WfHC - cover page (not to be used with pre-printed report ... - CSIRO

Wilfred Jimmy: Too much water.
Marcus Barber: Does the pigs digging up the ground there, does that wash away the
channel?
Wilfred Jimmy: No, not the pigs, just the floodwater. It comes very fast, when it rises up it
spins around. The water goes around and around in that little curve in the creek. It cuts all
the ground out, the bank, [and] makes it wider and wider.
Ivan Jimmy focuses on the impact of water on roads, and that roads in turn can spread sand,
but also notes when prompted that areas without roads can erode in the floods:
Marcus Barber: What happens when the water goes everywhere?
Ivan Jimmy: It mucks up the country, you get erosion. We had a place that was graded and
you come back next year and if it has flooded, there‟s no road there, there‟s nothing. Sand
everywhere.
Marcus Barber: What about where there is no road, where it is just the normal bush. Does
it get eroded, does it get changed?
Ivan Jimmy: Yes. It gets changed. When you want, you know that the place where you was
fishing last time because, it changes with all that flood and rain, it washes it away.
The cattlemen emphasise the erosion processes occurring in high flow and flooding
situations, but Viv Sinnamon noted gentler processes occurring as the wet season water
drains:
Viv Sinnamon: the erosion [here at Oriners] might be like Sandy Creek. We were watching
the Coleman Yard there, that year we were there. The erosion, those finger eroded areas,
and the tunnelling stuff, seems to happen on the drain off.
Jeff Shellberg: On the draw down, yeah. So it comes up strong, [and then] it‟s drawing
down, and all the banks are wet, saturated, and the banks start caving in.
Viv Sinnamon: And these little places, like over there we were watching them, these funny
little places that you would not really think of. If you looked at them in the dry, you‟d think
„Oh yeah‟ [it‟s nothing], but [in the wet] they are little waterfalls.
Viv Sinnamon and Jeff Shellberg also see a relationship between erosion and the roads:
Viv Sinnamon: You go out to Mosquito [Lagoon] there, and you can feel that sand, feel the
soil moving under your feet at Mosquito. The places where that water comes up, it is really
quite funny how those spalds of sand happen. You have not been there? You‟ve been
down the road there and can see on that box flat, there is a spaldl of sand. They come from
across the road eh? The road will be running this way, and it will trigger something, and this
big spald of sand will come out. This high, just like a wave. It‟s triggered by the road but it
doesn‟t run down the road, it runs off the road, across the road, then comes back out on
the flat. It‟s another effect, a different one. It‟s not incising as much, it‟s taking the sand out
of the soil.
Jeff Shellberg: All these floodways up here, these fingers, these different little drainage
networks, if you‟ve got a road cutting across them they‟re prone to eroding. The roads
erode down [due to excess water from roads] and in a sense, head cuts or little waterfalls
move up these little valleys and can essentially drain them of water. They are originally like
sponges and then as soon as [gullies] cut down into them, it becomes a leaky sponge,
essentially. It‟s not holding that soil and water together
.
Working Knowledge at Oriners Station, Cape York
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