Success in managing for rainfall variability
(Read Part One)
The results of the changes on Gunningrah
We thought that the changes resulting from the grazing and stream interventions would have been slow, and maybe not noticeable to the eye for some time.
This couldn't have been further from what happened on all fronts.
First, the grazing management changes…
With the whole farm change in the manner in which animals grazed, the resulting changes to ground cover and infiltration rates were quite rapid.
The first thing we noted was that our 55 dams we once relied upon for stock, were no long reliable. A decade after the change, only 25% of our dams had water in them, when most neighbouring dams were full........ the water cycle was slowing.
Through adjustments to stock numbers, to better suit feed availability, we were able to get ground cover up (from the 70% start), to the 80 - 90% range quite rapidly (in years not dissimilar to that year in which we started).
Improved groundcover (left) and cattle reaping the benefits of the grazing practices onGunningrah (right).
Our animal health levels improved. While we only drench on the basis of worm egg levels, under the set stocked regime we had to drench on average around four times per year.
With pastures rested, combined with perhaps an improvement in diet, we need to drench only twice in most years, and just once in some of the drier years. The animal health budget, as a result, has halved.
Another big gain has been from the efficiency of our use of labour. Under set stocking, over 300 man days per year were spent doing stock work, such as mustering, drenching, marking, checking... (This was 4 years records prior to the change).
Now, (with the same number of DSEs run), that figure is down by 33%, to average less than 200 man days per year. In some years, it has been almost half the previous requirement at 160 man days.
With wages being our most significant cost, this benefit alone has produced great financial gain, in the order of $30,000.
Michael Jeffery visiting Gunningrah to discuss its successes with Charlie Maslin.
Second, the stream changes…
The extent of the slowing of the stream flow, as a result of the work done, basically depends on the magnitude of the runoff event.
Where the rain event is large and widespread, the effect on slowing flow is minimal. The main gain in such a case, is the additional water stored high in the catchment, which under normal circumstances would have ended up much faster downstream. [Read more about how Charlie has reinstated natural flood plain processes and view corresponding images from Gunningrah on the Earth Integralwebsite.]
However where the event may have been a thunderstorm downpour, the slowing effect is very noticeable, where the weirs would fill up and then gradually over subsequent weeks/ months, permeate into the soil profile and slowly drain downstream.
One small stream, which previously after a storm flowed for 24/48 hours, now flows for up to 12 weeks in winter, and about 6 in summer, with just three weirs to slow the flow.
The sediment capture aspect of the weirs also became quickly apparent.
Another weir, below a fenced out granite gully, has had sediment deposited at the rate of around 20 tonnes per year. (Previously no sediment ever deposited anywhere on our property below that weir, and now it is over 1.5m deep at that spot).
Measurements have shown sediment build up of over 1.5 metres in some locations.
Before the weir was built, that part of the stream could not even be crossed by bike... now you can drive easily across in a 2wd ute.
Sediment capture in other weirs has been similar. Plants are able to grow in the stream bed, as a combined result of the sediment deposition and the resting of paddocks.
In many places, plant growth in the riparian area is now prolific.
Left: Healing gully erosion is evident as a result of the practices being applied on Gunningrah.
Right: Healthy vegetation along slow-flowing creek lines
Leaky weirs slow the flow of water
Additionally, species not seen in the stream bed area previously, have appeared. They all add to the stability and resilience of the streams, and add to the future ability to trap even more sediment and runoff debris.
Water quality has also improved markedly.
Turbid water entering the stream above the weirs, becomes clearer as it moves downstream. A neighbour, on seeing one of the streams flooding, reported seeing the first "clear flood" (downstream of the weirs) he had ever seen.
The further the flood water can flow out over well-covered riparian areas, (due to the weir’s location), the greater the resulting reduction in the stream’s turbidity, as a result of the slowing of the rate of stream flow.
The changes over the last couple of decades, to our water management, here, has been quite marked. Some of the changes you can attach a dollar figure, others are giving very observable environmental gains.
Without doubt, the greatest impact to managing our rainfall, has come from our changes in grazing management. Making the land more receptive to moisture infiltration has been of great benefit.
This, when allied with the weirs in the streams for when runoff does occur, has further benefited, both our water management and those downstream of our property.
As far as the changes we have made to our management of water, I have no hesitation in recommending similar changes to others, if they are encountering problems along the lines of those we faced.
While the restoration does involve some cost, maybe some forgone income, and possibly a change in management philosophy, we have found the environmental and financial benefits in the longer term, to definitely outweigh any near term sacrifices.
We hope you enjoyed reading Charlie Maslin’s story. Feel free to leave a comment or question below, or email us at firstname.lastname@example.org if you would like to get in touch with Charlie directly.
The Soils for Life Team