UNITED STATES DEPARTMENT OF THE INTERIOR

BUREAU OF RECLAMATION

HYDRAULIC MODEL STUDIE S OF THE

REGULATING GATE AND STILL ING WELL- ­

TRENTO N DAM CANAL O UTLET W O RKS- ­

MISSOURI RlV ER BA SIN PR OJECT

Hydraulic Laboratory Report No. Hyd. -300

RESEARCH AND GEOLOGY DIVISION

BRANCH OF DESIGN AND CONSTRUCTION DENVER, COLORADO

April 11, 1951

..

.,

Purpose

Conclusions

CONTENTS

Page

1

1

Recommendations 2

Acknowledgment 3

Introduction 3

Investigation 4

Description of 1: 12 Model Outlet Works 4

Regulating Gate and Downstream Conduit Pressures . 5

Discharge Capacity Curves 6

Stilling Well and Deflector 6

Stilling Well Exit into the Canal 7

Scour in the Irrigation Canal . . 8

•

LIST OF FIGURES

Location Map . . . . . . . . . . . . . .

Canal Outlet Works, Plan and Section .

1 :12 Scale Model . . . . . . . . . . .

Regulating Gate, Conduit, and Stilling Well

Schematic Views of the 4' -0" x 4' -0 11 Modified Slide Gate and the Piezometers in the Conduit .

Standard 4' -0 11 x 4' -0 11 Slide Gate

Pressures on the Bottom of the Gate Leaf

?igure

1

2

3

4

5

6

7

Pressures in the Conduit Downstream from the Regulating Gate 8

Discharge Curves . . . . . . 9

Stilling Well Baffle Designs 10

Pressures on the Stilling Well Walls 1 1

Stilling Well Exit into the Canal . . . 12

Flow Conditi_ons in the Well and through the Well Exit into the Canal. . . . . . . · . . . 13

Scour in the Canal Entrance . . . . . . . . . . . . . . . . 14

..

UNITED �ATES DEPARTMENT OF THE INTERIOR

BUREAU OF RE_CLAMATION

Branch of Design and Construction Research and Geology Division Denver, Colorado

Laboratory Report No. Hyd-300 Hydraulic Laboratory Compiled by: W. P. Simmons, Jr. Reviewed by: J. W. Ball and April 11, 1951

W. C. Case

Subject: Hydraulic model studies of the regulating gate and stilling well-­Trenton Dam Canal Outlet Works--Missouri River Basin Project

PURPOSE

(a) To study the feasibility of using a modified, *high pressure slide gate for regulation under submerged conditions.

(b) To determine the effectiveness of a side-entry, vertical stilling well i.n dissipating the destructive energy of the released water.

*Note: The modification includes narrow gate slots, wedge-shaped gate slot flow deflectors, and either a flat or a concave gate leaf--see Report No. Hyd-245.

CONCLUSIONS

1. The regulation of the water flow is accomplished smoothly by the modified high pressure sli.de gate, shown schematically on Figure 5, at the submerged conditions applicable to this installation. The head difference between the gate centerline and the maximum reservoir water surface is 112. 42 feet, while the minimum difference between the gate centerline and the tail-water elevation is 27. 42 feet.

2. At all conditions where the 300-cfs canal capacity is not exceeded, subatmospheric pressures will not occur on the gate leaf bottom (Figure 7). Subatmospheric pressures as low as 6. 2 feet of water will occur on the bottom of the leaf when the reservoir is full (elevation 2785. 00) and the gate is 99 percent open. However, this operating condition would result in a di.scharge of 776 cfs which greatly exceeds the 300-cfs capacity of the canal. This condition should, therefore, never be encountered.

3. No seriously low pressures or vibration will occur in the conduit downstream from the gate, even wi.thout an air vent. All pressures recorded were positive at all gate settings and at an equivalent total head of 70 feet at the gate entrance (Figure 8). The lowest pressure, a positive 4. 4 feet of water, occurred on the top of the conduit 1 . 5 feet downstream from the

centerline of the gate stem at a gate opening of 95 percent and with a discharge of 690 cfs. Therefore, there should be no need for an air vent.

4. The stilling well shown in Figure 2, using the recommended baffle, satisfactorily dissipates the destructive energy of the discharging water.

5. The vertical placement of the preliminary design stilling well baffle (Figure l0A) was critical and to be effective a higher elevation was required for small gate openings than for large openings. The recommended baffle design (Figure 10B) is not critical to gate opening

• and operates effectively in any position where the baffle top lies between elevations 2680. 0 and 2690. 0.

6. The walkway and two dividing piers at the exit of the preliminary stilling well design (Figure 12A) partially obstruct the flow into the canal at discharges greater than 700 cfs. Improved flow conditions into the canal at all flows and an economy in construction are obtained by removing these obstructions (Figure 12B).

7. The invert of the canal may be lowered 1 foot below the well exit sill to provide a step to restrict the upstream movement of debris into the well (Figure 12B).

8. Any debris, such as stones or large construction material, should be removed from the well as it will produce abrasive erosion on the floor and lower walls of the well during operation.

9. No objectionable scour occurs in the riprapped portion of the canal at the well or in the unlined canal immediately downstream (Figure 14). The 24-inch, dump-placed riprap in the final design extends 65 feet downstream from the well.

10. Discharge capacity curves for the canal outlet works with the modified gate are presented in Figure_ 9.

RECOMMENDATIONS

1. Use the modified design of the standard high pressure slide gate, shown schematically on Figure 5, for regulation in the Trenton Dam Canal Outlet Works.

2. Use the recommended stilling well baffle design in the prototype structur·e (Figure l0B).

3. Omit the walkway and the two dividing piers on the prototype structure to effect a flow improvement and an economy in construction.

4. Lower the canal invert 1 foot below the well sill to restrict the upstream movement of debris into the well (Figure 12B).

2

5. Remove all debris from the well before releasing any water to prevent abrasive erosion of the well floor and walls.

6. Install, during construction, sufficient piezometers in the conduit downstream from the gate to obtain prototype data for future design use.

ACKNOWLEDGMENT

The reco'r:rim_ended design of;the Trenton Dam _Canal Outlet Works is the result of cooperative efforts of the Spillway and Outlets Section No. 1 of the Dams Division and the Hydraulic Laboratory of the Research and Geology Division.

INTRODUCTION

Trenton Dam is an earth-fill structure about 9, 000 feet long which rises 103 feet above the Republican River. It is located 3 miles upstream from Trenton, Nebraska, and will be used for storing irrigation water and for flood control (Figure 1). A spillway controlled by three 42-foot wide radial gates is provided at the left abutment to pass flood waters while river outlets, located underneath the spillway crest to discharge upon the spillway face, are provided to release the required river flows. An addi­tional outlet works is provided 6, 300 feet to the right of the spillway to supply water into an irrigation canal. The final design of this outlet works, which incorporates the model test results, is shown in Figure 2.

The necessity of obtaining a discharge of 300 cfs (the canal capacity) at the minimum operating water surface elevation of 2720. 00 fixed the size of the regulating slide gate at about 4'-0" x 4 1 -011

• At higher heads it will be necessary to partially close the gate to avoid exceeding the 300 cfs canal capacity.

The design of the canal outlet works was complicated because bedrock was at elevation 2674. 0, while the invert of the irrigation canal was at elevation 2699. 0, or 25 feet higher. It was desirable to have the outlet conduit through the dam placed solidly on bedrock, so an unusual design was developed wherein the conduit dropped vertically from the intake at elevation 2710. O_, then turned horizontal with the centerline at elevation 267 3. 75. The 66-inch round conduit then continued downstream past the emergency gate structure to the transitions leading to the 4-foot by 4-foot regulating slide gate. A short section of straight pipe and another transition completed the conduit and connected the gate to the vertical stilling well (Figure 2). The well carried the water upward to the elevation of the irrigation canal and dissipated the destructive energy of the flow. The well was octagonal in cross section, 16 feet across the flats, and the bottom was at elevation 2666. 75. The top of the preliminary design well was at elevation 2708. 00 giving a well depth of 41. 25 feet. A deflector similar to a dentated sill was placed on the wall opposite the inlet to increase the energy dissipation within the well. The centerline of

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the 56-inch-diameter inlet pipe was 5. 66 feet above the well floor and 27. 59 feet below the sill. The water discharged from the well at eleva­tion 2700. 0 through openings in the three downstream walls to enter the irrigation canal (Figure 12A). The well sill-to-floor depth was 33.25 feet. Twenty-four-inch dumped riprap was provided in the first 20 feet of the unlined canal to prevent excessive scour.

There was considerable doubt about whether the regulating gate, modified as for the Cedar Bluff Outlet Works (Report No. Hyd-245), could be operated at partial openings without damage to itself or to the conduit downstream when used to discharge underwater against a back pressure of 27. 5 or more feet. Information was also required of the effectiveness of the side entry, vertical stilling well in dissipating the destructive energy of the water and of any design changes necessary to the well to insure smooth delivery into the canal. Accordingly, hydraulic model studies were requested to determine the operating characteristics of the regulating gate, the pressures on the bottom of the gate leaf and in the conduit between the gate and the well, the effectiveness of the stilling well in dissipating the destructive energy in the water, the entrance conditions into the canal, and the nature of the scour at the canal entrance. This report concerns the method of conducting these studies and the results obtained from them.

INVESTIGATIONS

Description of 1 :12 Model Outlet Works

A 1 :12 scale model was constructed which included the 4-foot by 4-foot regulating gate, the conduit. between the gate and tp.e stilling well, the well, and 98 feet of the unlined canal (Figures 3 and 4). A 6-inch gate valve was installed IO. 5 feet upstream from the regulating gate so that any applicable flow and pressure head could be obtained by manipulation of the two gates. Water was supplied to the model by the laboratory system which contained venturi meters for measuring the flow rate. The pressuF.e head acting on the model regulating,gate was measured with a water manometer connected to the reference piezom­eter located on the conduit horizontal centerline 2 inches (model) up­stream from the gate stem centerline (Figure 5). Pressures were measured at 9 points on the bottom of the gate leaf (Figure 7). The sections of conduit between the regulating gate and the well were made of transparent plastic so the flow within the conduit could be more readily studied. A total of 22 piezometers were installed in this con­duit and connected to water manometers to measure the pressure distribution (Figure 5). Three sides of the octagonal stilling well were made of transparent plastic while the remainder of the well was for med by a sheet-metal lining on a wooden base. The deflector was made of oil-treated wood and it was fastened to the downstream well wall in a manner permitting it to be moved vertically. The irrigation canal was constructed in a metal-lined wooden box that was provided with a tail gate for regulating the canal water surface elevation and a point gage

4

for measuring this elevation. During the early stages of the model tests the full length of the model canal was formed in compacted sand. For the final tests pea gravel was placed downstream from the well for a distance equivalent to 20 feet to represent the 24-inch dumped riprap. A box trap was provided near the end of the model to retain any canal bed material washed downstream, and the water leaving the model flowed freely back to the main supply channel.

Regulating Gate and the Downstream Conduit Pressures

Model tests showed that the high pressure slide gate, modified to the design recommended for Cedar Bluff Outlet Works, can be operated safely und.er water for the design conditions of the Trenton Dam Canal Outlet Works. The model studies herein described were conducted using the modified gate design with the flat leaf (Figure 5 ), and the results of the tests are not to be applied to the standard gate design shown on Figure 6.

In the Trenton Dam Canal Outlet Works the difference in elevation of the upstream gate frame centerline and the maximum reservoir water surface (2785. 00) is 112. 42 feet. The minimum back pressure on the downstream gate frame centerline when the water in the stilling well is at the elevation of the discharge sill (2700. 00) is 27. 42 feet (Figure 2).

Regulation of flow in the model occurred smoothly and without vibration. Subatmospheric pressures were found on the bottom of the gate leaf at high heads with gate settings of 99 and 1 0 0 percent open. The pressure data shown on Figure 7 , were obtained at an arbitrarily selected total head of 70 feet at the gate entrance for a series of gate openings that covered the operating range of the struc­ture. This data may be converted for other total heads by the use of the pressure coefficient Pk, where the coeffkient for a desired piezometer is given by the relation,

p reference piezometer pressure-desired piezometer pressure

k = velocity head at the reference piezometer

An example of the use of the pressure coefficient would be to determine the minimum pressure which is likely to occur on the gate leaf at the maximum reservoir elevation with the gate 99 percent open. From the model data for a 70-foot head the pressure coefficient for the lowest reading piezometer, No. 3, equals 36. 72 - (-2. 40)-:- 33. 28 or 1. 177 The discharge with a full reservoir and a 99 percent gate opening would be 776 cfs, (Figure 9). The velocity head at the location of the reference piezometer will be 36. 6 feet and the piezometric head will be 36. 9 feet. The pressure coefficient,. 1. 177, multiplied by the velocity head of 36. 6 equals 43. 1--this is the pressure drop from the reference piezometer to the point on the leaf. Subtracting this pressure drop from the available piezometric head of 36. 9 feet results in a sub atmospheric pressure of 6. 2 feet of water at this particular point on the leaf.

5

..

The only time subatmospheric pressures occur is when the reservoir is at or near the maximum elevation and when the gate is near or at full opening, a situation which would flood out the irrigation canal with more than twice its capacity of 300 cfs. At smaller open­ings or in the lower head range there will be no subatmospheric pressures at any point on the bottom of the gate leaf.

Pressures were measured at the 22 stations in the conduit downstream from the gate (Figure 5) at representative operating conditions and all pressures were positive. The pressures for 17 piezometers are shown in Figure 8. The lowest pressure, +4. 4 feet of water, occurred at the top of the conduit 1. 5 feet downstream from the centerline of the gate stem at the total head of 70 feet, and with the gate 95 percent open, an operating condition which would produce a flow of 690 cfs. Opening or closing the gate from this position or decreasing the head on the structure caused the pressure to increase rapidly.

The absence of subatmospheric or highly fluctuating pressures on the bottom of the gate leaf or in the conduit downstream from the gate structure (within prototype operating limits), together with the smooth flow regulation obtained, makes the modified high pressure slide gate design acceptable for use in the outlet works. No air was admitted into the conduit in the model studies because none was found necessary.

Discharge Capacity Curves

The discharge capacity of the recommended outle.t works was determined by model tests for gate openings varying from 10 to 100 percent open and for heads on the upstream gate frame centerline vary­ing from Oto 112 feet (Figure 9). No flow will occur through the outlet works until the head at the gate entrance exceeds the submergence of the gate. The actual head differential across the gate will thus vary with the elevations of both the reservoir and the canal water surfaces. Due to lack of information concerning backwater the canal water surface was maintained at 2705. 00 for all discharges in the model tests.

The available total head on the horizontal centerline at the gate inlet is shown in dashed lines for the normal and maximum reservoir water-surface elevations, 2752. 00 and 2785. 00, respectively. The head difference between the no-flow conditions and the dashed lines at any discharge condition is the computed head loss incurred through the conduit to the gate entrance. The head loss computed by the Hydraulic Laboratory is less than that used in preparing the curve shown on Figure 2.

Stilling well and Deflector

Water enters the octagonal stilling well through a 56-inch­diameter opening in the center of the upstream wall at elevation 2672. 41 (Figure 2. ). The water flows across the well in a high-velocity stream

6

..

t o strike the d ownstream wall which dire ct s part of the flow back upstream along the side walls and floor toward the well entrance . The high velocity eddie s and current s which result in the lower portion of the well hurl debris within the we ll violently against the sidewalls and floor . A handful of 1 / 2 -inch by 3 / 4 -inch rocks {prot otype siz e , 6 inches by 9 inche s ) were placed in the well of the model, and the resulting abr asive action of the r ocks remov ed the paint from the floor near the well entranc e in 20 hours of model ope ration . Care must be taken, the refore , t o remove all foreign mate rial from the well afte r c onstruc ­tion and to prevent . othe r mate rial from ente ring .

The water turned upward at the downstre am well wall was directed bac k toward the cente r of the well by the de_flector (Figure 1 0A) to prevent it fr om rising dire ctly to the surfac e to cause exce ssive turbulence . The c ontrol exe rted on the wat e r by the defle ctor was found in the model t e sts t o be an important fe ature of the well de s ign, and e s s ential for good ope ration.. The height the preliminary defle ct or design was placed above the well floor was c ritical . A great e r height was required when the regulating gate w as operated at small openings than when it was op� rated at large openings . This c ondition was c orrected by revising the deflect or de sign . The radius on the low e r upstream portion of the defle ctor was changed from 8 feet to 1 6 feet and the dist ance between the upstream and the d ownstream fac e s was reduced from 5 feet 4 inches to 4 feet 9 inche s (prot otype) , (Figure 1 0 B) . In tests which were first made with no d e nt at e s in the defle ct or the wat e r was thrown violently upstream t oward the top of the well . Dentat e s were cut into the t op upstr e am edge of the ba.ffle to produce the r e c omme nded design . This defle ct or produce d good flow c onditions , and it was much le s s s ensitive to position than the pre liminary des ign . It ope rated effe ctively at all positions where the t op surface was between e levations 2 6 8 0 . 0 and 2 6 90 . 0 , a range of 1 0 fe et . Best results were obtained, howeve r, at e levation 2 6 8 2 . 7 5 , and thi s is the position rec ommended for the prototype structure . The strength of the currents diminished greatly as the water ros e· t oward the top of the well . Mode rate b oils oc-curred occ asionally at the wat e r s urface . The waves created by the s e b oils were dissipated within the riprapped portion of the c anal, and, no obj e ctionable e rosion of the c anal banks was indic ated .

Pre s s ure measureme nts were made at 2 5 stations on the lower parts of thre e walls and on the defle ctor t o det e rmine the pres sures acting on the s e surface s (Figure 1 1 ) . All the pressures we re positive, and the higher ones oc curred on the d ownstream wall where the flow from the c onduit impinges .

Stilling - well Exit int o the C anal

In the preliminary design the well exit c onsist ed of openings 7 feet high by about 6 feet wide in the · three downstream walls (Figure 1 2A) . The bott oms o f the openings were at elevation 2 7 0 0 . 0 0 and were formed by sills 3 feet wide . The t ops of the openings (elevation 2 70 7 . 0 0) were formed by the underside of a walkway which pass e d ar ound

7

/ .

the downstream portion of the well and was supported by tw o 8 -inch-thick pie r s at the intersec tions of the three downstre am walls . The top of the well was at elevation 27 0 8 . 00 while the invert of the c anal was level with the bottom of the well exit . The canal invert was 20 feet wide at the well, and the side s rose on a 1 - 1 / 2 : 1 slope .

The normal maximum c apacity of the c anal is 3 0 0 c ubic feet per s ec ond, and the c anal rate of discharge will b e restricted to this or ::.mailer flow s . However, discharge s up to 7 84 cubic feet per s ec ond may inadvertently be released through the structure . Model te st s were made to determine if these flows could be handled . The walkway over the stilling well exit was found to partial ly ob struct the flow and splash ­ing ove rtopped the well at discharge s exc eeding 7 0 0 cfs . The walkway and two pier s were removed and the top of the well was raised 1 foot to e levation 27 0 9 . 00 . The canal invert was lower ed 1 foot b elow the well o utlet to elevation 2 6 9 9 . 00, thus providing a step to prevent riprap or other foreign material from being c arried back into the well . The r ec ommended design of the stilling well exit is shown on Figures 2 and 1 2B . F low c onditions within the well and through the exit into the canal a re shown at gate settings of 25, 50 , 7 5 , and 1 0 0 perc ent open in F igur e s 1 3A, B, C , and D, r e spectively. The discharge with the gate 2 5 percent open represented 1 80 cubic feet per second at the m.aocimum r e s ervoir elevation, 27 8 5 . 00 feet while the flow was limited to 300 cfs at the 5 0 , 7 5 , and 1 0 0 perc ent gate openings by adjusting the total head at the gate . The heads we r e 8 6 . 0 , 5 L O and 3 9 . 6 feet, respec tively .

Scour in the Irrigation C anal

The water leaving the stilling well flows across the exit sill and de sc end s 1 foot to the invert of the irrigation c anal at elevation 2 6 9 9 . 0 0 . This drop, together with the mild turbulenc e and the attend ­ant surface waves of the oc casional boils in the well, might cause erosion in the unlined c anal near the well . To protect the c anal the de signer s specified 24 -inch dumped riprap for a distanc e of 20 feet downstream from the well, and gravel corresponding to the prototype riprap size was plac ed in the model for an equivalent distanc e . The remainder of the c anal wa s formed in c ompacted sand to represent the earth material (F igure 1 4A ) .

Water was pas sed through the model at a gate setting of 2 5 p ercent open and at a head equivalent t o the maximum reservoir eleva ­tion ( 1 1 0 . 3 feet at the valve) to produc e an e quivalent flow of 1 8 0 cfs . The model was also operated at 5 0, 7 5 , and 1 00 perc ent gate openings and at reduc ed heads to repre sent a flow of 300 cfs (Figure s 1 3A, B, C , and D ) . After each of the above flow conditions was established, it was maintained for 3 0 minute s ; then the flow was stopped, and the model was draine d . Contours were determined at 2 -foot (prototype) intervals, laid out with white c otton string, and ea,.ch c ontour line was marked with the c ontour elevation . Photographic rec ords were taken and the c anal was re shaped to the original contour s in preparation for the next test (F igure 14A ) . The scour i n the canal for a 25 percent

8

gate opening and a discharge representing 1 8 0 cfs is shown in Figure 1 4B, while the sc ours at 5 0 percent and 1 00 percent gate openings at a flow of 3 00 cfs are shown in Figures 1 4C and D . Almost no movement of the c anal bed occurred in the riprapped area and only a moderate amount occurred in the sand bed downstream . The maximum sc our took place at the 50 percent gate opening, but even this was negligible . A final test was made at the maximum possible flow in the prototype of 784 cfs ( 2 . 6 t imes the de sign flow) without excessive scour . Therefore, it is expected that the prototype canal will operate without obj ectionable scour at any p oint near the stilling well . As a final precaution, the designers elected to extend the riprap 45 feet further downstream therepy providing a total r iprap length of about 6 5 feet (Figure 2 ) .

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DEPARTMENT OF THE INTERIOR

BUREAU OF RECLA MA TfON

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MISSOURI RIVER BASIN PROJECT

FRENCHMA.N-CAMBRIDQE DIVISION - NEBRASKA

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N O TES

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UNITED STA T E S DEPA R TM E N T O F T H E I N TERIOR

B UR E A U OF RECL A M A TION MISSOURI RIVER BASIN PR OJECT

FRENCHMA N - CA M BRIDGE DIVISION - NEBR.

TREN TON DA M

CANAL O U TLET WORKS PLAN AND SECTIONS

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6" CONTROL VALV E -,, I I I

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2'0" LONG F LOW STRA I G H T E N E R PLACED DOWNSTREAM F RO M VA LV E •,

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S EC T I O N O N C E N T E R L I N E

T R E N T O N DA M C A N A L O U T L E T WOR K S

I : 1 2 SCA LE MODEL

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No dis.charge

Trenton Dam Canal Outlet Works

Regulating Gate, Conduit, and Stilling Well

1 : 1 2 Scale Model .

Figure 4 Report Hyd 300

W E DG E - SHA P ED 18 19 20 21 22 I I t I I

- ·- 0 - 0 - · -0 --0 - - - 0 ·.;r- � .,,,.

F I G U R E 5 R E P O R T H Y O . 300

FLOW DEFLECTORS,,,_ L.r.====:l====;-;� I I I I I

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E L E V A T I O N

T R E N T O N D A M C A N A L O U T L E T W O R K S

S C H E M A T I C V I EW S OF TH E 4 1- 0" X 4 ' - o" M O D I F I E D S L I D E G A T E AND TH E P I E ZO M E T E R S IN TH E CO N D U I T

1 : 1 2 SCA L E M O D E L

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SEC TION C - C SECTION B - B

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SHOP NOTE

With Screws !!±. and Bronze Seats 2, .§. ,2. • !Q and .11 in place, lock Screws with 4 centerpunch scores in head. After this Assembly make Final Machininq on Slidinq Faces of Bronze Seats , which must be in a True Plane .

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DEPARTMENT OF THE INTERIOR � -B UREAU OF RECLAMATION

,tlllV (i) DENVER OFFICE STANDA RD DESIGN -t C 4'x4' HIGH PRESSURE GATE

::X: ::0 ASSEMB/..ED SECTIONS � "" SHEET 2 OF 8 I ' i

� c>- J-_ �o;;:BE:R /92� .J: cln �· m . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . c:f . . . . . � . COMMISSIONER CHIEII=' ENGINEEeFI 0 ACCESSION No.22030 DRAWING No.100-0-2030 0

REV. JAN. /930 - D£C. 1936 11. B NOV. /'9i.2 1//,y7

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A. L O C A T I ON OF P I E Z O M E T E R S O N T H E B O T T O M O F T H E L E A F

GATE OPENING 100 % 9 9 % 95 % 90 % 85 % 80 % 75 % 60 % 20% 1 0 %

DISCHARGE c.f.s 7 54 740 685 6 2 6 5 5 4 490 4 3 6 3 1 3 1 0 6 64

RE F. PI E Z . 35 . 40 36 . 72 4 1 .40 46 .20 5 1 . 00 5 5. 3 2 58. 44 63 .96 69. 1 2 69 . 72

P I E Z. I 4. 80 4.80 1 1 . 76 1 3 . 9 2 1 8 . 7 2 2 2 . 68 24. 96 2 7. 72 42 .00 4 2 .00

2 ' - 0.60 - 1 . 9 2 1 2 .00 15 . 9 6 20. 04 22 . 8 0 25.08 27.60 4 1 . 5 2 4 1 . 64

3 - 0.96 - 2 .40 1 2 . 1 2 1 5. 2 4 1 9. 80 2 2 . 9 2 25.08 2 7. 72 4 1 . 52 4 1 . 64

4 6 .96 5 . 5 2 1 1 . 88 1 3. 80 1 8. 6 0 2 2 . 6 8 2 5. 0 8 2 7. 84 4 1 . 1 6 4 1 . 1 6

5 4. 44 2 . 4 0 1 2 . 36 1 4 . 6 4 1 8 . 4 8 2 1 . 8 4 24 . 96 28 .32 4 1 . 5 2 4 1 . 64

6 7. 3 2 6. 4 8 1 1 . 64 1 5 . 60 20. 1 6 2 2 . 80 24 . 96 27 . 24 4 1 . 40 4 1 . 5 2

7 7. 08 5. 7 6 1 1 . 52 1 4 . 1 6 1 8 . 3 6 2 1 . 7 2 24 . 84 2 7. 72 4 1 . 7 6 4 1 . 76

8 1 3 . 56 1 2 . 7 2 1 1 . 64 1 4 4 0 1 8 . 1 2 2 1 . 0 0 24 .00 2 7 .6 0 4 1 . 2 8 4 1 . 28

9 1 3 . 3 2 1 2 . 6 0 1 1 . 1 6 1 3 . 5 6 1 8 . 1 2 2 1 . 60 24 . 60 2 7 .4 8 4 1 . 5 2 4 1 .76

B. P R E S S U R E S O N T H E BOT T O M O F T H E L E A F

N O T E S

I . Discharge capa c ity i s 300 cfs . 2. D i scharges a nd pressures g i ven as p roto type va l u e s . 3. A l l data w e re token o t on equ i va l en t total head at the

gate entran c e at 70 feet.

T R E N T O N D A M C A N A L OU T L E T WO R K S

P R E S S U R E S ON TH E B O T TOM OF T H E G ATE L EAF

DATA F R O M 1 : 1 2 SCA L E M O D E L

F I G U R E 7 R E PO R T H Y O . 300

44

40 a: UJ

I- 36 ; � 32

.., IL 28

I ui 24 a: ::, <ll 20 UJ f 16

UJ

� 12 ... e s 0 ll: 4

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0

0 0

0 2 4 6 8

44

a: 4 0 UJ

!;i 36 ;i:

� 32 1--' "- 28

' �24 ::, ::l 20 UJ a: ll. 16 UJ

� 12 ... e s 0 [ 4

0

44

a: 40 UJ

!;i 36 ;i:

l!, 32 .., "- 2 8

I

�24 ::, ::: 2 0 UJ a: "- 16

� 12 ... e a 0 a: "- 4

D I STANCE FROM GATE STE M t I N FEET

1 00 % G A TE OPENING

D

.. 125

8 0

- , _ 0

D I ST A N C E FROM GATE STEM t I N FEET

85 °/o GA TE OPENIN G

e a � ) - - . "

o 2 4 6 e D I S T A N C E F RO M GATE STE M �

IN FEET 40 •/0 GA TE OPENIN G

44

40 a:

!;i 36 ;i:

� 32

.., "- 28 '

� 24 :, : 20 UJ f 16 UJ � 12 ... 0 ... 8 0 a: Q. 4

I

M 0

M

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0

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o 2 4 G e

44

a: 40

l!! <( 36 ;i:

l!, 32 .., "- 29 I

� 24 ::, � 20 UJ a: <>. 1 6 UJ � I l­o ... 0 a:

2

8

Q. 4

D I STA N C E FROM GATE STEM t I N F E E T

95 % GA TE OPENING

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Q

0

-

0 2 4 6 8

44

40 a:

� 36

� 32

.., "- 2 8

�24 :, :20 UJ � 16 UJ

� 12 ... 0 8 b [ 4

D ISTANCE FROM GATE STE M � I N FEET

80 % GA TE OPENIN G

ii IJ I l!I I 0 0

0 2 4 6 • DISTANCE FROM GATE STE M t

IN FEET 20 •,-. GATE OPENIN G

T R E N T O N D A M CA NA L O U TL E T W O R K S

44

a: 40 UJ

!;; 36 ;i: l!, 32 .., "- 28

I UJ 24 a: ::, � 20 UJ [ 16 UJ � 12 ... � 8 0 g:: 4

I D

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0

D .. 8

0

0

0

F I G U R E 8 REPORT HYO. 30D

o 2 4 6 e

44

UJ a: 24 :, "' U> 20 UJ a: "- 16 UJ Q. >- 12 l­o ... 8 0 a: Q. 4

DI STANCE FROM GATE STE M It. I N FEET

90 % GA TE OPENIN G

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0 2 4 6 8

44

a:40 UJ ... ;36

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�24 ::, � 20 UJ a: "- 16 l/J � 12 l-,-. e 0 a: Q. 4

D ISTANCE FROM GATE STEM t IN F E ET

60 % GA TE OPENIN G

r"'1-'-I I! Ii! Ii s 0

o 2 4 6 e D I STA N C E FROM GATE STEM t

I N FEET

I O '¼ G A TE OPENING

PRESSURES IN THE CONDUIT DOWNSTREAM FROM THE REGULATING GATE All data ,,.,. tak•n at an •quival•nt total head at the gate ontranc• of 10 ,.,,.

o Top o f conduit on £, piezo,.,,eters 1 - 7 inclusive. c Side of conduit 6"abo'tl floor, piezameters s-12 inclusive. a. Bottom of conduit on £, piezometers 13 -17 inclusive.

Data from I: 12 scale model.

0

1 10

100

90 ... ... >-I-0 I-

i ao

I a: ... I-

; 70 ... 0 I-... ... IL 60 !, ... I-

tu 50 :c I-

I-4 0 � 40 :c ..J 4 I-

I:! 30

20

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' .._ V : o/ Ava i lable total -..,t_ V head at gate

I I I V /v V ,,, V with max. res. / / El . 2 785.00

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'.llvoi loble tota l head at gate w ith normal res. El. 2752 . 00

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0 o 100

CD I

'I' 200 300 400 500 600 700

DISCH A R G E I N CU B I C F E E T P E R S E C O N D - P R O T O T Y P E

T R E N T O N D A M C A N A L O U T L E T W O R K S

DIS CHARG E CU R V E S D A TA F R O M 1 : 1 2 S C A L E M O DE L

800

F I G U R E 9 REP O R T H Y O. 300

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P L A N

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E L EVAT I O N A . PRELI M I NARY DESIGN

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F I G U R E 10 REPORT HYO. 300

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E LEVATION

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B. R ECO M M E N D E D D E S I G N

T R E N TO N D A M CA N A L OUT L E T WO R K S

ST I LL ING · W ELL BAF F L E DES IGNS

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P L A N

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F R O N T V I E W D E F L E C T O R

CO N T R O L G A T E A N D S T I L L I N G W E LL

Ii. 4' - o" x 4'-o" MOD I F I E D H . P. S L I D E GAT E STA. 7 + 38.04 - - - - - - --- .

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S T I L L I N G W E L L W A L L PRESSU R E S GAG E Z E R O AT E L E V A T I O N OF W ELL FLOOR

PR ESSU R E I N FEET OF WATER

A. ST I L L I N G WELL STA . 7 + 54.58

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, _ _ . - DE FLECTOR. ti- -�1,i- -:; . . / -'-- - ----.-

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E L E V A T I O N

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- -o' 15 \ I I

o - - - l - o-l-o- o - -�-7 8 9 10 11 12 I

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PI E Z O M E TER NUM B E R S

I . 2. 3. 4. 5. 6 7 8 9 10 I I .

12 13 14 15 16. 17 18 19. 20 2 1 22. 23 24. 25

T R E N T O N D A M

25 % G A T E OPE N I N G

O = 1 70 c f s 38.6 4 3 7 68 37.20 38 76 38 28 37.92 38 .04 37. 56 38. 1 6 37.80 37. 56 44 52 37.80 3792 40.92 38.40 38.40 38.40 38 .52 46 32 4 1 .40 4 1 .76 42.60 36.60 37 80

C A N A L O U T L E T W O R K S P R E S S U R ES ON S T I L L I N G W E L L W A L L S

DATA F R O M 1 : 12 S C A L E MODE L

50 ¾ G A T E 75 % G A T E 100% G A T E 100% GATE OPE N I NG OP E N I N G OPE N I N G OPE N I N G

O = 3OO c f s Q : 300 c.f .s . 0 = 300 c .f. s 0 = 700 c.f .s . 39.84 39.60 38.40 38.40 38.04 38.40 39. 1 2 43.20 37 20 38 40 4008 49 44 39. 96 39. 36 38.52 38.40 39 1 2 39.00 38 76 38.88 38 88 39.48 38.88 4 1 . 1 6 39.00 39.60 39. 12 42.60 38.04 38.52 39.36 43.80 39.24 39.24 39.24 42.96 38.40 39.00 39. 1 2 42.48 3708 39.00 39. 24 44.64 49.20 4 3.92 4 1 ,04 54.60 38.28 38 64 38 88 40.80 38.40 38 52 39 00 4 1 .64 43.56 4 1 .64 39 48 44. 28 39. 1 2 39.00 39 00 4 1 .88 38.88 38.76 38 76 4 1 .28 39.00 38.88 38.88 40.80 39 00 38.88 38.64 3888 5 1 .00 44.04 40.80 53.40 44.04 4 1 .40 38 76 42.60 44.40 40. 56 40.44 5 1 00 48.00 42.84 39.60 33.60 36.60 3744 37 56 36.00 38.40 38.64 38 40 38.40

"' "" "11 -o _ O G'l :! c :r :0 -< rr, 0 "' = 0 0

ELEVAT ION 270 7.00--.

// E L E VAT I O N 2 7 0 8 .00

A . P R E L I M I N A R Y D E S I G N

ELE VAT I O N 2700.0 ,

, I

/ -ELE VAT ION 2709 .0

B. R ECO M M E N D E D D E S I G N

T R E N TO N D A M C A N A L OU T L E T W O R K S

ST I L l,. I N G W E L L E X I T I N TO C A N A L

F I G U R E 12 R E P O R T H Y O 3 0 0

•

•

A . Gate 25% Open. Q = 1 8 0 cfs . Head at gate = 1 1 0 . 3 feet (Max . reservoir elevation)

C . Gate 75% Open. Q = 300 cfs .

Figure 1 3 Report Hyd 300

B. Gate 50o/o .Open : . Q = 300 cfs . Head at gate = 8 6 . 0 feet

D . Gate 1 0 0% Open . Q = 300 cfs . Head at gate = 51 . O feet Trenton Dam

Canal Outlet Works .

Head at gate = 3 9 . 6 feet .

Flow conditions in the well and through the well exit into the canal

1 : 1 2 Scale Model.

'

A. Canal previous to each scour test .

C . Scour after 3 0 minutes operation at 50% gate opening. Q = 300 cfs . Head at gate, 86 . 0 feet

Trenton Dam

Figure 14 Report Hyd 300

B. Scour after 30 minutes operation at 25% gate opening. Q = 180 cfs . Head at gate = 1 1 0 . 3 feet (Max. reservoir elevation)

D . Scour after 30 minutes operation at 1 00% gate opening . Q = 300 cfs . Head at gate , 3 9 . 6 feet

Canal Outlet Works Scour in the Canal Entrance

1 : 1 2 Scale Model.

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