Damming Water: The Human Island (Chapter 13)

It’s always disturbed me; fresh water filling that ceramic bowl just waiting for someone to relieve themselves in it. We must be the only non-aquatic species that makes the conscious decision to putrefy clean water.

Hypocritically to this is the rage discussed in chapter five regarding the Murray Darling Basin Plan. How can we get angry when water rates or water restrictions increase, but still feel comfortable plumbing out toilets to a drinkable water supply?

It’s an all too often occurrence nowadays to complain about the expense of resources (ie. water, food or energy) while making at best token gestures to reduce waste. Sivak and Tsimhoni (2009) for instance found that vehicle efficiency only showed signs of dramatic improvement in the wake of oil scarcity, to only plateaux again when general concern had waned [17].

The Australian Bureau of Meteorology has stated that as the climate continues to change, we are more likely to experience increasing numbers of hot dry days and an increase in intense rainfall. In this regard, the prolonged drought over the south east of Australia over the first decade of the 21st century followed by the record breaking rainfall, causing widespread flooding, throughout spring and summer of 2010-2011 may provide some indication of what we can expect to become increasingly normal weather patterns.

Precipitation will forever remain the cheapest and most efficient source of desalinated water and yet we seem so quick to forget the past few years debate over desalination plants, soil salinity, aquifer pollution / recharge, waterway bank erosion / pollution and widespread wetlands loss / stagnation to instead debate increased dams and flood prevention planning. Of all our resource management issues, water is arguably the worst managed; where the public tend to be the most fickle.

Is it that we see our planet as the blue ball?

As mentioned above, precipitation is the cheapest source of desalinated water and is likely to become more infrequent, but more intense, as the world continues to warm (think also of the freak snow storms of the northern hemisphere over the past couple years). We will need to wizen up on water management and do so quickly.

Over recent decades, there has been a growing awareness of the importance of wetlands, not only for the abundance of species which they generally support (see chapter 5 above and Innovation is Key, chapter 6) but also for their ability purify water. This is yet another wonderful example of ecological services that we rely upon.

The problem for wetlands and river ways however, is that human diversion of water tends to restrict water movement (especially in drought conditions), leading to oxygen levels to decrease, where harmful bacteria can then take over; ie. stagnate water (image 7). Species survival is threatened by restrictions to water movement both through stagnation and potential limitations to suitable mates (see the Victorian Fishways Passage for an example). Overall, stagnation reduces water quality, thus stands as another example of water mismanagement.

Another important aspect not often discussed is evapotranspiration. It is a difficult life, believe it or not, relying on the sun and water (and of course CO2) to produce food, but also water to remove heat caused from too much solar energy. It’s a balance that arid plant species are amazingly adapted to coping with.

Think, for instance, of a mallee eucalypt: it’s the middle of a summer heat wave. There’s been little rain the past four months. You have more than enough sunlight, but very little water – how do you both transpire, to remove heat, and photosynthesise to sugars? Amazingly, many of these species are incredible water conserves and also able to tolerate temperatures that would cook many temperate species (well, these species are likely to transpire and thus wilt rather than cook).

Evapotranspiration is an important part of climate, being that it uses a significant proportion of the solar energy at the Earth’s surface, as well a major component of the hydrological cycle (ie. in Australia, evapotranspiration returns close to 90% of precipitation back to the atmosphere) but most importantly, water availability to ecosystems (for evapotranspiration as well as other functions) is most essential for ecosystem health and all the ecological services that they provide.

This in turn ensures increased fresh water security for human activity through various means:

  • Improving water movement, especially through diverse wetland habitats, is one of the easiest methods for improving water quality.
  • Cloud forests directly capture water for the atmosphere, providing a source of fresh water.
  • As mentioned in chapter 3, forests also provide storm surge protection, which will also assist with managing future flooding events, while also assisting in the capture of fresh water as precipitation becomes less frequent but higher intensity.

By islandising our species, fresh water will be without a doubt the most unreliable resource available to human activity. As water is so important to every aspect of human life, this fact should merit management that is both persistent and long term rather than the typical knee-jerk reaction. We can’t simply dam every last drop until we wish to use it, nor can we expect waterways to remain health whilst supporting whatever industrial, agricultural and residential use it meets along the path.

We’ve tried all of this; only to turn on each other to find someone else to blame when it eventually fails. We must stop this now or else we run the risk of a similar fate to the next cistern full of fresh water.

Reference
[17] Sivak, M., and, Tsimhoni, O. 2009. Fuel efficiency of vehicles on US roads: 1923-2006. Energy Policy. 37(8). pp 3168-3170. doi: 10.1016/j.enpol.2009.04.001

This is chapter thirteen of the series The Human Island: A Place of Ecological Ruin. To see the previous chapter, click here. As the series grows, the complete work can be found here.

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