Gladstone Pass navigable after recent rains?

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Gladstone Pass navigable after recent rains?

Postby mandragara » Tue 05 Jan, 2021 1:52 pm

Hi,

I'm looking to take my father along the Lindeman Pass and up Gladstone Pass this Friday.

However due to the recent rains there have been some closures in the Blueys due to saturated creek catchments.

My understanding is that the catchment of Gladstone is so tiny that this isn't an issue, it should be the same as it always is as long as there has been a day or so of no rain.

However I'd just like to calibrate my thoughts against someone who knows the area better, I've only walked Gladstone's twice.

Cheers,
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Re: Gladstone Pass navigable after recent rains?

Postby mandragara » Mon 11 Jan, 2021 2:54 pm

Just to answer my own question, walked it in gentle rain last Friday and the water level seemed ever so slightly elevated but not in a way that is at all meaningful, so you'd really need a major downpour to get the constricted area with the stairs to flow dangerously IMO
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Re: Gladstone Pass navigable after recent rains?

Postby FatCanyoner » Thu 14 Jan, 2021 12:09 pm

I was going to answer and say it should be fine, but I haven't actually been down there following heavy rain. The catchment is extremely small though. And even in bigger catchments, sandstone areas see waters rise and fall quite quickly. Even in canyons in the area, water can flow at dangerous levels one day and be back to safe levels the next day. It's amazing how quickly it drains in the Blue Mountains.
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Re: Gladstone Pass navigable after recent rains?

Postby mandragara » Thu 14 Jan, 2021 10:12 pm

What I don't understand is where all the water comes from if the catchment is so small. It' always has a solid amount of water pouring out of it in all weather. Is it possible for the catchment to be larger and flow subterranean perhaps? Or is it all just bound up in the vegetation like a huge, deep sponge?

Hydrology is so interesting...
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Re: Gladstone Pass navigable after recent rains?

Postby tom_brennan » Mon 18 Jan, 2021 11:48 am

Sandstone is like a sponge (both porous and permeable). Water soaks slowly into the sandstone and then emerges when it hits a less permeable layer of rock (eg shale). So after persistent rain, you may get water draining out of the sandstone for a long time, because the sponge is saturated.

Depending on the rock strata, the "underground" catchment may be larger than the surface one (eg if the shale layer is tilted in the direction of Gladstone Pass).

The rock strata in the upper mountains generally tilt gently to the south east - so Gladstone Pass could in fact be getting much of the underground water that soaks into the plateau around Leura.
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Re: Gladstone Pass navigable after recent rains?

Postby FatCanyoner » Fri 22 Jan, 2021 3:56 pm

As Tom correctly points out, much of the water found flowing in Blue Mountains creeks is effectively spring fed. This process is visible wherever you see a hanging swamp (and there are many of them in the upper mountains). Water flows through the sandstone, hits a layer it can't get past, then slowly moves along that plane until it reaches the surface. These reliable seeps then support hanging swamps.

Sandstone country drains very quickly, so most rain flows off within a matter of a couple days. Most of the water that continues to flow after this is water seeping out of the rock or held back by swamps. That's the reason why, even deep in drought, many creeks still continue to have a trickle of water. It's also what keeps those hanging swamps lush and green throughout summer. Once you disturb that underground water movement -- such as with longwall coal mining -- swamps and perennial streams end up running dry. There's several clear examples of this on the Newnes Plateau, which is quite tragic.
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