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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