Understanding Water Part 1: The Theory of Flow


It’ such a key part of our lives – indeed, all of life – that it can be said to be quite literally elementary; but much of the way in which this vital force is being used appears sometimes to lack some understanding of what water is, and how it behaves.

A Fragile Resource?

Much of current thinking (see for example 1) emphasises the fragility of our access to water and the dangers of using too much of it.

“Save water,” we are told; the implication being “This is a finite resource – be careful of using it up!”

This notion of scarcity and wastefulness is akin to the perception of fossil fuels and their use, but when examined closely it can be seen that as a resource water behaves somewhat differently.

We use fossil fuels by burning them up; changing them into something totally different which cannot be (with current technology) reconstituted back into what it was.

Their replenishment runs on a different time scale: what we can burn in a matter of minutes is being recreated right now, but will not be ready for use, in all probability, for a few million years or so.

The water cycle, however, is on a timescale comprehensible to human lives. It does not rain oil, but the cycle of water is constantly going round and round. It is also, in spite of all the harmful substances which we fill it with, almost infinitely re-cleanable – even sewage water can be purified to become drinking water (2) – so that we can keep using it again and again.

Whatever we drink goes out of our bodies, into the soil or sea and then back up into the air again; the same goes for any water which flows away.

Using Water Well

Knowing this does not necessarily mean we should be leaving taps running all the time, or use water for things which may not be appropriate e.g. drinking water to flush toilets. It is simply a recognition that in order to truly appreciate and thus effectively manage such an important resource we need to see it as what it is and treat it accordingly. This involves respecting it as well as respecting the fact that, regardless of any appearance of scarcity, it can be found pretty much anywhere on earth.

Water makes up much of this planet and is present in large amounts in all life forms on it (3); wherever it goes, it comes back around. The only times when this becomes a problem are when we cause large unbalances in the way in which water works. For example, some groundwater exists in places where there used to be much more humidity but now there is not (known as fossil water); so when such water is used it must be at a slow enough rate that it can be replenished, or it can cause the entire water table in the area to drop and so create less of a resource (4). This is something which needs to be considered in particular in places such as the Sahara Desert, where there is a growing demand for modern water extraction techniques which are perhaps not always conscientious of water usage (5). On the other hand, if as many scientists argue (6) the ice caps are melting, then rather than running out of this resource we are in fact in for an overabundance.

From this perspective the idea of not wasting water is relevant only in terms of efficient planning and distribution.

It is physically possible for everyone to have access to water; it is simply that often the organisation of this, for many reasons including financial-based ones, does not always take everyone into account.

In many places, indeed, using water efficiently is actively discouraged. Creating a greywater system in many states in the US often involves a lengthy legal permit process which can be quite restrictive (7).

Considering the Resource

My own experience of people living in the mountains of Spain is of a handful of self-built houses whose inhabitants pipe water to where they want using simple methods and unobtrusive hoses. The amount of water being taken from the stream in this way is negligible as long as the stream keeps flowing; yet if these hoses are unregistered they are illegal. Despite this the local council have entered into agreement with a major international water company allowing them unrestricted access to a certain number of litres per year of one river, regardless of the amount of water which is actually in the river to begin with.

These examples again suggest a view of water as a thing which needs to be gathered hold of; protected; kept. But this idea disregards the basic energy of water itself which is that of flow.

This movement is perpetually happening: at the beach, even in between tides on a still day, the waves are still rippling along the shore; in the height of a dry summer, even when the path of a stream has seemingly turned to cracked dirt, the stream has not gone away. Step a little closer; bend under the hanging branches of the crowding shrubs at the bank and put your hand out to investigate… as you dig your fingers down into the mud you will begin to reveal the steady drip of the water over the jumbled rocks once more.

It may be difficult for us to be consciously aware of this flow, but understanding that this is the way that water behaves is a key part of understanding how we can best use it to benefit us and the world around us.

Harvesting Right

In many places, water is not obviously occurring or the landscape is not conducive to efficient use of water, so it is difficult to grow crops. These problems have been being turned into solutions for centuries, from the impressive aqueducts of the Roman (see for example 7) and Moorish Empires (see for example 8) to the simple activated charcoal filters traditionally used for drinking water in Japan (see for example 9). The finely contoured terraces which abound in China, South East Asia, Spain, and indeed anywhere the landscape was a little too vertiginous for optimum growing are testament to the ingenious ways we have found to catch and store water. The terraces are an example of the use of the “three s’s” : Slow, Sink and Spread – rather than letting water to flow swiftly over the surface of the slope they catch it and allow it to permeate more slowly into the earth. When made in a way which flows with the water such systems can be very effective; it is only if something starts blocking the flow completely that problems may arise. As Juliana Birnbaum and Louis Fox (10) put it,

“Cultures throughout the world and throughout history that developed stable, sustainable relationships with nature did so through observation—a primary principle in permaculture.” – Birnbaum and Fox, 2014 (10)

As the climate continues to act in unpredictable ways, it seems more pertinent now than ever to utilise well the water around us in a way which takes into account the natural flow. We can do this in a number of ways, from landscaping our land to incorporate the “three s’s” by making swales and diversion drains, to building our own rainwater harvesting or greywater systems or compost toilets. I shall go into more detail on practical ways to do this in a following article. The most important thing to remember with all such systems is that water can really work nicely for us, if we work nicely with it.

There’s no need to worry about forgetting, however; our bodies, with every pump of blood our hearts create, are constant reminders of the principle of flow.


  1. Filho, W et al, 2014. Integrating Sustainability Thinking in Science and Engineering Curricula: Innovative Approaches, Methods and Tools. p.599. Springer: New York
  2. Cho, R, 2011. ‘From Wastewater to Drinking Water’. Columbia University, State of the Planet, 4/4/2011. http://blogs.ei.columbia.edu/2011/04/04/from-wastewater-to-drinking-water/- retrieved 16/03/15
  3. Murphy, M, 2004. ‘Global Water Cycle and Supplies’. http://academic.evergreen.edu/g/grossmaz/murphymw/ – retrieved 16/03/15
  4. Elmhurst College, 2015. ‘Water Table Draw Down or Groundwater ‘Mining”. http://elmhcx9.elmhurst.edu/~chm/onlcourse/chm110/outlines/pumpwater.html – retrieved 16/03/15- retrieved 16/03/15
  5. Consultative Group for International Agricultural Research (CGIAR), 2012. Groundwater Availability and Use in Sub-Saharan Africa: A Review of 15 Countries. CGIAR: Montpelier. http://www.iwmi.cgiar.org/Publications/Books/PDF/groundwater_availability_and_use_in_sub-saharan_africa_a_review_of_15_countries.pdf – retrieved 16/03/15
  6. Radford, T, 2014. ‘New Satellite Maps Show World’s Major Ice Caps Melting at Unprecedented Rate’. Ecowatch, 1/9/14. http://ecowatch.com/2014/09/01/greenland-antarctic-melting-climate-change/ – retrieved 16/03/15
  7. Babcock Jr, RW and Walton, R, (eds) 2008. The Hydraulics of Roman Aqueducts: What do we know? Why should we learn ? ASCE-EWRI: Hawaii, USA. Available as a PDF here: http://espace.library.uq.edu.au/view/UQ:138266 – retrieved 16/03/15
  8. Crow, JA, 2005. Spain: The Root and Flower: An Interpretaion of Spain and the Spanish People. p. 74. University of California Press: California
  9. White Charcoal, 2015. ‘History and Origin of White Charcoal’. http://www.whitecharcoal.com/history_country.php – retrieved 16/03/15
  10. Birnbaum, J; Fox, L, 2014. Sustainable (R)evolution: Permaculture in Ecovillages, Urban Farms, and Communities Worldwide. North Atlantic Books: Berkeley, California



5 thoughts on “Understanding Water Part 1: The Theory of Flow

  1. Not taking anything away from anything else, but, is it true that oil is being recreated as we speak; at the same rate as before? I thought much of the oil was deposited during the carboniferous period, before the fungi evolved to break down the new group of plants, i.e. trees. And so, in the absence of these fungi, the carbon from the air was locked away in the trunks that fell over the years and got buried deep down before the decomposition process even began… Just throwing this out there…

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