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HYDRAULICS BRANCH

OFFICIAL FILE COPY

'

UNITED STATES

DEPARTMENT OF THE INTERIOR

BUREAU OF RECLAMATION

CHARLLS W. n,O'..�l'.S

CALIBRATION OF THE

CONSTANT-HEAD ORIFICE TURNOUT

I TO 2 SCALE MODEL

Hydraulic Laboratory Report No. Hyd.-216

II, I L-t,1

1\,. ,../-. �

BRANCH OF DESIGN AND CONSTRUCTION

DENVER, COLORADO

NOVEMBER 25,1946

I

•

..

., •

-,

UNITED STATES DEPARTMENT OF THE INTERIOR

BUREAU OF RECLAMATION

Cl i/\RL�C W. TH("'ll':l

Branch of Design and Construction Engineering and Geological Control and Research Division

Denver, Co,loradQ November·25, 1946

Laboratory Report No a 216 Hydraulic Laboratery Compiled by: B o R 0 Blackwell Checked by: H o M 0 Martin

Subject: Calibration of the const.ant=head orifice turnout-One to two scale modelo

INTRODUCTION

The constant-head orifice turnout has become an increasingly p(>pular de�e for the diversion, control, and measurement of canal flow into laterals o Although several hundred of these turnouts have been constructed for such projects as Altus, Mirage Flats, Buford-Trenton, Buffalo Rapids, and Tucumcari from the standard designs as shown on Bureau of Reclamation Drawings Nos e 40,,,D-3672 and 40-D-3673 (Figures 1 and 2 in this report) the device has never been calibratedo The temporary discharge tables included on the drawings are based on an assumed coefficient of approx.i.ma.tely 00 66 in the following equation�

1� Q � CA r2gH

where Q � discharge in second=feet H � differential head on the orifice A= area of the orifice gate opening C :: the coei'fici.ent of discharge g � accelera.tion due to gravity

gate: Oo 2 foot in square feet

The constant-head orifice is operated as follows: The orifice gate opening fo� the desired discharge is obtained from the discharge table0

With the orifice gates set at this openL�g, the turnout gates are adjusted until the differential head on the orifice gates, as read on the weir gages, is at the required constant head of Oo 2 foot0 The discharge is now at the desired valueo Figure 3 shows a single-barrel constant-head oriffoe turnout in operation on the Tucumcari Project in New MeJdco0

Calibration of the constant-head orifice turnout was made in the Jiydraulic Laboratory in Denver, using a 1 to 2 scale model0 A total of ,s·tests were made on six different designs of turnouts at various gate o-oenings and canal water surface elevations o Discharge coefficients were obtained and discharge tables preparedo

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.THE MODEL

The model (1 to 2 scale) ns· constructed of timber and lined with sheet metal ard included the complete constant-head onfice ttµ'llout and a short �ectiQn of . c�'-1 bank, with a 1-1/2. � 1 slope o The various designs studied_ are �hewn in figures 1 and 2o The 20 second-to�t capacity, double barre+,� 1 design_� const��ted tirsto . The o�her designs were obtained b7moditying this first installationo The 20 second-toot capacity, double barrel., Plan 3 installation is shown in Figure l+o

In the model the heads on the orifice gate were measured by piezo­meters connected to a manometer boardo

The water in the model was measured with three devices having over­lapping dischaJ-ge _ranges:. {1). i�S-incb ti.ow nozzle., (2) 60 5-iDch AoS oMoE o

meter, and .(3) 8-inch BoioF o venturi metero These meters have been calibrated at intervals using the laboratory volumetric tanko · Recalia:1 bration at this time was not necessaryo

THE INVESTmATION

. The model was operated by �etting the orifice_ gate and adjusting .... ��e discharge _and_tll.e turn�� gates to obtain tests coveri.,Dg_��e d,sired range of water surface el�:t,ion_in the canal with approximately OolO,.:,foot (Oo20,,;.fcot pi-ototype) differential head on the Qri..tice gateo Where necessary, the model dischcU'ge was adjusted to OolO-toot differential head assuming the discharge proportional to the square root of the heado

. 'lbe 2�second�:foot capacity turllout� Tests on Pian i� double barrel g.��ign with �C)� gat� ope�s,. showed that the discharge . coefficient was essentiallY' constant for a given gate opening for various canal water surface elevations but increased slightly with increased gate openings up to a prototype gate_ ope�ing ot lo S ,eet (Figure S) o .F�r larg�r gate ope�ings the coefficient_in��eased appreciably·wit� an in­crease in the gate opening as well �s var.ring_ with the c�� :wate�... . surface elevationo The same results were .obtained 1n Plans 2, 3, and 4o

Wa��r eurta�es � �lan� 1 � 2 were rel�t1�7 SJl9Q�h and flow conditions stead70 Plan 3 gave ._somewhat rougher con(:fitj�� o P.lan .4 gave the poorest operation, Ju though tbe. . coettici�nt of. discllarge averaged the same as for the other plari.so Surges in the s�illiq-pool made the differential head bard to reado Water �_iling up in fron� o� the turnout gates resulted in a tilted �ter surface in the st�JJing-poolo

. . . �p,ratton with only one ot th� tw gates open, gav� satist�Qt�ey

��tticie�s_f..-. small gate_ openings when the turnout gate below the opeaed oriti�� gate �8 u.� � with the dowi�t�am-��� gage located on.�hf.�idewt;Lll n� w the c,pa.n g�t��o .. �ce�o:t_��s-��---$� )then the downstream weir gage was located on the sidewall opposite the open gates or when both turaottt gates were opened with.only on� orifice gate.. � consistent results· �e� �bta�ed_ whe� the do�stre� w,ir. gage was located adjacent to the orifice gate instead of adjacent to the

2

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9

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turnout gateo Operation of one gate of two is not desirable. because of the difficulties in obtaining the corre6't differential head due to the rough and tilted water surface between the orifice gate and the turnout gate.

The s�le barrel type gave similar operation to the double barrel type and the same discharge eoetficientso

The 20-���o.�-foot_ c���it:r.t���� i� de,signed to operate with. the £.-J­c�al water em-face from,2 feet � inches to 6 feet above th'3 oritiqe gate 2�11h-t:;.l s�t

9 _ _ P�pth gre�te� than 6 feet will not effect the coetficie�� of

discharge. The mSnimmu satisfactory depth must fulfill two con.Utions; (1) the orifice gate opening must �e completely submerged, and (2.) the water surfaces mut be ,smooth.enough to satisfactorily read the weir gageso

The mod�l indica� that a 2-foot prototype depth is about the lowest satistactoey depth at max:lmum. gate �pening o For smaller gate opening this minimum �epth could. be reduced 0

. . . . .

The 10-second-toot capacity turnauto Du� �o. the Qonsisteac;y of r,sul.ts tor the.vario�s p� ot the 20:second-foot ��1)$.�i�Y-��out, only Plan� of t�e various lOc-aecond-foot capacity turnouts. was testedo

The coefficient of discharge for gate openings up to l oQS feet prototype were essentially the same as for the 20-second-foot capacity tUl'Douts o

For larger gate openings the coefficient increased appreciably with an increase in gate opening as well as varying with the canal water surface elevationo

The 10-seoond-toot capacity turnout is designed to operate with the canal water surface from21 inches to 6 feet above the_ orifice gate seato

Greater depth will not effect the coefficient o Minimum o·perating depth as indicated b)" the model for maximum gate opening is about 18 incheso

PBEPARATION OF DISCHARGE TADS

The coefficient of discharge varied from 00685 at a gate opening ot 0006 fo9t to 00 715 at a gate opening of l o.6 teeto A coefficient versus gate epening plot was made by averaging the tests for each gate opening o

A straight line �s drawn through the points {Figure S) o From this coefficient curve discharges were computed� a �ischarge versus gate opening curve plottedo Values in the discharge tables giving the gate opening for f1'18ry one-halt second-foot ot discharge were obtained ·rro:m the discharge ve�sus gate opening curvefo . . DJ��hargt and g•te op81ling 1;abulations are.given in Table l for the 20-second-foot capacity constant-head orifice turnout and in Table 2 for the 10-second-foot capacity turneut o •

�---- ·--··--·-------------------� ...

3

TABLE l ·•

Discharge tables for the constant-head orifice

turnout o Capac!ty 20 second-feet, •

gate size 24 inches by·30 inches

Discharge Second-feet

OaS Oo04 0�08 10o5 Oo8.3 loO 0�08 Ool6 ll oO ·0087 lo5 0.12 Oo24 llo5 Oa 91 200 Oal6 Oo32 12o 0 Oo95 2o5 -Oo20 Oo4O 12o5 Oo99

.3o0 0'024 Oo48 .13o0 llo0.3 3o5 Oo28 Oo56 l3 o5 lo07 4.0 O/32 Oo64, 14o0 lolO 4oS Oa.3.6 0072 1 14oS lol4 5o0 Oa40 Oo79 15o0 1.1s

5.5 Oo44 Oo87 15o5 lo22 60 0 . Oa48 Oo95 1600 1.26 6.5 0.52 10 0.3 16aS 10.30 7.0 Oo56 lolO l7o0 lo.34 7.5 Oa6O lol8 17.5 lo.37

800 Oo64 1.26 180 0 lo41 S.5 0068 lo.34 18o5 lo45 9o0 Oo72 lo4J. 19o0 1.49 9o5 Oo76 lo49 19o5 lo53

lOaO Go79 lo 56 2008 lo56

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• TABLE 2

, Discharge table�-for the constant-head orifice

turnout. Capacity 10 second-feet,

gate size 18 inches by 24 inches

Gate opening Discharge in feet

second-feet 2 �ates 1 e:ate

Oo 5 O o 05 OolO 1.0 0.10 Oo 20 1.5 0.15 Oo 30 2.0 Oo20 0.40 2.5 Oo25 0.50

3.0 0.30 Oo60 3.5 0.35 Oo 70 4.0 0.40 0.79 4.5 0.45 O o 89 5.0 Oo 50 Oo99

5.5 Oo55 6.o Oo60 6.5 Oo65 7 oO Oo 70 7.5 Oo74

a.o Oo79 8 .5 Oo 84 9.0 0.89 9.5 0.94

10.0 Oo99

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AL

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: f;Lonqif. .. 1 bars @ 9.0••• I I ·' I

' .1· 1 8 ;rronsv.bo 1 @9'. Continuous : in floor and wall�, I I

Mox. W.S:',i

: - --

.s Min. W�:hc:.: �

-----==-._. : . � �:.!'; �

f;@g·Both ways.--.. ff @12·Both ways,., \.. 4-

� / :_ .. .--fi @/2'.

€ Structure-.

\.-1{{; � -:: . -�---- -- --� -- ___ ] -11, ·.- • ···· · ·,\ Gates not shown - ' I ' ._ , ---t,,c::-,-+-,�-+.�.-:-,,'-:;,-.,-7 :,,\� '--2-fx1z·Anchor bolts. 1""12->j6:- °':::!; Project 3:

.... r �,z� ....... 1J·-o: .. ..... .,...:5·i .....

PLAN Cl-,.

_JA

SHOWING RE:INFORCE:MENT FOR 1•7; DOUBLE: BARREL ONLY ,-rs· Dia. screw I,'{; vertical gate.

/ (turnout gate) 2ti·x1e·Screw tiff

,

2-3"xl2" ,, :-,·· ·M_ormal ban/1 lop width ··>-:

vertical gate. ..··· j'laphs._-.- ·- : . , - ' r·' (orifice gate)- -··· s•. : ' ;,-2�

1: 6 : .. ·

j ,

rq�- - . - 1,.- --··Anchor bolt 1/1. �?. · -�···::. :::_-_�-- - .I f.. 1 �ifh 2 nuts. "' . i • �-. :•-g t @ 12'. rre1r gage · : ·. .

D L_J.

,\�x�W�S.3--

· : ·- / � @ 9" Ex/end 15"11 J inlo wing walls. U -- Weir 909e

Min. W.S:·1 .-s?: Canal bottom.- - · 0

).[ See de/01t I ft Precast concrete pipe:;

f-.-4· 1<,:ci �t I ._-:c:i w

• ; c: ···-Level. '··-Slope as �� directed .

...: , ..... . •'- --·· · · · El-,.

PLAN 3

Place gofes of some elevation if canal bottom is level with or above turnout gate invert.

Gates not shown.

..Je·:.-.

fff'rom floor.-----•·

ft@Approx

SECTION E - E. .-·ix B'Anchor bolts.

c _ , r· .. ../

Project 3{

.J . · · - '.ff

bars.

··+---f/>@12·

"'

SECTION F-F

FIGURE I

, .. ff @12_:_£if PiPL -- - · i ··• _Gales nof shown _ _ _ _ .':" .. . . . . \.'·--2-fx!O"Anchor

c:=-;_-'-!',c:±: ... -!--: 7-'--:-"u.u.+,--j <ti.S bolts project 3'. "'�

zti·x1s• Screw lift vertical gale. (orifice gate}-············--...

SECTION G - G

. :i!."..t. Js-�

SECTION 0 - 0

if Structure.-

BL

L- - - -

: � I ..._ I <:,

: t \ -� I L

.'<..J- � -+H+-' I "' I �

I � ' ,: I .._ I '-I C I :0 I , r-I.-

Max.w.s.--1 =--�- --- I. �

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WHERE: INLET FLOOR SLOP£ E:XCEEOS 4:l,S££ PLAN 2

,,:ft Transv. bars @ 9· continuous in floor and walls.

1 r -----�

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SECTION B -B

··-ft n.-f;@,2:

INLE:.T WALLS AND FLOOR THICKNE:SS AND RE:.INFORCE:.ME:.NT

H

21' lo 4 ·-o· f-----4 c3• lo s·-3• s·-5· to 5·-0·

t

s· --5• 7"

I' R£INFORC£A1£NT AS SHOWN

EXCEPT AS NOTED BELOW

s· C and O ·bors @9"(Plan Z) Cand O·bo;.; @°i1Plan 2)-s·

6" Se;-;;/ons I and 3 ·-

• .--Weir gaqe dwq_. 40-C-71 � ! (or as modified)

Y •• •• P-::t I ' 3·

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r1· .]� Fac?_efx,,qjt'b·

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I, - ;.,.zf.,;

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' I I j,• -138T13J� ,sxio·Ancho,: bolfs. �- - · · · · · · ·�·' Pro1ect 3{

l!d! 1•,L - -_s_T_ongd. bars.

··f+rransv. bar.

S CA LE: OF FEET DETAIL

NAILING CONCRE:TC flFrom rtoor:•·· ·· ·· ·

�o� _./ "'(••·•• •:••-'.,

, .. J:{ e· Anchor bolfs / Project Jf

ANCHORS ·, -.._·Precast nailing concrete

anchors. See detail.

--:-r­' I : I �ll l

OE.TAILS OF GAG£

· ·}"flongif. bars @ 9.'

GAG£ SETTING (VCRTICAL OIME:NSIONS)

H. NORMAL HEIGHT OF ZCRO OF GAG£

·AG£ LCNGTH ABOVE ORIFICE'. G,ffC: SILL

*o+(O'or3") *a 6' .. o+(5'or91 *a,lft.

-0-.----

OPERATION OF ORIFICE GATE WITH LOSS OF o.z· OF HEAD

f;UANTITY SEC. FT.

1-'-- -2

3 4 s

APPROX. ORIFICE GATf: OPENING

.20'·

.4 0' .60' ,79' ,9 9'

fl@Appro<.9'"; '

SECTION

f"' lf : •I

N

H - H

SECTION J - J

* a •l',Z;3; ·· · ······6'AS RC:QUIRE'.O

For any desired Q set orifice gate o t opening shown (or os deter­mined by calibra tion) and ad_jus t turnout gale to obtain o differ-ence of t.20 rt. in the aoge readings.

Discharge shown is for wi qaft only. Use both gates on 2-boy structure.

SECTION C - C

� . �

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NOTES

All reinforcement shall be placed so that the centers of bars in the outer layer will be 2· from face of concrete, unless otherwise shown.

Lop oll bars J4 diameters of splices. Provide head in addition fo that requirea for operation

of orifice gale fo cover losses through turnout qate and pipe. Where sufficient head is available turnout pipe and gate may be made smaller as directed.

Zero point of both gages to be set al same elevation. £stablish W in 3' increments begining at z•.9• Plans I ond 2 may be adapted fa single barrel sfrucfures.

and Plans 3 and 4 fo double barrel structures within limits of operating head requirements.

For ouflet transitions and collars, use Dw9s. 40·0·564, and 40-0-S65 with modified pipe spac,ng.

t • thickness of walls, floor, and cross wall of inlet. t'·fhickness of apron of alternate inlet design. H•heod on orifice qate sill. Mox.6'-0� Min.21: H'·head on turnout 9ate sill. no f!ow,·H orH minus 3• h -min. head on orifice gate sill measured r. - • ..., 'Tlin.

wafer surface assumed in canal for full ·· delivery fo lateral.

For H of 3·-o·or less use orifice gate Dwg.40-0.·Jl/7 and turnout qate Dwq, 40·0· 370i.. ,

For H of 3'·3' to s·-o·use orifice qafe Dwg.40·0- 3701, and turnout qate Dwq. 40-D· 36 99.

U N I TEO STATES DEPARTMENT OF THE INTERIOR

BUREAU OF RECLAMATION

DENVER OFFICE

CONSTANT HEAD O R I F I C E TURNOUT

MAX. CAPA C/TY 1 0 SECOND FEET

ORAWN: .. . .f!:?.-.T-.7.l:�·.lf.-.... SUBMITTEO: .. ��• r��---··

TRACEO:.: it/.'_#,···,;· RECOMMENOCO:. -'-�(�:··· · · : ·· CHCCKEO •. • .••• • Ii'. ,.A.PPROVI:D:. . . . q.,.�.,L� . ..... .

OC:NVC:R, COLORAOO. MARCH z•, 19,4/ 40-0-3672'

•

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FiGURE 2

C

r>- .-f<P

• ••. -;J"IP@JZ' •• J"IP @Jl" H r

-f¢@9· Both ways.·:.

n

,.-j'¢ @ 12·

([. Strucfur!::i._

A L

Max. W.S.··�· -

Min. W.S.·y ___ __ g �· .

I I I

ftLongit. · .. bars @ g:--·

: f;Transv. bars 1 @g·continuous

oL _ _ ··-· ([. Sfrucfurej

__ _j-A : in floor and walls'.· I I I

P L A N 3 .-24" Dia.screw tiff

:' ver fical qafe. ! (Turnout qote)

.3.• 1, @ 8Approx.9"-+-----·· � j

Showing reinforcement for I •7", double borrel only.

.-24 • D,a. screw lift vertical _/ qate. ( Turnoutgafe.J

30'x24" Screw lift vertical ·

f<····Normalbank fop widfh.····>i gate. (Orifice gate.)·-·-·-·-·--:

8'1<· A'

ho bolt )hf f """�

3J" x 24" Screw !if f vertical 1-<·Normal bank t,,:, width.·"'

qafeJOrifice qafe.1- ·-·-·-·--· : _ � i.. .�·� :

B'r __

. ...::;i�o:;sbo

t_tt with -·""'-..

IAax. �I.S.-#' · :/ · ·----- ------ - - - . --=----=-c_=--==-------=-�-- � .,-J IP @l2"

·r·· -·J'<l>@9" Extend into winq walls. .

1 1 JI 1

: �-� ::·-rJ."¢ @/2" .Mm. W.s_:- {f · -- Weir qoqe. See petoil. · -- · - - ---- - - , 8 - - -

�:·\· '!·· : : ___ .,.-·· nc r w

�

, wonus. _ '

---=-=--- ---, 1 _.- Co� . M r·4' : -- ·Precasf

I N Q I ::,..\:! kJ concrele

j"¢Lonqi( __ .. ·--·: / � J. t_ . . i:· :, p,pe.

Level/ ;-Slope as directed.

SECTION E-E

� 13f\.f3J·� .-fx 8 'Anchor bolfs

� ----i··•- -·k·/

Project 3r ' � ' I

S ECTION F-F

boc, ®'.··· /4 ' p::

=ce•p

u

ipe.·-.

" "',Cl ., i ____ _ _ .i'.. . ,.i�v _ _ _ _ - - · · ·· 4· -;::�- - ---���- ':�·- l� f> .... , ·-: . ., . . · •

·.--.�-�:�-�-�,-t:. . : '

Conal boffom.··· ,' Mox.slo_ e . . : .: . . . ;..:.4,�-� �--�4,, . :

c ·Level '·S/ope osdirecfed. SECTION 0 - 0

� ]

<,ii __¥.

a L

,----1 I I I I I I I I

C: �

I .IQ

I �

i :§ I i I I .._ I .�

I \.0 1--·L

Max. W.S.--,

� � �-...... " . ...,. X C: I � ---- � :,, �

'' , • �&:��:::=,t• • •r• 4�J ��2� -� j I I · � · �·

J'tP@9• Bofh ways incenfer of wall. / Bend vertical bars 15" info floor .. /

SECTION A - A Where inlet floor slope e:"<ceeds 4:/ see Plan 2

· --·--· CJI[

'· 'Y..-tf </> T ronsv. bars @ 9'

continuous in floor and walls.

I �-§--= __ _.. �

P L A N 2 (ALTERNATE INLET DESIGN/

·;t �

�;

f

S E C TION a-a

· · t

J'x10· Anchor bolts. Project 3f··, .. __ _

INLET WALLS AND FLOOR

THICKNESS AND REINFORCEMENT

H t f' REINFORCEMENT AS SHOWN EXCEPT ASNOTEOBELOW

2'·3' fo 4'-0' 5• 5• CandDbars @9'(Plan 21 4'·3" f,;,5'·3' 6" s· CandD bars@6" (Plan 2J 5'·6" to 6'·o· 7" 6" See Plans I and 3

0 S C A L E OF FEET

'�����--+-rt. � rit 1 f<I> � Approx.9'.·-··'

S E CTION C - C

--r. _Q_ r--J· ... LT

-,:�. . ... ( ..

Face_o!.'Y?!!:·.) __ o .. i - ' /II I

t-- z:: .. .. --Weir qaqe "'·22 ·"'

. -·fx/0" Anchor bolts. r -- -

7 r;:_.- Project 3r 11

• ·-• ___ f 4> Tronsv. bars. ·2'

,., j.J.'<i>L "f b :---,,-· B ong, . ors . , Owq. 40-C·ll

f--· 1.- ;;,

: ' : ! · --Precosf noi/inq

.. J.

J'l> From · .!'/�

�;::::-��1-··J·Jµ,.;. i .s- concrete .,. anchors. See : _ deluil.·, L .1.-, __ _.

DETAILS OF GAGE

DETAIL NAILING CONCRETE

ANCHORS

GAG£ SETTING (VERTICAL DIMENSIONS)

H NOMINAL HEIGHT OFZEROOFGAGE pAGE LENGTH ABOVE ORIFICE GATE SILL

• a+(O"or 3"1 • a 5• • a+f6"or 9") • a.-fft. o•

• O= z; 3• ... . . .... .. 5• as required.

OPERATION OF ORIFICE GATE With loss of 0.20' of head

QUANTITY APPROX. ORIFICE SEC. FT. GATE OPENING

3 0.48 4 0.64 5 0.79 6 0.95 7 1.10 8 1.26 9 1.41 ·--- -- - - --/0 1.56

For ony desired Q set orifi,e gate of opening shown ror as determined by calibration/ and adjust turnout qCJfe to obfoin a difference of 0.20 ff. in the gaqe readings.

Dishoroe shown is for one oofe ·on/y

Use bofh gofes on 2·bay structure.

S E CTION H-H

t, __ ·!3�:.,..t3f-' ,--g'x 8' Anchor bolts. · . .. . · .. . �-;,;1 Pro jecf 3fr',

'

�

·;·!·<l> Transv. bars.

::::-·--- -f <1> Long it. bars.

, .. ·f¢ @12·

SECTION J-J

. ,

,·24" D,a. screw lift vertical / qate. (Turnout qafe.i

SECTION G - G

NOTES

All reinforce=nt shall be pbced so that the centers of bars in the outer foyer will be 2" from foce of concrete unless otherwise shown.

Lap all bars 34 diameters of splices. Provide head in 'Jddifion to that required for cperotion of

orifice qafe fo cover losses through turnout qate nnd pipe. Where sufficient head is available turnout pipe and qote may be made smaller as di reefed.

Zero point of both gages fobe set at same elevation. Establish Win 3' increments begining at 3'-3: Plans land 2 may be adopted to single barrel structures

and Plans 3 and 4 fo double barrel structures within limits of operating head requirements.

For ouf/et transitions and collars use Dwq·s. 40·0· 564 and 40·0·565 with modified pipe spacinq.

t= thickness of walls, floor. and crosswo/1 of inlet. f'= thickness of apron of alternate inlet desiqn. H=head on orifice gate sill. Max. 6'·0' Min. 2'·3". H'=head on turnout gate sill. no flow,=H or H minus 3 ·: h= min. head on orifice qote sill measured from min.wafer

surface assumed in canal for full delivery fa lo feral. ."or Hof 3'·0" or less use orifice qafe Dwg.40-D·37JI and turnout

gafe Dwq. 40-0·3705. For Hof 3'·3' to 6'·0' use orifice qole Dwg.40-0·3702 and turn­

out gate Dwg.40·D·J700.

UNITED STATES OEPARTMENi OF THE INTERIOR

BUREAU Of,: RECLAMATION

DENVER OF"F/ CE

'.'jl CONSTANT HEAD ORIFICE TURNOUT

:e � MAX. CAPA C I TY 20 SECOND FEET

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Constant Head Orifice TUrnout, Single Barrel Type Location: Tucumcari Project in New Mexico A constant head of 0,2 feet ia being maintained

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Constant Head Or1f1ce Turnout - l to 2 Scale Model Max1mum Capac1ty ( Prototype ) - 20 Second Feet

Plan 3 - Double Barrol Type

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M O D E L S C A LE t : 2