150 lines
5.1 KiB
Plaintext
150 lines
5.1 KiB
Plaintext
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duodgmo lie downsrruarn loner nreoays
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also lul wxlh sand and link: a llal
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all bed all me edges ol wnren we planr
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large rrees (pecun. palm. avoeado, manga)
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—leeup are uponearn lures! Such [126 can elm
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dressesrwarer dam (um darn leresu.
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me barrler darn ls rand—ruled. several deep
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mouanes will grow mere, eg. aepemgns,
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're pelms, cnlnese warer enesrnur, swamp
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a, elr. Full, me nrbble and sand an era buried
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reseyrrlrwnldn beeps lbe dam iull il kmw ol one
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film ural dropped only a rm m level nvtl a 7-year
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), and also as a deep Ire-save ol nuroi sand [or
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me downsrearn loresl may erlrnd I—Z lrm rn me
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sandsomse rivetflola will only so in wide}
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Th! are hundmds or llrousands ol such sues a lew
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born lombllls in deserls, and llus sunple bul
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red sysiem rieaies oases wnere llrere were
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belore. me figure shaws a darn buili by r rallway
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al oddnadalia, Saudi Ausmlh, |l| ibe mas;
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k sail lunrnonlng well in lire lame.
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Iduw roosr nees around such dune, ibe guano lronr
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ids-en buds may be guinered as sham ol pnospnare
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lesrlllgr, and lbese are or greal yalue ln esiablislung
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issue or roelr wlndrow irees lss a dlluie soluilon or
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used wlrlr and pans af damp sand). 0n rlie srlr dam,
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.elorogrow vrly well as m! rusl swampy eondmon
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reader. and a good rrbp ol legumes and melons ean be
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yhnld ar rlnl ome. A lew suen dams snpperrl a ebong
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rlllage popula on. and will keep seuur nules
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downsrreern reenargod wlrn waierlor swlmmlng holes.
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MI elearwarer dams should be 5.9 m deep and di
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redueel surlree area, railier man shallow end wrde
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DAMS
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barrier dams aeross sue-ms ur wooded and sraole lulls
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an be erpeered n) have a long lile ol loo-dob years or
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more, belere sale and humus lill lne ralenmenl, end
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evul belore Glen a wellvdeslgned darn ean be
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Illt-fillslltd lrom lire base but barrier dame in and
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arersnurel be planned lrbrn |M oursei lo lill in me brun
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wxlh slli and rubble ln ine lusi lew years nre waler
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rliey bold wlll beslorednr sands and rubble
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Thus, dam-m dams ur desens slrould be bull! well
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Iwa from suen valley sues, and RI: iorbelenl now
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lnun wadir or lorulull sandebed and boulder sneams
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unoi be bled all lnlo almpsHtl/d enanneLr llilcd wlrn
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sand naps, and only alier um lo a darn nus dam
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sbrruld IIM inellbesued so am lasr walnuxl run in lo
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lr over loosesurlrre rnalenal || snrmld be (reused, and
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me margin; planied io rurnes and shrubs. rlgure ms
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some lrelplul landrs lor an elleuire and darn an be
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ebeelred belrue rensburoen begins, Ideally, ine rubble
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and sllr m are dry ereelr bed slould be very open and
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permeable, ol slones, pebbles, and coarse sends mus
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wlll alrnosl eerlarnly mean rner lne dam is near rlre
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looanllls or In a valley elose in me neadwaier roelrsl.
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Sewlldly, rbe lloorol elredam rs ldully day or massive
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nxk, and benre Ink-pm, Huwcvu. even If neither ol
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inese lanors are rdeal, sand dame will roll be good
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growing iiis, as we wll] be slowing down llood waler
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on a long "1de rue,
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An errenslve srlr darn ol 9—12 m in neigm n alwaye
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buill in IE or z rn mges. and rbe wall nosed ar ibe
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earlier sages srll up belund badl wall, gabions allow
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warer rd filler down lo e bare p pe, wlueb eanbe led lo
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.eulernenl. me wbole Am el siren alebrnenl needs m
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be proieeled lrom sprays, lenllrsers. and browsing
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rnrmals (o plmxl lie-mun selllnnznfi.
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RDCKHOLES AND CNAMMAS
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lek basun, ollen filled wlur waver, adse lrdm a senes
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nfudgns; some are
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- koek seounng ln snearn llow losrroeloni on stream
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beds.
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. preeoeunw and welslry rwelllng and snrlnlrlng
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plor roelr nunenl bydrellon
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- Salmoded ponds |l| roams nearrliesea.
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there are many ways ro assisi mm eonseryanon m
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roelrnoles,e.g,
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- Flll lrole wllh pebbla to lower eraporeuon; some
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waler ls losi,
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. Thakh or eoyer lrole.
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. build guners lo bole
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. Ereri a melal mesb lenee io direei dew
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rondensauen rd hole,
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. Deepen bole, and plssier n wlllr eenreni ll u lens.
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EVAPORAHON AND EVAPUFRANSI'IRAHON
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As we baye defined the rllmaoe nope ol nus cbaprer,
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Wye" eraperauon iparo ol wrber exposed la arr)
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will alwayr erreed or equal predpanon over me year.
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ln leer, I|nws| all ol lire sub—nurmd rd and areas reeled
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have a polenbal evaporaden well abone deal 0! enual
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ramlall. This means manor mos! oldie year, were ls no
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longer any rree waler lo eraporale ereepl lor lbe waier
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in drum or nlber upen—waler slareges A iypreal gram
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eropsuenar mruerneedssoernolweierromamre liis
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dnlrrely ro obraln enough were. unless waler srorage
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lrom run—o" is available, or unless run<rll has been
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.nlrlnaled in» me soil
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Dneer eraporenon ln sell an lure "nails elleevl wlll
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ereeed polzlmafly lm ern per year in mosl arid areas,
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bui a lar more severe elleri ls rnar ol nor wlnd
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eraporauon lrne wrloilresllne elleer‘i, whlch ln
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unsbellered llelds mosl elleere lne lreld edge and
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lnereaees omnprrabon lull—we lave! lbs barlrgroend
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affects Chang llml reeords lbar winds blowing lnun
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arid mhumldamsmyaflmnwpsolmimmm
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belrne aequrnng a non<raporanre waler moislure
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load ln enema «lb rn wide erapdrelalon bordrroluees
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may be needed berween rlre desen end produeuye
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(mplawds, There is no doubr |hil a windbreele 0! lens
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uses less waoer man mar removed by me hm winds
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355
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