Water Miles

The following is a copy of an article I wrote which was published in the October/November 2008 edition of the NZ Plumbers’ Journal. Feel free to comment on the article or the concepts within it.

Introduction

New Zealand has an abundance of water compared with most countries and is able to export 5,000 tonnes of ‘virtual water’ per person every year in our – primarily agricultural – exports. In a sense then, Kiwis have a negative Water Footprint. But complacency about this fact leads to a failure to conserve water. The problem then becomes one of infrastructure cost and energy use rather than water use. This is a critical fact to understand and is effectively the opposite of hydro power (using energy to ‘create’ water) argues sustainability consultant Craig Brown.

Here, he describes his concept of ‘Water Miles’ – a measure of how much energy is required to provide water and wastewater services. He also defines and discusses Virtual Water, Peak Water and Water Footprints – concepts you’ll be hearing more about over the next year in the media.

Water Miles

Our water and wastewater systems are killing people. Here’s how:

• Significant amounts of energy are required to treat and move water and wastewater.
• Energy use causes greenhouse gas emissions.
• Greenhouse gas emissions are responsible for climate change.
• The World Health Organisation has stated that climate change is already responsible for 150,000 deaths and around 5 million Disability Adjusted Life Years (DALYs) globally per annum (Patz et al., 2005).

In New Zealand water and wastewater services account for around a quarter of all the greenhouse gas emissions for which local councils are responsible (Communities for Climate Protection NZ, 2006). It’s higher in Auckland, where councils currently generate 35-40% of their greenhouse gas emissions providing these services (Rodney District Council, 2006; Waitakere City Council, 2005). This is the biggest single contributor to climate change of any council services. Just think about that – councils use more energy moving water around than they do in their buildings, vehicle fleets or street lighting. Not only that but they also report that the level of energy use will grow at a greater rate in the water sector than in the other services they provide. And it costs a phenomenal amount of money – over a third of the rates bill in Waitakere City!

One major contributing factor to Auckland’s high energy use is the additional water supplied via the Waikato pipeline (and the additional wastewater burden this creates). In the Assessment of Environmental Effects for the Waikato pipeline project there was no consideration of the carbon emissions arising from the construction and operation of the pipeline (or the Mangere wastewater treatment plant upgrade that was required as a consequence of the new water supply) and yet it is hard to think of a more significant environmental effect than climate change. The designers of this massive construction project, which involved a huge number of heavy truck movements, and vast quantities of concrete, and which has tremendous ongoing electrical pumping and treatment costs, simply didn’t have to consider climate change – or peak oil, for that matter.

Once a city is fully utilising its nearby high quality water, further supplies require greater levels of pumping and treatment. Additional supplies of water create additional volumes of wastewater. Additional volumes of water and wastewater result in the need for upgraded pipe networks. Claimed economies of scale with centralised infrastructure do not apply once certain critical constraints are exceeded, as they have been in Auckland.

These issues are not well-understood. And when they are not understood large corporations can convince the government to allow them to build unsustainable schemes of questionable benefit, whilst stating that ‘demand management options are limited’. By law corporations must maximise profit to shareholders, which for water companies that does not mean selling less water. Try telling the people of Seattle that demand management isn’t a viable option: the Seattle area used less water in 2003 (the year after the Waikato pipeline began operation) than it did in 1950 and has managed to keep water use constant as the region grows by employing demand management strategies. Seattle is the most educated and latterly one of the most economically powerful cities in the US, with a population of more than 4 million people in the metropolitan area.

To increase awareness of this issue and to promote sustainable behaviour I have proposed a new concept: Water Miles, which bears comparison with the popular concept Food Miles. Simply put, Food Miles are a measure of the environmental cost of a food item, which is often related to the distance it has travelled from the source to the consumer, but also encompasses the overall environmental impact of its production and transport, including production costs such as feed, fertiliser and pesticides as well as distribution method and distance (including the consumer’s journey). It is usually expressed as a carbon emission. It could also include an assessment of other environmental impacts (such as eutrophication of lakes due to high fertiliser use or stock effluent run-off).

‘Water Miles’ relates to the energy expended or carbon emitted in the sourcing (dams, pipelines, pumping), treatment (chemicals, energy) and distribution (pumping) of water. It extends to wastewater, which has to be collected (pumping), treated (chemicals, energy) and disposed of (pumping). It could also include an assessment of other environmental impacts (untreated or poorly treated effluent entering the harbours, the embodied energy of concrete pipes, plants and dams, etc.).

With this concept in place, it is easier to understand the need to:

• reduce water use
• recycle greywater onsite (there’s no point pumping it a long distance for treatment and then pumping it all the way back)
• capture water from the roof
• dispose of wastewater onsite (where possible).

Without it, one can end up with the current situation where Watercare can propose yet another round of major infrastructure upgrades including a new wastewater treatment plant and new pipes and pumping stations to service them at a capital cost of many thousands per person served (Watercare, 2008). Although the latest report pays lip service to demand management, it bases its calculations on the assumption that rainwater tanks cost more than a desalination plant, which is highly questionable, and it ignored greywater altogether, which is currently already cheaper than Auckland water (Brown, 2007). Without adequate demand management a new water supply source will be needed by 2026. Any new infrastructure will use more energy than that presently in place and will come at a time when energy costs keep increasing, reflecting the economic, if not social costs of climate change and peak oil.

(928 Words – not including references below)

References

Brown, C. (2007) ‘Greywater Recycling – Risks, Benefits, Costs and Policy’. Presented at the NZ Water and Waste Association Conference, September 2007, Rotorua.

Communities for Climate Protection – New Zealand (2006) ‘Inventory Report’. CCP-NZ: Wellington. Retrieved on 5 August 2007, from: http://www.iclei.org/fileadmin/user_upload/documents/ANZ/CCP/CCPNZ/Measures/CCP-NZ_InventoryReport2006.pdf

Patz, J.A., Campbell-Lendrum, D., Holloway, T. & Foley, J.A. (2005) ‘Impact of Regional Climate Change on Human Health’ Nature. 438, 7066, 310-317.

Rodney District Council (2006) ‘Greenhouse Gas Emissions Analysis and Forecast: Milestone One Report’ Appendix to September 2006 Minutes. Retrieved on 5 August 2007, from: http://www.rodney.govt.nz/council/2006minutes/September/CEA2109_Item9_Appendix1.pdf

Waitakere City Council (2005) ‘Agenda of City Development Committee, 2 December 2005′. Retrieved on 5 August 2007, from: http://www.waitakere.govt.nz/AbtCnl/ct/pdf/citydvlpmt2005/081205ag.pdf

Watercare (2008) ‘Three Waters Draft Strategic Plan: Discussion Version’. Retrieved on 6 September 2008, from: http://www.watercare.co.nz/default,publications.sm

Related Concepts

Peak Water

This concept is similar to Peak Oil in the sense that the world’s easily available water is being used to full capacity or indeed beyond full capacity. For example the green revolution in India and the Western United States irrigated area (which grows more than 50% of the crops produced in the US) are both supplied from underground aquifers at rates many times greater than the recharge rate (up to 100 times). Prior to the discovery of the Ogallalla aquifer in the Western US the area was a dust bowl (as described in ‘The Grapes of Wrath’) and without a replacement water supply will soon revert. As with oil, new supplies will be more difficult to obtain, being of lower quality and geographically distant. As with oil there is likely to be conflict.

Water Footprint

A water footprint is a measure of the total water used to produce goods and services that a particular individual, business or nation uses. It is made up of two components: direct water use and indirect use, where indirect use comprises virtual water. It bears comparison with carbon footprints.

Virtual Water (aka Embedded Water)

Food and other products which are imported from overseas have an embodied water content. In other words these goods have required a certain amount of water to make them (the water is ‘virtual’ or ‘embedded’ as it is no longer there in a physical form). It is related to the embedded energy concept. The following are some examples:

• A cotton shirt uses 2,700 litres of water
• A cup of coffee really requires 140 litres of water to produce (without milk or sugar)
• 1 kg of beef requires 10,000-20,000 litres of water
• 1 kg of milk powder requires 8,500 litres of water
• 1 kg of rice needs 2,300 litres of water
• 1 litre of milk needs 800 litres of water

Most western countries could not find the water required to make all of the products themselves if for some reason they could not import them. For example, Britons consume thirty times as much virtual water as physical water, amounting to 58 bathtubs full of water for every person every day (WWF, 2008).

The increasing cost of energy and rising standards of living in the developing world, plus absolute water resource limitations, mean that it will become less affordable to import goods, so the water demands will increasingly fall back to the consuming countries.

(409 Words – not including reference)

References

WWF (2008) ‘You Take 58 Baths a Day – Virtually’. Retrieved on 9 September 2008, from: http://www.wwf.org.uk/news/n_0000005278.asp