The Tacoma times. [volume] (Tacoma, Wash.) 1903-1949, 1941-07-03
HERE'S MORE ABOUT
Flood Control

under TIE primary plane q The
rest Of tne valley bat when u -
cultivated tbs ox-heN and = fer
tie.
- lew nik~s
IRE retaining - this secondary
plane eN bow land IL accomplished
IN ms3or part through the use -
~ los dIkes or reck lserss These
dlkes have been raised q such
level that TIE normal sprlnk and
summer funoff wlr not ovsrtop
them. However. floods 81 sven the
smaller TYP. vii crest ihese
isvees snd inundste The secondary
plane lands thereby sitting them
IN.
Th's continual sitting process
first uscd ~ the Egyptians cen
turtles sgo. viii ultimately bring
al q the 200 acres ~ secondary
plane land up to gcod farm land.
solve other Problem.
Besides the reclamation q these
/ 200 acres three other problems
Of river control are being solved
through the establishment Of =
channel OF fixed location for the
river through hank sterilization.
drift removal and rip-rapping
These three problems Of river
control are: - Prevention Of Pc
riodical erosion. ~ Curtailment
Of the meander area which the
river uses In flood times 81 Han
ding Of the river burden theasy
gravel. silt and dnfp which comes
down the steep gradient Of both
rivers.
use Tractor
Ons ~ the first and most i'm
portant steps Of river control IA
drift removal. which In this case
means the removal ~ all trees
stumps. logs ana drift Of any ns-
ture which impedes the smooth
flow Of water within the defined
banks Of the channel. This work
is being accomplished by the use
OF q small crew working with a
caterpillar tractor
Secondly. extensive rip-rapplng
especially essential around bridge
"bottlenecks. lie being carried out
through the use Of rock hauled
from the quarry near the soldiers
Home at Orting. This revetment
work was first done on curves
where the erosion effect Of the
river IL strongest.
Thus with the low bikes protect
ing the straighter flows Of the
river an established channel can
be maintained which viii seour H.
SELF clean and tend To eliminate
the building up Of gravel bars
caused by permitting DRIFT 10 stay
in the channel or allowing the
river 10 carry on extensive erosion.
Rank Failure
Years ago the lover ruyallup
vas Strengthened and a permanent
channel established by the USE Of
concrete rsvetments. This work
was expensive and occasionally
this permanent concrete hank
would he undermined, resulting In
csve-in and a flood. This was
what occurred in 1884 when a bank
failure caused the floods around
Fife.
From that experience. river en-
gineers learned that while perma-
nent channels tend 10 help carry
the river burden out TO sea. they
also by this same securing action
may undercut your permanent
channel.
Then IT WAS that the use Of large
rock quarried near Orting WAS be-
gan. Underwriting IL practically
impossible, As the rock just drops
down into the hole Thl. IL some
thing which concrete reVstment
was unable 10 do.
Nv Case OF Rock
Consequently II Was discovered
that all the basic forms Of flood
control could best bs obtained
through the use Of rock and this
discovery has enabled the river
control program for tho upper
Puysllup and Carbon rivers To be
carried out at a much lower cost
than for the lower Puyallup.
And As the control program for
the upper Puysllup reaches It,
conclusion ten years hence. then.
too. the danger put on the lower
river by floods will be lessened.