The so-called "green" harvesting of roof-shed rainwater with above-ground rain barrels or catch tanks reduces the watershed that currently overloads some of our municipal sewer and storm-water drainage systems. Still, could we do the same thing by installing underground cisterns similar to those used during the 1800's and early 1900's?
Description of theearlier cisterns
Many older homes and estates today still have the remnants of their early underground rainwater cisterns. These fairly large round, water-tight, root-free, 500-to-5000-gallon cisterns were madefrom brick, stone, rock, plaster,concrete, or combinations of these materials. They were each capped withan above-ground manhole-typeof openinglarge enough totake a big bucket. Thisopeningallowed the cisternto be periodically cleaned-out and repaired by the owner or by a third-party service.
The tin or zinc-plated guttering used on the house eaves then, whichcarriedthe rainwaterdown to the cisterns, were open and not covered. So,quite a bitofwind-blown tree leaves andseeds,and other debriscould maketheir into the cisterns. For that reason, the suction end of theiron plumbingwas located above the cistern floor, where the debris would eventually settle.
This relatively clean, soft,outsidewater supplywas plumbed directly tothe long-handle hand-pumps installed at the kitchen and bathroom sinks and thebathtubin the main house. Itwas also plumbed to the hand-pump in a small building behind the house that served as a summer kitchen and a place to wash laundry, to can garden produce, and to butcher chickens and hogs. This water supply remained relatively cool and unfrozen the year around. Generally, it was used for cooking, washing dishes, cleaning, canning, butchering, and bathing. But it could be drunk, too, after boiling it.
Modern cisterns
Modern cisterns operate much like the ones described above. However,instead of being built into the ground from scratch, they are buried prefabricated ones instead. That is, these cisternscould beprefabricated concrete receptacles, orthey could be large prefabricated heavy-duty plastic tanks capped withfairly large screw-on tops, similar to the ones seen on certain lawn-treatment trucks.
Also,today'saluminum, steel, plastic, or coppereave gutterswill haveporous or solidcoverings. Thus, the amount of debris entering the cisterns from the rooftops will be minimal. Yet, the fine sand-like material shed by asphalt or composite shingles willneed to be filtered out earlyduring the harvesting process; else, it will eventually have to be removed from the buried cistern. Theplumbing for the moderncisternwill beheavy plastic pipe. Of course, the pump itself will probably be an electric one, its size and accessories will depend on how the harvested water is used.
More-than-likely, becausemost of us alreadyhavereliable purified municipal indoor drinking and bathing water supplies, this cistern water will be used for outdoor purposes, like, for the sprinkling of lawns and gardens, for filling fish ponds and small treated swimming pools,for watering trees and animals, and for washing vehicles, driveways, patios, decks,andhouses.The following three advantages ofthe modernburied cistern system suggest this technology will work well today: 1) theyare hidden from view and out-of-the-way by being underground, 2) theydo not foster the production ofalgae or mosquitoes in the summer time, and 3) theyhelp conserve themunicipal storm-drainage systemsand drinking water supplies.
Further information on cisterns
Wikipedia, The Free Encyclopedia Cistern http://en.wikipedia.org/wiki/Cistern
Author contact: j__l__d@sbcglobal.net
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