I had never heard the term atmospheric river until recently, but now it is a thing we hear frequently.
One reason for this shift is that humans have disrupted the water cycle. Water that should be stored in the earth, nurturing the ecosystems which balance rainfall is not being replenished, due to poor water management. Deforestation and other clearing of vegetation bares the land leaving it denuded of the protective covering that holds moisture in the soil. This degrades the soil as it leaks out its soil carbon. At the same time as we bare the land, humans are pulling more and more water from deeper and deeper wells to supply industries and an increasing population with ever growing needs for water. As it gets drier we irrigate crops more, pulling water from lakes, rivers and underground reserves. The water that we pull out of these underground reservoirs took a very long time to get there.
This is the equivalent of burning the deep fossil stores of underground carbon, gas and oil. It takes a long time for those underground aquifers to fill up. They have the capacity to hold a tremendous amount of water. According to Professor Haikai Tane, an expert in watershed ecology in New Zealand, the deep underground reservoirs have the capacity to store 1000x more water volume than the earth’s surface. But we have to make sure we are replenishing as much as we take out. For this to happen, water needs to infiltrate deep into the ground. As much water as we pump out needs to sink back in.
Each time it rains, some of the rainfall runs off the earth’s surface. Some is soaked up by vegetation. Some of it evaporates quickly. The rain that is retained near the surface of the land may slowly infiltrate deeper through crevasses and cracks created by plant roots, insects and other features within the landscape. The water that is stored within rivers is 6–8 months old. The water stored within the aquifers of a floodplain is 8–10 years old. But the water in deep underground aquifers may be more than 20 thousand years old. It is the nature of water to flow downwards. It will flow downwards with gravity until it is trapped at a level of impermeable rock. As water accumulates below ground against an impermeable surface, it builds pressure. The more water that is stored underground, the more pressure it builds. It is this upward pressure that causes water to burst upwards, feeding natural springs and keeping streams, lakes and rivers flowing through the summer. The underground storage feeds life on earth and gives resilience to seasonality.
Climate change and South Africa’s water woes — an urgent call to community action
The top layer of Earth’s surface, where the plants grow, is the richest place for terrestrial biodiversity. This layer, from the top of the canopy of the tallest trees to the depths of their root systems is teeming with life, from the soil microbes, to the many plant species, to the insects, birds, animals and humans that derive their sustenance from this rich life. Without adequate fresh water, none of these life forms can survive. So the reserves of deep stored water are critical for mitigating climate extremes. But we can’t just keep drawing on those fossil water reserves without regenerating them.
The area below the rhizosphere, where the soil with all its soil life and the entangled roots of all the vegetation penetrates, is made up of rock in various stages of weathering. Closer to the surface rock breaks down into soil from the microbial action of biological life. The deeper we go the less biological life can survive without oxygen or light. Rock also breaks down from friction, collisions of materials, seismic activity. Every planet has layers of degrading rock and dust containing different textures and different sizes of rock, but only Earth has soil and life. This vast storage area under the rhizosphere is called the regolith. Earth is unique as well in that we have water, which can filter down and be stored in the cracks and fissures of the regolith.
So how can we assure that water, when it comes to us as more rain than we can use at once, finds its way into our deep reserves rather than washing away into our waterways carrying soil fertility away with it? The solution is actually simple. Allow excess water to accumulate and penetrate on the land in ponds, wetlands and soil organic matter. Seal it in with deep rooted perennial vegetation.
In a restoration study done in Australia in the salt-ravaged floodplain of Tarwyn Park, led by Peter Andrews, founder of the Natural Sequence Farming method, soil organic matter was raised back to pre-colonization levels of 16–18%. By excluding cattle grazing, creating small dams to slow the flow of the river and revegetating with indigenous plants the area was able to store 95% of the rainfall which fell in the area. One of the major findings of the project was that the floodplain was holding 1000x more of its moisture in the regolith than in the soil layer of the ecosystem.
Basically the whole area becomes like a large hydroponic system. The vegetation is taking its nourishment from nutrients dissolved in the water table. The water table becomes within reach of the rhizosphere. Deep rooted plants can reach down and pull water up to the soil level. Peter Andrews was able to document and show Bankers Trust R&D project that a 100 ha site increased floodplain soil storage from 200 Megalitre/100 ha to 2–3 Gigalitres / 100 ha ~ in the same area … an increase in watershed storage in regolith aquifers more than 1000 times greater than that in the high carbon soils.
This way of storing water meant that Australia was once a stepped threshold diffusion system of broad acre HYDROPONICS, a system which had been able to promote a rich and biodiverse fauna and flora including, until relatively recent times, megafauna. Many other parts of the world also supported similar traditional terrace terraqua cultures. But regardless of what part of the world we are talking about, restoring the earth’s capacity to hold water reserves is essential for life on earth. Collecting the water that falls on land, retaining it where it falls so that it seeps gradually into the deep aquifers of the regolith is the only way to provide the resilience we need to survive.
It means putting water first, at the beginning of ALL living processes, because without adequate water, no form of life can flourish.
