[Tagging] Non Proposed Features

Nathan Edgars II neroute2 at gmail.com
Tue Aug 31 03:45:52 BST 2010


On Mon, Aug 30, 2010 at 10:10 PM, John F. Eldredge <john at jfeldredge.com> wrote:
> -------Original Email-------
> Subject :Re: [Tagging] Non Proposed Features
> From  :mailto:neroute2 at gmail.com
> Date  :Mon Aug 30 20:44:53 America/Chicago 2010
> So how do you specify that (a) you mapped a waterway but don't know
> the direction of flow, (b) it's a stagnant channel with no real flow,
> or (c) it's an artificial drainage canal with flow changing based on
> rainfall and opening or closing of gates?

> I would expect that case (c) would still have the water flowing downhill.  Even if you have a series of pumps, water in the sections between the pumps will still flow downhill, not uphill.  About the only time I would expect any counterflow would be if water were to be added to a given section rapidly enough that its surface level was temporarily higher than in the upstream section, making that a downhill flow also.
>
Depends. The canals may be flat (or nearly so, such that one can't
know which way is downhill) and managed by pumps. I believe this is
common in "reclaimed" swamp lands.



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