[HOT] What's water?

Prabhas Pokharel prabhas.pokharel at gmail.com
Mon May 4 03:59:20 UTC 2015


On Mon, May 4, 2015 at 9:33 AM, Pat Tressel <ptressel at myuw.net> wrote:

> ;-)
>
> I'm seeing some rivers mapped in areas that didn't have high-res imagery,
> that (in the DG imagery) cross over dry land, or through areas were tree
> tops are visible against a dark background that could be either water or
> shadow -- it's a dark gray-purple.  What I'm interpreting as the actual
> river channel is more turquoise and has (what look like) white rapids.  The
> imagery has no clouds, and land looks fairly dry, so this imagery may,
> perhaps, be dry season.
>
> Note the previously mapped rivers in this area are very rough -- points
> are far apart -- which implies they were mapped from low-res imagery.
>
> Some questions:
>
> Is there a large change in water volume in rivers during the dry season?
> I'm wondering if water recedes to the deepest channel, and does show more
> whitewater then.
>

Yes, changes in water volumes between wet and dry season can be immense in
Nepal. Some stream beds may also go dry in the dry season.
I would guess that some mountain streams may behave as you suggested, but
generally, my expectation would be for more whitewater in the wet season.



>
> Do trees grow in standing water (deep enough to appear dark) in Nepal?
> That's not unheard of -- it's true in the Everglades in Florida.  Or is an
> area with treetops and dark between more likely dry but shadowed?
>

Generally, most of the water in Nepal flows fast (we have lots of elevation
changes), and there are very rarely trees growing in standing/moving water
as in Florida.
I don't understand your second question.



> Thanks!
>
> -- Pat
>
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-- 
Prabhas Pokharel
http://prabhasp.com
twitter/skype/facebook/whatever: prabhasp
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