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Re: Swale Question
Toby Hemenway wrote:
> Claude wrote:
>
> > What I'm looking for is better comebacks to the people who insist that in
> > Northern Vermont, with its 30 plus inches of rain a year, earthworks are
> > redundant.
>
> Here in Oregon we get 40 inches a year (though with a dry summer) and my
> swales have made a tremendous difference in fertility. In your region, I'd
> say earthworks would:
>
> -prevent puddling, low and boggy spots with attendant mosquitoes,
> compaction, and anaerobic decomposition. The last two reduce soil life due
> to low oxygen levels, reducing fertility
>
> -prevent gullying (I've seen 'em in Vermont), erosion, and soil loss during
> heavy rain
>
> -eliminate hardpan (especially if the soil is ripped with a keyline plow; I
> know you've got rocky soil, but it should still work)
>
> -help get through dry spells (That 30 inches doesn't fall in nice weekly
> allotments), which will allow more even growth of crops and more even
> moisture levels in the soil, which will result in greater soil life and thus
> better fertility
>
> There are lots more reasons; I'll bet Rick Valley, or Dan H with his New
> England experience should have more to add.
>
> Toby
Claude and Toby,
Although I am now in Santa Fe NM (12-14 in/yr) where swales and soil moisture are
definitely an issue, I am also native to the mid-Atlantic states (specifically NJ and
northwest Connecticut.)
Several additional points to make:
Earthworks are analgous to the work of beavers in drainages. Most areas now are
devoid of these hydro-engineers - (the price of being classified as rodentia and
making great hats.)
Beavers (and the dams they build) mitigate intense storm flows, lessen topsoil runoff
and downstream siltation, recharge the grounwater table, provide wetland habitat for
migratory waterfowl, and build soils.
Any groundwater recharge, if excessive will be released in the form of natural
springs (of which there used to be many more) useful for water supply as well as
(historically) cooling/refrigeration.
With the proper design,(see Yoeman's Water for Every Farm ), excess surface water in
New England can be diverted to a series of keyline ponds and used for dry season
irrigation, animal watering(away from riparian area), fish production, water power
(Pelton and overshot wheels), trompes (f/ compressed air and cooling), summer
skinnydips, winter ice production, etc. Also, marshes and bogs are a specialized and
very productive habitat, producing many medicinals and ancient plants, peats and
mosses, amphibian life, blueberries, etc.
In my experience, there are very few places in New England where the retention of
precipitation is not advantageous when handled rationally. Often, the problem is in
the "uses" to which unsuitable land has been put, the domination over nature
phenomenon rather than designing and working with the natural characteristics of a
place.
Nuff for now,
Vint Lawrence
Apache Creek Ranch
Santa Fe, NM
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