harvested water is going to be used to flush toilets, so the cistern needs to remain as full of water as possible all the time.  Too little water is not an option” Dr. Gee said. “Using the forecast real-time control system, we can release only the amount of rain predicted.  This keeps fresh water moving through the system, and never leaves it too low to be available for the intended needs.”

The cistern and rain garden elements of the system were paid for through a cost-share program managed by the Piedmont Soil and Water Conservation District. The Virginia Conservation Assistance Program, or VCAP, is a cost-share program that addresses the need to engage residential and commercial property owners in conservation efforts that will help Virginia meet its Chesapeake Bay Watershed Implementation goals.  Cost-share is available for rainwater harvesting, rain gardens, impervious surface removal, bio retention, constructed wetlands, permeable pavement, green roofs and other practices. Cost-share is not available to assist new development sites to meet state and federal storm water mandates.  The cost-share program incentive will encourage individual landowners, and businesses to incorporate water quality best management practices (BMPs) that are or were not required by regulation.

The Piedmont District has been serving Amelia, Nottoway and Prince Edward Counties since 1938, helping farmers install agricultural best management practices on the land, but the Piedmont District also wants to help town residents use water resources in the wisest way possible.  Applications are currently being taken for VCAP projects.  For more information or to apply contact Robin Buckalew at (434) 392-3782 ext. 131.