Re: River Slopes (was: Hiking Rates)

From: dzo01 <dzo_at_...>
Date: Fri, 16 Apr 2004 16:03:39 -0000

wrote:
> Joerg -
>
> Without taking any position on whether the horizontal distances in
> Glorantha are too short, I've got a few quibbles with you about
the
> vertical distances.
>
> My own map of west Sartar, uncanonical as it is, has Clearwine at
> about 2000 feet above sea level and the Upland Marsh at about 1250
> feet above sea level - not the 3000-4500 foot elevation that you
> have it. For what it is worth, I think the Pharoah's Marsh is
maybe
> some 500-750 feet above sea level.
>
> >Following the old bed of the Creek-Stream River, I found this to
be
> >on a distance of about 30-40 miles.
> > In other words: the land rises about 10 metres for every mile you
> > travel on the river.
>
> Or in my case about 5 or 6 metres for every mile.

So, 15-18 feet per mile average gradient. On a small river, say around 5000 - 8000 cfs (185 - 300 cumecs), this is not going to present a lot of problems for very small boats (read canoes, kayaks or rafts) going downriver, but anything going upriver, forget it. Any river substantial enough to allow decent sized boats traveling up it - i.e. sailboats capable of going against the current is going to be very scary and unnavigable to anything of any size - particularly without a system of locks.

With the higher figure of 30 fpm gradient it is going to be serious fun - particularly as I believe it travels through a gorge. I would love to paddle that if there is substantial water (in a modern plastic kayak downriver or course!)...

>
> > These distances _are_ extremely short. The Oslir has maybe 500
> miles
> > to descend from Furthest to the Thunder Delta, which gives it an
> > average slope of 2 metres per mile - ten times that of the Rhine
at
> > Bacharach. You could probably surf down the Creekstream River...
>
> I think Furthest is maybe only about 1000 feet above sea level
> (maybe less), which gives it an average slope of 1 foot per mile.

1 fpm is more respectable for a river the size of the Oslir. 2 m (6 ft) per mile is pushing it!

Cheers,
Yak