Is saving water enough?
‘When we try to pick out anything by itself, we find it hitched to everything else in the Universe’ (as John Muir wrote). Never is this truer than in the world of water.
We hear a lot about saving and conserving water. Sustainable Development Goal 6 aims to “Ensure availability and sustainable management of water...” since “More than 2 billion people globally are living in countries with excess water stress, defined as the ratio of total freshwater withdrawn to total renewable freshwater resources above a threshold of 25 per cent” (https://sustainabledevelopment.un.org/sdg6 )
Agriculture is a key part of delivering SDG 6. The FAO estimates (2016) that up to 69% of the world's freshwater withdrawal is being used for agriculture. So it would seem to make good logical sense to talk about aspiring to ‘save’ water in agriculture.
But what do we mean when we describe ‘saving’ water as a goal in agriculture?
In many cases, “saving water” is about reducing the amount of water a grower withdraws for irrigation while aiming for the same yield. In this case the main challenge for the producer is to apply all the water that a crop needs, right when it needs it; therefore avoiding evaporation from the soil and runoff. This efficiency improvement is often referred to as saving water, and while more efficient use is a good thing, we need to consider the full effects to understand the outcomes and not simply call this a sustainable practice on its own. Do we know if someone or something is relying on that ‘excess’ water, for example the runoff recharges some groundwater stores that are used further downstream? Are there important off-farm impacts in the community and broader watershed?
Some years ago the International Water Management Institute (IWMI) found out that the ultimate outcomes were not as they expected. The case in Pakistan it is a great study to challenge some of our thinking. While farmers had adopted water conservation technologies, water use had actually risen http://www.iwmi.cgiar.org/2013/12/water-savings-arent-always-what-theyre-cracked-up-to-be/
There is a fundamental context to consider too - whether there is even enough water in the river basin. Many of the world's river basins are either 'closed' or are 'closing', which means that the water used within them already exceeds or is approaching the amount of renewable water available. If we make more efficient use of water, do these ‘savings’ make a real difference or is it still that there is just not enough water to go around no matter how efficient we are?
That’s not to say that trying to be more efficient with water isn’t worthwhile but, ultimately, the delivery of sustainable outcomes is not simply about just applying proven best practices or focusing on ‘water saving’ as your indicators of success. It depends upon understanding water availability, the interdependence of water use within water basins as well as the signals and behaviors that define water use. So when we pick out saving water as a measurement of success we need to be mindful of the full picture - and what else it is hitched to.