design elements - San Jacinto Texas Historic District

Rainwater Harvesting & Reuse
Defi nition
Downspouts from roof runoff , which are
typically routed to the municipal sewer
system, can be directed into a vessel specially
designed to capture and temporarily store
rainwater for various uses, including
greywater reuse and landscape irrigation.
Applicability
Rain collectors and cisterns can be used at a
variety of scales on new and retrofi t buildings.
The area and confi guration of the roof, as
well as the desired volume of collected
water, will determine the size and location
of the vessels. As the cost of potable water
rises, and as the availability of groundwater
sources decreases, collecting and using this
‘free’ water becomes an economic necessity,
both on an individual and a regional scale.
136 │ APPENDICES
Benefi ts
■
■
■
■
■
■
■
Reduces annual runoff volumes fl ows into
the sewer system and streams and rivers,
which can also help reduce downstream
fl ooding.
Conserves water for reuse (e.g. irrigation
of lawns and gardens).
Collected water can be used to irrigate
landscapes or for some internal building
uses such as toilet fl ushing, or it can be
released into the sewer system between
storm events.
A mesh fi lter or screen can be inserted at
the top of the collector to prevent leaves
and other debris from entering.
One inch of rainfall over 1,000 square feet
of roof area is equivalent to 625 gallons of
rainwater.
Rain collectors can be used in combination
with bioretention, green roofs, and other
practices to increase stormwater benefi ts.
Larger cisterns in some sett ings may be
used to provide greywater for use in toilet
fl ushing and other non-potable uses.
Caption for IMAGE shown above.
An above-ground cistern.
Cistern at the Kresge Foundation Headquarters.
IMAGE: CONSERVATION DESIGN FORUM IMAGE: CONSERVATION DESIGN FORUM