Categories Of Rainwater Harvesting

There are three major categories of rainwaterthe first step in the design of an integrated system
harvesting. Active systems utilize tanks, pumps, pipesand is sometimes the only technique used when
and energy inputs. Passive systems use gravity,further improvements are not planned for a natural
topography, swales, ditches and ponds. Integratedsetting.
systems combine both of these and, sometimes,A common passive catchment in urban areas is a rain
greywater and wastewater to ensure that each dropgarden. Creating a shallow basin that is about one and
of water is used many times. It is important to notea half to two times the expected diameter of the
that transferring or removing water is never thecrown of a tree, when mature, and then heavily
intention of a collection system, simply the efficientmulched is another example. Rain is directed into
use and reuse of the water before being releasedthese contours to store water in the soil where the
back into the watershed from which it was diverted.roots will seek it out and the resulting root system
Allowing the rain to infiltrate through the soil and intowill make the plant more vital and drought resistant
the aquifer is the end goal. To do this we slow itrequiring little or no irrigation. Vegetated areas along
down, spread it out and soak it in so that nothing isroads or parking lots that are slightly below grade
wasted or left out.with skip curbs or no curb rather than raised beds or
Components of an Active Systemislands, is another example of passive rain harvesting.
Active systems use rooftops, gutters, pumps, pipesLooking for ways to use passive collection is a good
and tanks to collect and store the harvested water.way to reduce demand for stored water and,
This type of system is common when the water isthereby reducing the cost of an active or integrated
going to be used for potable purposes or to feed asystem. Less pumping means less energy and
conventional irrigation system. Retrofitting rainwatermaintenance cost for the pump. There's no sense in
catchment to built structures and landscapes requirewasting energy in order to conserve water.
an active interface such as a pump. Roof water isIntegrated Systems
usually cleaner and has less suspended solidsAn integrated water system is where active and
(sediment) in it so the water is suitable for thepassive rainwater harvesting meets greywater
primary water uses in a household such as bathing,recycling and, sometimes onsite wastewater
cooking and drinking. Many homeowners don'ttreatment and reuse. This is where the rural,
disinfect the water since it has not been exposed toself-sufficient, off-grid rubber meets the road. There
the ground. Proper techniques and plumbing practicesis not always an opportunity to incorporate all the
must be observed to maintain the quality of theelements into one system but, when possible, this
water if disinfection is not desired. Components mustrepresents the ultimate in water efficiency. After
be made of materials known to be safe for potableoptimizing the site with passive features to minimize
water especially where the water is going to bethe size of the storage facility, utilizing the most
resident for long periods of time, like the cistern, toefficient toilets and appliances, then capturing rain in
prevent leaching of contaminates into the slightlythe cistern, each drop of water is cycled through the
acidic and aggressive rainwater.system up to three times before being released into
Components of a Passive Systeman infiltration field where bioremediation cleans the
Passive systems are much different in that naturalwater and the natural hydraulic cycle takes the it
drainage and topography is utilized to direct thedeep below the surface to replenish the aquifer. The
water to high value assets such as gardens, trees,pure cistern water is reserved for domestic use and
landscaped areas, livestock and wildlife habitats. Thethen recaptured as greywater and directed to the
idea is to use gravity, swales, berms, ditches, gabionsgardens and groves. The onsite wastewater
and basins to slow the water down and store it intreatment system effluent irrigates any turf and
the root zone of the selected plants or make itornamental landscaped areas or is infiltrated. No steps
available for animals to drink and bathe. It is oftenare skipped and nothing is left to waste. After all it's
difficult to notice the elements of a passive systemonly wastewater if you waste it. If you're also off
since it sometimes appears to be the naturalthe energy grid, solar pumping can provide pressure
conditions of the site with few enhancements. It iswater for the house.