The purpose of rain water
harvesting is to catch the water and store it for future use
before it has a chance to run off into lake, stream, river or
soak into ground A typical system would collect the rainwater
from the roof or pavement using course mesh to prevent large
debris from entering the system. It is important, however, to
check existing catchments to prevent contact with hazardous
materials such as lead paint, asbestos roof, etc.
The
initial first few minutes of rain can be diverted known as a
first flush diverter to remove airborne pollutants that are
present in the sky and on the roof or pavement. However, this
might not be needed if rainwater is harvested strictly for
irrigation. The purpose of a first flush is to remove debris and
reduce sediment build-up in system. After the first flush,
rainwater is filtered of suspended debris and sediments. There
are different types of filters available such as sand, bag,
cartridge, automatic, charcoal, etc.
The rainwater is then stored in underground or above-ground
storage tanks depending on space limitations at the project
site. Adequate provisions to prevent contamination from humans,
animals, and other contaminates is very important. The tank
should have a tight cover to prevent algae and mosquito growth
inside the tank. Various materials of tank construction are
available such as concrete, steel, fiberglass, plastic, etc. The
tank must be structurally sound so one can store enough water to
sustain demand until the next time it rains. Keep in mind that
an alternate source of potable water may be necessary to
supplement rainwater during drought conditions. Backflow
protection is necessary and a pumping system is needed to
provide adequate pressure an irrigation system. Any tank
overflow is drained to storm sewer or other means available.
Harvested Water Uses
►Landscape
irrigation
►Flushing
toilets
►Car/truck
wash facilities
►Cooling
tower make-up
►Can
be used for potable purposes?
(CHECK LOCAL CODES PRIOR TO
INSTALLATION)
