UNITED ST A TES DEPARTMENT OF THE INTERIOR

BUREAU OF RECLAMATION

HYDRAULIC MODEL STUDIES

ON THE BIFURCATION STRUCTURE AT

STATION 283+11 . 98--POUDRE SUPPLY CANAL

COLORADO .: BIG THOMPSON PROJECT

Hydraulic Laboratory Report No . Hyd-379

ENGINEERING LABORATORIES

OFFICE OF THE ASSISTANT COMMISSIONER AND CHIEF ENGINEER DENVER, COLO RADO

June 7, 1954

UNITED ST ATES DEPARTMENT OF THE INTERIOR

BUREAU OF RECLAMATION

HYDRAULIC MODEL STUDIES

ON THE BIFURCATION STRUCTURE AT

STATION 283+11 . 98--POUDRE SUPPLY CANAL

COLORADO-BIG THOMPSON PROJECT

Hydraulic Laboratory Report No . Hyd-3 79

ENGINEERING LABORATORIES

OFFICE OF THE ASSISTANT COMMISSIONER AND CHIEF ENGINEER DENVER, COLORADO

June 7, 1954

S\IIIIIIBrJ' • • • • • • • • • • • Introducticn •••••••• The Model ••••••••••

. . . . . . . .

. . . . • • . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

~

l 2 3

Velocity detel"llination in :measuring flume • • • • • • • • • 3 Water surface elevation. • • • • • • • • • • • • • • • • • 3 Water surface fluctuation • • • • • • • • • • • • • • • • • 3

'!'he Investigation • • • • • • • • • • • • • • • • • • • • • • • •

Dravdown Elimination • • • • • • • • • Alteration of Stilling :ea.sin •••••

. . . . . . . . . . . . • • • • • • • • • • • •

Wave Dampeners • • • • • • • • • • • • . . . . . . . . . . . . !a:ttles or blocks . . . . . • • • • • • • • • • • • • • • • '1'1mber ratt . . . . . . . . . . . . . . . . . . . . . . . . Curtain walls, recC111111ended . ., . . . . . . . . . . . . . .

3

4 4 5

5 5 6

Model-prototype Conformity. • • • • • • • • • • • • • • • • • • • 7

Figure

Bifurcation Structure at Station 283+11.98 Prototype Operation at 1,275 eta . • . . . • . . • . • . . . . • . • . • . . . . • l

Bifurcation Structure Profile, Check, and Parshall Flume • • • • 2 Bifurcation Structure, Model Layout • • • • • • • • • • • • • • • 3 Water Surface Profile Upstream fran Check Station. • • • • • • • If, Bifurcation Structure Preliminary Design • • • • • • • • • • • • 5 Addi tiODS to Floor of Parshall Flume • • • • • • • • • • • • • • 6 Energ Dissipator • • • • • • • • • • • • • • • • • • • • • • • • 7 Energ Dissipator, Operati011 at 1,000 and 1,500 eta • • • • • • • 8 Curtain Walls . • . f • • • • • • • • • • • • • • • • • • • • • • • 9 RecC111111ended Curtain Walls • • • • • • • • • • • • • • • • • • • • 10 Water Surface Fluctuation in Model and Prototype • • • • • • • • 11 Water-Surface Profiles in Model and Prototype. • • • • • • • • • 12

I

UNITED STATES DEPAR'IMENT OF 'l'HE IlffERIOR

BUREAU OF·RECLAMATION

Office of the Assistant Camniss1oner and Chief Engineer

Engineering.Laboratories Denver, Colorado June 7, 1954

Laboratory Report No. IJ1d-379 Bydra.ulic Laboratory Can.piled by: T. J. Rhone Checked and

reviewed by: A. J. Peterka

Subject: Hydraulic model studies on the bifurcation structure at Station 283+11.98--Poudre Supply Canal--Colorado-Big Thompson Project

SUMMARY

'!'he Poudre Supply Canal, which connects Horsetooth Dea Reservoir and the Cache La Poudre River, contains a bifurcation structure just upstream trcm the Junction of the canal and the river. Just down­stream tran. the bifurcation structure is the only water-measuring station on the canal; and since the canal replenishes water borrowed fran the Cache La Poudre River, it is necessary that an accuratE! measure­ment of the flow be made at this point. As is the custaa for small canal structures, the canal was constructed without benefit of a model st~. The fact that the canal had been designed r or velocities about twice as great as :normally used made it difficult to predict flow condi­tions.

When the prototype canal was operated for the first time, it was apparent .that flow conditions in and downstream trm. the bifurcation structure were not satisfactory. The flow around the abrupt turn pro­duced a tilted water surface at the radial gate and poor distribution of flow entering the stilling basin. The uneven water surface and an inefficient hydraulic Jump in the stilling basin caused surges ana.·wavea 10 to 18.inches in height that carried down into the measuring flume making it impossible to obtain a reliable water surface elevation for an accur~te discharge dete~tion, Figure 1.

Initial operation of the model showed a very similar flow pattern including the tilted water surface around the turn, the rough hydraulic jump, and 10- to 18-inch waves in the measuring flume, Figure 5.

Several methods were tried to obtain satisfactory flow con­ditions in the measuring flume. Unsuccessful methods included several attempts to even the tilted water surface at the curve, all of which caused the upstream water level to rise and overtop the canal banks.

Equally unsuccessful were attempts to improve the energy dissipation by the use ot battle blocks on the sloped floor upstream. traa the measuring flume and to dampen the waves by log rafts.

'l'he method ultimately used tor the rec(lllllended design made use ot two curtain walls placed across the channel. in the transition section a short distance downst;ream traa the bifurcation structure, Figure 9. The curtain walls were very ettecti ve in producing a smooth water surface at all discharges • In the model the waves were 4 to 7 inches ~gb caapared to the original 10 to 18 inches.

Prototype wave measurements made after the recamnended changes had been.installed showed very close agreement to similar :model measurements, Figure 11.

IR'l'RODUCTION

The Poudre Supply Canal runs between the Horsetooth Reservoir and the Cache La Powlre River and is used to restore any water that is diverted upatream. tor irrigation purposes. At Station 283+11.98 the Poudre Supply Canal branches into two sections, the Windsor section mid the continuation of the Poudre Supply Canal, Figure 2. · The Poudre Supply Canal section carries the greater portion of the discharge and also makes the more abrupt turn of the two sections. '!'he now in the Poudre Supply

. Canal section discharges into the Poudre River a short distance down­stre&l!l fraa the bifurcation structure. Prior to entering the Poudre River~ the flow goes through a Parshall-type measuring flume so that an accurate ·record of the discharge can be maintained. ·

Prototype operation bad revealed that the flow in the measuring flume was too turbulent for current meter ratings and the waves too high for accurate water surface determination by either statt gage.readings or water level recorder charts • The rough water surface was the reflec­tion of an uneven approach condition caused by the abrupt turn at the bi~cation structure ·upstream and an inefficient hydraulic Jump. The t~ow around. this turn had an extreme drawdown that was not leveled before

· :it· entered the stilling basin upstream traa the measuring flume. The drawdown at the bifurcation turn and the rough water surface in the measuring flume are shown in Figure 1. · '

The water surface fluctuation was as great as 18 inches in the measuring flume, and in order to obtain an accurate discharge record this fluctuation had to be reduced to about 4 inches.

2

THE MODEL

The model of the bifurcation structure was constructed to a scale of 1:18 and included a 100-foot section ot the canal upstream tr0111. the bifurcation structure and approximately 100 feet of both the Windsor section and the Poudre Supply Canal section, Figure 3o The canals and measuring flume were constructed fraa plywood and the radial control gates at the bifurcation structure were made frcm sheet metal. Water was sup­plied to the model through a 6-inch pipe connected to a portable labora­tory pump. The discharge was measured with an orifice Venturi meter.

Three criteria were used in judging the effectiveness of any modifi·cation made to -improve the flow conditions. The measurements and the equipnent used to obtain them are as follows:

1. Velocity determi~tion in measurire flume. Obtained as a measure of the evenness ot the flow distri ution. A J3entzel tube_ was used to obtain the velocity measurements.

2. Water surface elevation. The water surface elevation in the canal was obtained by a point gage and.in the measuring flume by means ot an open tube mananeter connected to a piezaneter opening located, to scale, in the standard location re·commended for a Parsball.;.type measuring flume.

3. Water surface fluctuation. The water surface fluctuation was measured at the staff gage in the measuring flume by an elec­tronic wave-measuring device. The electronic device is a. varying capacitance-type instrument consisting of a 32-gage enamel coated copper wire stretched between the two arms ot a ''U" support. This Wire, placed vertically in the water so that the waves cover a center portion ot its length at all times, acts as a capacitance. The copper wire and the water form. the two capacitance plates, and the enamel coating the dielectric. This capacitance is con­nected as a part ot the active leg of a balanced 5,000 c7cles per second alternating current bridge. Any change of water level_ on the wire throws the bridge ott balance. This off balance is linear with the wave height, within limits, and can be recorded as a continuous trace on an oscillograph. A profile ot the wave motion can thus be st\ldied and its time cons tut, frequency, and amplitude analyzed.

THE INVESTIGATION

All of the investigations included in this report were perfomed to improve the flow in the Poudre Supply Canal section of the biturcation

3

structure. No tests were made on the Windsor section after preliminary model investigations had shown that it operated satisfactorily.

Three methods appeared as possible means of' correcting the existing poor flow conditions. They were (1) to correct the extreme drawdown around the turn of the bifurcation structure and thereby provide a level water surface before the flow enters the stilling basin; (2) to improve the efficiency of the energy dissipation in the check section by means of baffle blocks, end sills, or other appurtenances. This would provide a smooth water surface before the flow entered the meas­uring weir; (3) to reduce the water surface fluctuation in the measuring flume by the use of rafts, baffle blocks, or curtain walls located in the transition.

Drawdown Elimination

Several methods of eliminating the water surface drawdown at the gate were tried. These included placing straightening vanes of various heights in the canal upstream from the turn to guide the flow around the turn and placing baffle blocks of several sizes at the turn to reduce the velocity su:f'ficiently'to produce a level water surface. In all tests the corrective value was slight and all caused the water surface elevation to rise and to overtop the canal banks upstream.

The drawdown could have been decreased by replacing the turn with a curve of longer radius, but this would have necessitated extensive revisions to the prototype structure; no investigations of' this type were made.

Alteration of Stilling Basin

The stilling basin or check section Just downstream fran the turn consisted of a drop and a stilling basin with chute blocks and baffles, Figure 2. The flow entering the check section was not evenly distributed, Figure 4, and combined with the turbulence in the stilling basin caused the very rough water surface in the measuring flume. Figure l shows the water surface in the prototype structure,and Figure 5 shows ccmparable pictures of the action in the mod.el.

Several methods of increasing the amount of energy dissipation were investigated. The first investigation was made to determine the effectiveness of different size chute blocks and baffles; al.though several canbinations were tried, none showed sufficient promise to warrant extensive investigation.

The next tests were ma.de to improve the stilling action by increasing the water depth in the check section. This could be accan­plished by either lowering the floor of' the check section or by raising

4

the floor of the downstream measuring flume. The latter method was investigated in the model by adding 9- and 12-inch thicknesses to the floor, Figure 6. In both of these tests the irregular flow and rough water surface were slightly improved but the added height caused the water surface to overtop the structure at a discharge of 1,250 cfs. Since none of the tests had shown pranise in improving the flow at the stilling basin, no further tests were made at this section.

The accurate measurement ot the flow was required by the State Engineer. His representative, Mr. Ralph w. Parshall, a frequent observer during the model tests, suggested that a·system of IDdragons teeth" placed on the drop might serve the purpose of both straightening the flow and improving the energy dissipation in the check section. In keeping with this suggestion an energy dissipater was made from thirty­nine 8 by 8 angles, 8 feet long, placed in six l"OVs on the curve of the drop, Figure 7. The model was operated at 1,000 and 1,500 cfs, and the flow appearance upstream and downstream fraa the dissipater checked for uniform! ty. Figure 8 shows the downstream flow appearance in the check section at the two discharges • The dissipater provided a very even flow distribution and reduced the water surface fluctuation in the measuring

· flume tran a 10- to a 4-inch average. The flow downstream from the check section was excellent in all respects; however, the flow upstream was not satisfactory. The dissipater caused so much flow resistance• that the upstream water surface overtopped the canal banks at all discharges greater than 1,090 cfs. Since the cost of increasing the height of the canal lining would be very high, the designers decided not to adopt the dissiJ>ator as a corrective measure.

Wave Dampeners

The·m.ost effective method of reducing the water surface fluctuation in the measuring flume was to incorporate some method of dampening the waves in the transition section located between the drop and the measuring flume. Three methods ¥ere investigated in the model, they were (1) small blocks or baffles on the sloped floor of the transi­tion,· (2) a timber raft in the transition, and (3) one or more curtain walls or skimming weirs in the transition. ·

1. Baffles or blocks. Al though several different sizes and arrangements ot blocks were tried, none seemed to give pr~se of more than a very slight improvement of the flow.

2. Timber raft. Two types of rafts were investigated in the model; one simulated a flat, or two-dimensional timber raft. The other was a three-dimensional system of timbers fastened together in such a manner that the natural period of oscillation of the system. was as far different as practical tram the period of the

5

waves in the transition. Thus, the natural inability ot the raft to oscillate at the wave period had the effect ot dampening the magnitude of the total water surface fluctuation..

The first type of raft was not satisfactory since it had a tendency to accentuate the wave action instead of dampening it. A raft of the second type was developed that was effective in producing a comparatively smooth water surface for the maximum discharge; however, for smaller discharges with other wave periods it was not ettecti ve. Several designs of the second type vere tried but in all cases if the raft ve.s effective at one discharge it vas not effective at others.

3. Curtain walls, recwnded. Al though the laboratory hesitates to recanm.end and the designers are reluctant to accept curtain walls and s~iJ11Ding weirs for use in canals because of their makeshift appearance and the tact that they are trash collectors, they will usually produce a quiet water surface vben all else fails • Because nothing else that was econani­cally feasible produced the desired results, it was decided to develop a curtain vall arrangement to quiet the water sur­face in the measuring flume.

For the initial tests the curtain wall vas placed across the transition section about 8 feet downstream frcm the end of the check section, Station 284+05.5. The lover edge vas placed 4 feet above the transition floor; this dimeDSion was-determined by the water surface elevation for a discharge of 600 cfs. Field and laboratory tests showed tbat at this discharge the surface waves first appeared. When the lower edge of the curtain wall was placed about 4 inches below this water surface, the waves became negligible. 'l'his curtain wall was effective for all flows up to about l,100 cfs when the water surface again became too rough. In -order to extend the range of the smooth water, a second curtain wall was placed about 24 feet dOVDStream tran the first o This curtain wall was set with its lower edge about 4 inches below the water surface for a discharge of 1,100 cts. 'l'he combination of the two curtain walls, Figure 9, itept the water surface fluctuation at a minimum. for all ~scharges. Figure 10 shows the model and the appearance of the flow at a discharge of 1,250 eta. When canpared with Figure 5, the improve­ment in the appearance of the water surface is very apparent. Figure 11 shows a ~omparison of the water surface fluctuations before and after the. curtain walls were added. Curves A and Bare the fluctuations obtained frc:a the model before and after the curtain walls were installed; Curve C shows the water surface fluctuation measured in the prototype structure after the curtain walls were added. All measurements vere made at the standard staff gage location. The model indicated that before the curtain walls were added the average fluctuation was about 10 inches with a maximum of about 17 inches; after the walls were iDStalled the average fluctuation was about 4 inches and the max:lmta only 7 inches.

6

MODEL-PRO'l'OTYPE CONFORMIT!'

On April 8, 1953, the Poudre Supply Canal was operated so that the performance characteristics of the canal structures could be tested by the designers and laboratory engineers. The results of the tests have been reported in a Hydraulic Laboratory.Field Trip Report No. 1382.

One .of the structures that was checked was the measuring flume at the bifurcation structure. The recamnended curtain walls had been placed in the transition section upstream tram the measuring tlume,and prototype tests were made to determine the water surface fluctuations and the velocity distribution in the measuring flume. Two similar measure­ments were made in the model so that the degree of model-prototype con­formity could be determined.

Motion pictures showing the water surface fluctuation at the staff gage in the prototype measuring flume were compared with similar model measurements made with an electronic wave recorder. The frequency and magnitude of the fluctuations in the model and prototype are can.pared in Figure 11, Curves E and C. The model prototype contormi ty is very close. In both cases the waves seem to have a period of about 3 seconds and a magn1 tude of approximately O. 3 foot. The water surface shows more fluctuation between peaks in the model than in the prototype, but this is probably caused by the electronic recorder being more sensitive to the changes than motion pictures taken at 16 and 32 frames per second.

The prototype discharge was determined by current meter traverse in the measuring flume, and this value was used as _a check on the discharge indicated on the flume recorder. A similar velocity traverse was made in the mod.el to compare the velocity distribution. The two traverses are plotted on Figure 12., again the similarity between the model and prototype is very close.

1

A. Looking downstream in Measuring Flume. The water surface fluctuation averages about 10 inches with a maximum of 18 inches.

B. Water Surface Drawdown at radial gate.

Poudre Supply Canal Bifurcation Structure at Sta. 283+11. 98

Prototype Operation at 1275 cfs

Figure 1

'°' ~: :::,_ .._,a N")I...;

~I~ ,,.,., ~:~

I I

' I ~'­~ ,., ~:~ "''"' tilV')

~~

"<,

§

~ - "' OU s~ 0, ~ -- " ci "' I

'

' .... , .,,_ ~ ,., '"itl-:

~::.1 ti•V')

~:~ I

,,,, e;'

-q-1 ...,.i~ I r,,..., V)I . lf)I -+,.I~ 1n1'0-1G

~;~ ::~ ~:~ :;~ U)~~ ~l~ en:~ \ cn:;:j \:

C, C,

"' .., i~~;t:,.., ..... ,~-t-1'0

~·~~:~ t\l'c-.Jt\11(\J

.E:~~:~ V'))l&JV')1l&J . \

..._, ..,, -+-le, ..,,.., C01-.: "-'1~ cj1'0 -1-: "', ....

I

"'' ... , ... ,o

"''"' ~1oi ~:~ v,,-.,

..._, ::;:ia ..._la cola;

"''"' t:,lin -1. V')llu I

•

rL - 2f, 2", {, 20'-3" Placed

\ straight and level----------:-·,,, r,_::~;-~~;/;~"-- -- ------- -J'o" -"1 ~» ~ ;,--E/5233.50

, .. _,:.~ \ " .

'.,",{Straps @l8"±crs. welded to 2{, 2", {- L

:·,

FIGURE 2 REPORT HYD. 379

I ' " 8"N f<----9-0--- ..... K-_ ar

I ~':' ',<--e"Nar ',1'

Ll .. , : ·B"Nor

:--size and spacing of re,nfarcement in side wall same as_in adjacent floor See Section 8-8

/ I

PROFILE ,---Original ground surface r-----------P0U0RE RIVER----- -------j

I 2-J~-+-' 8'!.~ -t_ +<-B''

,.. . , D,mensian fram i~side face ta 22 Nor-· outside reinf same at base of

(DEVELOPED) ' I

0 50 100

I I I I I I I I I SCALE OF FEET

F'-t-//£lJJJ9w~{lf ___ ~ ___ ... !, Windsor Cooo/ Eitension

,:- ~ '<" : Aq,.--8" Timber bulkhead J a•"'-""t 1--- : "'--6'·1'.''-~ M

Undisturbed natural foundation in earth G:1-__-. ::t ,t::f r12~· 1<''of __ / ;K ,+ : ~ or thoroughly compacted backfill·, f f--·:· ' /·---;., I i k~r:_ .. 13co·--·: ,' : ~ • • -· 12:.; ,1...,r j,--s· Fillet

// ~ ;, __ J/ :; :"--- ~/: ~ :=l I

"' ,/ .. ?> . • ~-- : ~ /," /' .... _ ~

-;' q:, er, I

, : -I , /

~"' ~

\./ .. ~(. :\ -----

-.--._ i_

>--&»i au/ for wall plate and gate sill as directed.

Bai out for roilinf!~!~_!'s 1 •:v d1tectet1.------- I ---~

-•--- Note ·-,;::= Hoisl not shown. See r.f;-

~~ <, .t/ c·:> ,. ...... ~,_// -J' y

ins/01/ation t/rlg. forOfJtlnings _ in .tJeck and anchor bolt loyout. ".i,

--,% '

···t{ See Detail B·---·

I

I "''-"~- .

...I - ·--.f._~:,. ' ! i

46 'f<-s,6" •• /:' I '--a•

i----9·:~L::: • ,/j,@_12·-~

-~ 1'@12·----~Wf4@9~) ~~ )! El. 5239 56./

3~~i- · 16- H"" g:_.Jl.-6• .. I.?" -~

:,

~ l n 4· ff T,e bo1?j I

Note.-

"' ... .,. -

'···Channelize as directer/

Pr>-

' . ---*

s·screw lift rerticol gate and frame not shown. See IJ(Jte drawing for anchor boll location---_ . "' --

·o I

'·--1nrert El. 52Jl..64

~--J'-o"±

\:,,/ s· Std. black steel pipe painted.·

PLAN

side walls

I

or~

\Invert £1_ 5231.31

I ' ---. -------~--' ., :i'

-· -------- ------

"'' ..,, ~: .,,

..,

'--s,.o,

~I l.u1 ;;;;: ,·¾'@12· U

- TI '--i'@16· ; 11

, .• A .. !1 II

....jl..-6" ·--1•@16" ' ... 6"·"'><- ->!f---6"

,I "o,

,-·Hydragraphic bridge not shown. \ De/oils similar lo bridge an

."' \ Dwg. 245-0-5112 . I }

11:·• ,.., I I

I ' I I

DETAIL C

<].R O\~

..J Les" g'!~t1 11

"l __ 'f

---~--

? <:) ':' ; I

J ' -285 t /8·--,-------.. 1 --,u I ·c, Sta. : -~ - ~0 --- ,.. "' _,

~ I I I I ~ I I I I I I I,, , ... g

'II,

--{ Dehydrftted cork filler.

j A

wall as od;acent floor

SECTION E-E

----. -~ . i . ..i.

~ ~ ····{ >-·4· ¾' 4-J' U bars / ;..,4~ .. ,: with 6'-o'' legs·,< /1:·l'

/~ .... i

.

DETAIL OF BRACKETS ·-invert El 5230. 4

al>-

9,.t~ffL.52J5.75

·-lfll

"'

--.", .. -'8" Std. block steel pipe painted. Extend lo

outlet in chute as directed.

;;j i

--- a.I I -';;~59-}'@9" .? ;

i1 @9:., -------~-\

f '@IB-~ .... /

Detail

"' ~

ESTIMATED QUANTITIES Cancrele.. ______________________________ .740 Cu. Yds. Reinforcement steet ________________ J05,000 Lbs. Timber .......................... _______ ... J.8 M.B.M.

NOTES Place all reinforcement so that the centers of bars in the outer

layers wil I be 2" from face of concrete, unless otherwise shown.

Lap all bars 34 diameters of splices. Make fillets 6°; unless otherwise shown. Extend fillets as directed and terminate on 45' toper unless

otherwise shown. Concrete design based on a compressive strenglh of 3000

pounds per. square inch. See Dwg. 245-0-4783 for sections E-E to T-T inclusive. See Dwg. 245-0-4784 for chute and stilling pool. See Dwg. 245-0-5360 for float operated radial gate.

,s~o·,10·-o· Radial IJ(Jte, hois~ond oulomolic f/ool control, not shown. See installation drawing for de/oils and anchor boll loco/ion.

-:~· 14,J-' .. 1: . :i 6f-t•-J7-¾'@6" Each face

;.,,-,.(!i)6~l---24-f•@6"-->\

11 .- '°r" II .I" ,. "' ><k- --- ___________ 9J-L,"" 6

• __ :-_ _ .. _______________ .,J"" I 9· • •@6 ,Jl.c- - -34- 't '@6" - - - - - - - - - - - - - - - · - · 95- j•@ 6" I 8 "-"" I

f Dehydrated cork filler- ..

W. S,--:.kl&s@_ \, - YIE!! ....

See Detail A---------i

3·!...l

~ I1 .;;:::__~ '@9"

j .l,2d ! f 4

I f /40_; 1 • " ,,. ,,. " " f @

91·•@12,, "'f' .., ..... 3

3-!'@12·:-' \._3·]'@9"

SECTION B-B

i End alternate bars at ' ,_ __ /raff .all heiqhf ""

----8"• lfi Rough treoled timbers ------J,10· Rouqh treated timbers.

Fasten wilh 60d wire spikes

--"' _j·

1:::;~_::::?r--~ 6-,--/··'12!!~,?-

r< -- -- --End alternate bars at t,a/f wall height and quarter floor width--------------- - - - - - - - - - - - - -

C

:SE_CTION A-A I O 5 10 l,l 11 I! j e I I I I SCALE OF FEET

5•c.:;...:~,-i-l:::::--~ fl~ ~-3·-o·· ~ ~6" ---r __ _, :.!a"

PLAN OF WEIR WELL INLET

,·

~

'«> \}8"'t'8"1 . ,· '':' ....,fr-- 2 Dehydrated

m,--,6:--: cork f,t/er -

, ~ ·-,_ DETAIL 11 2- 2 Hoops:· ,>.1, bars with . - - ____ ._, ___ ,_ D-e-h-ydrated

\ -.1 ',·.,, * / 'wu~ 21" o,a precast · " •· ~- _ -~_:·- -_- ._ -_. __ · reinforced .- ·---;--·.: ·"' : · .. · - - ~-

,---·---T concrete pipe--··· '-~ .--4" , , " ,-;/ :~=.. -+18~ ,_a;· ..... !'@12"Both . .,,o,..- • @ 14 ------.--t:~8"~·-

1·1

2 ways 2-J t./ .

SECTION C-C SECTION D-D DETAIL A

;;;

~ ,;J

UNITED STATES DEPARTMENT OF THE INTERIOR

BIJREAU OF RECLAMATK>N

COLORADO-BIG THOMPSON PROJECT- COLORADO

POUDRE SUPPLY CANAL-STA. 283 + 11.98 BIFURCATION STRUCTURE

LE, CHECK AND PARSHALL FLUME

OFfllVEflt, COLOf'fADD, AiD""tL Z!J,1949 SH~ET t OF 3

RECORD ORA WING

SECTION C-C

NOTE Dimensions are given to the nearest finch .

POUDRE SUPPLY CANAL

1:18 SCALE MODEL STUDIES

BIFURCATION STRUCTURE

MODEL LAYOUT

FIGURE 3 REPORT HYO. 379

1-l&J l&J

5

·-

4

IL. 3 z

:c I-D. l&J 0

2

0 0

/ -..... ... ~ \

~ -- '\

2

\.

"" .........

" ' \ "'

4 6

Profile taken at Station 283 +71

./ ........ / -,,,

,J --~

8 10

WIDTH ( LOOKING UPSTREAM)

POUDRE SUPPLY CANAL 1:18 SCALE MODEL STUDIES

12

-- ..,

14

WATER SURFACE PROFILE UPSTREAM FROM CHECK STATION

...-_. - i---

16

-

18

;Q

"' ;g .,, ;Q ---iG)

:cc -< ::u plTI

!::: .,. IO·

Figure 5

A. Looking from measur­ing flume toward bifur­cation structure.

B. Appearance in stilling basin at 1250 cfs.

C. Appearance of flow in stilling basin and meas­uring flume at 1250 cfs.

Poudre Supply Canal Bifurcation Structure Model Studies

Preliminary Design

I I I

=' 0 - I 0 It)

PLAN

7,.-----1 I I I I I I I

10'- o!!.->k---------25 1- o•!.. ________ *_9•-0~->1 I I I I I I

-(J)

I

I I I

I

-------------------- ~---------------

--------

SECTION ALONG ~ 9-INCH ADDITION TO FLOOR

(.\J

I -- . j _____________ _

SECTION ALONG <i. 12- INOH ADDITION TO FLOOR

POUDRE SUPPLY CANAL 1:18 SCALE MODEL STUDIES

ADDITIONS TO FLOOR OF PARSHALL FLUME

FIGURE6 RE PORT HYO. 379

----I-- i

FIGURE 7 REPORT HYD. 3_79

I _, .,.,.STA. 283 + 55.31

< < < < < < < < < < < < < < < Supply Canal (t< < < < < :.i.,..

--STA. 283 + 36.6 N .:.!_IM<

-<-.:rw < < < <

I

5 I

.:1oi' -4( < N < < .:,;.,.i.., -< .:Jr N I <-;< < < < ,:_.LIM

PLAN

Only the positions of the angles on the apron are.shown in the Plan View.

< <

,..---Top of wa11----- ... ,' ',

------+----L---------' i Gate Seat--,~

-r I I I

-' (X)

ELEVATION

0 5 10 I I I SCALE OF FEET

.,-------;~8 X 8 L:,_s ,,,, .... - : ",

15 I

I ' ' ' ' ' ' ' ' ', ', \

POUDRE SUPPLY CANAL 1:18 SCALE MODEL STUDIES

ENERGY DISSIPATOR

Discharge 1000 cfs Discharge 1500 cfs

Poudre Supply Canal Bifurcation Structure Model Studies

Energy Dissipator Upstream from Stilling Basin . 1%! ..... ~ 1-j (1)

00

7

'

FIGURE' 9 REPORT HYO, 379

,.-STA. 283 +97.5 . 284 + 29.88--~i I I , r "'-,. I -- I :~,·+ Ii'

~

~-----Flanges 611 to 8 11 1-> I

STA

I n .: I --- a -r-> k-1 1 ± I I

I I

I I I -II I

[J

I I I I I I I I I - - - -I I I

-:..14- -Q:! FLOW -I rt) I ,,_

'}I I I I I I I I I I I ~ -' I II. I

I

~ _j II.. -PLAN

,.-w. s.--, ,' __ __._ __ ----See Deto i I

ELEVATION

t,--450 .__ __ _,._ - -" I I

: , .... -i---4 f to 6 11

j-C,---"-->1

-,,----1 I I

_I LO

d T I I I

. -:· :·}f :-/:-:-::~: :·: :·.-.~:._::_·. :_~:·:. ... _ .............. : ._ · ..

Water surface is for a discharge of 1500 c.f.s. and shows maximum surge.

5 0 5 10 I I II I I I

SCALE OF FEET

DETAIL OF LOWER EDGE

POUDRE SUPPLY CANAL I: 18 SCALE MODEL STUDIES

CURTAIN WALLS

'f i

'f I

Figure 10

A. Curtain walls looking up­stream . B. Stilling basin performance

at 1250 cfs.

C. Smooth flow in measuring flume at 1250 cfs.

Poudr.e Supply Canal Bifurcation Structure Model Studies

Recommended Curtain Walls

6,90

6.80

a: g 6,70

.J .. .. >

6.60

j 6.!50 .. ti 6.40 .. .. I 6.30 z 0 ;: 6,20

~ ~ 6.10 .. lal 6.00

" :! D: 5.90 :, ., a: 5.80 .. ... ; 5,70

z 0

5.60

6.60

- .... ... ~ 1&1 6.40 .J ..

uo .. " ~ 6.20 :, <I>

a: .. 6.10

I

11 I

II

!c 6.00 ;o

V

6.60 z 0 ;: 6.50

~ .. 6.40 .J ..

U0 .. " ~ 6.20 a: :, <I>

6.10 0: .. I- 6.00 .. ;o

A I I

I I

II ' II

l..1 '

11 u

B.

I/

I I

V

' I

I \ .... I/ I

w 11 I I I

I

\

10 12 14 16 18 20 22 24 26

TIME IN SECONDS

A. WATER SURFACE FLUCTUATION BEFORE MODIFICATION OBTAINED FROM I: 18 SCALE MODEL

,.., ··~.

I I\ \ 1,-.,.. l'I II A

' I I\ I/ \ II 'I I ' , I

~ "' I I I' ' I I I I I I IA I

\ ~ ll \ . ' ,I ' I ' 1• V • I-'

1, ~.

10 12 14 16 18 20 22 24 26

TIME IN SECONDS

WATER SURFACE FLUCTUATION AFTER RECOMMENDED MODIFICATION

I

OBTAINED FRQM I: 18 SCALE MODEL

I l

I "I ' II I I r I I ' ' r r ' .., ~ \ I I

" "N II - L I '

10 12 14 16 18 20 22

TIME IN SECONDS

C. WATER SURFACE FLUCTUATION AFTER MODIFICATION OBTAINED FROM PROTOTYPE OBSERVATIONS

POUDRE SUPPLY CANAL

J:18 SCALE MODEL STUDIES

WATER SURFACE FLUCTUATION IN MEASURING FLUME

I ~ \

V

V

.24 ..

FIGURE 11 REP.ORT HYO. 379

I I

28 ..

IA ' II\ I

,, I

,I

\

28 30

" l

I/ I

28 ..

;u ----------;:;:==7;====r==1===r==7==~~~~~~~~~~~1~;~~~;i::J:::~::f :::r---- "' ,, 'Tl o_. :II G')

"""c :z:~ p~ 1,1 N> .....

9

8

/> --o..._ - __,_x- i--x, "-- ~, ~

' -- ,.,.. "" r--u......

.,." ~ .,,-. ..... -x--- .. .. __ "-1,i..... .... ~

~/ ~~ ~ _ ... -x--....._

---a.:;::: ~--~ -- -->< - - -0- ........ ~x - - -07

z 0 0

-/

~x- / ~/

/ -- I ~"'O....""' --.....: ')c..._ .....

' UJ (/) 6

a: UJ

..... ....... ' /' a x_ ,...x

' x.-' ,/

' Q..

I- 5 UJ DATA OBTAINED FROM H'(DRAULIC MODEL ~OT, ES UJ LL

4 2

-Q =- ,soo c. t.v Curtain walls installed in model and DEPTH OF FLOW=- 6.88' prototype structures. ---0---0.20 =-1. 38' ---x---0.80=5.50' Model velocities measured by Bentzel

>­I- 3 _ DATA OBTAINED FROM FIELD OBSERVATIONS tube.

0 0 ..J UJ 2 >

-

0 0 2

<1=1477 c.fs. Prototype discharge computed from DEPTH OF FLOW= 6.71' velocities measured with current -0-0.20= 1.34' meter. --x- 0.80 = 5.37'

4- 6 8 10 12 14 16 18 20 22 24 26 28

TRANSVERSE SECTION LOOKING UPSTREAM

POUDRE SUPPLY CANAL MODEL AND PROTOTYPE VELOCITIES AT STATION 285 + 12

RECOMMENDED MODIFICATIONS

' b-

' X

-

-

-

30

IO