Aquarius Rainwater Harvesting Systems offer sustainable recyclable rainwater for use around the home and business. Replacing mains water supply for use on appliances internal and externally.
http://www.designbuild-network.com/contractors/water_supply/...

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Note added at 6 mins (2012-04-18 17:02:34 GMT)
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Design and construction of an experimental pervious paved parking area to harvest reusable rainwater.
http://www.ncbi.nlm.nih.gov/pubmed/22020491

a more general term

other option

Another option:

http://www.ucowr.org/proceedings/2010_Proceedings/Seattle_Po...
Harvestable Rainwater Use = Potable Water Saving

http://rainman.ie/wp-content/uploads/Rainwater Harvesting Pi...
To quantify the amount of harvestable rainwater in an Irish location.

http://greenremodelinthewatershed.wordpress.com/2008/10/30/c...
Calculating Harvestable Rainwater from Roof

http://www.harvestingrainwater.com/rainwater-harvesting-info...
Capacity of harvestable rainwater varies due to factors such as roof surface and rainfall variability.

http://www.erahydrobiotech.com/rain_water_harvesting_system ...
Following table illustrate the calculation of harvestable rainwater quantity from your roof in one monsoon season.


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Note added at 1 day1 hr (2012-04-19 18:52:19 GMT)
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New thought: could this refer to "leachate"?
Note the following, and particularly "leachate, which may be contaminated" and "the leachate that passes through the landfill since it contains contaminating substances."

http://curiosity.discovery.com/question/what-parts-make-up-l...
Rainwater that falls on the landfill is collected in the storm water drainage system. Contaminated substances mix with the water to form "leachate" that can drip through the landfill, and the leachate collection system collects the contaminated water.

http://sites.google.com/site/landfillsandleachate/parts-of-a...
There is also a storm water drainage system that collects the rainwater that falls on the landfill. A covering or cap is used to seal the top of the landfill. The leachate collection system collects the leachate that passes through the landfill since it contains contaminating substances.

Recycling and Recovery of Plastics, edited by J. Brandrup
This barrier layer must also be capable of preventing the passage of the accumulating leachate, which may be contaminated,


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Note added at 1 day1 hr (2012-04-19 18:54:09 GMT)
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http://www.groundwateruk.org/downloads/industrial_and_urban_...
The leachate is drained to collecting sumps for subsequent treatment.


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Note added at 1 day8 hrs (2012-04-20 01:29:19 GMT)
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Of course you're right about leachate, Lisa. Going back to your first discussion entry, how about something with "operational stormwater"? Such as "operational stormwater runoff" or just "operational stormwater"?

http://psb.vermont.gov/sites/psb/files/docket/7628LowellWind...
operational stormwater discharges/ operational stormwater runoff
The operational state stormwater discharge permit requirement is in place to ensure proper design and construction of stormwater treatment and control practices that may be necessary to minimize the potential impacts of stormwater runoff from impervious surfaces to receiving waters.

http://geoearth.uncc.edu/Full-Time-Faculty/allan-craig.html
…research group is actively involved in the field testing of structural and operational Stormwater Best Management Practices (BMP’s) and land development regulations at the watershed scale.

and for the "balsa" bit, perhaps "stormwater settling pond" or "stormwater settling basin"?
See the following with "operational" in front...
http://waterviewapplication.nzta.govt.nz/eBooks/AEEPartD/fil...
is required to develop an operational stormwater settling basin to treat stormwater from



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Note added at 1 day8 hrs (2012-04-20 01:43:34 GMT)
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Or perhaps "operations stormwater":

http://www.townhall.state.va.us/L/GetFile.cfm?File=E:\townhall\docroot\Meeting\103\3942\minutes_deq_3942_v1.pdf
The order requires submission of a permit application and plan for separating the landfill operations stormwater from the old quarry pond system

"Operation"/"operations" might be the equivalent of "explotación".