Rainwater has great potential with proper storage

Water is a human essential: 80 percent of our weight is made up of it.

We can live for weeks without food but only days without water.

It is also imperative to our lives. We use water for drinking, cooking, washing and providing for plants and animals that sustain us. We also use it for food and industrial processing and for resource extraction.

Water is a resource that is not spread equally, whether geographically or seasonally.

Many parts of the world have dry and wet seasons, as opposed to our cold and hot seasons. The rain can be torrential in the wet season, resulting in land erosion, flash flooding and infrastructure damage, while in the dry season, it can be sparse if at all.

Water must be taken from nearby streams that are often polluted or from underground aquifers and a well or borehole, often by pail and rope or a hand pump. Washing of clothes is done in residual pools of water that are stagnant and increasingly dirty for millions of people.

In our part of the world, we largely take water for granted.

Canadians are the largest per capita users of water in the world. Where a person in a refugee camp might receive as little as four to five litres of water per day for drinking, cooking and washing, in Canada we consume almost 350 litres of water per day per person, with much of that being used for more than the basics, everything from flushing toilets to dishwashers and clothes washers to the sprinkling of lawns and gardens to the washing of cars and driveways with pressure washers.

And regardless of how it is used, municipal water is all filtered and treated for human consumption.

We are fortunate to have an abundance of fresh water, although most of it is in northern areas, far from our concentrations of population.

We still have enough melting from glaciers and rainfall to replenish our water sources, but droughts occur around the world and we have not been immune from them.

Historically there have been many periods of drought, and our experience in what was called the Dirty Thirties proved that droughts can last a long time, easily as long as a decade.

Sometimes we have too much water.

In cities, rainwater is retained or detained to prevent the overcharging of storm water systems. Temporary ponding areas, such as storm water detention ponds, delay water discharge until the storm water systems are capable of handling them. Urban subdivisions have storm water retention ponds, which are man-made lakes that provide bird habitat and increased biodiversity

We generally don’t think much about capturing and storing water, but that was not always the case.

A century ago, rural houses were built with a cistern incorporated in the basement concrete work, which captured rainwater from the roof by diverting it from eaves trough downspouts. Those cisterns could typically hold all the water from a good rain, which from an average house roof could provide enough water to serve the household until the next rain.

There is much to be said for rainwater or snow water. It tends to be softer than well water, making washing of most things easier with the use of less detergent. Plants also seem to thrive better on it. It is not advised to drink rainwater without filtration or treatment, but it certainly can be used for all other uses.

There are a many ways to capture surface water.

Early settlers learned the benefits of dams and reservoirs. The development of what are known as dugouts came from the need for good water. Dugouts capture water when snow melts and cannot penetrate the frozen ground, while dams keep runoff water from racing to the ocean. In steep terrain, people use terracing to hold water and prevent erosion.

The simplest way for the average person to capture rainwater is to position a rain barrel at an eaves trough downspout. There it can be used to water the garden when the dry soil beckons. However, a rain barrel is likely to overflow in all but a small rain.

To capture a lot of rain takes a serious sized tank. Two challenges are location and aesthetics.

A 25 millimetre rain on a 1,500 sq. foot roof will net almost 3,500 litres of water, which would require a tank two metres in diameter and 1.8 metres high. A tank that size might seem a bit large sitting next to the house, but think of the potential for an outbuilding.

One side of a 40 by 80 foot machine shed will receive the better part of 4,000 litres in a 25 mm rain. It can be pumped to the house, although with all surface tanks, it is subject to freezing, as is the pump. As a result, such capture is really a two or three season situation.

Any surface water must be treated with respect.

If the source is a dugout, it is important to remember the catchment area will determine the water quality. Water quality will be suspect If the dugout is downstream from intensive livestock facilities. It is best if the area immediately upstream from the dugout is covered with grass to prevent erosion and siltation. It also is important to remember safety with children around a dugout.

Water from roofs is also questionable and can never be assumed to be of potable quality. All roofs will have dust, bird feces and pollutants, while asphalt roofs have more runoff debris. The first water off a roof is likely to be contaminated, and there are now devices that dump that first water to prevent it from entering into storage.

However, with filtration and judicious use of the water, there are plenty of options for using the stored water, such as gardens, livestock, toilets and washing.

Water is plentiful in much of Canada: our rivers are flowing full and aquifers are largely undiminished. But we know from the experience of others, including the United States, that sources such as underground aquifers can become substantially depleted under intensive use from population centres and irrigation.

Water catchment is mostly a distant if not radical idea, but someday, when water is more precious, we may look more seriously at holding water a little longer before we let it go its way.


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