c:::l >-

HYDRAULICS BRANCH OFFICIAL FILE COPY

~ ,.!TED STATES DEPARTMENT OF THE INTERIOR

OFFICE

fit£ COPY BUREAU OF RECLAMATI ON HYDRAULIC LABORATORY

BUREAU OF RECLAMATION -~~----i:11-:nJ.a ::CL...--------------------------

HYDRAULIC STUDIES OF THE SKI-J UM P SPILLWAY

FOR CLEVELAND DAM

GREATER VANCOUVER WATER DISTRICT

VANCOUVER., BRITISH COLUMBIA 0 CANADA

Hydrau15c Labor atory Report No. Hydu369

ENGINEER[NG LABORATORIES BRANCH

DESIGN AND CONSTRUCTION DIVISION DENVER, COLORADO

May 19, 1953

CONTENTS

Purpose of Study o • • • • • • • • • ·• • • • • • • • • • • • • • •

Conclusions • • • • • • • . • . . • • • • • . • • • • • • • • • • Intrcxluction . • · • • . • . • • . . • • • • • . • • • • • . • • • • The Investigation • • • • • • • • • • • • • • • • • • • • • • • •

1 1 2 2

Toe problem • • . • • •. • • • • • . • • . • • • • • • • • • • • 2 The mod.el • • • • • • • • • • • • • • • • • • • • • • • • • • • 3 Tests • • • • . • . • . • . • . • • . . . • . • . . . . • . • • 3 Test results ••••••••••••••••••• • • • • • • 4

Figure

Model Plan and Section • • • • • • • • • • • • • • • • • • • • • • 1 Spillway Sections • • • • • • • • • • • • • • • • • • • • • • • • 2 Discharge Curve Spillway Crest. • • • • • • • • • • • • • • • • • 3 Pressure on Edge of Bucket Flow Splitter. • • • • • • • • 4 . • • • Model Construction • • • • • • • • • • • • • • • • • • • • 5 • • . • Flows of O and 5,000 cfs over Crest with Gate Down. • • • 6 • • . • Flows of 15,000 and 25,000 cfs over Crest with Gate Down. 7 • • • • Flows of 35,000 and 43,000 cfs over Crest with Gate Down. 8 • • • • Plan Views of Downstream River Channel with Flows of O and 5,000

cfs ••••••••• . . . . . . . . . . . . . . . . . • • • • 9 Plan Views of Downstream River Channel with Flows of 15,000 and

25,000 cfs • • • • • • • • • • • • • • • • • • • • • • • • • • 10 Plan Views of Downstream River Channel with Flows of 35,000 and

43, 000 cf s • • • • • • • • • • • • • • • • • • • • • • • • • • 11 View of Left Side in Ski-jump with Flows of O and 5,000 cfs ••• 12 View of Left Side in Ski-jump with Flows of 15,000 and 25,000 cfs. 13 View of Left Side in Ski-jump with Flows of 35,000 and 43,000 cfs. 14 View of Right Side i~ Ski-jump with Flows of O and 5,000 cfs ••• 15 View of Right Side in Ski-jump with Flows of 15,000 and 25,000

cfs •••••• • • • • • • • • • • • • • • • • • • • • • • • • 16 View of Right Side in Ski-jump with Flows of 35,000 and 43,000

cfs • . . • • • • , • • • • • . • • • • • • • • • • • • . • • • • l 7 View of Jet Impingement and Downstream River phannel with Flows of

15,000 and 25,000 cfs •••••••••• ~ •••••••••• 18 View of Jet Impingement and Downstream River Channel with Flows of

35,000 and 43,000 cfs •••••••••• \• • • • • • • • • • • 19 View of River Channel and Spillway with Flows of O and 5,000 cfs. 20 View of River Channel and Spillway with Flows of 15,000 and

25,000 cfs •••••••••••••••••••••••••• 21 View of River Channel and Spillway with Flows of 35,000 and

43,000 cfs • • • • • • • • • • • • • • • • • • • • • • • • • • 22 Scour in River Channel after Discharge of 35,000 cfs ••••••• 23 Scour in River Channel after 43,000 cfs Discharge •••••••• 24

CONTENTS--Continued

Flow Pattern in River Channel as Shown by Floating Confetti • • • 25 Flow in Spillway with Gate Maintaining Water Surface at El 570 • 26 Flow Conditions for Spillway and Outlets • • • • • • • • • • • • 27 Flow Conditions in River Channel with Bucket Splitters 'Removed • 28 Flow Conditions at Left Bank with Bucket Splitters Removed • • • 29 Flow Conditions in Jet Impingement Area with Bucket Splitters

Removed • • • • • • • • • • • • • • • • • • • • • • • • • • • 30 Flow Conditions in Spillway and River Channel Bucket Splitters

Removed • • • • • • • • • • • • • • • • ~ • • • • • • • • • • .31 Scour of River Channel for Plain Curved Bucket Splitters

Removed • • • • • • • • • • • • • • • • • • • • • • • • • • • 32 Flow Pattern-in Pumping Plant and Fishway Area for 15,000 cfs

Discharge as Shown by Floating Confetti • • • • • • • • • • • 33 Flow Pattern in Pumping Plant and Fishway·Area for 25,000 cfs

Discharge as Shown by Floating Confetti ••• ~ • • • • • • • 34 Flow Pattern in Pumping Plant and Fishway Area for 35,000 cfs

Discharge as shown by Floating Confetti • • • • • • • • • • • 35 Flow Pattern in Pumping Plant and Fishway Area for 43,000 cfs

Discharge as Shown by Floating Confetti\ • • • • • • • • • • • 36

ii

UNITED STATES DEPARTMENT OF THE INTERIOR

BUREAU.OF RECLAMATION

Design and Construction Division Engineering Laboratories Branch Denver, Colorado ·

Laboratory Report No. Hyd~369 Hydraulic Laboratory- Section Written by: L.V. Wilson Checked and May 19, 1953

reviewed by: W .c. Case J.W. Ball

Subject: Hydraulic studies of the ski-jump spillway for Cleveland Dam--Greater Vancouver Water District-Vancouver, British Columbia, Canada

PURPOSE OF STUDY

To determine the feasibility of substituting a ski-jump bucket for the original extensive rectangular stilling basin of Cleveland Dam spillway. "

CONCLUSIONS

1. In general the spillway now conditions were acceptable, particularly at the smaller discharges.

2. The ski-jump bucket slotted to form flow splitters, satis­factorily deflected the water into the river channel downstream away .from the toe of the dam at all flows (Figures 9 through 14).

J. The slotted bucket,distributed the spillway flow over a larger area of the river bed than a plain curved· bucket.

4. Subatmospheric pressures, sufficient to cause cavitation, occur on surfaces just below the sharp edges of the flow splitters (Figure 4). Cavitation can be eliminated by rounding the edges o.f the splitters, or its tendency reduced by chamfering the edges.

5. Water fins, caused by the flow from the crest spreading behind the piers and striking· the training walls, overtopped the tra.irling walls at discharges of 33,500 cfs and more. The high quality rock o.f the canyon walls should preclude any damage to the spillway structure or dam by this overtopping. Reducing the offset distance between the

. downstream edges of the crest piers and the inside surfaces of the training walls would eliminate the fins and overtopping.

6. Water overtopped the crest piers, elevation 572.25, at spillway nows greater than 30 ,000 cfs. The reservoir elevation tor the maxiJIUII discharge, 43 ,ooo cf s, was 577. Floating debris will strike the upstream spillway bridge girder during capaci t7 floods unless it is raised. The elevation of the water surface at the dam axis for this discharge will be about 574.5. ·

. 7. Removal of the flow splitters or the portion of the bucket between the slots to make the surface continuous, causes the spillway flow beyond the bucket to be more concentrated.

8. The spillway now surface has the appearance of a corrugated surface with the grooves and ridges parallel to the direction of flow. The size of the corrugations or "ropes" increase as the flow increases. The roughness is accentuated by the narrowness of the spillway and by the upstream overhang of'the crest. ·

INTRODUCTION

Cleveland. Dam was originally designated Capilano Dam. Hydrau­lic model studies were conducted on the spillway of this early design in the Hydraulic Laboratory of the Bureau of Reclamation in 1946. The results of this study are contained in Hydraulic Laboratory Report No. Hyd-222, entitled "Hydraulic Model Stu.di~s on the Spillway for Capilano Dam" dated December 6, 1946. Report No. Hyd-222 is included as an Appendix to this report.

The spillway design was modified from the stilling basin type to the ski-jump type to realize a reduction in initial cost. The. Bureau of Reclamation was authorized on December 22, 1952, to make hydraulic model studies of the modification. Field construction was in progress at the time the model studies were authorized, and it was expected that concrete would be placed in the bucket area by the·middle of January 1953. The model was put into operation January 15, 1953. Mr. H. A. Halland., a representative from the Greater Vancouver Water District, witnessed the operation of the model on January 20. He was satisfied with the performance of the ski-jump to the extent that field construc-tion could be continued without delay. ·

The primary features of the dam, except for the ski-jump, are discussed on page 1 of the Appendix, and their relative location shown on Figure 1 of the Append.ix.

THE INVESTIGATION

The problem. The primary purpose of the model investigation was to study now conditions in the ski-jump bucket and in the canyon and river bed imnediately downstream from the dam.

2

The model. A 1:60 scale model was constructed for the study; complete with crest~ chute, training walls, ski-jump, and topography · downstream to a point about 780 feet below the axis of the darn. The drum gate was represented by a curved metal sheet hinged to the wooden crest. River outlets were omitted. because it was considered that the now from them would give conditions in the bucket similar to those for now over the spillway •

The model is shown schematically on Figure 1. Sections or the prototype spillway are shown on Figure 2. A 4- by 5- by 8-root deep head box made or sheathing and sheet metal lined was used to represent the spillway approach. The crest was set in the box so an inside edge or the box represented the upstream race or the dam. The spillway was constructed in three parts. The crest and piers were made as a unit of sugar pine. The straight portion of the chute and training walls were made of plywood. The ski-jump bucket and training walls were made of sugar pine. Special shaped blocks were individually glued to the surface of a plain curved bucket to form a slotted bucket. The blocks could be removed for study of the plain bucket. The chute was attached to the crest with a mortise joint, and the ski-jump bucket was secured with screws and glue to the face of the chute. All parts of the spillway were given a coat of glyptol base paint as waterproofing.

. The tail box was framed with 2 by 4 stringers and studs and sheathed with plywood. The joints were sealed by covering with muslin and doping with the glyptol base paint. The topography immediately downstream from the dam conformed with the canyon wall scaling planned for the original rectangular stilling basin design. Vertical topography bents were used from the end of the ski-jump bucket to the point where the river channel angles to the left. From this point downstream, hori­zontal bents were used (Figure 5). The bents were covered with metal lath and plastered with 3/4 of an inch of concrete. The floor of the box represented elevation 260 and the topography was leveled off at the equivalent o.r eL~~ration 390. The bottom of the box was covered with gravel to elevation 300 at the toe of the bucket and tapered to elevation 260 at the tailgate. The material was a random mixture, and varied in size from pea gravel to 1-1/2-inch maximum.

An 8-inch centrifugal pump was used to supply water through an 8-inch line to the model. Discharge,was measured with a 6-inch standard Venturi met.er. Reservoir elevations were measured with a hook gage in a well connected to the head box. Tail water was regulated to a staff gage fastened to the floor of the box upstream of the tailgate at a location corresponding to that of the gaging station, about 700 feet downstream from the dam a.xis.

Tests. The model was operated at discharges equivalent to 5,000, 15,000, 25,000, 35,000, and 43,000 cubic feet per second with

3

respective tail water elevations of 288, 299, 307, 314, and 319 feet. A piece of 14 gage sheet metal was curved to conform with the top surface of the drum gate and secured to the crest with p~ano hinge and discharges of 8,000, 14,000, and 22,000 cfs studied with a constant reservoir elevation of 570. A discharge, representing 1,750 cfs, was passed through a fire hose and short pipe nipple to represent flow con­ditions through the ski-jump bucket with the left outlet operating. The latter test was made to illustrate that the outlet flow will not be adversely affected by the ski-jump bucket.

A calibration of the free crest was made and pressures taken on the edge of one of the bucket flow splitters. Approximate surface velocities were taken in the river channel below the hydraulic jump where the jet from the bucket plunged into the tail water. These veloci­ties were obtained by observing the time required for a small block of wood to travel a distance of 4 feet in the model.

The model was filmed with still and movie cameras to obtain a photographic record of flow conditions.

Test results. The calibration of the free coincided with the calibration of the original model Appendix), so no further calibration was performed. Appendix can be used to determine flood quantities.

crest (Figure 3) (Figure 6 of the The curves in the

A limited study was made of the pressure on .one of the edges of a bucket flow splitter. This test was planned after the model had been constructed, and only one piezometer was placed in the critical area near the edge of the splitter because of the difficulty of inserting tubes in wood. Location of the piezometer and the pressure curve for various discharges are given on Figure 4. Subatmospheric pressure occurred at high discharges. Low pressures can be expected along the splitter edges, with probable cavitation damage prevailing at smaller discharges than is indicated by the curve.

The crest piers, constructed to elevation 572.25, were over­topped at a discharge of 30,000 cfs so the height of the model piers was increased. In order to contain the maximum expected discharge of 43,000 cfs between the piers, the piers would have to extend to about elevation 577.

A plan view of the crest operating at different discharges is shown on Figures 6 to 8 inclusive. The flow.over the crest is rough. The roughness becomes noticeable at 15,000 cfs (Figure 7A) and progresses with increases in the flow. The irregular flow produces corrugations or "ropes" down the spillway chute (Figures 21 and 22). This characteristic was observed in the original studies (Figures 9 and 10,Appendix). The "ropes" are accentuated by the combination of the contracted flow at the

4

piers, and the vertical flow past the overhanging portion of the crest. The rough flow on the model was improved but not eliminated by placing a fillet on the upstream face of the spillway to eliminate the overhang.

The downstream progression of the jet impingement on the river bed with increasing flow and the enlargement of the turbulent area wherein the flow energy is dissipated is shown on Figures 9 through 11. The water "ropes" sometimes give a straggly appearance to the jet as shown on the right side of the jet in Figure llA. The slotted bucket produces alternate ridges and troughs in the flowing water spreading it longitudinally. This increases the area of impingement at the tail water surfac~ over that for a plain curved bucket.

The left side of the ski-jump area with different discharges is shown on Figures 12 through 14. The right side is shown on Figures 15 through 17. The water was relatively undisturbed at the toe of the.dam at all flows. The jet cleared the canyon walls above the water surface at all flows. Discharges of 25,000 cfs or more produced considerable splashing from underwater impingement in the region where the canyon is restricted.by the protuberance in the right canyon wall.

The water fins formed by the impingement of the spillway flow on the training walls downstream from the crest piers began overtopping the training walls at a flow of 33,500 cfs. These fins formed at low flows and increased in size with increases in flow until they eventually overtopped the training walls (Figures 14 and 17). This condition was eliminated by holding temporary slightly converging walls in the model with the upstream ends near the backs of the crest piers. Splashing over the training walls occurred in the tests on the original model and is discussed on page 4 of the Appendix.

The water action in the narrow portion of the gorge below the dam is shown on Figures 18 and 19. At 43,000 cfs the prominent point on the left and just downstream from the deep narrow section of the gorge gets splashed and washed over occasionally from wave action. The model operating at various discharges is shown from downstream in Figures 20, 21, ?nd 22. ·

Surface velocities measured in the channel downstream from the. jump are tabulated below:

Discharge cfs

5,000 15,000 25,000 35,000 43,000

Velocity feet per second

5

9.1 11.9 15.5 22.1 23.9

Detailed scour studies were not conducted but the general disposition of material by floods of various magnitude was note.d, Figures 23 and 24. It appears that loose rock in the impingement area will be piled to form a bar at the bend in the stream channel.

Flow conditions on the spillway face with the gate holding a constant reservoir elevation of 570 are shown on Figures 26 and 27A. The gate position has no effect on the flow conditions in the ski-jump bucket. Additional information concerning the spillway flow is con­tained on page 4 and on Figures 6 and 8 of the Appendix.

The assimilation of an outlet in operation on the model by a hose and pipe nipple was crude, but it illustrated how the flow from the outlets will pass down the face of the spillway and through the· ski-jump bucket (Figure 27B).

Flow lines, obtained by taking a 1/10-second exposure photo­graph of confetti scattered on the water surface in the downstream river channel were obtained, for comparing velocities and flow patterns in the pumping plant and fishway areas, Figure 25. Too much of the main channel was covered in the first tests and the high velocity water made the flow lines valueless at high discharges. Exposures of 1/10 and 1/5 of a second were used in later pictures of the left side in the pumping plant area (Figures 33 through '36). At low flows the water flows downstream with little turbulence along the stream edges, Figure 33. Reverse flow occurs along the left bank with a relatively slow counterclockwise whorl in the pumping plant area. An increase in dis­charge carries the reverse flow farther upstream along the left bank with indications of small whorls forming inside the general whorl (Figures 34 through 36).

The model in operation with the plain curved bucket is shown on Figures 28 through 31. The only noticeable difference is in the jet downstream from the bucket. The jet is solid. and not as thick as with the slotted bucket. The jet was more concentrated when it con­tacted the river bed and more scour occurred eroding a larger pool (Figure 32). The erosion would take place far enough downstream to. preclude any damage to the structure.

6

.,Wire Mesh and Gmvel Baffle

:/ •••·• Head Bax ,

·-Dom Axis

-Crest Axis

·--·--·AL-+!-+-----

EL547 -

34

PLAN

.•• -Grovel Bed

SECTION A-A

GREATER VANCOUVER WATER DISTRICT VANCOUVER e.c.

CLEVELAND DAM MODEL PLAN AND SECTION

MODEL SCALE 1: 60

SCALE IN FEET-MODEL

60 0 ~

.. 1

, .. J

SCALE IN FEET-PROTOTYPE

~~ ;Ja, "'C: "'::a "'"' -< P-l!: ..

34

Roadway El.580--\

------- ! ---

Block 9-, ,:) y

------------10'-- ·---------Block 1_-\

·-:;,.J

q· ;::o ·{}.

f:·

(~' I I I I I I I I

Spillway

Assumed Original Rock ----, on i of Spillwoy.----... ____ /- \

----,.: \ I \

I \ I \ -----------/ \

' ' \ I

:~; Original Excavate as Shown· From Sta. J + 93 ·_;1 Rock--.,_-,

to Sto. 2+ 10. s,0.125: 1----- / ................. ,,, . ·_,\~/,"/

', ' ' ' ,, '

.1::-EI. 364.67

~,-,.,.. _ _:;';:;J)'::El.360

-,,.

p.:.

I J J I I 11

s' I-<----

·-----

Block 8-. q) r

J-'i. lSpillwoy

'"' -~"-;t ,,;,.,_,,

,.;,;,, j,.,,, , a

5'),,oll[-

~-, Excovat! to Sound Rock----___ ,.., ""-.... '---..,

'

I I I

' I ',.._..,../ I J J I .

_) _ _,---Approximate Rock Surface, Block 7-B _.:.-~------../:'_ ---------

------::TION ON i S:::~~~------------------ SECTION AT STA. 2+00 (Looking Upstream)

GREATER VANCOUVER WATER DISTRICT VANCOUVER B.C.

CLEVELAND DAM SPILLWAY SECTIONS

·-;

"20 e~ lil C ~ .2 «.a..

,'i. Spillway

I I-

I-

I -

SECTION X-X

't,i.,,.Y 'f 2f 3F 410 6f 'f 710

SCALE IN FEET

-

-

'11 G) C: 21

~"' ;~

34

z 0

~

580 I

i 575

570 I

i;'.j 565 ....I w

0:::

0 > 0::: W 560 (/)

.w 0:::

555

550

I/ 545

0

V

/ /

10

I~ .-----

I~ .,,,-

20 30

DISCHARGE IN 1000 CUBIC FEET PER SECOND

GREATER VANCOUVER WATER DISTRICT VANCOUVER B.C.

CLEVELAND DAM

DISCHARGE CURVE - SPILLWAY CREST

~ .-----

Dot-a based on 1 : 60 model spil I way

40

1---11

50

:a ,,, ""O 0.,, :o­-t G)

C ::c ::0 -< 111 ~

(>I (>I m <D

34

.,, I I I ,.,

0 _, I'-

I I I

a: IJ.J ~

;· LL 0

10

I 0

I ~ -10 LL.I LL.I LL

I I .,-20 C <t LL.I :I:

'

'

10

~

"

"

I

~ of spillway

-

- .

----------.., -- ...............

" ~ -, ~ --.....:..

~

20 30 40 DISCHARGE IN 1000 CUBIC FEET PER SECOND

-

-,

,' I

ij----

l<-1511

(\J

+

t of splitter

GREATER VANCOUVER WATER DISTRICT VANCOUVER 8.C.

Piezometer--,,' ' CLEVELAND DAM

PRESSURE ON EDGE OF BUCKET FLOW SPLITTER

I i k-------a·-o~-----~ MODEL SCALE 1:so

PIEZOMETER LOCATION

A:J ITI

-0 "" o-A:J G') -t C :::c :::0 -< ITI p (J,I~

en co

A. Contour bents from downstream B. Plan view of spillway and contour bents

Greater Vancouver Water District Vancouver, B. c., Canada

Cleveland Dam ski-jump spillway Model Construction

:a lzJ tz.t a ~ c:: :a:U ~tzJ =c.n ~

I w en co

A. No discharge

B. 5. 000 cfs discharge

Greater Vancouver Water District Vancouver. B. c. • Canada

Cleveland Dam ski-jump spillway

Flows of O and 5. 000 cfs over crest with gate down

FIGURE 6 REPORT Hyd-369

A. 15,000 cfs discharge

B. 25, 000 cfs discharge

Greater Vancouver Water District Vancouver, B. c., Canada

Cleveland Dam ski-jump spillway

Flows of 15, 000 and 25, 000 cfs over crest with gate down

FIGURE 7 REPORT Hyd-369

A. 35,000 cfs discharge

B. 43, 000 cfs discharge

Greater Vancouver Water District Vancouver, B. c., Canada

Cleveland Dam ski-jump spillway

Flows of 35,000 and 43,000 cfs over crest with gate down

FIGURE 8 REPORT Hyd-369

A. No discharge

Greater Vancouver Water District Vancouver. s.c .• Canada

Cleveland Dam ski-jump spillway

Plan views of downstream river channel with nows of 0 and s. 000 cfs

B. 5. 000 cfs discharge Tail water el. 288

:oizi t_:lli5 c3 C: :o:O i-:3t_:ll III co

~ I

CA> Cl) (0

A. 15. 000 cfs 'discharge Tail water el. 299

Greater Vancouver Water District Vancouver. B. c •• Canada

Cleveland Dam ski-jump spillway

B. 25. 000 cfs discharge Tail water el. 307 .

Plan views of downstream river channel with nows of 15. 000 and 25. 000 cfs

~ltj tz.15 ii:, c:: 0~ ~tz.l ~ i:i:=c;; ~

I ~ Q) (0

A. 35., 000 cfs discharge Tail water el. 314

Plan view of downstream river section

Greater Vancouver Water District Vancouver., B. c •• Canada

Cleveland Pam ski-jump spillway

B. 43., 000 cfa discharge Tail water el. 319

Plan views of downstream river channel with flows of 35., 000 and 43., 000 cfs

::a 1-J:j f::!J .... '1:10 oc:::: ::a ::a i-3 f::!J

::i::::: -a

I c.:, C)

C0

A. No discharge

B. 5, 000 cfs discharge Tail water el. 288

Greater Vancouver Water District Vancouver, e.c., Canada

Cleveland Dam ski-jump spillway

View of left side in ski-jump area with flows of O and 5, 000 cfs

FIGURE 12 REPORT Hyd-369

A. 15,000 cfs discharge Tail water el. 299

B. 25,000 cfs discharge Tail water el. 307

Greater Vancouver Water District Vancouver, B.C., Canada

Cleveland Dam ski-jump spillway

View of right side in ski-jump area with flows of 15,000 and 25, 000 cfs

FIGURE 13 REPORT Hyd-369

A. 35. 000 cfs discharge Tail water el. 314

B. 43. 000 cfs discharge Tail water el. 319

• Greater Vancouver Water District

Vancouver. B. C. • Canada Cleveland Dam ski-jump spillway

View of right side in ski-jump area with flows of 35. 000 and 43. 000 cfs

FIGURE 14 REPORT Hyd-369

A. No discharge

B. 5,000 cfs discharge Tail water el. 288

Greater Vancouver Water District Vancouver, B. c., Canada

Cleveland Dam ski-jump spillway

View of right side in ski-jump area with flows of O and 5,. 000 cfs

FIGURE 15 REPORT Hyd-369

A. 15. 000 cfs discharge Tail water el. 299

B. 25. 000 cfs discharge Tail water el. 30!7

Greater Vancouver Water District · Vancouver. B. c •• Canada

Cleveland Dam ski-jump spillway

View of left side in ski-jump area with nows <>f 15. ooo and 25. 000 cfi

FIGURE 16 REPORT Hyd-:369

... ~i--, ~· .- . ,

A. 35,000 cfs discharge Tail water el. 314

B. 43, 000 cfs discharge Tail water el. 319

Greater Vancouver Water District Vancouver, B. c., Canada

Cleveland Dam ski-jump spillway

View of left side in ski-jump area with nows of 35, 000 and 43, 000 cfs

FIGURE 17 REPORT Hyd-369

A. 15, 000 cfs discharge Tail water el. 299

Greater Vancouver Water District Vancouver, B. C., Canada

Cleveland Dam ski-jump spillway . View of jet -impingement and down­stream river channel with nows of 15, 000 and 25, 000 cfs •

B. 25, 000 cfs discharge Tail water el. 307

=x:ll'Zj tz.15 "ti c:: O=x:i =x:i tz.l. ~ III; ~

I w en C0

A. 35. 000 cfs discharge Tail water el. 314

Greater Vancouver .Water .District Vancouver. B. C •• Canada

Cleveland Dam ski-jump spillway

View of jet impingement and down­stream river channel with nows of 35. 000 and 43. 000 cfs.

B. 43. 000 cfs discharge Tail water el. 319

::ti l'!l:j

tr.Is '"Cl c:: O::i:, ::d tr.I t--3

=~ ~ c.:, c» co

A. No discharge

Greater Vancouver Water District Vancouver. B. c •• Canada

Cleveland Dam ski-jump spillway

View of river channel and spillway with nows of 0 and s. 000 cfs

B. s. 000 cfs discharge Tail water el. 288

=al%J tzJ a c3 C: =a~ ~

r:i::t5 ~

I c.o 0) co

A. 15. 000 cfs discharge Tail water el. 299

Greater Vancouver Water District Vancouver. B.c •• Canada

Cleveland Dam ski-jump spillway

View of river channel and spillway with flows of 15. 000 and 25. 000 cfs

B. 25. 000 cfs discharge Tail water el. 307

::c, 1'%1 tr.I ..... '1:10 oc:: ::c, ::c, 1-j tr.I

::r:~ "< 0. I

C,)

c:i co

A. 35,000 cfs discharge Tail water el. 314

Greater Vancouver Water District Vancouver, B. C. • Canada

Clevelp.nd Dam ski-jump spillway

View of river channel and spillway with flows of 35,000 and 43,000 cfs.

B. 43. 000 cfs discharge Tail water el. 319

~~ tr.ic5 "ti c:: 0~ ~tr.I 1-:l ::,::~ '< Q. I

(,I) 0)

co

A. Plan

Greater Vancouver Water District Vancouver. B. C. • Ca.na.da

Cleveland Dam ski-jump spillway

B. Close-up from right side

Scour in river channel after discharge of 35. 000 cfs

:,:i:ll'Zj tzj s "tic:: @:.:i:i 1-j tzj

::i::I!.) ~~

I ~ C) (0

A. Plan

Greater Vancouver Water District Vancouver. B. c •• Canada

Cleveland Dam ski-jump spillway

Scour in river channel after 43. 000 cfs discharge

B. Close-up from right side

:;a:1'-r:I tz.1-"tlo 00 :;a:, :;a:, i-i tz.l ::Il to,)

(,< is. Q. I

c.:I a, co

A. 15, 000 cfs discharge

B. 25, 000 cfs discharge

Greater Vancouver Water District Vancouver, B. c., Canada

Cleveland Dam ski-jump spillway

Flow pattern in river channel as shown by floating confetti.

FIGURE 25 REPORT Hyd-369

A. a. 000 cfs discharge

Greater Vancouver Water District Vancouver. B. c. • Canada

Cleveland Dam ski-jump sp~way

Flow in spillway with gate maintain­ing water surface at el. 570.

B. 14. 500 cfs discba~ge

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=~ ~

I c.o = co

A. 22. 000 cfs discharge Gate raised rese~oir el. 570

Greater Vancouver Water District Vancouver. B. C •• Canada

Cleveland Dam ski-jump spillway

Flow conditions for spillway and outlets

B. 1. 750 cfs discharge Assimilated outlet now.

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=~ ~

I ~ en co

A. 35~ 000 cfs discharge

Greater Vancouver Water District Vancouver. B. c. • Canada

Cleveland Dam ski-jump spillway

Flow conditions in river channel with bucket splitters removed.

B. 43. 000 cfs discharge

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N ~ oc, ll, I w en (0

A. 35. 000 cfs discharge

Greater Vancouver Water District Vancouver. B. C •• Canada

Cleveland Dam ski-jump spillway

Flow conditions at left bank with bucket splitters removed

FIGURE 29 REPORT Hyd-369

A. 35. 000 cfs discharge

Greater Vancouvel' Water District Vancouver. B.C •• Canada

Cleveland Dam ski-jump spillway

Flow conditions in jet impingement area with bucket splitters removed

B. 43. 000 cfs discharge

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=~ ~

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A. 35. 000 cfs discharge

Greater Vancouver Water District Vancouver. B. C. • Canada

Cleveland Dam ski-jump spillway

Flow conditions in spillway and river channel bucket splitters re­moved.

B. 43. 000 cfs discharge

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I c., Cl) a:,

A. After 35. 000 cfs

Greater Vancouver Water District Vancouver. B.c •• Canada

Cleveland Dam ski-jump spillway

Scour of river channel for plain curved bucket (splitters removed).

B. After ,3. 000 cfs

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A. 1/10-seconc:I exposure

B. 1/5-second exposure

Greater Vancouver Water District Vancouver. B. C. • Canada

Cleveland Dam ski-jump spillway

Flow pattern in pumping plant and fishway area for 15. 000 cfs discharge as shown by floating confetti.

FIGURE 33 REPORT Hyd-369

A. 1/10-second exposure

B. 1/5-second exposure

Greater Vancouver Water District Vancouver. B. c •• Canada

Cleveland Dam ski-jump spillway

Flow pattern in pumping plant and fishway area for 25. 000 cfs discharge as shown by floating confetti.

FIGURE 34 REPORT Byd-389

A. 1/ 10-aecond exposure

B. 1/5-second exposure

Greater Vancouver Water District Vancouver. B. C. • Canada

Cleveland Dam ski-juinp spillway

Flow pattern in pumping plant and fishway area for 35. 000 cfs discharge as shown by fioating confetti.

FIGURE 35 REPORT Hyd-369

A. 1/10-aecond apoaure

B. 1/5-second exposure

Greater Vancouver Water Dlatrict Vancouver. B. c. • Canada

c1ev:1and Dam ski-jump spillway

Flow pattern in pumping plant and. fishway area for· 43. 000 cfs discharge as shown by floating confetti.

FIGURE 38 REPORT Hyd-389

Ap.pendix

UNITED STATES DEPARTI~lFNT OF THE INTERIOR

BUREAU OF RECLl,MATION

Branch of Design and Construction Engineering and Geological Control

and Research Division Denver, Colorado December. 6, 1946

Laboratory Report No. 222 Hydraulic Laboratory · Compiled by: Ben R. Blackwell Reviewed by: J.E. Warnock and

J. N. Bradley

Subject: Hydraulic model studies on the spillway for Capilano Dam­British Columbia, Canada.

INTRODUCTION

On March 22, 1946, an agreement (Contract No. I2r-15805) was made

between the United States, represented by the Chief Ene;ineer, Bureau

of Reclamation, and the International Engineering Company, Denver,

Colorado, where~y the Bureau of.Reclamation would conduct hydraulic

model tests of the spillway and outlet works for the Capilano Dam

being designed for the City of Vancouver, British Columbia. The

designs have been submitted by Mr. J. J. Hammond. Mr. John L. Savage

is consulting engineer for the project.

The principal features of the design to be investigated were:

1. Flow conditions in the approach to the spillway

2. The characteristics and efficiency of the overflow

crest section

3. Flow conditions in the chute and stilling-pool

4. The general operation of the outlet works.

The Capilano Dam of the Greater Vancouver Water District is

located on the Capilano River 2 miles above North Vancouver, British

Columbia, Figure 1. This concrete-gravity type structure will rise

300 feet above bedrock, Figure 2. The average hydraulic head will be

260 feet. River flow, past the dam, will be controlled by one 70-

by 23-foot drum gate and by two river outlets with 5- by 6-foot

high-pressure slide gates. The spillway is designed for a maximum discharge (1,000-year flood) or 43,000 second-feet. The 100-year flood was considered to be 33,000 second-feet. The domestic water supply will be released through two 72-inch diameter tunnels and controlled by two 5- by 6-foot high-pressure slide gates. An 8-foot diameter connection w.i..11 be provided in the face of the dam for a penstock for future power development.

SUMMARY

The results of the hydraulic model studies of the Capilano Dam may be sum.arized as follows:

1. The flow conditions in the approach to the spillway were satisfactory •

. 2. To pass the maximum discharge of 43;000 second-feet., the maximum reservoir elevation will be 577.

3. While there was considerable splashing over the chute training walls.at the higher discharges., the operation was con~ sidered acceptable because of the excellent rock in the vicinity of the dam. Operation of the stilling-basin as originally designed was entirely satisfactory.

4. General exterior operation of the river outlets at full­gate opening was satisfactory for all combinations of flow.

DESCRIPTION OF THE MODEL

A 1:60 sca,le hydraulic model of Capilano Dam·was constructed at the new Bureau of Reclamation Hydraulic Laboratory located in the Denver Federal Center, Denver, Colorado. Standard c onstruction was used in the model. The heacl and outlet boxes were of timber and lined with sheet metal. The crest, river outlets, and upper part of the chute were constructed of sheet metal, while the stilling-basin was construc·ted of wood. The topography in the outlet box. was constructed of wood and

2

metal lat}}. frames covered with a thin layer o.f concrete. The model

layout is shown in Figure 3. The model., ready for operation., is

sho\m i11 Figure 4A.

THE INVESTIGATION

The approach. With the exception of the trashrack for the

domestic water supply., the approach to the spillway is straight and

symmetrical. and., _therefore., presents no hydraulic problem. The trash-' rack is located closer to the spillway than is customary, so model

studies were made on the spillway operation and efficiency with and

without the trashrack structure. The trashrack structure did not

effect the qperation or efficiency of the spillway in the model.

F~gure 5A shows the approach conditions at the maximum discharge or

43.,000 second-feet.

The overflow-crest section. F1ow conditions at the crest were

satisfactory for the design as submitted. The nappe was completely

aerated with the drum gate in raised positions except at very low

heads.when the sheet of water from the crest did not clear the self­

aerating piers. This latter condition., while not serious., may be avoided

by using the river outlets instead of the spillway for very small

discharges. The coefficient of disch~rge at maximum reservoir elevation

of 575 feet was found to be 3.71, as compared to the design coefficient

of approximately 4.14. The difference in coefficients resulted in a

maximum free discharge of 38.,400 second-feet, as compared to a discharge

of 43.,000 second-feet for the maximum design head. Due to the nature

of the topography of the site., a longer spillway crest was found to be

Ul'leconomieal. It was therefore decided to increase the maximum reservoir

elevation by 2 feet to bring the spillway capacity to the required

43.,000 second-feet. The model tests indicated a maximum reservoir water

surface of elevation 577.0, as compared to the design water-surface of

elevation 575.0 feet. Head-discharr,e curves obtained from the model

calibration are shown in Figure 6 for the free crest and several

3

raised gate positions. Coefficient of discharge curves for flow under

the same conditions are shown on Figure 7.

The chute• There was considerable spl~shing over the chute training walls at spillway discharges of over J0,000 second-feet. The spillway jet expanding from the 70-foot spillway gate section to the 80-foot chute combined with the steep slope of the chute produced fins of water along the training walls. The majority of the splashing was produced by these fins. 11 Sea walls," Figure 5B, were effective in confining the splashing to the chute. Considering the solid rock in the canyon walls, the minor nature of the splashing, and the infrequency of occurrence of the higher discharges, the "sea wall" design was discarded and the original wall design retained.

Considerable splashing occurred within the chute during spillw~ operation with the drum gate in raised positions. For several combinations of discharge and gate opening the jet from the spillway impinged in the river outlet openings as is shown in Figure 8. · The combinations of discharge and gate position that this can occur are so frequent that no attempt is being made to limit operation to avoid this condition. It is not expected that any damage will result from the spillway sheet striking the outlet troughs. A test on the prototype will be more convincing as to this point.

The stilling-pool. Operation of the stilling-pool was satisfactory at all discharges. At discharges of over 30,000 second-feet, the action over the end sill was rather rough but was not serious because of the solid rock in the canyon. At 43,000 second-feet, a drop in the tailwater elevation of over 6 feet below normal was req_1.1ired to sweep the hydraulic jump off the apron. At 33,000 s~cond-feet, the drop in tailwater elevation was increased to 12 feet to accomplish the same result. At discharges of 25,000 second-feet and less, the control section in the river immediately downstream from the stilling-pool maintained sufficient tailwater elevation to prevent the jump washing off the apron under anlr condition. Stilling-pool operation with normal tailwater elevations is

4

shown for spillway discharges of 15,000, 25 1 0001 33 1 0001 and 43,000

second-feet in Figures 9 and lOo

The river outletso General exterior operation of the river

outlets at full-gate openings was satisfactory. The outlets discharged

smoothly down the face of the spillway and into the stilling-basin.

Model operation of one and two outlets is shown in Figure 11. The

action in the stilling-basin was satisfactory for all combinations of

discharge with full-gate openings.

5

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"'.• ,., ~· y &CAL.£ 01" MILES

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GREATER VANCOUVER WATER DISTRICT

VANCOUVER, 8 C

CON TRAC r IVO

CAPILANO DAM LOCATION MAP

SCALE

- - ·~CHIEF' COllf11r,s10NE'1 ~ATE . -~-·/¥. ~IIIG £1V6tlll~ilf .. • COIU ,,..T, FILE ~'0

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SCALE OF FEET

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UPSTREAM ELEVATION (PROJECTED/

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FIGURE 2

.---·Top of paropet ·£1. 58J.75

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'·5·, 1' Adil to gallery system -

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P.I. El. 595.38··'\ 1_ , , I.~ 2J -~ ... 4-

:J'-6",,~ I _ ..... , E Roadwoy-£158000 '. , 1·

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· · - ,\ ,£1558.46 ,_-24 • •, ,-i 5',1' Uppergrout,ng and

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El 470.56··· ,-5',6' High PflSSlll'e ~l*-'i"f"J.,~'*;j•:>;.J'#,' · slide got, \ I__ :..L __ + --J J

ABUTMENT SECTION

0ut1,t woru _. frashrack---­

L----J.. ___ --- - --

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cancret, /Jullth«HI---·· DOWNSTREAM ELEVATION

0 10 20 30 40 110

SCALE OF FEET

( l'ffOJ~CTED}

Axis of dam----· ,--Spil/rtoy training woll

·/ ..:

Assum Id fin, a f 11ca,otian . /

SECTION

se,11,? A-A

SCALE OF FEET

IIO I

IIESElll/0111 AREA IN HUNDIIEDS OF· ACRES 2 :S 4 5 6 511lo

.LW i 11_ 7 8

z 0

550

I 500

!c -450 > .., ...J ..

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350

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0 10 20 30 40 50 60 .70 80 RESERVOIR CAPACITY IN THOUSANDS OF ACRE - FEET

TAILWATER AND_ DISCHARGE IN THOUSANDS OF SECOND FEET

,-·-El :Jtt.00 :-·Max. TWS. E/.320.00 c.- - ·=

<<·---4-70'-d' To oxis .......

NOTE Acfuol r,q111r,d foundations may vary widely from

/)rofi/e and assumed e,cavatian lines shown

OffEATEff VANCOUVEff JIATEff D/STfflCT

t.A'IICOUVER, B C

CAPILANO DAM PLAN, ELEVATIONS ANO SECTIONS

CONTRACT NO.

"Oll'M·SS C-\.E.it

$.;ALE , :,, • so•, OA'rE

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AREA, CAPACITY, TAILWATER AND DISCHARGE CURVES SHEET NO

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£,..,,,, .... ,.

,,Axis of dom

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SCALE OF FEET

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I I.

(-·Riverbed profile

SECTION A-A

CAPILANO D-AM HY D.RA UL IC MODEL I :eo PLAN AND ELEVATION

i

,_ .. f.W .. Control gote

__ -Return channel J.f'''

,. ci i Ill c,I

I

I

.l

A. Splll,rq model req toi- opei-at1on.

CAPILANO DAIi

1:60 SCALE MODEL

B. 8p11ln7 model opent1ng Q=ta.ooo cte.

~

I "'"

···Chute flaar

ORIGINAL OESIGN

A. Spillway approach Q=43,000 o.ts.

l.Trainint wall

.-·· Chute floor

SEA WALL DESIGN

B. Details of chute training-walls.

CAPILANO DAM

1:60 SCALE MODEL

FIGURE 5

' '·Tralnlnt wall

I-l&I l&I ~

!

z 0

5 ~ ..J l&I

II: 0 > II: l&I en l&I II:

Gate El. 570 ft.-, Gate El. 565 ft.·, Gate El. 560 ft., Gate El. 555ft., Gate El. 550 tt.1 ' . ,• ,,-' ,," ,,, /

580 ' '

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570

515

HO

SH

ssoJ--~'-----+-------t-----+-------+-----+------+------,1------+------t----....,...+-------+-----+------1

545 O 4000 8000 . IIOOO 11000 10000 14000 HOOO IROOO HOOO 40000 44000 48000

DISCHARGE IN C. F. S.

CAPILANO DAM DISCHARGE CURVES FROM CALIBRATION OF 1: 60 SCALE MODEL

,, G)

C :-, "1

en

FIGURE 7

.... w w u.. z

z 0 -.... <l > LA.I ..J w

a:: -0 > a:: La.I (/)

La.I a::

590-----------------,.---....,...--~---r---"T"""'---,

580

' Gate El. 568.5'-'

570

560

550

540 ..._~--+---+---+--+---------ir---+---+---+--+------1

530'-----'----'----'---...... ----ii.----------....... ------3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8

COEFFICIENT OF DISCHARGE

CAPILANO DAM

3.9

COEFFICIENT CURVES OBTAINED FROM CALIBRATION OF A 1:60 SCALE MODEL

4.0

Interior - Reclamation - Denver, Colo.

!Jpillwa7 jet impinging above river outlet openings.

"

CAPILANO DAM

1:60 SCALE MODEL .. SPILLWAY GATE PARTIALLY OPEN

Spillway jet impinging in river outlet openings.

~

i o:>

Q=ls.ooo cfa.

CAPILANO DAM

1:60 SCALE MODEL

STILLING-POOL OPERATION

Q=25•000 cfa.

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Q::331000 ota.

CAPILANO DAM

1:60 SCALE MODEL

STILLING-POOL OPERATION

Q=:43,ooo ota.

l:i;I H

i b

One river outlet operating.

CAPILANO DAM

1:60 SCALE MODEL

ho river outlets operating.

~

I ~