Water Ponding/Management

John Schinnerer eco_living at yahoo.com
Thu Dec 27 01:08:27 EST 2001


Aloha,

> Is there a way to use graph paper to determine, and mark out keylines
> from a contour map?

It's the contours that matter, that determine key points and lines...in
your case, just get out and start looking around and see if you can see
some bits of your place that look a bit like Yeomans' examples
topographically.

> Hmmm.... I understand the need for subsoil ripping, but these are
> forested 
> areas that I'm not planning on using for grazing. The leaf litter
> from the 
> trees etc. built up overtime has improved water retention as they
> march down 
> th slopes. The problem is where the landscape creates natural
> drainages that 
> carry water swiftly away from those areas.

Right, thanks for the clarification - see my most previous post re:
forested areas, which if healthy do a pretty darn good job of
retention/infiltration without any need for protracted labor.

> This year too it has become more feast, 
> and famine type rain fall. Months of droughty conditions followed by
> periods of heavy rain which turn parts of land into a muddy mess.

This seems to be an emerging pattern in lots of places.  East Hawai'i
has been more that way the past several years as well, and so has W.
Washington state...and N. CA... 

Implementing keyline strategies addresses both of these extremes - less
trouble with excess precipitation and more water in soil and ponds,
etc. in droughty times.

> Somehow I'm not so sure what you mean by lower down ridges. 

I'm generalizing from keyline concepts, not knowing what your place
looks like.

> Slopes seem to run down from my top ridge steeply at first then more
> gently as they approach base, where land is fairly flat or very
gently
> sloped. There are sometimes what I call benches or wider flat areas 
> that were probably flattened over years as hills age/erode.

Are some of these side ridges, so to speak, from other ridges?  That
is, there's your top ridge, and then are their lesser ridges angling
off from it?  If so, do some of these have flatter areas where water
could be led via keyline drains from the main ridge(s)?  Such areas
would be possible pond locations.

> Yes...I'm thinking of making the broader base of hills into park like
> pasture 
> for grazing cattle and growing trees. And cattle do walk those fence
> lines. 

So for example, fences on keyline layout not far below the edge of the
forested areas would lead livestock to tromp down your uppermost drain
as they graze that area.

> I also need to consider best areas for logging roads etc. for minimal
> damage...yet ease of movement.

Consider laying out access roads according to keyline principles.  That
is, keep the slope very gentle and make them double as keyline drains. 
Then they're also less likely to slide, wash out, washboard, etc.

Horse logging can be much lower impact than motorized.  There are some
slick cable logging systems that really minimize disruption as well -
saw pictures and first-hand description at the keyline course.


=====
John Schinnerer, MA
--------------------
- Eco-Living -
Cultural & Ecological Designing
Food - Shelter - Community
john at eco-living.net
http://eco-living.net

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