Solutions to droughts, fires, and floods

How restoring the water cycle mitigates these connected issues

A cycle of drought, fire and floods is currently entangling the earth; California, British Columbia, Australia, Greece, Brazil are some examples of places that recently have had been hit by all three nature events. That these disasters are interlinked is not always noticed.

Fires can lead to floods. When fires get too hot they can cause a waxy coating to form on the soil, that then stops the landscape from absorbing huge rains when they arrive. Instead the stormwater flows downhill, gathering speed, to inundate urban areas with floodwaters. In 2020, wildfires unfurled across the Australian landscape, which resulted in a degradation of the soil. Two years later in 2022, the state of the soil, unable to absorb all the stormwater, was a cause of the floods in Australia that have affected millions of people.

Floods can lead to droughts and wildfires. When floods come it can wash away topsoil and create landslides. The loss of topsoil leads to less water getting absorbed into the landscape in the future when it rains and less water sinking down into the aquifers below. With less water infiltrating underground, less water will slowly seep out over the ensuing months, to keep rivers running, and to keep the soil and vegetation moist into the dry season. With a less hydration, the land becomes more susceptible to wildfires.

Fires can lead to droughts. As we deforest the land, and as fires destroy a lot of the vegetation, there is a disruption of the water cycle in terms of an important mechanism that has yet to get a lot of attention. Forests act as conveyor belts of moisture inland. Without a chain of forests going inland, rainfall decreases exponentially the further inland one goes inland. With a chain of forests the rainfall continues to be about the same amount as one goes inland. Two Russian physicists Anastassia Makarieva and Victor Gorshov have mapped out this pattern of rainfall. [1] This phenomena of moving the water is called moisture hopping in the climate science literature. Climate scientist Francina Dominguez did computer simulations of the moisture hopping in the US, and found that the drought in the US midwest in 2012 had partly to do with the drought in California, because not enough water vapor was being passed inland. Moisture from California accounted for 15% of the rains in the Midwest. [2] Climate scientist Antonio Nobre has shown how the burning of the forests in the Amazon will cause loss droughts in other parts of South America.[3] Meteorologist Millan Millan has shown how the paving over of nature in Spain, has led to the loss of rains there. [4,5] Nature normally evapotranspires water to combine with the ocean moisture to create rain, but with the onset of urbanization, comes the loss of evapotranspiration, and the onset of subsequent droughts. Michal Kravcik, Jan Pokorny and their colleagues in their booklet “Water for the recovery of the climate ; the new water paradigm”, termed this process of water evapotranspiring from the land into the air and then raining back to the land again as the ‘small water cycle’. This small water cycle can help propagate water across the land in lateral ‘hops’. [6]

In the 2020 California wildfires, two million hectares of forest was lost, and 20% of old growth trees. That means the rain conveyor belt weakened significantly, which will lead to more droughts further inland in the US in the future.

So what can we do about this cycle of disasters?

Enhancing the ability of landscapes to retain rainwater is a solution which addresses all of the types of disasters.

If landscapes can retain more water, then it will become more hydrated into dry season, which will then lead to less wildfires. And if landscapes can absorb more water when it rains uphill, then the volume and velocity of floods will be less at lower elevations.

There are many ways to retain more water in the landscape.

One is to increase the ability of the soil to retain water. Increasing soil sponginess can decrease flood strength by 20% [7]. Each one percent increase in organic matter in soil increases the soils ability to hold water by 20,000 gallons per acre. Many methods exist to increase organic matter. Hugelkultur is a process where branches and logs are buried in the ground to decompose to form organic matter. Inoculation of the soil with mycelium which helps to break down biomass to form organic matter. The fields of permaculture and regenerative agriculture provide a compendium of methods to improve the ‘soil carbon sponge’.

Another way to retain more water in the landscape is to use a variety of earthworks like berms, swales (digs dug into the ground), terraces, check dams, water pianos [8] that slow or catch the water, where it can then sink more easily downward. When the water goes underground it usually travels at a much slower rate. This means it can still be seeping out to keep rivers flowing, and landscapes hydrated into the dry season. If enough water seeps underground to create shallow water tables, plants can use capillary action to draw up that water from the groundtable.

A third way to retain more water in the landscape is to restore wetlands in the floodplains and the rivers that feed them. Wetlands and their vegetation can absorb a lot of floodwaters. [9,10,11] One acre of wetland can hold one million gallons of water during floods. Wetlands can release water slowly so that the landscape can be more hydrated into dry seasons. Wetlands also are a way to fill up aquifers and to raise the water table. Wetlands can also increase the humidity, and lower temperatures.[12,13] This lead to winds which are less dry and hot, winds that are thus less likely to fan wildfires. Wetlands are also natural firebreaks.

If we restore our rivers, and remove the levees and concrete banks, they can overflow into the floodplains and wetlands during larger rains.

The ability of the landscape to absorb floodwaters is important. Half of the water that California gets is from atmospheric rivers which are huge amounts of water vapor originating from the ocean, that then dumps itself on the land. If that water is not absorbed, then the drought situation in California becomes worse.

Dams are not the best solution to absorbing atmospheric river waters, as they have to release a lot of that water after big storms in order to maintain a buffer for more storms. Wetlands and aquifers are a better solution for storing our water. Wetlands can guide the water into the aquifers below. Aquifers have much larger storage ability than dams. And then farms and cities can use wells to bring up the waters.

Dams also also problematic because they remove soil and sediment from the ecosystem, and the role they can have in growing more vegetation.

So we want to transition to a water infrastructure that so dependent on dams, to one that is more of a dam-wetland hybrid. A transition to nature based solutions is both more efficacious and financially wise. [9]

A fourth way to retain more water in the landscape is to shift our modern farming system to one of regenerative agriculture. Modern farming with its tilling, monocultures, pesticides, and synthetic fertilizers has been degrading our soil over the decades so that it can now no longer hold as much water. Because crops cannot have too much water, modern farming installs drainage systems under the soil, to drain the water away to rivers and then the ocean. If instead we switched to regenerative agriculture, this would increase the organic matter and microbial life in the soil, which would then allow the soil to absorb more water, and farms would no longer need to have so much tile drainage to drain the waters from the soil.

Modern tile drainage systems are causing our continents to lose a lot of water [14,15,16,17], and plays a huge role in creating our drought- fire- flood cycle. The farms get water funneled to them, water which is taken from naturally flowing rivers which could be hydrating other part of the landscape, and then funnels that water faster back out to the ocean. When our continents lose water, they is less water to hydrate the landscape, less water to fill the aquifers, and less water to evapotranspire to help create rains. As permaculturist Sepp Holzer says "The soil is drying out, water is being lost, and the retention space, the natural water storage system of the earth is becoming dry. Flora and fauna are disappearing. In the end the earth will burn because it is so dry”. Its important we raise awareness of how modern farming practices and the role they are playing in our ‘natural disasters’. Heres a video I made to illustrate this issue

A fifth way of retaining more water in the landscape is stop siphoning off the water through aqueducts to far away cities. For instance Owens valley in California has become dry and desertified as most of its water is siphoned off to Los Angeles. Winds originating from, or moving through Owen’s valley then become more dry and hot, and help fan wildfires across California. The solution is to instead have cities, like Los Angeles, provide its own water. The rains in LA can provide for half the drinking water of its inhabitants. LA is currently depaving land and creating 9 multi-billion dollar wetland projects, so that it can funnel its rainwater into the aquifers below [19]. The wetlands will have woodchips, microbes, biochar to cleanse the water as it moves downward. LA will then use wells to bring up the water when needed. The aquifers below are a much larger facility to store water than dams. As cities provide their own water, it saves enormous amounts of electricity, as they no longer need to pump water long distances.

Our urban areas would also siphon off a lot less water from the wilderness if they separated our sewage system from the water system. There is no need to use a lot of our freshwater to wash away our waste, and thus help propagate the drought, and the possible subsequent fires. As Brock Dolman says, we should shit in the carbon cycle, not in the water cycle. This would take a deeper cultural shift, so is more of a longer term solution, but its an important shift to start beginning to make. We can start by seeding these ideas and creating smaller demonstration projects.

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The issue of how we can have grow more vegetation and trees while also reducing wildfire risk is a more nuanced question. We need more vegetation to in order to create a conveyor belt of water moving inland. We need more vegetation to slow floods, and to help prevent soil getting eroded during floods. And we need vegetation to help slow rainfall and guide it into the soil to hydrate our landscapes. However one could also argue that we need less vegetation to lessen wildfires.

The issue of fire is a complex and multidimensional one. Nature if left alone creates wildfires, and in the USA forests pre 1900s used to resemble a patchwork quilt, with some areas having been burnt down. This patchwork quilt was a lot less likely to lead to larger wildfires. [19] Smaller fires help prevent bigger ones. Smaller cool fires also can help the carbon cycle, by turning dead biomass into a burnt carbon form that enriches the soil. Indigenous tribes in the US used to do controlled burns to prevent larger wildfires.

Wildfires have been getting bigger and hotter over the years, and this is a problem, because hotter wildfires can lead to the soil getting a waxy coat that prevents water from infiltrating. Hotter wildfires can also kill all the bacteria and fungi that help decompose bio-matter. And the wildfires are also burning a lot of toxic material when it gets into urban areas. It used to be the policy in the US to put out all wildfires, and not to start any, but now the policy is shifting to controlled burns to clear out some of the dried underbrush, and to create more of a patchwork quilt of forest that is less likely to create huge, hotter fires.

Clear cut forests that have been replanted over the years too close, have led to trees that are homogenous and too densely packed. Thinning of some of these forests can help with fire prevention.

On the other hand there is also evidence that naturally grown forests in the Western US that have been thinned are more at risk of wildfire. [20] Curtis Bradley, Chad Hanson, and Dominick DelaSalla studied 1500 wildfires between 1984 and 2014 in pine and mixed conifer forests, and found those that have been thinned had more wildfire. [21] The theory is that intact forests can create humid microclimates that fend off wildfires. Dead logs in those areas, hold 24 times the amount of moisture of soil, help create this humidity, and so do not need to be cleared. Old growth forests in particular are good at holding moisture, and so those need to be protected from forestry management.

The balance of growing more vegetation and fire prevention will be different in different climates and bioregions. Different techniques will be applicable in each area.

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In restoring our forests and vegetation, its best to let nature do as much of the work as possible, our human role is to remove some of the impediments. Vegetation has a way of dispersing their own seeds through wind, and animals. In that way we avoid issues like growing trees too closely together, and the ecosystem can adjust to the many rhythms of nature, from the winds, to the fires, to the rains. Restoring becomes rewilding. Nature knows how to dance to the needs of water and fire.

Alan Watson Featherstone, forest restoration expert from Scotland, has put together a set of ecorestoration principles 1. Work from areas of strength - the areas where the ecosystem is closest to its initial condition. 2. Pay particular attention to ‘keystone species’ 3. Re-establish ecological processes such as the use of pioneer species, natural succession etc to facilitate the rewilding process. 4. Mimic nature wherever possible. 5. Recreate ecological niches where they have been lost. 6. Re-establish ecological linkages- reconnect the threads in the web of life 7. Control and/or remove introduced non-native species 8. Remove or mitigate the limiting factors which prevent rewilding from taking place naturally. 9. Pay special attention to species with limited ability to disperse - eg aspen, woods ants, twinflower. 10. Reintroduce species that are unlikely or impossible to return by themselves. 11. Re-establish essential ecological processes, such as predator-prey dynamics and natural disturbance, which are absent. [22,23]

These eco-restoration principles combined with methods to rehydrate the landscape can help our continents deal with drought, fire and floods. As we shift from the grey infrastructure of our manmade water structures to the green infrastructure, back to the original nature based solutions, we will find ourselves saving billions of dollars in drought, fire, and flood costs [9].

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If you would like to financially support my water projects as we work to grow the regenerative water movement : www.patreon.com/watercology, or you can also become a paid subscriber of this newsletter.

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References:

[1] Makarieva, A. M.and Gorshkov, V. G.: Biotic pump of atmospheric moisture as driver of the hydrological cycle on land, Hydrol. Earth Syst. Sci., 11, 1013–1033, https://doi.org/10.5194/hess-11-1013-2007, 2007

[2] Dominguez, F., Villegas, J. C., and Breshears, D. D. (2009), Spatial extent of the North American Monsoon: Increased cross-regional linkages via atmospheric pathways, Geophys. Res. Lett., 36, L07401, doi:10.1029/2008GL037012

[3] Sampaio, G., Nobre, C., Costa, M. H., Satyamurty, P., Soares-Filho, B. S., and Cardoso, M. (2007), Regional climate change over eastern Amazonia caused by pasture and soybean cropland expansion, Geophys. Res. Lett., 34, L17709, doi:10.1029/2007GL030612. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2007GL030612

[4] Millán, M. M. et al (2005). Climatic Feedbacks and Desertification: The Mediterranean Model, Journal of Climate, 18(5), 684-701. https://journals.ametsoc.org/view/journals/clim/18/5/jcli-3283.1.xml

[5] Millán,Millán. (2014). Extreme hydrometeorological events and climate change predictions in Europe. Journal of Hydrology 518 (2014) 206-224. Journal of Hydrology. 518. 206-224.  

[6] "Water for the recovery of the climate: A new water paradigm" M. Kravčík, J. Pokorný, J. Kohutiar, M. Kováč, E. Tóth http://www.waterparadigm.org/download/Water_for_the_Recovery_of_the_Climate_A_New_Water_Paradigm.pdf

[7 ] “Turning Soil into Sponges” Union of Concerned Scientists https://www.ucsusa.org/resources/turning-soils-sponges

[8] Their is a picture of a water piano in thumbnail of this blog post https://peopleandwater.international/project/wildfires-in-greece/

[9] “How nature can help reduce flood risks” The Nature Conservancy 1/28/20 https://www.nature.org/en-us/what-we-do/our-priorities/tackle-climate-change/climate-change-stories/natures-potential-reduce-flood-risks/

[10] Acreman, M., Holden, J. How Wetlands Affect Floods. Wetlands 33, 773–786 (2013). https://doi.org/10.1007/s13157-013-0473-2

[11] Bullock, Andy, and Mike Acreman. "The role of wetlands in the hydrological cycle." Hydrology and Earth System Sciences 7, no. 3 (2003): 358-389.

[12] Liu, Y., Sheng, L. & Liu, J. Impact of wetland change on local climate in semi-arid zone of Northeast China. Chin. Geogr. Sci. 25, 309–320 (2015). https://link.springer.com/article/10.1007/s11769-015-0735-4

[13] Sudd wetland in upper Nile which is approx 150x150mile in size, if drained would lower humidity by 30-40% during dry season and temperature would rise 4-6 celsius. During wet season impact is small <10%. This is in area of Sudd and downwind. Their conclusion is that impact on rainfall is small because of amount of water , but if its a catalyst for rainfall is something paper does not take into account

Mohamed, Yasir A., B. J. J. M. Van den Hurk, H. H. G. Savenije, and W. G. M. Bastiaanssen. "Impact of the Sudd wetland on the Nile hydroclimatology." Water Resources Research 41, no. 8 (2005). https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2004WR003792

[14] Golmohammadi, Golmar, Ramesh Rudra, Shiv Prasher, Ali Madani, Mohamed Youssef, Pradeep Goel, and Kourosh Mohammadi. "Impact of tile drainage on water budget and spatial distribution of sediment generating areas in an agricultural watershed." Agricultural Water Management 184 (2017): 124-134.

[15] Abtew, W. and Khanal, N. (1994), Water budget analysis for the Everglades Agricultural Area Drainage Basin. JAWRA Journal of the American Water Resources Association, 30: 429-439. https://doi.org/10.1111/j.1752-1688.1994.tb03302.x

[16] Skaggs, R.W., Breve, M.A., & Gilliam, J.W. (1994). Hydrologic and water quality impacts of agricultural drainage. Critical Reviews in Environmental Science and Technology, 24(1), 1-32

[17] Dinar, Ariel, and David Zilberman, eds. The economics and management of water and drainage in agriculture. Springer Science & Business Media, 2012.

[18] TED talk David Sedlak  and  https://www.stormh2o.com/bmps/article/13004313/nature-makes-a-comeback

 [19] TED Talk Paul Hessberg

[20] “Smokescreen” book by Chad Hanson. NCCCA video about Chad Hanson on youtube.

[21] Bradley, Curtis M., Chad T. Hanson, and Dominick A. DellaSala. "Does increased forest protection correspond to higher fire severity in frequent‐fire forests of the western United States?." Ecosphere 7, no. 10 (2016): e01492.

[22] TED talk Alan Watson Featherspoon

[23] https://alanwatsonfeatherstone.com/