permaculture

[Permacltur@aol.com]

There are a number of strategies for storing water on land, including 
farmland, all well developed through permaculture.
    The first strategy is to intercept water in high areas through a variety 
of measures.  The principle measure would be, where land is sutable for 
cultivation, to develop keyline cultivation practices.  This stores water in 
the ground, reducing or eliminating runoff, and thus limiting or eliminating 
flooding in low areas.  Sometimes these are on the same parcel.  This 
approache is well described  in Water for Every Farm by P. A. Yeomans, as 
updated by Ken Yeomans.  A close second is the interception of high runoff by 
diversion drains to high ponds created by saddle dams, contour dams, and 
such.  This is described well in Permaculture Design Course Pamphlet III, 
Permaculture for Humid Landscapes by Bill Mollison.  These techniques store 
water that would be flood waters at the highest possible points on the 
landscape.  Where water is held in soil, local hydrology is enhanced and dry 
springs begin to run again.   Where water is held in dams, some percolation 
also takes place, but mainly the water is held for irrigation during dry 
periods or for other uses where gavity feed provides great utility.  If one 
waits until the water has reached a low point, it has had maximum opportunity 
to cause opportunity and takes maximum energy to move to a useful place.
    In land of gentle contours and in low lands, swales are a secondary 
strategy.  The swales hold flood waters with the expressed intent of 
recharging ground water.  I have used this technique in semi-arid places, 
even, to catch downpours permit percolation laterally into adjacent beds in 
production.  In effect, the asiles between beds (on contour) double as 
swales.   This was very effective.  It is written up in The International 
Permaculture Solutions Journal, Vol. I, No. 3, as "dryland chinampas."
    Swales can be planted to species that tolerate flooding from time to time 
including some cultivated species of hawthorn (e.g. mayhaw), jujube, 
elderbery, and certain species grown for firewood or biomas, such as alder, 
willow, etc.  Larger swales can be planted to paddi rice that tolerates 
upland conditions, such as M101, so that it will grow either while flooded or 
as if in upland conditons.  
    By adopting Asian water buffalo to replace Bos genus cattle, flooded 
pasture land is fine pasture  land.  There are species of perennial grasses 
that grow on dry land or as emergent species under water.  Waterfowl 
obviously are addtional animal species to consider to raise on such farms.  
Both geese and ducks feed under water and forage crops such as chuffa will 
produce well in lowland areas, serving as emergent crops if the water does 
not get too deep.  If one has some portion of the land dug deep enough to 
always hold water, than plant and animal species can migrate quickly to 
flooded areas.  Mosquito fish operate in well under an inch of water and help 
control the mosquitos during flood periods.  Azolla should be grown in such 
biological reserve ponds, and duck weed, so that they can rapidly expand when 
conditions allow.  This strategy is inappropriate where flooding is due to 
cold spring melt-off, however.  Depending on duration of flood waters, such 
cold waters could grow trout, native catfish, buffalo fish, etc.   Note that 
annual flooding with a crawfish harvest alternated with plant crops is a well 
established mainstream practice in Louisana where they benefit from a cycle 
of Winter rains and summer dry periods. This is well documented in extension 
documents from Louisiana. Along the Gulf states, bald cypress and crawfish 
farming produce a semi-aquatic agroforestry.  Crawfish provide many of the 
same services in water that earthworms do on land.  They grow from Canada to 
the tropics, with care in species selection.  
    Even chickens can be managed to take advantage of flooding.  
Air-breathing invetebrates concentrate at the edge of the advancing flood 
waters and chicken on free range quickly learn to harvest them.  Ducks would 
do well also.  Retreating flood waters generally leaves a wet edge full of 
crawfish which pigs and ducks can harvest (if they get there ahead of the 
wild pigs and racoons).  
    Finally, the ultimate approach in such areas is the development of 
chinampas, specially made raised beds which extend above the flood limit (in 
most cases) and grow crops.  Channels developed in the construction of 
chinampas (built of alternating layers of vegetable matter and mucky soil) 
are very useful in aquaculture.  By having some channels "blind", meaning cut 
off from the others by chinampas beds, species can be grown in one channel 
that is incompatible with species in others.  For example, one would prefer 
to keep catfish out of channels in which crawfish are to be harvested 
directly (not as catfish).  Chinampas are extremely high yield, when 
surrounded by flood waters exhibit moderation due to thermal mass and phase 
change energies (evaporation and condensation), have elevated light levels 
due to reflected light from water, never need irrigation, and lend to simple 
movement of harvest by boat.  Beneficial edge effects are very high.
    In sites such as Barking Frogs Permaculture Center here in Florida, we 
plan to time fish harvest with diminishing water tables.  (That is also the 
strategy of the wild predators, so some crop will go in that direction.)
    We are presently in process of designing and testing stategies suited to 
rather random flooding (the last being a 7-foot rise in the water table 
during the "dry" winter season of 1997-1998 that just recently returned to 
normal levels.)  Water buffalo, which are the prime strategy, are as yet 
outside our budget.  By eating rampant floating weeds they would increase 
fish production by orders of magnitude.  The light penetrating the water 
would stimulate algae production which would release oxygen.   At the moment, 
oxygen levels are so low that even crawfish production is limited (which is 
probably one reason why they invade freshly flooded land so 
rapidly--uncovered water means higher oxygen content plus an abundance of 
food, decaying plant matter.)  We are also looking at pigs because the 
turnaround timne is short so herd size can be quickly adapted to reflect 
forage conditions.  Pigs WILL root in water of up to 3 inches--at least the 
feral pigs around here do.  We have been hesitant regarding waterfowl because 
of the liklihood of predation by alligators and because it would be difficult 
to prevent escape.  On the other hand, my wife is seriously interested in 
investigating gator farming.  Sort of solves the racoon problem, but round-up 
could be hell.  (We remove about a racoon a week, on average, which seems to 
be a steady-state situation--still plenty of racoons.   There is another cash 
crop--pelts--for someone who wants to bother.)
    A major problem on flooded pasture is that we seem to loose almost all 
our legumes for fixing nitrogen.  Supression of nematodes by flooding is a 
somewhat compensatory benefit as is the fertilization by stranded floating 
plants and detritus, notably azolla which gives a bump in production for a 
few years.  
    I guess flooding that is reliably seasonal would be a fairly simple 
design problem--here it is random, though the greatest liklihood over a 
millenium would probably be the fall months of hurricane season.  Still it is 
hit or miss on a year-to-year basis.
    There are of course many more design considerations in flooded land, 
including access for livestock, people and crops, potential for plant 
diseases of certain crops promoted by anerobic conditions, and even 
prevailing wind direction.  Here we benefit from being at the East edge of a 
large floodable area.  With our winds very commonly from the West, we get 
deposits of nutrient-bearing floating detritus and plants during flood cycles 
that has made our side of the wetlands far more fertil than the far shore.  
Wind can build up a fair bit over open flooded areas and we are developing 
shelter belts of bald cypress (adimittedly for future generations) and hybrid 
willow to deal with this.  We have also found one species of bamboo that 
persisted under water for months and still thrives.  
    Well this is a very fertile area for productive design, but maybe these 
starter notes will jar a few thoughs loose.


For Mother Earth, Dan Hemenway, Yankee Permaculture Publications (since 
1982), Elfin Permaculture workshops, lectures, Permaculture Design Courses, 
consulting and permaculture designs (since 1981), and annual correspondence 
courses via email.  Copyright, 1999, Dan & Cynthia Hemenway, P.O. Box 52, 
Sparr FL 32192 USA  Internships. YankeePerm@aol.com  

We don't have time to rush.

A list by topic of all Yankee Permaculture titles may be found at 
http://csf.colorado.edu/perma/ypc_catalog.html
Elfin Permaculture programs are listed at the Eastern Permaculture Teachers 
assn home page: http://home.ptd.net/~artrod/epta/eptahmp.html
----------
In a message dated 9/25/99 1:57:17 PM, london@metalab.unc.edu writes:

<<-------- Forwarded message ----------
Date: Fri, 24 Sep 1999 14:32:14 -0400
From: Crosswhite.William@epamail.epa.gov
To: sanet-mg@ces.ncsu.edu
Cc: Manale.Andrew@epamail.epa.gov
Subject: Storage of Flood Water on Farmland



Short-Term Storage of Flood Water on Farmland

A colleague is developing and examining the idea that the benefits of 
short-term
storage and management of  flood water on farmland may be much greater than 
the
associated costs.  This storage would supplement the storage that is already
available in COE and Small Watershed structures.  If large amounts of flood
water could be stored on farmland, the effective operation of all these
activities should be closely coordinated.  I include a summary of the idea 
and a
request.

Summary

Short-term storage of flood waters by the temporary plugging of ditches and
drainage systems and holding water on farmland with berms around the edge of
fields and other actions could reduce the social and environmental cost
associated with downstream flood impacts.  In return, farmers would be paid an
amount that would cover the opportunity cost of the land for the period of
runoff storage including crop loss and any other related costs.  Additionally,
there could be cost sharing of installing berms and risers to store water on 
the
surface, gates to retain water in drainage ditches, and modifications to
drainage systems to temporarily store water in drainage pipes and the soil.

Request

First, I solicit and welcome comments on (1) the feasibility of storing and
managing runoff on farmland and (2) any suggestions and ideas on ways that can
be used to provide short-term storage of water on farmland.

Second, if you have installed berms and risers, gates in drainage ditches,
controlled drainage and subirrigation systems, or other systems that would
provide short-term storage of water on farmland, please share information on 
the
costs associated with these systems in as much detail as is available.

Thank you very much for the information and ideas you share.  Publications and
other materials welcomed.

William Crosswhite
USEPA Mail code 2121
401 M Street SW
Washington, DC 20460

202-260-6804
Fax 202-260-2300



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