Rain water harvesting has been used throughout history as a water conservation measure,particularly in regions where other water resources are scarce or difficult to access. According to
the U.S. EPA, from the last half of the 20th century, the U.S. has enjoyed nearly universal access
to abundant supplies of potable water. But as witnessed by the recent serious and sustained
droughts in the Southeast and Southwest, this past luxury is not something that can be expected
for the long term. Future population growth will exert more demand on water systems while
climate change is predicted to decrease. These challenges will require a more sustainable
approach to using water resources, looking at not only how much water is used, but also the
quality of water needed for each use.
The overwhelming majority of the water used in the U.S. comes from freshwater supplies of
surface and groundwater. Water extracted for public systems is treated to potable standards.
Rainwater harvesting (RWH) in its essence is the collection, conveyance and storage of
rainwater, is a technique that has been used for many years. It has not been widely employed in
industrialized societies that rely primarily on centralized water distribution systems, but with
limited water resources and stormwater pollution recognized as serious problems and the
emergence of green building, the role that rainwater harvesting can play for water supply is being
reassessed. Rainwater collected from roofs is not “recycled water”, nor is it “gray water”. It is
fresh water that is in abundant supply, and is generally undervalued in the United States.
Rainwater harvesting has significant potential to provide environmental and economic benefits
by reducing stormwater runoff and conserving potable water, though several barriers exist that
limit its application. According to the U.S. EPA, the U.S. uses more water per capita than any
other country, with potable water delivered for the majority of domestic and commercial
applications. Installing a rainwater collection system requires diverting roof downspouts to
cisterns or rain barrels to capture and store the runoff. Potential uses include indoor non-potable
applications (toilet flushing, cooling tower make-up) and outdoor non-potable applications
(irrigation systems, hose bibs, etc).
Select a commercial or residential or institutional building near where you live for this
assignment. I would like you to design a Rain Water Harvesting system for the building
where you can make some reasonable assumptions concerning land use and average daily water
use. Design your system based on the Georgia Rainwater Harvesting Guidelines Manual:
http://www.dca.state.ga.us/development/constructioncodes/programs/downloads/GeorgiaRainWaterH
arvestingGuidelines_2009.pdf
