A Self-Contained Harvester

REF Christopher Greaves Standalone.xls

A blurry screen-capture from 0m40s point in a YouTube movie by Graeme Reid Reidgek@nex.net.au

Perhaps your roof is rotten or is a familiar perch for birds. Or you pitch your tent in the bush and have no roofed cabin.

No matter. Build a simple stand-alone tank from braced 2x4 timber, nail or screw down an appropriately sized piece of galvanized iron or fiber-glass corrugated sheet.

A simple eaves trough channels the caught water into a five-gallon keg (such as the ones hoisted atop the office water-cooler, a spigot screwed into the base of the carboy or keg, and you’re in business!

The Downside

... to a standalone collector is that you will need to set aside a large enough area of your property for the roof, the roof of the collector.

I am harvesting for my house, so I have access to 800 square feet of roof.

If you are harvesting for your cottage, you will need to calculate your storage needs – let’s say one hundred gallons – and the long-term average rainfall over a given period to accumulate one hundred gallons based on the collector area.

Here’s an example:-

Of course, you could just make use of a four-square-metre roof and see how you go. Your diary would provide feedback and let you know whether you need a larger roof.

Appendix – Rainfall Records

This data is a capture of part of the month of July 2003

The table below uses this data to calculate how many litres of rain we would have harvested for successively larger roof areas.

For this month’s (admittedly low) rainfall, a roof area of one million square millimetres (one metre square) would have provided forty litres of rain water. That’s not quite two twenty-five litre plastic pails.

Basically, each square metre of roof supplies one litre of rainwater from a one millimetre rainfall.

Wednesday, December 13, 2023

While my trough is out of action, and while I consider buying small un-watered plots of land, I think about a first version of a standalone system for use at home, that could be dropped on a vacant lot.

There are three essential components and one optional.

(1) A roof; an angled solid platform on which are nailed roofing shingles. The rain falls on the shingles and runs to the lower edge, into an eaves trough, and drains through a short length of old garden hose or polythene tubing.

The roof is of the order of one metre square.

(2) A wooden frame that can carry the roof. Made from scraps of 2x4 lumber with triangle braces.

(3) A local reservoir, preferably about 40 or 50 gallons, but a 25-litre pail will suffice, or a series of such pails.

I wrote “local” meaning that it fits within the roughly one-cubic-metre housing so that the footprint remains at one square metre.

A series of short hoses can couple pails into a battery, with a single outlet. For drinking water this would make a series of settling tanks.

A spigot at the outlet will have a regular hose connection, so we can run a hose (or two) across the property, perhaps with drip-hosing at the far end.

[4] An optional platform, could be an old pallet. This platform would keep the pails off the soil at ground level.

I envisage such a structure would allow us to water seedlings until their roots have tapped well into the sub-surface soil layer. My idea for vegetable lots is that they host plants that can survive unattended. on our summer rainfall.

Water Volumes

I have harvested about 125 litres of rain-water for domestic use in four weeks.

Average rainfall in Bonavista is 1,056 mm per year.

Assume 100% collection from a one-metre square roof.

Then in one year we could harvest just over one cubic metre of rain.

The table provides only an example of a calculation. It is not a prediction nor is it an assurance.

It assumes that every drop of rain on a one square-metre roof can be collected without loss, and that I can live on about five litres of drinking and cooking water each day.

Several factors are not taken into account. Amongst them that we have a rainfall drought December through March. Snowfall we get, but the snow mostly blows off the roof before it melts.

We can get a heavy rainfall over a 24-hour period, rainfall which exceeds the storage capacity in our cubic-metre module. We need a reservoir inside the house with enough volume to hold incoming heavy downpours and to tide us over a drought. Inside the house means that it will nit freeze.

If I placed a collector at the SW corner of my lot, gravity (and a one hundred foot hose!) would fill a pail in my kitchen, I think.

Tuesday, March 26, 2024

Gerry Hussey has lent a barrel to me; he uses these for harvesting marine life. This barrel has a height of 31 inches and an outside diameter of 20 inches.

The outside of the barrel is oily and grubby as befits a container that is put to use aboard a marine vessel, but the inside is free of oil and other visible chemical material.

Wednesday, April 10, 2024

My sketch design for a proof-of-concept. The barrel is the barrel and is on loan. I am not free to drill holes in it. The barrel will stand on a platform – probably an old pallet – and will be surrounded by a four-panel cage.

Each panel will be 36” wide which should leave space for the 23” diameter barrel. Each panel will be 48” high which should leave space for the 31” high barrel

Each panel will be braced by two triangular braces. You have noticed that the sides of the panels are 4’ and 3’, so Pythagoras’s Theorem tells us the diagonals will be 5’ long.

The four panels will be assembled using drop-pin hinges for ease of stowage and transport.

Once the four-panel frame is assembled, a lid frame will be dropped on top; this lid will be fastened to the frame by drop-pin hinges or dowel pins in the frame timbers.

Wind is a problem here, so will be anchoring the kit when the barrel is empty.

On the lid I will use plastic sheet of some sort to funnel water to the centre of the lid and hence into the barrel. This avoids fitting eaves-troughs, piping and so on. A filter is unnecessary because this water is being collected for plant life. It could be argued that a bag of grass clippings would be a good priming.

The lid could be made large enough to fit snugly around the frame.

The lid could use metal sheet as a water-trap, or even old plywood.

A first estimate is for 44.5 feet of small timber, but allowing for scrap ends of eight-foot lengths this ought to be thought of as 64’ in eight foot lengths.

Tuesday, May 28, 2024

David has supplied me with three large drums, two-feet diameter and three feet tall. 59 gallons, buit that is the outside volume. Nominally 55 gallons.

I will need a bigger cage.

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