FIGURE 17

A ¢
INS

h HYDRAULIC JUMP STUDIES

RECORD OF APPURTENANCES
BASIN II

A437



FIGURE 7

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1 =4
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e 91 * 2 0 e 9 ° z °
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INISV@ ONITNTNILS
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dWNf JO HLONIET
'
S3IQNLS dWAr OIINWHOAH ~ =
i
fl
z
-—©® 384 -UNIY@G yO “ALUN “yoo, |
—_—_—— ® yey £304030q07 yo1snz| 7
——— (1) 30y 95740W puo sy0sowy¥og) .
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pno4 wisog OuIIINS aasusdxg = LEY q
ta *
—— 5
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|
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Fr s
[ he /
‘an.
a + v pepuswwosey ~ B
Pee wee - fold] \
as mY a aoe a 9
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FIGURE 21

10

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S3IGNLS dWN OIINWYOAH

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Columns 1 and 2 give the pipe sizes used in designs origi-
nating in the Commissioner's Office, Denver, Colorado. These may
be changed as necessary, however. These suggested sizes were ob-
tained by assuming the velocity of flow to be 12 feet per second. The
pipes shown would then flow full at maximum discharge or they would
flow half full at 24 feet per second. The basin operates as well whether
a small pipe flowing full or a larger pipe flowing partially full is used.
The pipe size may, therefore, be modified to fit existing conditions,
but the relation between structure size and discharge should be main-
tained as given in the table. Infact, a pipe need not be used at all; an
open channel having a width less than the basin width will perform
equally as well.

The invert of the entrance pipe, or open channel, should be
held at the elevation shown on the drawing of Figure 42, in line with
the bottom of the baffle and the top of the end sill, regardless of the
size of the pipe selected. The entrance pipe may be tilted downward
somewhat without affecting performance adversely. A limit of 15
is suggested maximum, although the loss in efficiency at 20° may not
cause excessive erosion. For greater slopes, use a horizontal or
sloping pipe (up to 15°) 2 or more diameters long just upstream from
the stilling basin.

Under certain conditions of flow, a hydraulic jump may be
expected to form in the downstream end of the pipe, sealing the exit
end. If the upper end of the pipe is also sealed by incoming flow, a
vent may be necessary to prevent pressure fluctuation in the system.
A vent to the atmosphere, say one-sixth the pipe diameter, should be
installed upstream from the jump.

The notches shown in the baffle are provided to aid in clean-
ing out the basin after prolonged nonuse of the structure. When the
basin has silted level full of sediment before the start of the spill,
the notches provide concentrated jets of water to clean the basin. The
basin is designed, however, to carry the full discharge, shown in Ta-
ble 11, over the top of the baffle if for any reason the space beneath
the baffle becomes clogged, Figure 45C. Performance is not as good,
naturally, but acceptable. With the basin operating normally, the
notches provide some concentration of flow passing over the end sill,
resulting in some tendency to scour, Figure 45A. Riprap as shown
on the drawing will provide ample protection in the usual installation,
but if the best possible performance is desired, it is recommended
that the alternate and sill end 45° end walls be used, Figure 45B. The
extra sill length reduces flow concentration, scour tendencies, andthe
height of waves in the downstream channel.

Conclusions and Recommendations

The following procedures and rules pertain to the design of
Basin VI:

36


FIGURE 44

90

80

EL
&
3 gS 3

+
t=}

LOSS IN ENERGY IN PERCENT
w
°

20

LT
Impact basin ty 1
ZA
VY
VAL Jump on horizontal floor
Li iV
/
|
i
|
|
|
|
ie) 2 4 6 8 ite) 12 14 16 18 20
F,= ne

COMPARISON OF ENERGY LOSSES
IMPACT BASIN AND HYDRAULIC JUMP



FIGURE 18

Leo

SNOILYOdOud G30N3SWWO03HY
III NISvV@ ONITNLS
S3IQNLS dwar OlINWYyGAH
(2161 aes)

wet rrr ee He eH Are LL. >
Wm 1

gO yg ig

be ~~~ -20 8 0--- 54

Syooig ayyog---" Sy901q aynyo-*
£, 0O-+
SS ius pug 420 4 ke



FIGURE 24

S’p-G'24 HOS
(AI 3adAL) YOLVdISSIG ADYIN]S dowd
S3lanis dWnf O1INWYGAH

ie Og Oe Oo ne Oe Oe.

“subaq JO 44PIM
XY sionba sjojs Jo upIM -~



FIGURE 20

S31IdOU¥d SYNSS3Yd GNV 30v4SUNS YSLUM ALVWIXOUddVv
Ill NISvV@ ONITNILS
S3IQN1S dWAr ONMNWHaAH

1
8'0---- >,

. ee ----3g
aay se bo

“Yidep Ja¢0M] [Dy
e40Bn[uo0s 40} ajiyoud
S4.uasesdes-Des0 pepoys

rx)



FIGURE 45

A. Erosion of channel bed-standard
wall and end sill,

B, Less erosion occurs
with alternate end sill and
wall design,

C,. Flow appearance when
entire maximum discharge
passes over top of baffle
during emergency operation,

Channel Erosion and Emergency Operation for Maximum Tabular Discharge
No Tailwater
Impact Type Energy Dissipator - Basin VI


FIGURE 12

Ter

YOO14 TVLNOZIYOH NO dW 4O HLONSD

III GNV ‘IE ‘I SNISV@ ONITNILS
S310NLS dWAr OIINVYEGAH

oA,
=l4
"
02 a ot vi ci on 8 9 + z o
7] T

1

(-y aido1) uisog T11 adky -sysay u

(€ a1q0L) uIsog 1] adh, - sysay ul

(2 a1go1) suisog IT adky buysixg @
{ft
2
7
le
eid
2 eo =
A
ulsog III adky le
* €
~ a
2 olr
le s
| 4
o {= U mi
uisog IT adky o>
va
/; s
Vi
—~
= 7
—
— 9
re 104njON-T aah,
SS SS



FIGURE 2

TEST FLUME C
Width 1.5 feet,drop 10 feet, discharge 5 cfs, slope 2:1

TEST FLUME D
Width 4 feet, drop 12 feet, discharge 28 cfs, slope 0, 8:1


FIGURE 42

\
+
2
Fat
| &
H ira
p—| po. oe ieee ino
=
' kd»
y ak
t 2
+ if :
y |
a _
' . LAN
‘<- thw’ (equals tw with 8°max)
=~ 4 Dia (min) -->

SECTION * Bedding” SECTION
ALTERNATE
STILLING BASIN DESIGN ALTERNAT!
WET OTT TTT TTT

Tee Tee TTT TTT TT TT TITTY
i ' io

PRUE LLL
t
Piel

T

+

1

|
3 | |
oad | |
lf i
. +
“ oo
zé
IE
56
2

= 1 ! : 4

fp) SR eU Ee FUNTIN VET We MRO RESEADCITEMTIVIVININ IT THININ MUERSSITECCLItIT tom Ne NUON EuESEN EVIE UBUD SUELSESECETE:,
10 20 30 40 60 80 100 200 300 = 400
DISCHARGE IN C.F.S.

DISCHARGE LIMITS

IMPACT TYPE ENERGY DISSIPATOR
(BASIN WZ)



FIGURE 27

o

PC. STA.4+18.02

a ee

VERTICAL W.S. FLUCTUATION IN FEET
8

PLAN

“APPROX. WATER SURFACE
{FLUCTUATION AT Q=5000 cfs

8 10 12 14 16
VERTICAL DISTANCE BETWEEN
FLOOR OF CANAL AND ROO

TEST NO.!

To DETERMINE MOST EFFECTIVE
ELEVATION FOR ROOF - Q=5000 cfs.

SECTION

@

VERTICAL FLUCTUATION
WITHOUT UNDERPASS)

cy

a

pea

VERTICAL FLUCTUATION
WITH UNDERPASS)

is

VERTICAL W.S. FLUCTUATION IN FEET
ny +

-

VERTICAL W.S. FLUCTUATION IN FEET

509

|
Ql
00) ‘3000 5000 0 10 20 3
DISCHARGE IN CUBIC FEET PER SECOND ROOF LENGTH IN FEET
TEST NO. 2 TEST NO.3
TO DETERMINE EFFECTIVENESS OF EFFECT OF UNDERPASS LENGTH
UNDERPASS AT VARIOUS DISCHARGES ON WATER SURFACE FLUCTUATION

WAVE SUPPRESSOR FOR
FRIANT -KERN CANAL

RESULTS OF HYDRAULIC MODEL TESTS



Discharge

(Col. 3 Table 11) 21) 38] 59]/ 85/115} 151} 191] 236] 339
Nominal
[Rock Dia. (inches) | 4.0] 7.0/8.5] 9.0/9.5 |10.5/ 12.0] 13.0]14.0

38


1. Use of Basin VI is limited to cases where the velocity
at the entrance to the stilling basin is about 30 feet per second
or less.

2. From the maximum expected discharge, determine the
stilling basin dimensions, using Table 11, Columns 3 to 13. The
use of multiple units side by side may prove economical in some
cases.

3. Compute the necessary pipe area from the velocity and
discharge. The values in Table 11, Columns 1 and 2, are sug-
gested sizes based on a velocity of 12 feet per second and the de-
sire that the pipe run full at the discharge given in Column 3. Re-
gardless of the pipe size chosen, maintain the relation between
discharge and basin size given in the table. An open channel en-
trance may be used in place of a pipe. The approach channel
should be narrower than the basin, with invert elevation the same
as the pipe.

4. Although tail water is not necessary for successful oper-
ation, a moderate depth of tail water will improve the performance.
For best performance, set the basin so that maximum tail water
does not exceed d+ g, Figure 42.

2

5. The thickness of various parts of the basin as used in the
Commissioner's Office, Denver, Colorado, is given in Columns
14 to 18, Table 11.

6. The entrance pipe or channel may be tilted downward
about 15° without affecting performance adversely. For greater
slopes use a horizontal or sloping pipe (up to 15°) 2 or more di-
ameters long just upstream from the stilling basin. Maintain
proper elevation of invert at entrance as shown on the drawing.

7. If ahydraulic jump is expected to form in the downstream
end of the pipe and the pipe entrance is sealed by incoming flow,
install a vent about one-sixth the pipe diameter at any convenient
location upstream from the jump.

8. For best possible operation of basin use the alternate end
sill and 45° wall design shown on Figure 42. Erosion tendencies
will be reduced as shown on Figure 45.

*9. To prevent undermining of the end sill of the structure
and erosion in the downstream channel, place riprap as shown on
Figure 42. Suggested minimum sizes are as follows:

*The riprap sizes given have not been thoroughly tested and

approved. At the present time this is the best information known, how-
ever, and it is believed to be on the conservative side. The Hydraulic
Laboratory of the United States Bureau of Reclamation in Denver,
Colorado, would welcome your comments based on experiences, data,
photos, or other sources, either confirming or refuting the riprap
sizes recommended.

37



FIGURE 16

HYDRAULIC JUMP STUDIES
SAF STILLING BASIN



FIGURE 1

TEST FLUME A
Width of basin 5 feet, drop 3 feet, discharge 6 cfs

TEST FLUME B
Width 2 feet, drop 5.5 feet, discharge 10 cfs


FIGURE 22
es

— (0:7 %-1.0h a |
P7781. OAL
or oor"
—s TTU7S- 1.0 h o* 0,
mz ;

Ten Sey: «=| Se BSH
HYDRAULIC JUMP STUDIES
RECORD OF APPURTENANCES
BASIN IV. J



STILLING BASIN FOR PIPE OR OPEN CHANNEL OUTLETS
NO TAIL WATER REQUIRED
(Basin VI in Frontispiece)

The stilling basin developed in these tests is an impact-type
energy dissipator, contained in a relatively small boxlike structure,
which requires no tail water for successful performance, Although
the emphasis in this discussion is placed on use with pipe outlets, the
entrance structure may be modified to use an open channel entrance.

Generalized design rules and procedures are presented to allow
determining the proper basin size and all critical dimensions for a range
of discharges up to 339 feet per second and velocities up to 30 feet per
second.* Greater discharges may be handled by constructing multiple
units side by side. The efficiency of the basin in accomplishing energy
losses is greater than a hydraulic jump of the same Froude number.

The development of this short impact-type basin was initiated
by the need for some 50 or more stilling structures on the Franklin
Canal, Bostwick Division, Missouri River Basin Project. The need
was for relatively small basins providing energy dissipation independent
of a tail-water curve or tail water of any kind. The demand for infor-
mation on general design procedures for use on other projects prompted
the laboratory to include further investigation of this basin in the labora-
tory's general research program. Continued research on this type of
basin will be made as time and funds permit.

Test Procedure

Hydraulic Models

Hydraulic models were used to develop the stilling basin,
determine the discharge limitations, and obtain dimensions for the
various parts of the basin. Basins 1.6 to 2.0 feet wide were used
in the tests. The inlet pipe was 6-3/8 inches, inside diameter,
and was equipped with a slide gate well upstream from the basin
entrance, so that the desired relations between head, depth, and
velocity could be obtained. The pipe was transparent so that back-
water effects in the pipe could be studied. Discharges of over 3
cubic feet per second and velocities up to 15 feet per second could
be obtained during the tests. Hydraulic model-prototype relations
were used to scale up the results to predict performance for dis-
charges up to 339 second-feet and velocities up to 30 feet per sec-
ond.

The basin was tested in a tail box containing gravel, formed
into a trapezoidal channel. The size of the gravel was changed several

¥The laboratory has developed two basins for specific installa-
tions where velocities were considerably higher. One basin was for 10
second-feet at 80 feet per second, the other for 4 second-feet at 106 feet
per second, Sufficient data are not available, however, to provide gen-
eral design rules or procedures,
32


FIGURE 4

STOGWAS 40 NOILINISAG
INISW@ ONITTILS

Saiqnis dwar

MOTd JO Hid3d OL
AOYMANA DdlDadS 40 NOILW134

AOYIN]

DITAWUGAH

YOO1d IWLNOZIYOH NO - dWAP DIINVYEGAH

4 le

Oo
----N-- >

aN

10914143 9q ->

\
k------fq

HLd3d

2N
ra 2
<duinf ur ssoj Abuaug = 29 -'9

-—e --------¢g-}--4,

CS)

‘duinf 40 yyBiay - 'q-2q = fa
1

A ~ «(Aequinu apnosy = Yy
‘dunf 6buiavay Absaug =23

‘dunf 6bulsajua Absaug = '3

“UFPIM JO Jooy 4ad ‘sy ut abspyrsiq = b
"$223 ul auIN|} JO YLPIM = M

“S79 Ul abspyosip jojo, = &

Ley)



FIGURE 3

TEST FLUME (E)
Width 4 feet, Drop 0,5-1,5 feet, Discharge 10 cfs

TEST FLUME (F)
Adjustable tilting type, maximum slope 12 degrees,
width one foot, discharge 5cfs


FIGURE 29

A = Flow area beneath underpass
h = Flow-producing head
hy= Velocity head in approach

C IN Q=GA J2g(h+hy)

13
12 SS
Tm] _--+1D, to 2D
Ml MK. PE 2 2
3D, to 4D,/--* [—
1.0
03% 6 8 10 12 14
AVERAGE VELOCITY ,V, IN UNDERPASS
B
100
2
4
& =
2 2 CARTER --? r
co)
28 90
ge
ew
oo
at
vs 80
x
7)
a / rriant->NL_
my
&
=
706 10 20 30 7, 40
% SUBMERGENGE OF UNDERPASS ~ ©
2

HYDRAULIC CHARACTERISTICS
UNDERPASS WAVE SUPPRESSOR



FIGURE

STA. 1122.33

‘S'4D 001 3OUWH
“4 - oP : io
3 8
gs |) 8
i || 3
5 \ Py
2 | 4,
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a i 3
us Ff
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ee |, ty
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ray Fs ard &
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34 F 38 19
3 8 a8 or
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ral 1 '
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eez| oS E
Bee sal «
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genie e
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i a Atal mA Nh fA
aaa
— < Toe ~P Ee - |
< - ie
° __ Vy
=a I i= a _ Nap wyapisan:
= 0°8r oe oe °

09 7
AdALOL0Ud - SGNODIS NI aWiL

CARTER LAKE DAM NOI * OUTLET WORKS
WAVE HEIGHT RECORDS
(MODEL SCALE 1:16)



APPENDIX



FIGURE 19

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me)
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~ fUZOS kk



FIGURE 25

G¢v-SZ-4 YOJ
(Al 3dAL) YOSS3YddNS 3AVM L3VY
S3IGNLS dWNF JITINVYGAH

——~

ANNAN NAN

/

11,8X,9

VIS 9X8 oF
A

-



Urseq pus 0 Usamjeq UOTIBTaI Inq ‘AV = O Aq BaTFOOTAA TeyIO OJ peTITpoM oq Aum ozTS
st AYPOOTaA USYyA TINS JTey 10 puodes tad 4a03 ZT ST Ay F90TaA

saga as pé

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*puooas tad yaex 42

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(IA utseg)
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SNOISNGWIG NISVd ONITILLS

TT STqeL

35



FIGURE 8

160
140
120
100
20
«0
40
20
°

2a

z
<0 °
ey
ceo a
EEE oZ& «
333 wo a
Prana $36
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5 Zu z
2,32
3542 |.
Ne Sab © |*
owZz
Seo5
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Suga
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o
8
a
F |ela 24
is] + 2
ald :
N le

ie

Pl
"4

<a

leo

8 3 z 8
t
3B unzoug ni aowana Ni sso7

0
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10
20
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437



FIGURE It

Tw OEPTH

22

be |_|
r At.
By TTS
44
VL
SLL
an
97 |
VA cee
(i >a
7, vai
7 ; “nmi
EY TT AA Zanene
4
{TI
L-Winimum TW Depth |
z, Basin III im
baa
4 t
in
D | imam
ca Z T T
Al p it
e% i
Hd L

|

x Verification tests basin I
+ Existing type basins (Tobie 2
Al © Minimum TW ~ type I b
Minimum TW ~ type IT

{Table 1)

asin (Table 3)
basin (Toble 4)

| it

-

7 c 1s
re
a oo
HYDRAULIC JUMP STUDIES
STILLING BASINS I,II AND IIL

MINIMUM TAILWATER DEPTHS



performance of the recommended stilling basin for the three
limits discussed. It is evident that the center photograph rep-
resents a compromise between the upper limit operation, which
is very mild, and the lower limit operation, which is approaching
the unsafe range.

Using the middle range of basin widths, other basin di-
mensions were determined, modified, and made minimum by means
of trial and error tests on the several models. Dimensions for
nine different basins are shown in Table 11, These should not be
arbitrarily reduced since in the interests of economy the dimen-
sions have been reduced as far as is safely possible.

Performance of Basin

Energy dissipation is initiated by flow striking the verti-
cal hanging baffle and being turned upstream by the horizontal por-
tion of the baffle and by the floor, in vertical eddies, The structure,
therefore, requires no tail water for energy dissipation as is neces~
sary for a hydraulic jump basin. Tail-water as high as d + & Fig-

ure 42, however, will improve the performance by reducing out-
let velocities, providing a smooth water surface, and reducing tend-
encies toward erosion. Excessive tail water, on the other hand,
will cause some flow to pass over the top of the baffle. This should
be avoided if possible.

The effectiveness of the basin is best illustrated by com-
paring the energy losses within the structure to those which occur
in a hydraulic jump. Based on depth and velocity measurements
made in the approach pipe and in the downstream channel (no tail
water), the change in momentum was computed as explained in Sec-
tion 1 for the hydraulic jump. The Froude number of the incoming
flow was computed using Dj, obtained by converting the flow area
in the partly full pipe into an equivalent rectangle as wide as the
pipe diameter. Compared to the losses in the hydraulic jump, Fig-
ure 44, the impact basin shows greater efficiency in performance.
Inasmuch as the basin would have performed just as efficiently had
the flow been introduced in a rectangular cross section, the above
conclusion is valid.

Basin Design

Table 11 and the key drawing, Figure 42, may be used to obtain
dimensions for the usual structure operating within usual ranges. How-
ever, a further understanding of the design limitations may help the de-
signer to modify these dimensions when necessary for special operating
conditions.

The basin dimensions, Columns 4 to 13, are a function of the
maximum discharge to be expected, Column 3. Velocity at the stilling
basin entrance need not be considered except that it should not exceed

about 30 feet per second.
34


FIGURE 23

Jouol4¥do ISS,

Le

S'b-S'2 '4 uO "
mm Nisva ONITTILS
S3IQNLS dWNP ODIINVYGAH

eITa org ttt (21614 88S) 15------72 >
° o- .,

vant ---/f--

adojs 5g uo adnjuns doy -” ras
_,---p, me
a 4
M GZ = 82005 ~-m! Sur ‘lg 2
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times during the tests. The outlet channel bottom was slightly
wider than the basin and had 1:1 side slopes. A tail gate was
provided at the downstream end to evaluate the effects of tail
water,

Development of Basin

The finally evolved basin was the result of extensive
tests on many different arrangements. A detailed discussion of
these tests is not given, since they had little, if any, bearing on
the final design, except ina general way. This is discussed be-
low.

With the many combinations of discharge, velocity, and
depth possible for the incoming flow, it became apparent during
the early tests that some device was needed at the stilling basin
entrance to convert the many possible flow patterns into a common
pattern, The vertical hanging baffle proved to be this device, Fig-
ure 42, Regardless of the depth or velocity of the incoming flow
(within the prescribed limits), the flow after striking the baffle
acted the same as any other combination of depth and velocity.
Thus, some of the variables were eliminated from the problem.

The effect of velocity alone was then investigated, and
it was found that for velocities 30 feet per second and below (for
a 42-inch pipe) the performance of the structure was primarily
dependent on the discharge, Actually, the velocity of the incom-
ing flow does effect the performance of the basin, but from a prac-
tical point of view, it could be eliminated from consideration. Had
this not been done, considerably more testing would have been re-
quired to evaluate and express the effect of velocity.

For velocities of 30 feet per second or less, the basin
width, W, was found to be a function of the discharge, with other
basin dimensions being related to the width, Figure 42. To de-
termine the necessary width, erosion test results, judgment, and
operating experiences were all used, and the advice of laboratory
and design personnel was used to obtain the finally determined
limits. Since no definite line of demarcation between a "too wide"
or "too narrow" basin exists, it was necessary to work between
two more definite lines, shown on Figure 42 as the upper and lower
limits. These lines required far less judgment to determine than
a single intermediate line.

Various basin sizes, discharges, and velocities were
tested, taking note of the erosion, wave heights, energy losses,
and general performance. When the upper and lower limit lines
had been established, a line about midway between the two was
used to establish the proper width of basin for various discharges.
The exact line is not shown because strict adherence to a single
curve would result in difficult to use fractional dimensions, Ac-
curacy of this degree is not justifiable. Figure 43 shows typical

33



FIGURE 43

Lowest value of maximum
discharge - Corresponds
to upper limit curve

Intermediate value of
maximum discharge -
Corresponds to tabular
values

Largest value of maxi-
mum discharge - Corre-
sponds to lower limit
curve

Typical Performance at Maximum Discharges - No Tailwater
Impact Type Energy Dissipator - Basin VI


FIGURE 26

Suppressor in place - Length 1.3D2, submerged
30 percent

Performance of Underpass Wave Suppressor
1:32 Scale Model
Discharge 5, 000 Second-feet


_~

FIGURE 5

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4
HYDRAULIC JUMP STUDIES
RATIO OF TW DEPTH
e TO Dy
STILLING BASIN T
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a



FIGURE 9

—> > D,

A PRE JUMP

Oscillating jet

Roller,

cr SOUR Ty Smoaeae

EFFECTIVE BUT ROUGH

HYDRAULIC JUMP STUDIES

STILLING BASIN I
JUMP FORMS

437