Rain doesn’t cause most floods, humans do

Written By: - Date published: 12:11 pm, July 23rd, 2017 - 50 comments
Categories: climate change, disaster, Environment, farming, food, sustainability, water - Tags: , , ,

While NZ goes through another increasingly frequent round of flooding and evacuations (how many has it been this year?), I thought it might be good to look at how sustainable design responds to water in the landscape.

Back in April, when Australia had some very large rainfall events of its own, permaculturist Geoff Lawton made a video of how the property he and his wife run handled all the extra water. The Lawton’s Zaytuna Farm is a sixty-six acre (27 hectare) property in northern New South Wales just inland from the coast. The climate is sub-tropical and the area’s annual rainfall is 1,300 mm, around the same as Northland. 

In early April very high rainfall hit the east coast of Australia. Zaytuna Farm got 440mm in 24 hours. By comparison the Edgecumbe floods on the east coast of NZ a week later had 195mm in 48 hours. While other parts of eastern Australia flooded, Zaytuna Farm sucked it up, quite literally.

Flooding is a confluence of factors not just rainfall. How much rain there has been in recent weeks and months is significant, but so is the landscape and any modifications. Sustainable land management talks about the land’s ability to hold water within the landscape. This isn’t just rivers, swamps and streams, it’s also the water being held in vegetation and in the ground, and much of this depends on the kind of soil and what is planted there. Conversely, if the land is too dry, it’s ability to absorb water is limited and water will just run across the top.

In NZ, pre-colonisation river systems were adapted to flood cycles because of the huge amount of vegetation. A river overflows its banks in a forest, and all that really happens is the trees and undergrowth slow the water down so that there is time for all the silt and soil to settle out onto the forest floor before the water returns to the creeks and rivers as well as being absorbed into the ground. That’s a fertility cycle too btw.

Chop those trees down and plant pasture and now the same landscape is a super highway for fast moving water that removes topsoil and any remaining vegetation as it rushes past on its way to the low point. This also impacts on human landscapes. When you have too much water moving too fast and overtaking the capacity to manage the volume of water in such a short space of time, towns and cities flood. We can tinker at the bottom end of that process (better drains, more pumps) or we can take notice of where the water comes from and how speed and time are critical factors. Then we can look at how we modify the land throughout the catchment changes the volume, speed and timing of water and where it goes.

In this sense much flooding is about what humans are doing. The same amount of rainfall can either bring health to an ecosystem or destroy it.

What sustainable design does is try and find the best of those varying factors, taking its cues from the shape and structure of the land and what will grow there, and balancing them with the need to produce food and other things people find useful. Mimicry of nature is central because nature already knows how to manage large amounts of water. The Lawton’s property has been intentionally designed to harvest water, spread it out through the landscape both to feed the soil/plants but also to mitigate flooding. On-farm dams, swales (water-harvesting ditches on contour) and overflow systems are the framework,

A central part of the Lawton’s design is pacifying the water. In their 9 minute video Geoff Lawton shows how their sustainability design pacified the water from the April deluge, preventing erosion and damage to infrastructure.

(If video won’t play, try here or non-FB version here)

There’s a definition of resiliency there –  when you get 400mm rain in 24 hours and the worst erosion on your property can be repaired in ten minutes with a bucket and a shovel.

Another aspect of sustainable design is the principle of the problem is the solution. In countries that are increasingly experiencing drought, large event rainfalls in conventional land management are a liability because of the damage they do. In sustainable management large amounts of water are captured and stored, not just in dams but in the ground itself, so that in the long dry spells that follow the water is available as a much needed resource.

Given the new predicted climate change pattern for many places in NZ is higher rainfall but with long dry in between, we should probably start thinking about how to not just manage that but take advantage of it.

50 comments on “Rain doesn’t cause most floods, humans do”

  1. greywarshark 1

    Great post weka. Informative, timely, hopeful, instructive. Understandable and idea-filled with doable objectives. Probably get the Robert G accolade of the month.

    The local council has used swales and grass berms with attractive trees lining the road to make an area of once grey roadway into a scenic drive or walk. The pavement was wide enough to slope to a wide v at the side of the grass berm, the stormwater passes along that and is soaked in to the berm and the tree can draw much of it off.

  2. Sabine 2

    i don’t think you can compare what a private person does to what has gone wrong in NZ since at least the last 20 years i have been here.

    we are ripping trees out in record numbers to create dairy land – in NZ.
    we are paving over large tracts of land to build roads.
    we are building houses much closer together then ever before

    fact is it rains, and then the water has to go somewhere. If it has no where to go it floods. If to much comes down to quickly it floods.

    Its nice what this farmer does. But this is not going to solve the problems of high tides, weather bombs, increasing storm activities and high seawater levels.

    So i think to compare this guys ‘feel good’ project to Edgecumbe or if you look at the flash flood in New Lynn at the same time is a bit much.

    As i said in another post, my Mil house flooded because at a bridge that was being fixed the metal stakes holding up the structure acted as a barrier acumulating debris effectively creating a damn. When that burst, all houses around this are were two meters under water. Now, the council is at least looking at the overal draining issue as in the same floods much ‘dairy’ land was rendered useless for the time being. saying that, this land should be marsh land, but how can we make a profit of marshland?

    • weka 2.1

      You’re still looking at the end point of the water though Sabine. Of course by the time all that water gets to the bridge in such a short space of time and going so fast you are going to have pieces of infrastructure fail. That’s the point I was making. The water over the whole catchment needs different management.

      And yes I am suggesting that if the whole catchment around the Edgecumbe flood area had been under sustainable management then the damage would have been far far less. That’s what is being actively demonstrated in the video. It’s physics in fact.

      Here’s an example of the UK where towns have been protected from flooding with very similar principles. This has already been done on a large scale.

      https://permaculturenews.org/2016/01/07/despite-uk-flooding-a-yorkshire-town-remains-dry/

      “but how can we make a profit of marshland?”

      We can’t. Making profit is why we design unsustainable and fragile land systems. No reason we can’t make a living and use sustainable design though.

      • Sabine 2.1.1

        i don’t say your post is not right.

        heck in germany it took them many floods in the eighties to understand that the ‘concreting’ of river beds is actually what causes the floods. Good work has been done in removing the concrete and replanting the riverbeds and in some areas floods have stopped being an issue.

        What i am saying is that we need to look at all the issues, over crowding in our cities with every square centimeters being concreted over for driveways, roads and houses. Huge carparks for shopping Malls instead of easy access busses stops. Cleansing the country side of every shrub and tree in order to plant cows. Etc etc.

        We need to look at ripping up concrete, as the water will need to be able to sicker in. This has yet to sink in.
        Driving yesterday over dairy land i was amazed by the amount of paddocks being water logged. Well actually i was not amazed, but still, we are ripping out trees like our lives depend on it and then we get surprised when the soil bakes hard and water can’t drain. Or worse what little soil there is washes away and you hit rock.

        You can’t pacify water, as water in itself is not an aggressor. It is water. You could argue that we need to pacify humans and their desire to need four carports and huge houses and roads to the everywhere.

        And unless the realization hits that having Marshland is profitable simply because it can help prevent large scale floods we will simply expect the insurances to pay out should we get flooded or to suck it up if one does not have an insurance.

        So while i think what this farmer does is recommendable its not gonna work in a City like AKL that has no draining system set up for increased rains and storms, but has instead an increased need for roads by steadfastly refusing to properly invest in public transport and in incentivisng people into ditching their cars.

        • weka 2.1.1.1

          I agree about concrete, that one needs a serious rethink by town planners.

          You can pacify water, the video just showed that. I’ve lived in native rain forest with higher rainfall events than what just hit the east coast, and where those events are normal, and I’ve seen it in action many, many times. There are ways to slow water down so that it does less damage, and that is what happens in nature most of the time.

          Yes there are multiple issues that all need working on. Sustainable design can be just as easily applied to cities as to the country. I’ll see if I can dig up some examples.

          • Sabine 2.1.1.1.1

            pacifying implies violence

            Water is water. it is not violent, its not out to kill you.

            it rains, it comes down, it has to go somewhere.

            we need to pacify the humans.

            • weka 2.1.1.1.1.1

              Some humans use language metaphorically.

              I’ve heard Lawton talking about pacifying water for a long time. When I watched this video, I was hearing ‘passify’ (as in make passive). Of course when I went to write it up it looked wrong, so I used pacify. I think it’s clear what he is meaning, and he’s not meaning that the water is being angry and violent like humans. He’s talking about actively encouraging the water to be less agitated, fast, damaging. Personally I like the use of a single word metaphor that can replace a whole post worth of explanation 😉

              Here’s the vid they took while it was still raining,

              http://abundantdesigniowa.blogspot.co.nz/2017/04/pacifying-extreme-rain.html

              • Sabine

                you can not actively ‘encourage’ water to be ‘less agitated’.

                you can do that with a human or maybe with an animal that has emotions.

                however, you can create a system or systems that allow excess water to drain by creating or maintainging existing marshlands, not building or overbuilding flood plains, removing any concrete that does not need to be, remove the need for more roads by building a functioning high value and high occupancy public transport system and the same for heavy traffic.

                You can not actively ‘encourage’ storms to be less ‘agitated or less powerful or less violent’. Wind is what wind is. Same for snow, dust storms, sunshine etc . You can harness the energy of some of our natural resources but you can’t ever control it fully.

                You can not actively ‘encourage’ nature to give a shit about us. Nature cares about the species but not about the individual. So natures systems are set up to protect species or provide a system under which certain species trhive, but you can not encourage nature to do what you want without modifying nature, and that is what got us in the shitter in the first place and that is what will keep us in the shitter until and unless we ‘individuals’ are ‘encouraged’ to be more pacifist and less demanding in our wants and focus more on our needs.

                Again, i do not dispute that what the guy does is not the right thing to do, but you would have to do it on a nation wide scale and that ain’t happening now.

                • weka

                  It’s basic physics. Put things in the way of water and the water slows down. Humans can do this. Beavers can do it too, so it’s not just a human thing. Nature does it all the time.

                  Weather is different, for such obvious reasons I’m not going to explain. However we can also design around the outcomes of the weather too. Drought, snow, dust, sun can all be incorporated into sustainable design, mimicking nature in order to produce resiliency and systems that are self-sustaining.

                  “but you would have to do it on a nation wide scale and that ain’t happening now.”

                  Actually, a catchment wide scale is the thing to aim for. Once one catchment does it, the idea will spread. But even the Lawtons doing it on a part-catchment scale is powerful. By the time the shit hits the fan, there will be people throughout NZ who’ve been practicing exactly this for decades and will be able to help others transition. The Lawtons and many others (where are you Robert?) teach this stuff precisely because we need to upscale it. Feeling good about it is how change happens.

                  • Sabine

                    i don’t share your optimism Weka.
                    but to each their own.
                    also, these people are only teaching to those that own land and can do what they want if they have the financial resources.

                    the people that don’t own land have no say what so ever how we form and bend nature to do our bidding.

                    and the reason we are in this situation is because we are bending and ‘pacifying nature’ do to our bidding and we have yet to learn, that nature cares nought about us.

                    so do i think that a few farmers building catchment areas are going to stop raising sealevels and floods? no.

                    • weka

                      “also, these people are only teaching to those that own land and can do what they want if they have the financial resources.”

                      You’re very wrong about that Sabine, and I think that shows across all your comments. Perhaps the pessimism is detracting from learning what this is actually about.

                      We can carry on having a semantic argument, or we could look at what actually works.

                      The Lawtons and many other permaculturists and regenag people have been teaching all over the world in some of the poorest places. The Lawton’s routinely run workshops for Westerners and use the funds from that to give free places to students in poor places.

                      The same people that are into regenag are into changing how land is owned.

                      “so do i think that a few farmers building catchment areas are going to stop raising sealevels and floods? no.

                      Carbon farming and regenag just got acknowledged by leading climate scientists as a critical factor in reducing the worst effect of climate change.

                      People need to choose a side and pretty damn fast.

                • greywarshark

                  Can we stop being so nitpicky and argumentative. It doesn’t help with discussing a problem to take another’s suggestions and criticise and diminish them. Let’s use one idea as part of a larger argument rather than taking time to criticise the way it is expressed and derail the good points made.

                  This is so common to us all – how can we get together and achieve if there is this a constant drip of bellyaching. It’s time to think ‘Don’t sweat the small stuff’. Ad complained recently about the term ‘guinea pigs’. How can we fight for a better world if we just squabble and nitpick when we should be encouraging the noble band of practical activists. Haha! It sounds so pompous but I do think it is noble to try for better society.

        • Pat 2.1.1.2

          +1….is a good post and as you say it is not wrong but it hits the same old problem…the changing of the landscape to feed and accomodate too many consumer humans…..we cannot have both a functioning ecosystem and the number and type of peoples we have become as amply demonstrated by the reported 6th great extinction underway.

          • weka 2.1.1.2.1

            I tend to agree that population is an issue, but feeding and accommodating humans seems doable. It’s the need for iPhones and flatscreen TVs and a new car every few years and being able to use resources without regard for nature that seems to be causing the problems.

            China has excelled at sustainable food production for very large numbers of people for thousands of years. If we had to, we could do that again. But yeah, stabilising the population has to happen at some point, again it’s basic physics.

            • Sabine 2.1.1.2.1.1

              hahahahah

              and that is why china is buying up agricultural land everywhere on this planet with nary a fuck to give. Cause their land is fucked. brother in law sending us updates about smog, uniclouds, pollution, algae covered rivers/beaches etc etc etc for years now.

              • weka

                China is a modern state just like all the others quite capable of being greedy fucks and screwing up the planet. But that doesn’t negate the fact that they have the historical technology to feed lots of people sustainably and did so for thousands of years. Laugh all you like but it’s those kind of techs that will feed us in the decades to come, and it’s those kinds of techs we could adopt now to prevent the worst of climate change kicking in.

                • Sabine

                  china for the large part is screwed. there is a reason why they are buying agricultural land overseas.

                  China is screwed environmentally not forcibly because they are bad stewards of the land, but because they have been made the manufacturing base for anyone everywhere, and with little regulations and little regards to the well being of many of their citizens has been polluted beyond believe. In fact, one could say that many western countries only managed to keep their own pollution in check because they outsourced their polluting manufacturing to china.

                  if you want to look at ‘techs’ that will save the world – and again, the world does not care about humans – so we are looking at ‘techs’ to save human kind, you could go back into the past and find things like windmills, watermills, communal bakeries, communal living structures, farming without machines, and also less humans.

                  literally the only thing that human kind will allow to survive would be a. to reduce human kind (can we really afford 9 billion people living, eating and flushing the toilet several times a day?), remove private owned transport other then bicycles and any other push operated vehicles, remove all electronical gadgetry that is not needed for live, bring back the public pay phone, and then also bring back common sense in how people get to decide their health care and end of life decision, reduce the size of housing anyone can have, rationing of all other resources. And above all we must ‘pacify’ greed and avarice. And as long as our economy is build on individual lust, greed and avarice nothing is going to be changed.
                  i.e. Bill English did not need to fraudulently claim a housing allowance, he did so because he ‘wanted’ the extra cash. Unless that mindset is changed nothing, absolutely nothing will change.

                  You need a holistic approach to ‘saving the world’, and saving the world does not necessarily mean saving human kind.

                  • weka

                    You’re teaching your grandmother to suck eggs there Sabine.

                    What China does now is irrelevant to my point, which was when Pat talked about population I pointed to one culture that has historically fed lots of people sustainably.

                    if you want to look at ‘techs’ that will save the world – and again, the world does not care about humans – so we are looking at ‘techs’ to save human kind, you could go back into the past and find things like windmills, watermills, communal bakeries, communal living structures, farming without machines, and also less humans.

                    Sure, the kinds of things that China also used to do. Not sure what your point is, but am wondering if you don’t understand what I meant with my Chinese reference. Pretty sure you weren’t trying to imply that cultures that had windmills were sustainable but China wasn’t.

                    • Pat

                      “Historical population[edit]
                      The population of China fluctuated between 37 and 60 million for a thousand years. In the period between 1749 and 1851, the population doubled in a century. After 1950, the population doubled from 600 to 1300 million in a half century.[4]”

                      https://en.wikipedia.org/wiki/Demographics_of_China

                      chinas population growth has mirrored that of the rest of the world and like them its unrestrained increase has coincided with the industrial revolution (not any cultural advantage)…..the main cause of CC.

                    • weka

                      Yes.

                      Let me rephrase my point. It’s possible to have large numbers of people and feed and house them, and not cause climate change*. What’s pushing climate change is the industrialisation of huge numbers of people over the past two centuries.

                      Population needs to stop growing, and we need to stop industrialising the population we already have.

                      * of the kind we are seeing now.

                • But that doesn’t negate the fact that they have the historical technology to feed lots of people sustainably and did so for thousands of years.

                  No they don’t else they wouldn’t have needed to go for the One Child policy.

  3. RedLogix 3

    Same from me; I really love this post. Thank you for the thought and effort you’ve clearly put in.

    It’s one of the most frustrating paradox’s in NZ politics. So much damage being done by agriculture, yet so many really fine, decent rural people who love the land, care for it and want to do their best by it.

    TOP’s Nicky Snoyink has a thoughtful post that’s really helpful:

    On Sunday morning TVNZ’s Q+A reported on the so called rural/urban divide around the state of waterways. The story attempted to show another perspective to that portrayed by environmental groups. Surmising that the rural urban divide is a myth, and that they too want clean rivers, several Federated Farmer advocates spoke out in their defence claiming that urban rivers are just as dirty and that urban folk ought to look at their own back yard before pointing the finger. The same old rhetoric.

    As a long time rural resident, I however concur with Q+A’s farmer advocates, that the rural urban divide is simply a myth perpetuated by the media. The divide instead lies within the rural community itself and is between large scale industrial agriculture and progressive small scale farming, two very different farming systems with two very different agendas.

    http://www.top.org.nz/the_urban_rural_divide_is_a_myth_but_not_for_the_reason_you_think

    • weka 3.1

      Cheer Red.

      I think the whole rural urban thing is tricky and complex, but I agree that the industrial vs progressive is a good way to think about it.

    • Sanctuary 3.2

      The farming lobby are always careful to present family owned, owner operated dairying units as the human face of the industry. “These are fair dinkum Kiwis who live their county and their environment!” They cry, whilst nearly avoiding the reality that most dairy farms are owned by absentee corporate landlords and run by managers who don’t give a shit about the environment.

  4. Poission 4

    The sunday lesson is the pharaohs dream and josephs interpretation (which is widely used in climate hydrology) .

    Then Joseph said to Pharaoh, “The dreams of Pharaoh are one and the same. God has revealed to Pharaoh what he is about to do. 26 The seven good cows are seven years, and the seven good heads of grain are seven years; it is one and the same dream. 27 The seven lean, ugly cows that came up afterward are seven years, and so are the seven worthless heads of grain scorched by the east wind: They are seven years of famine.

    28 “It is just as I said to Pharaoh: God has shown Pharaoh what he is about to do. 29 Seven years of great abundance are coming throughout the land of Egypt, 30 but seven years of famine will follow them. Then all the abundance in Egypt will be forgotten, and the famine will ravage the land. 31 The abundance in the land will not be remembered, because the famine that follows it will be so severe. 32 The reason the dream was given to Pharaoh in two forms is that the matter has been firmly decided by God, and God will do it soon

    https://www.biblegateway.com/passage/?search=Genesis%2041

    https://www.researchgate.net/publication/242428765_The_Nile_River_Records_Revisited_How_good_were_Joseph%27s_predictions

    http://onlinelibrary.wiley.com/doi/10.1029/WR004i005p00909/abstract

  5. Ad 5

    You don’t need to go to overseas examples to see that kind of catchment planning and amelioration. Much of west Auckland is already controlled by it, as a project that’s already a decade mature:

    http://projecttwinstreams.com

    http://projecttwinstreams.com/?p=2820

    The whole thing was instigated by Waitakere Council, back in the day.

    • mauī 5.1

      That sounds more like restoration type work, trying to reduce potential water issues when you’re restricted by the infrastructure that is already in place and where has already been built out.

      Every bit helps, but Lawton is talking about designing for water flows/use from the beginning and using controls that is more than just piping the water away.

      If our driveways were built so all water was caught in a parallel ditch beside it and all roof water was caught in a tank on the property and used for the household and garden. That is more what he is getting at

      • dukeofurl 5.1.1

        Thats what I think WCC was doing , that onsite storage was mandated, porous driveways for urban areas and in the semi rural areas requiring stormwater neutrality- that usually meant much larger storage tanks for roof runoff and extra planting to mitigate for paved areas. Theres a whole range of methods to retain water on site longer before it even gets to a stream.

        • greywarshark 5.1.1.1

          Porous driveways – good idea. Would that be using gobi blocks? Rain water storage ditto.

      • Ad 5.1.2

        Lawton is a farmer. About 4% of New Zealand’s population live in or on farms. By about 2030 it’s about 95% urban worldwide. So the more useful models for people are those that plan whole catchment treatments in cities.

        Have a good look at the site, and then consider it over the top of a satellite photograph of west Auckland: it’s the only major city in the world that has to intersect with an actual rainforest.

        It did so by dealing not only with softening flood impacts through riparian absorption, it also reversed large planned subdivisions and throned them into floodplains, and also did so by turning on the whole of its affected communities to interacting with the land around them.

        This approach is certainly not enough by itself for Auckland and it’s 1.6m people.
        It needs a centralized drainage system, and a sewerage and water supply system that is fully separated from each other.

        But it can be done at scale, in an urban environment, and it can last.

        • weka 5.1.2.1

          Thanks for that explanation, I hadn’t picked that from the link. I agree it can be done to scale and in urban environments. It’s about design and knowing what is needed and the tools and processes that need to be put in place to make something sustainable.

          Communities interacting with the land seems central to it all, nice one.

  6. joe90 6

    Back in April, when Australia had some very large rainfall events of its own, permaculturist Geoff Lawton made a video of how the property he and his wife run handled all the extra water

    Scaled.

    [Requested] River basins of Australia in rainbow colours

    http://imgur.com/user/Fejetlenfej/submitted

  7. mauī 7

    Whoop! Geoff Lawton. He’s good value and well explained post too.

  8. CLEANGREEN 8

    Great article WEKA.

    “Chop those trees down and plant pasture and now the same landscape is a super highway for fast moving water that removes topsoil and any remaining vegetation as it rushes past on its way to the low point.”

    Yes people cause many issues and impacts to our “Built Environment”

    There are many reports/studies we have alerting us to this phenomena.

    We are the problem as we think what we are doing is not causing any harm to the environment & ourselves. This is folly!!!!

    When you stated this above; – “a super highway for fast moving water” – it provoked me to give some solid support to your statement there.

    From now on every time anyone who goes out on that road in any vehicle that has tyres they need to know that they are spreading the surrounding area with a fine black tyre dust (known now a a cancer causing compound found in the tyre dust called 1,3,butadiene & styrene, they are allowing that tyre dust to runoff the road and down into our drains along the road and into our rivers,streams, lakes and our aquifers and finally our own drinking water.

    How bloody dumb are we???

    This demonstrates that we are not actually told the truth about the products we assume the “higher authorities” are protecting us from the public hazard is a fallacy.

    That is where the blame lies as many who read this will not have been aware that tyre dust is a toxic component that will bring harm to all our health someday.

    Never mind the exhaust pollution it is another story again.

    Remember that US Studies have confirmed 1,3,butadiene causes cancer and nervous system damage.

    For any road that carries 25 000 vehicles every day those tyres will shed 9kg’s of tyre dust on that road for every km every day. 9kg’s each day per single km.

    http://www.abc.net.au/science/articles/2012/07/31/3554997.htm

    That toxic tyre dust gets washed off the road into our waterways & now you know the rest.

    • Grafton Gully 8.1

      “US Studies have confirmed 1,3,butadiene causes cancer and nervous system damage.” Are you sure it has been “confirmed” as a cause ?

      As well as the cancer and nervous system associations there is epidemiological evidence that in-utero exposure may increase the risk of autism in children. https://www.ncbi.nlm.nih.gov/pubmed/25051312

  9. Cricklewood 9

    On a bright note a lot of what you talk about is now par for the course in new developments even residentially in Auckland. We are building quite sophisticated systems to slow the progress of water in the waste system if at all that includes roof collected water.
    Most large developments also have swales, raingardens, storage ponds even reticulation of storm water. Stonefields for example has non potable taps for watering and the like which utilize stored water in the ponds.

  10. johnm 10

    Not True!

    Each 1 Degree C We Warm the Planet adds 7% increase in Moisture.

    https://kevinhester.live/2016/06/07/for-every-1-degree-c-we-warm-the-planet-we-will-see-7-more-moisture-in-the-atmosphere/comment-page-1/

    We are now at 1.6c above the baseline of 1750 and climbing.

    Yes humans have caused this with our addiction to fossil fuel burning. More rain to come!

  11. Duncan 11

    Trees also help the water cycle through transpiration which reduces drought.
    As vast areas of Aus are now realising.

    • Pat 11.1

      yep..trees are likely our best hope….or maybe our only

      • joe90 11.1.1

        ….or maybe our only

        If they are, we’re fucked.

        Abstract

        Quantification of global forest change has been lacking despite the recognized importance of forest ecosystem services. In this study, Earth observation satellite data were used to map global forest loss (2.3 million square kilometers) and gain (0.8 million square kilometers) from 2000 to 2012 at a spatial resolution of 30 meters. The tropics were the only climate domain to exhibit a trend, with forest loss increasing by 2101 square kilometers per year. Brazil’s well-documented reduction in deforestation was offset by increasing forest loss in Indonesia, Malaysia, Paraguay, Bolivia, Zambia, Angola, and elsewhere. Intensive forestry practiced within subtropical forests resulted in the highest rates of forest change globally. Boreal forest loss due largely to fire and forestry was second to that in the tropics in absolute and proportional terms. These results depict a globally consistent and locally relevant record of forest change.

        http://science.sciencemag.org/content/342/6160/850

        • joe90 11.1.1.1

          And sometimes it seems we’re on a runaway CO2 train.

          An international team of researchers – led by Professor Jim Hansen, Nasa’s former climate science chief – said their conclusion that the world had already overshot targets to limit global warming to within acceptable levels was “sufficiently grim” to force them to urge “rapid emission reductions”.

          But they warned this would not be enough and efforts would need to be made to reduce the amount of carbon dioxide in the atmosphere by about 12.5 per cent.

          This, the scientists argued, could be mostly achieved by agricultural measures such as planting trees and improving soil fertility, a relatively low-cost way to remove carbon from the air.

          Other more expensive methods, such as burning biomass in power plants fitted with carbon-capture-and-storage or devices that can remove carbon from the air directly, might also be necessary and would become increasingly needed if steps were not taken soon.

          http://www.independent.co.uk/news/science/carbon-dioxide-remove-atmosphere-climate-change-greenhouse-gas-scientists-jim-hansen-a7847426.html

        • Pat 11.1.1.2

          “If they are, we’re fucked.”

          so i’ve heard

  12. Ian 12

    Good post weka
    An unintended consequence of moving from open channel to piped irrigation water can be noted in this flooding scenario in mid Canterbury.The open channels acted as a stormwater system and the channel banks as floodbanks.
    Remove them and surgace water flows back into the old channel’s.
    Interested to know how much nitrate gotflushed out to sea

  13. Jenny Kirk 13

    Excellent post, Weka. Colonisation and urbanisation has certainly helped create many of the problems we’re experiencing now – and a lack of forethought and knowledge of what-might-come-in-the-future on the part of local authorities, government and the general public.
    The difficulty now is to try and work out how to resolve these problems without displacing too many people from their current homes or livelihood.

  14. jaymam 14

    The Edgecumbe flood would not have happened if someone had built the stopbank in an adequate manner, i.e. the way they have now done it.
    But no, years ago someone built an L-shaped concrete wall with no proper foundations. On the day of the flood there was a truck there that dropped a load of rock on the foot of the wall and it tilted over. There are videos of that being done and of the truck. There is a video of the water leaking through the bottom of the wall.
    The river was quite able to cope with the amount of water going down it, until the wall fell over. The flooding was simply caused by bad engineering, starting from when the road was built too close to the river.

Recent Comments

Recent Posts

  • New digital service to make business easy
    A new digital platform aims to make it easier for small businesses to access services from multiple government agencies, leaving them more time to focus on their own priorities. Prime Minister Jacinda Ardern and Minister for Small Business Stuart Nash ...
    13 hours ago
  • Million-dollar start to gun collection events
    Million-dollar start to gun collection events  Police Minister Stuart Nash says a solid start has been made to the gun buyback and amnesty after the first weekend of community collection events. “Gun owners will walk away with more than ...
    2 days ago
  • Praise after first firearms collection event
    Police Minister Stuart Nash has praised Police and gun owners after the first firearms collection event saw a busy turnout at Riccarton Racecourse in Christchurch. “Police officers and staff have put a tremendous effort into planning and logistics for the ...
    2 days ago
  • New Police constables deployed to regions
    Seventy-eight new Police constables are heading out to the regions following today’s graduation of a new recruit wing from the Royal New Zealand Police College. Police Minister Stuart Nash says the record high number of new Police officers being recruited, ...
    1 week ago