Hydrology and Human Understanding

By Alex Wisser

The Capertee Hydrology project continues to roll along at pace and the learning deepens.  Last week we met at the project’s default home ground, The Glen Alice Hall, to listen to presentations by Hydrology experts Allan Nicholson and Andrew Wooldridge.  After tagging along to Stuart Andrew’s Natural Sequence Farming presentation and field day, I was keen to see what scientists would add to or take away from the understanding I was starting to build about how water works in the landscape.  

From the beginning, Andrew and Allen reiterated a number of the principles that Stuart Andrews had shared with us. One of these was that the land’s capacity to absorb water in a rain event depends on biodiversity and organic content in the soil.  Biodiverse ground cover, and soils with rich organic content, are able to absorb large amounts of water very quickly, reducing runoff and erosion and holding water in the soil so that it doesn’t enter the water table. This is what Allen described as “The Door” which permits water to enter the land and limits the rate of absorption. The amount of water that the land can hold, Allen referred to as “The Room”. When the room fills up, the water table rises. Eventually it reaches the surface and this is often when salt deposits are brought with it to cause salinity problems on the land.

I noticed here a divergence in perspective from that presented by Stuart Andrews.  Here hydrology was presented in terms of how it affected salinity.  From what I gathered, salinity becomes an issue when the water tables rise and salt is either flushed or rises from deposits in the land to the surface.  Cleared land, for instance, can suffer from salinity because without the heavy perennial vegetation to draw surface water, this water enters the groundwater, which rises, bringing salt with it. Much of what Andrew and Allen talked about was tied to how you could remove water from the landscape to reduce the rise of saline deposits to the surface. I regret that I didn’t ask whether our ambition to rehydrate the landscape could have any negative effects on salinity.

This question also marked another difference between Stuart’s presentation and those of Allen and Andrew. The former was unified, and compelling while Allen and Andrew’s presentation seemed scattered and left questions unanswered.  This is not to discredit their presentation, which delivered a wealth of fascinating information, but it did so in a manner that made it difficult to grasp. I realised it was a product of their scientific training and their long experience applying that understanding to diverse landscapes across Australia.  The fragmented nature of their delivery was due in part to their awareness that every general principle they employed was limited and contingent to the specific complex conditions of the particular situation to which it is applied. They even said this outright at several points.  The knowledge they presented was fascinating and substantial but if it gave me understanding with one hand, it took away something of the confidence with which I could hold it with the other.

The scientific method is essentially resistant to the kind of exposition that Stuart engages in. Not that Natural Sequence Farming isn’t predicated upon scientific fact. It is, but it also converts it into and mixes it with much that isn’t strictly science. It speaks with a confidence that ignores the partial and contingent nature of all knowledge, it leaps over contradiction and dispels the complexity of detail in order to deliver a cohesive, and convincing body of knowledge. Science must scruple over the partial and contingent nature of all knowledge, it must remind us at every step that what we don’t know is always greater than what we do. It is a powerful method for generating a certain kind of understanding, but at the same time it makes it difficult to communicate that understanding to non-scientists.

These were the thoughts swirling around in my head as I struggled to retain a few of the concepts being thrown at me.  The great thing was that Allan and Andrew were aware of this. They constantly returned from their diagrams and schemata to particular instances. I was fascinated by the way they prevented their own material from cohering into something unified by insisting on the contingent nature of their knowledge.  The power of Stuart’s presentation was the grace of its synthesis, the ease with which it communicated the incomprehensible complexity of a landscape in a way that captured the imagination. This is very powerful, because it renders coherent something that is so complex as to present as chaotic. The two modes can be understood as different scales of perspective - that you can look at something up close, in its minutest detail and you can look at it from far away, in its broadest entirety.  Both perspectives yield understanding, and both produce errors in perception.

It makes me wonder, as we are learning of the importance of biodiversity to a landscape, to the health of its soil and to the health of its ability to capture and retain water, whether another principle might be extrapolated by way of metaphor. It occurs to me that the health of human understanding might be determined by the diversity of ideas that are brought to coexist and conflict, to benefit, to feed, to fight within it. Perhaps the point is not to come to the monoculture of thought which has been the ideal of our philosophical tradition, but to cultivate and encourage the diversity of our thought. Just a thought…