Biological Cleaning, Commercial Farm Projects, Conservation, Gabions, Land, Regional Water Cycle, Rehabilitation, Soil Conservation, Soil Erosion & Contamination, Trees, Water Harvesting — by Nick Huggins September 28, 2010
Story by Nick Huggins.
Video by Patrick Blampied.
For the past month I have been in and out of airports and driving from one end of the Australian continent consulting and talking Permaculture, and one topic that is of great interest to me – the repair of the Australian Landscape.
Fellow consultant Patrick Blampied came along for the ride, to see what’s required in the first steps of the repair of a 1.5km creek on the South Western slops of NSW, which was damaged when big rains hit in August of last month.
No one could have imagined what would have happened next. And the hardest lessons are always the best and most valuable. Using natural systems and Permaculture Design, we have to keep in mind we are pioneers. Like all pioneers there is no hard or fast rule for this type of work.
This photo shows one of the 16 gabions constructed in a 2 week period. The water in the centre of the photo after the construction works was about 700mm deep and was back flooding 80 – 100m back up the creek and there were already signs of water being sucked back up into the eroded creek banks by capillary action into the subsoil. It was like the land taking a big drink.
Same photo again from the opposite side. You can see between the water and the logs we used pea straw bales and submerged them in the water, unbroken and also broken up with the idea that the silt and sediment would be caught up in the straw and then the pea seeds would germinate and start to accumulate weeds and seeds to bind and filter the water.
After some of the biggest rain since the drought started our work paid off. You can see the sediment that has formed in the middle of the creek. There is over 1m difference in height in the creek now at this spot compared to before construction. Still some bales of straw can be seen, half were washed into the next gabion, still not wasted.
Just think of all that sediment now retained on the property. With a good warm spring this gabion will burst into life with all the silt collected and seeds of the ever ready pioneer species ready to take a foothold.
For some reason I didn’t take a post construction photo of this site. We are now 200m back up the creek and at the site of a natural choke point in the creek. By choke point, I mean a point at where the creek narrows naturally. Using the resources of 2 trees anchored to the creek bank, we locked in 3 large logs between them and then placed 4 large rocks and 5 tonne of small rocks to fill in the gaps on the upstream side of the trees. Again bales of straw were placed to filter the sediment and the water flow. Take note of the small track that cattle and sheep have used behind the willow to cross the creek in the past. Also the natural rock bottom of the creek just too the left, middle side of the photo and see how that rock is pushing the water across to the willow.
Bad news…. The water took a big bite out of the creek bank and caused some damage. This part of the creek had natural granite acting as the bottom of the creek. So what we think happened was the water came rushing down hit the rock and straw bales at the bottom of the picture and found the point of least resistance and decided if it couldn’t take the rocks, it would then instead take the soil.
Yes, lesson learnt. When opportunities coming knocking to do this sort of work and these sorts of results happen, we should let it be known. I don’t mind admitting it. You can’t second guess yourself and you can’t predict the season. As a good friend of mine, Matt Kilby from www.globallandrepair.com.au, said to me on surveying the triumphs and the failures “it’s taken 150 years to get to this level of damage in the Australian landscape, it’s going to take another generation to get us back”. There are no fast track solutions for this sort of work, but small steps over time will get us there.
The key point here in this project is that until you can educate the other property owners higher in the catchment to slow the water in the landscape, repair creeks and deep eroded streams and implement farm pasture regeneration, then the work in this 1.5km of creek will need regular maintenance to ensure their existence over time.
Most of the properties above this creek are flogged sheep properties. And I mean flogged – if there’s any sign of green grass the sheep are sent in to knock it down. As soon as rain hits the dirt, it’s 90% runoff. So it’s like having hundreds of thousands of acres of concrete ground channeling water into a small creek no wider than 2 meters at some points.
Later on in the year we hope to go back and see progress from this latest post-flood work. We contracted a local landscape company just before the willow trees burst their spring buds last month to plant 2000 willow cuttings. We planted them 3 cuttings wide with 1m spacing and 30m across the creek at each gabion, straight on top of our current gabions in the silt and straw bales. So around 200 trees per site. There has not been a season like it, to do this sort of pioneer work in many, many years. What we are hoping the willows will do is to bind our work together into the creek bank and over (tree) time they will form their own natural gabions, collecting dead trees, silt, leaves and restore the creek to a chain of ponds, that will spread the water across the flood plain and pacify the water flow.Comments (22)