lb ge wrong in desen, and us pur whole pepulariens al
risk; waier ln pariieuiar musl be subleei ia lreuueni
analysis lor ppllulidn and 5am. and deep bare All well
walers rlganiusly lesled lor excessive mineral and
radieaeuve pellulanls,

11.5
LANDSCAPE FEATURES IN DESERTS

Oeeupled and impmnlged and lands premu a lelal
mosaic DI vegeianerr, wlln very dilleiem changes
bbvious iu lhe iraveller. 1p lud" aueh a landscape
mean. a dsigner needs Io MK,

- l-mcss- wheiher wind, waler. er ml-lllrariun rs
aeuve Locally

~ ROCK AND soil. mm. lnese deerde leeal
.espunse la prueess and pruduee eharaeierirlie
landlenns.

- ASPECT. even slighi shading by hills ehanges
uppimunlries and piumplrs gnwlh

. FIRE FREQU£NCY, and ihe nine sinee lhe lasl lire.

- THE DATE or THE LAST HEAVY RAIN lmum
ihan I2 innil whieh may have been lhe lugger ler a
spedlie 51st ml plane (mmilmzm ol speeiesl.

ln drylandr. eresipn landlorms are balli rniire
signilieani, umsplcmus, and more nurnenius in rype
lhan in humid areas, Exrensive deserls may show
ranges or MOUNTAINS wuh (umple’x hug valleys and
sheavsldzd gnrgvs draining mse. lselared m grouped
gramne domes lleELbERcsl rise sleeply bui pl lhe
deseri plain, and lhe eumplex scAlP AND
PEDIMENTIindsupt-s nl laulees, Infill and wadis
lbdi clnyuns) are alsu lealures el lhe deserl
EADLANDS ul eomplea, eroded, seller sedimenls may
devekvp an unrunselidaled art», and sharp—sided and
mush blanched cuLcHrs lgulliesl develop on sleep
slopes Series 0! lulds give a BASIN AND RANGE
rppdgiaphy ever most desen borders near mounlains,
and are a leaniie 01m! areal basin desens ul Nunn
Amensa

True desers has lhe blond primary landseape
pavemeni elassiliealion nl ERG lsandy deserll,
HAMADA (lurk and boulder pavernenll, and m
lgravel iurlaeesl. oi iliese, erg is lurrher broken down
imn dune rypes and lurrnanuns, some elwhieh may lie
over the reg a! harnada base lieg u generally ralren us
he an area hum which sand and sill has bull removed
Eng is eumposed pl SANDPLMN as near—level sand
sneeis river various supsrrales lalsu eallrd sand heldsl
and dunes pl several types

in rural, deseri landseapes are angular, and aenvely
eroding Humid unis. and tspeually lhase darned
wilh grasslands and lemsls, have seller and more
runnded uullines, Nlm rare rilll laees al receni
laulkhnes nrshurellneslr- die my

lhe lewer slepes, basins, and playas lpansl a!
overgrared and eluded drylands need anenliun, as do
rhe dry river beds and iqulkn inal lie btlow lhe

316

surlaee sediments rur ihis mm and haul: a vu'y
seaireied lirerarure exlsls on deseri siraiegies wiih
respeei m speeilie landlprm lypes, l have med io
assemble here a rel olsrralegles suned ns speellie sires
and landlmlu lrlgure my.

schPs AND WADE
Wherever pedpds ol upr ,pr searps of laulls lraeiure
dseri peneplalna, lung rhll-unes lsduie nmnmg many
lens bl liilemeriesl srand abeve lhe lower erusldn
surlaee. While lhese uplili scarps are also visible in
humid lands, in desens lhey remain less mud, and
develop eharaclerirrie prullles. These pmliles, angular
and esseulially simple, wi|l qluckly emerge liens. lne
reunded hills bl laulied hunud areas enee lhe
vegemien iselmred and duem’mahnll selsln,as il h”
emerged in cuunny eleaied el lrees and ended in lhe
1920's in Sanlh Ausualia

The prueess develops as per ' use in ln lnie
dsens, lhe prplile is rypieally :5 per Figure “.5 (sear-p
seeder. above and men plan below) Usually, lhe real-p
laee is lairly siraignl or enly genlly eurved, and lhe
wadis are an near righr-angles in are scary Lire Mlhin
ihe wadl side, valleys leave again al near nthngles
iu ihe main valley; lhe pauern u lhai 0! parallel laull
wm and eumpensaung yeinls in ihe reek,

Cumplea bux eanyans lwadb ending in dim), mesas
lisblaied mm of lhe main searpl, and bunes (0‘le
searp seeiuuisl make varibus scirpellnes, Searps are
rapped llhe upper erdsinn surlaeei w' h durable
lmnslones, hard sandslpnes bands, lernerele, pr sllvaere
crustal malenal clills and searp laws are generally 0!
seller, samwmcs bauiuie ialumium paidel maierlal.
and lhe lower enisum surlaee ia euvered wl|h sills and
sands washed em 0! ilie wadis and laier dislnbuied by
winds

When u rains, lhe hard lock suilaee ol lhe upper
searp surlaee sheds inusi ul lhe waler, which lollnws
genlle valleys behind lhe srarp and lallr as sudden
waleilalls 0v" lhe clill ends el lhe wadis lusi belpre u
dees so, however, lurbulenee may sedur mu deep holes
in (M upper suflam irigure ml Warer may rush in
iurienis lhrerugh lhe sysiem lbr 34 days aller rain. and
llie volume diseharged largely depends on lhe
ealehrneni area

A tflflaln nl waver, or nlls, may lall alemg lhe whole
scalp lihere is usually a dbwrulupe iusl peluie lhe chm
bu| rnis is a mueh mole ephemeral linw. Nevenheless,
ever lime, lhls euriain pl waier or (Illlrbase seepage
may panlv undemu! lhe soll sear-p, and rlguie 11.5
shuws ene pl ruse searpliase eaves in lhe plume.

leq lhe rllll "sell. lhe nu|ch ai lhe base (in be very
large liall enough In rule a Emmy house) or very
small lnisl large enough |u e shade to a kangaroo m
a sheep) Norrlies in lhe clill lnee may be peeupied by
plgl'cus, ewls, swalldws and swuis, rpdenls, repules.
and M or lheir larval lenns. shade, like waier. is a
eniieal mu: m lhe deserl

The wadi pienle, m lair ippmximanun bl il, b Ibo