Deplh and plans: ragelher serve as a 5:1 of breedlng
reluges Ior lhe laud organisms a! n-nnwures and
earnmlres As we wlll laler see, the conllguratinn ul
levels al dlserenl depth may have a pmlound elreea an
lhe lanal yield dravallalalllly nleueh laud organrarn.
Thermodlnes may dtvdup above l5 m deplh, and
are lilrly typhra) of lakes sub|x| lu sudden seamnnl
thingzs In «her lemperarure Overturns m tempura»
mm lypleally o<<ur in aulunrn and spvlns Whlle In
summer he rurlaue walers rernarn mnslslemly wanner
lhan mos: al deplh, m wrnler we ran ge1 surfim lee,
llren wanner wuler al deplh, and finally lee again deep
m 1h: lake, where very euld interns peel up and heeze
sash rnay llve m a Sun a! lry sandwich, or mzked away
hemed m a modes: have nr hullnw ln shallwerwaler

rows IN smug AND FLOW
Funds ean he bail: Isolamd hum. pnrnlkl wrxh, ln
(omenmve sent: w. , uader sequenses wilh mhn
ponds, uras any eennlnnahen ol lhese They can aka he
annrdaled lnesledl one wlllnn earl. Milan and in lael
have some lealuree whreh pennrl linear Hangman:
uhe pond aseanal nrwmerway)

lselaled Punch and ‘lsalalmn Fund: are limxlur m

 

 

 

Evtry iqunnnm keeper New sleek, diseased stsxk, mal
polymflums, and an rnauranee agalnsl general Ivss may
dlelare a ael ol stlllrwuer Ponds in qrnre separale
§Imahons (um shiving any flow 0! wa-erl. A sel ol
fink: above grade, 07 snll»pands lllled one ar a urne
can be elleenuely mlaled. Even ii erealed rhe Sum,
lhey wrll s|ill manage |0 he dlllewnk, whuh IS one 0!
lhe la ahuns ol aquaeulnare Waler syslms are me
eenneered Wflhln rherneelves, and eunvey small
drllerenees mm ripldly lhan land sysxems

Ponds m parallel are perhaps lhe enrnrnon
lrah—euhure syslern, and are analagmus m Ilnsahon
hays an land In fllal lhey past-5‘ a head canal (inflw
syslernl, an lndmdual flow»mx-mlgh, and a nil eanal
ldrarnage system) whleh also wane lor surplus ware.
ln rarna, They are ellem'vely lsahud unlrss a diseau,
pollumfl, or qualllau-ve ehnnge mans m lhe cur-Ilium
walee supply, when all may Iall logahrt, unleee (as ‘5
alsu man-nan) flow regimes are suggend so that narne
new, elhera a! shll.

the pnrallel rerrea ls ideal lur valley [loot pends
where water al head has been dwmcd ilung nanmar,
lor alngle feeder plpes, and nar sarne nlrmw lldal
benehes There are many xdvanuges, and same haale
dreadvanlage; m um one eannar 'leed lhe elher- Thal
ls, we ennnol rel up a ednlmlled nophic ladder in

 

 

FlflfllE 1er

couszmws SERIES IN OPEN owns

A amneea fllllusa elannen ll .nlemls vwz malnana xml:
Mum. and small nemanenl was ln unmm

 

MWOUNED Win-—
MD are
mwe RIP-MP

 

I Pol-fl Wm w- hs animal! as mu ‘4: mm are...“ "we! ul
lampimmilsluuunm palm lsea lull

 

476