permaculture

["Kelly Finigan" <kfinigan@spots.ca>]

my two cents:

This past year I designed a roof catchment system for a family building a 
new house. They already had a shallow well on their land. The upslope 
neighbour runs cows (typical for here) so there was concern that the well 
is / would become contaminated. So we:

1) implemented demand side management to reduce consumption drastically;
2) installed a large (4,000 gallon if I recall correctly) cistern;
3) installed flow divertors to direct "first flush" to landscape - nothing 
like an hour's worth of rain - just enough to "wash" the roof...again from 
memory, I think this was about 100 gallons or so??;
4) installed pipes to the cistern;
5) installed a water level indicator to warn if levels are too low...then a 
truck of water can be delivered (this COULD be done away with by making the 
tank bigger, but bigger tanks are more expensive than buying a truck of 
water from time to time);
6) installed a sand filter, storage tank for treated water and ultraviolet 
treatment inside the mechanical room.


Notes:
1) This is in a rural area
2) This is the first winter of operation, we've hit -20C already and no 
complaints yet.
3) The building roof is metal. The cistern is food-grade plastic.
4) if the flow divertor has moving parts, you have to bypass it (and the 
cistern) for the winter.

Re: water quality:
There should be little if anything in rainawater that is worse than things 
found in "raw water" from a stream, river, lake or some groundwater. 
Treating the water removes those items. Disinfection is highly recommended. 
I prefer ultraviolet - no chlorine (poison) to handle, no chlorine by-
products (poison), no ozone to generate (high energy use and potentially 
explosive).

Roof material is important. Metal, ceramic tile are ok and do not affect the 
water. Asphalt and wood shakes (also living roofs I think) can add 
asphaltines and tannins respectively - YUKKY and more difficult to remove.

Somebody mentioned lead - where would this originate (is a neighbour 
throwing it on the roof or something?)

Re: economics:
This system is MUCH, MUCH cheaper than building a pipeline to each house and 
building a water treatment plant to get, treat and pump the water. This 
applies for rural (obviously) AND (I think) for urban areas.

For my city (Calgary), we have about 300,000 residences and two water 
treatment plants that cost about 1 billion dollars ($1,000,000,000 Canadian) 
to build. This is about $3333 per residence. Pipes to houses are additional 
(I roughly estimate $5000 each for the pipes and the street hookup) for a 
rough total of $7300 per residence.Operating costs additional. So are 
maintenance costs (e.g. replacing old pipes as needed).

I'm confident water catchment systems could be supplied for individual 
houses for this cost - especially for new ones (slightly more work for 
retrofits). Much lower environmental costs too.

ciao,
Kelly

--
Kelly Finigan, M.Sc. P.Eng. Permaculture Designer
~ Sustainability consultant & ecological designer ~ 

744 - 4 Street NW
Calgary, Alberta T2N 1P2
phone 1-403-283-7270