memex/0_inbox/in/books/PDM/Bill Mollison - Permaculture A Designer's Manual text/369.txt

somelliing less ihan is honrs Given lhis dais, lhe
widlh and deplh oi lolal inlereeplion by swales or
mile an be enleiilaled, and relardalion basins boill l0
redone waler loss, inerease vegelalmn, and eonlrol
bonds, These arlilieal inlakes are now neeessary over
rely large acres oi magnud and eroded eonnlry,

- WATER Viscosmi. Walerdensiry is lillle alieeled
by iemperaliire, while lemperaliire has signrlieanl
easel: on waier inssosily, heme on slreamllne shenr or
-irierion- Day—lime rains on warm silriases riiHil
lulu lhan mgm i-ains, or rain in eool mghl periods. As
many desens eneoiinier rain in summer (monsoon)
regimes, lloods peak earlier in lliese regions lhan lhey
do in wmlereram areas adlh lhe velooly oi now lllie
main erosive ianorl and iiirblilense are aeeennialed by
warrnlh and lower viseosily viseolis wales may eaiise
ml waler level rise in lovvander soeams al mghh and
sirpporr heavier llbaling loads oi delriliis

in many areas, ioeal |ong>lzrm slreaiai mine will
nor ekisl. The besl guxde io pasl flooding levels is
llieielare eareliil obseri-alion, based on damage lo bees.
old deleinis levels, ilood deoiriis ealiiihl lip in bees,
local knowledge, and a sensible aaiessrnenl oi lhe
ealehmenl area, ils rype, and rainiall dala imm similar
legion:

Any designer earl, by relerenee lo rain days,
ralshmenl area, and a ael oi IM ioropoino lanors, make
an eslimale ol lhe polenlial lor rim—on las overland
ilowl in a specilie loeallly Thus an eslimale oi lhe
polennal sloraees needed (in also be made. so llial loss
cl waler oneile is eliniinabai or iediieed

kunaaii in desens, depb'ndms on lhe permeabilily oi
lhe slirlaee, ranges liom “Ml ol rainlall Averages
may be low, biii in llash iloods lnoi iineomrnon n ihe
lolal preeipilanoril, hleher pereenlages are obiaiaed. l
have seen diversion rhannsls in slable nunswtlhllg
dimes flowmg as small sllearos in I em ol ram, and
lliese lllllng livgesmnyts in aday We ean aeeepl aboiil
217% as an average ol run—off, bill in praellen ll is salei
lo allow a 20 his run-on area is l heelare ol slop. or
eiillivaled vegetaflnn, lo onsilre slilheienl soakaee (or
[anylemi 5mm only in areas or reliable rains ean
we iediiee lhis ralio lo I?! iealelimenl area lo field am
or prodiielave mp),

HALTING AND ABEORHING WATER RUN-OFF
Th: hlhng and ammmn oi mail has iwn main
aims. lo eonven waler lrom a dalmfwz erosion loree
inlo a aiiieler llleemlive enemy llo develop loieslsl,
and lo reeliarpe sroiindwaleis so llial neshwaler sheeo
develop above lhe deeper saliwaler leads oi lhe deeen,
and lrees sari beneiil

However, we should always do our souls and keep
good rem-es ioi il we wilhdieiw liesliwaler horn llie
groimdwaler flange lasler lhan we can reeharge ll, we
are only lempoemy inlialallanls ol lhe desen. Trios our
rises mosl be Frugal, naediiil and devoled primarily lo
slablislimg deep—named and dmughlswslsunl rrees,

nol lo supply wasbeliil lawns, iliish loilels, and leaky
pIPs‘

Wherever we eslabllsh a surlase inlake lriim nine."
sleams, we may risk sill dogging ll we design a hlwd
"flake, wills bees on ilie onler banks, we earl iise lhis
sill land any eover erop we sow on ill as a rieli
sidedressing lo irees For a cheek on sill depih, ll may
be wise lo plare perrnanenl sleel pegs wllh clan:
gmduillnns m swsles, and lo sow and grade on or any
hme lhal riloie ilian 2n em or sill is drpoiilnd. ii only
hand labour is available, siieh sill removal requires
swales nol execdllls 4.5 m wide, bill wilh a [radar
and blade llir road yaderl, swales on be sis in wide
lnrillnlion ian beaided by ripping lhe swale base, and
using eypsiim in elay sails

snonld low slope soils lliemselves be snbieel lo
sieadv erosion swsle banks can be ekaeeeraled in ihis
way lo lorm evenlnal lerrases, Wllh lrees now on lhe
iiiiler lemee slopes Such evolnllosls ooeiir where she
slopes are sandy, or where eiiibvabon lakes plaee on lhe
slopes beiween swans. A5 lei-larva lwrlh «reed edges),
lhe 51096 slabillse. aod sill removal is a less pleasing
nmfly. siieli m are nor a eonlinlioiis series bill
spaoed downhill al lnlervala oim limes lheir widlli,

by a sneeeseion oi slieh slraeesiesi his: and small,
deserl proondwalers ean be rompelled lo snslain a
reeharee ll is oliile possible lo ereale Springs and lo
niamlain low sneamllow ii a siieeession 0! 5—7 swalee
are made lo behave zllmlvely on rimoll slopes; siieh
ellens oseiir nail-rally where rineelnll lakes Such as
l-yrarnid lake, Nevada, rereded in a slepped
sneeessiori, lawn; I m deep and 3-6 in wide bands ol
"beach boirldeis- aeross lhe slopes, and an hailing
mnfl" below lliese bands bill above lhe pieseni lake
level, heshwaler spnngi mi.

bleed-on syslerns lor liirbillanl and silleladen
sneams ean laa oiir ingenuity in every oasea resineled
waler ekil should open inlo a rniieli nsdev drain (lhe sill
lrapl, whiih laler leads inlo a broad reed bed, lroin
whieii ialrly elear wales rail be led lo a darn or swale
siled well away lroin lhe sbeam line ilsell, and nol
above a valley seldemenl area (Film: mil.

whi e dams stat! waler ior villaee use, awales lrom
the: syslenis (an be a lew kilomeoes lone llhoy ean
reaeh la live neirl lasl sbearn) and ean lheieiore glow
eklensive loresl lines wrlh no more iroiible lhan an
oeeasional sill eleai-mp and a lew hours wilii a road
grader, Seasonal sill clenrhi‘ in lhe sill lrap may be
neeessary iinlil bees are well eslablislied.

ii heavy maehinery land very large slonesl are
available, a more subilarilial dam on be buili, allowed
lo sill um and a wales channel on horn lhe level area
lusl beloie lhe dam.

The aim, however, is dear il is lo lead null-0H on
eonloiirloabsorplion oisoil smigé beioieil nowsoiil
w me sail llals and is made useless For minor liows. a
simple swale sniriees lodireei and absmb sheei waleis.
Even dam apillways in deserls ran be led iroiri lhe rear
ul lhe dam inlo lung swales belore being spill inro
minor ssreams we ran hold ihoiuands oi limes more

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