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UNITEU STATES DEPARTMENT OF THE INTERIOR
BUREAU OF RECLAMATION
Of-:::. f I cE
f !II[' cnny ~ tf ' (· J I · bs r~ H .; BUREP..U G? Rt:;C LAMAT I ON HY DH !.UL j C LABORATOBY
HYDRAULIC MODEL STUDIES o ·F THE
SOLDIER CANYON DAM OUTLET WORKS
COLORADO-BIG THOMPSON PROJECT
Hydrauli c Laboratory Report No . Hyd . 3 34
ENGINEERING LABORATORIES BRANCH
DESIGN AND CONSTRUCTION DIVISION DENVER, COLORADO
Feb r uary 12 , 1953
FORE!WORD
Hydraulic model studies of the outlet works for the Soldier Canyon Dam, Colorado-Big Thompson Project were conducted in the Hydraulic Laboratory of the Bureau of Reclamation at Denver, Colorado, during the period October· 19-46 to August 1949.
The final plans, evolved from these studies, were developed through the cooperation of the staffs of the Outlet Wor:ks Section of the Dams Division, and the Hydraulic Laboratory.
During the course of the model studies, Messrs. H. W. Tabor, I. B. Kirkwood, and R. W. Winnerah, of the Outlet Works Section frequently visited the laboratory to observe the model studies and to discuss the test results.
These studies were conducted by W. E. Wagner, L. R. Thompson, R. H. Slykehouse and T. J. Rhone under the supervision of Messrs. J. N. Bradley and A. J. Peterka of the Hydraulic Laboratory staff.
Reference is also made to the paper "Progress in New Designs for Outlet Works Stilling Basins" by A. J. Peterka and H. W. Tabor which was presented at the Fourth International Congress on Large Dams at New Delhi, India, in February 1951.
Excerpts from Field Trip Report No. 1191, a report on field tests performed on the prototype outlet works by B. R. Blackwell in September 1951, are included as an appendix to this report.
TABLE QF CQNTENTS.
Summary •• Introduction The ~odels.
. . • • • • • • • • • • . . . . . . . . . .. . . . ..•
The 1 :4. 67 model The 1 :6 model • • .. • • •
• . . . •, . . .. . •. . .. . . . . . . . ~ . .. • • • • • • • • . . . .. . . . .
The Investigatio~ . . . . . . . . . . . . . . . . . . . 1 :4. 67 Model., Hollow-jet Valve ·stilling Basin Studies • . ~--
Preliminary basin • Basin No. 2 ••• Basin ~o. 3 Basin No. 4
• • •
•
• ,;
• . .. • • • • 0
. . • . . . 0 • ... • • 0 • . . . . • . . . • • . . • • ... . . • • • •
Hood Studies . . . ' • :9! •• • • • • • • • • • • • • • •
• Deflectors • • Discharge guide .•
·~.
• • ·- . . . . . .. . . . . • •
... • • . . . . . . . ,;
. •· . .
. . . . 14~Inch Butterfly ¥alve • • • • • • • • • • • • • • • •
Preliminary studies .• . . .. . . . . . . . . . . . . . Basin No. 5 Recommended basin •
• • . . .•. . . . . . . . . . . . . . . . . .• . . . . . . . . . . . . Hood Studies . - . . .• .. . . ,. .. . . . . . . . .• . . .. . ...
. .... ·:• De.flectors • • • Disc~arge guides _. • II
. -· • • • . . • • • . ' . • •
....
. . • • • •
. . • • . .. 1:6 Model--Commercial Pivot Valve . . . . . . . ~ . ..
Introduction
Hood Studies
. . . . . • • • • • • • • • • • • • •
. . . . . .. . . . . . . . . •. . . Preliminary hoods Recommended hood
. . . . . . . . . .. . . . . . . . . . • • • • • • • • • • • • • • • • •
Stilling basin appearance Wave heights • • • • • Pressure measurements •
• • • •
• • • • . . • • • •
Valve Studies • • • • • . . . . . . . . Discharge characteristics Pressures • • • • • • •
• •
•
i
• •
• •
• • •
• • •
• • • . . .. . .... . . . . • • . . • • • •
• • • • • • • • • •
• • • •
. . . .
. . • •
3 3
5
5
5 5 6 7
7
7 8
9 9
10
10
10 11
12
12
13
13 15
15 15 16
17
17 17
LIST OF FIGURES
Figure
1 Location Map • • • • • • • • • ·• ·• • ·• • • • • • • • • • General Map of Reservoir Area • • • · ·• • • • • • • • • • 2 · . Preliminary Stilling Basin 1:4. 6'1 Scale Model • • • • • • • 3 Recommended Stilling Basin • • • • • • • • • • • • • • • 4 Preliminary Basin • • • • • • • • • • • • • • • • • • • 5 Preliminary Basin • • • • • • • • • • • • • • • • • • • 6 Stilling Basin Outlines • • • • • • • • • • • • • • • • • • 7 Stilling Basin No. 2 • • • • • • • • • • ·• • • ·• • • • • • 8 Stilling Basin No... 3 • • • • • • • • . • • • • • • • • • • • 9 14-Inch ButterflyV~ve · ~ • • • • • .;, • • • • • • • • • • 10 Flow Patterns for Three Types of Control Valves • • • • • • 11 Flow Comparison in Stilling Basin with and without
Side Rails •. -• • • • • • • • • • • • • • • • • • • • • 12 Deflectors for 14-lnch Butterfly Valve • • • • • • • • • • • 13 Hood for Butterfly Valve • • • • • • • • • • ·• • · • • • • • 14 1 :6 Scale Model, Recommended Stilling Qasin • • • • • • • 15 18-Inch Commercial Pivo~ Valve 1:6 Sc~e r,,fodel • • • • • 16 Model Pivot Valve and Hoods • • • • • • • • • • • • • • • 17 Operation of 18-Inch Commercial Pivot Valve without
Hood • • • . • • • • • ·· • • • • • • • • • •• ,.._ • • • • 18 Operation of 18-Inch Commercial Pivot Valve without
Hood • • • • • • • • • • • • • • • • • • • • • • • • 19 Operation of 18-Inch Commercial Pivot Valve with
Hood as Designed for Butterfly Valve • • • • • • • • • • 20 Operation of 18-Inch Commercial Pivot Valve with
Hood as Designed for Butterfly Valve · • • • ·• • • • • • • 21 Preliminary Hood for 18-Inch Pivot Valve • • • • • • • • • 22 Recommended Hood for Pivot Valve Showilu{ Piezometer
Locations • • • • • • • • • • • • • • • • • • • • • • 23 Hood for Pivot Valve Showing· Prototype Piezom.eter
Locations • • • • • • ·• • • • • • • • • • • • • • • • 24 Operation of Recommended Stilling Basin ;µid Hood • • • • • 25 Operation of Recommended ~tilling Basin· and Hood • · • • • · • 26 Operation of Recommended Stilling Basin with Side Bails
RemOY'ed • ··• • • • • • • • • • • • • • ·-. • ·-. • • • • • 27 Operation of Recommended Stilling Basin and Hood • • • • • 28 Pressures in Recommended Hood •••••••• ·• • • • • 29 Coeff~cient of Discharge Curve • • • • • • • • • • • • • • 30 Disc1*arge Curve for Commercial ·Pivot Valve • • • • • • • 31
APPE~DIX
Excerpt from Field Trip Report N:o. 1191
ii
UNITED STATES DEPARTMENT.OF THE INTERIOR
BUREAU OF RECLAMATION
Design and Construction Division Engineering Laboratories Branch
,Laboratory Report No. Hyd-334 Hydraulic Laboratory Section Compiled by: T. J. Rhone Denve.r, C9lorado ·
February 12, 1953 . Reviewed and checked by: A. J. Peterka
Subject: Jlydraulic Model Studies of the Soldier Canyon Dam Outlet Works, _Colorado-Big Thompson Project
.SUMMARY
· The hydraulic model s~udies discussed in this report were made to determine the operating characteristics of the Soldier .Canyon ·Dam Outlet Works and to develop a stilling basin ~t performed satisfactorily for a particular type of valve control. The stilling basin to be satisfactory not only pad to _p.rpvide effective en~rgy dissipation but also negligible wave _action in the unlined c~al section.
The results and recommendations contained herein were deter- · mined from studies, on 1:4: 67 anq 1:6 scale models of the control valve, stilling basin, and a section of the downstream canal. Tests were made using. hollow-jet; butterfly, and pivot valves for the outlet works control on basins using the hydraulic jump and dispersion devices foi- energy dissipation.
_ The preliminary design used a hollow-jet valve discharging horizontally ont.o a curved trajectory floor leading to a long, narrow stilling basin and utilizing the hydraulic jump as an energy dissipator. The tests made on the jump basin showed that a long trajectory was necessary to spread the jet from the valve and that even then there were large boils and surges in the stilling· basin that carried down into the canal section, causing high velocity, surface now and damaging wave action, Figure 5B. When the valve w~ depressed a small amount, the basin was still unsatisfactory, Figures 5 and 6. A longer stilling basin might have -quieted the water surface sufficiently to make the performance satisfactory, but since almost one-half of the length of this basin consisted of the trajectory curve, it was felt that better use of the basin length could be realized by using some other method of energy dissipation.
The trajectory floor was then removed and tests were made with the valve depressed at various angles up to 45°. The tests showed . that the high velo·city jet from ~e valve did not penetrate into the pool sufficiently to produce sati~factory energy dissipation.
At ·this point in the studies a lower cost butter.fly valve was substituted for the hollow-jet valve. The studie~ were continued using the basin that had been developed ·fo'I' the hollow-jet valve.
. The jet leaving the butterfly valve was· dispersed in such a wide variety of patterns for different heads and degree of openings that it became necessary- tQ use a hood to insure a uniform flow pattern entering the stilling basin at all discharges .. Accordingly; the basin was developed for ·use with a hood or discharge guide on the valve. A basin that operated, saiisfactorily with the butterfly valve and discharge guide was developed··and submitted to the designers so 'that the prototype basin could be constructed, ·Figure 4.
Several months after the prototype stilling basin had been constructed, increased discharge requirements made it necessary to use a larger valve, and an 18-inch commercial pivot valve was specified for the outlet ·works control. -Since this valve ha~. operating characteristics similar to the butterfly valve, minor modifications permitted the use of the·· same type of hood. ·
The stilling basin V\faS ·rebuilt to_a scale of 1:6, Figure 15, and the modified hood tested and developed, Figure 23. Operating tests · showed that the stilling basin was adequate arid that the energy dissipation was sufficient to provide a smooth water surface in the canal section, Figures· 25 and 26. · Piezometers placed in critical areas on the hood, . Figure 29_. indicated that the pressures were above atmospheric and that there was no danger from either cavitation or from excessively
. high pressures ..
· Calibration of the model ·valve -CQnfirmed that the. required dis-charges could be attained at the _ll!,Vai~ble heads, Figures 30 and 31. Piezometers placed in the invert of'the valve in~cated·that the pressures in that ar·ea·were also safe, Figure 16. However, no attempt was made to prove or disprove that the entt.re valve was safe from cavitation~ ·
In September 1951 tests on a limited scale were perfomed on the prototype of the Soldier Canyon Dam Outlet Works. The results of· these tests were reported- in Field Trip Report No. 1191. The essential parts of this .report ate included as .an Appendix to this report.
- The prototype tests showed that the model and prototype stilling basin performances are similar and that the pressures in the hood and wave hE!ights in t~e canal compare favorably.
Two pr~totype calibration points obtained for the pivot valve indicated that the prototype coefficient of discharge is lower than that obtained from the model valve. This discrepancy cannot be explained at the present time.
2
INTRODUCTION
Soldier Canyon Dam is one of four earth-fill dams impounding water in Horsetooth Reservoir, approximately 10 miles west of Fort- Colli11s, Colorado, Figures 1 and 2. Soldier Canyon Dam is ap-proximately 1, 400 feet long with crest elevation 5440 feet, and rises 150 feet above the original ground surface. The maximum water surface of the reservoir is elevation 5430.
The principal hydraulic feature of Soldier Canyon Dam is the outlet works which consist of the outlet conduit, the stilling basin, and the 18-inch pivot valve for releasing the water through a supply canal for irrigation purposes.
Water from the reservoir flows through a 5-foot-diameter circular concrete conduit, 550 feet in length, to the gate chamber which encloses a 24-inch wedge ·gate valve. From the gate chamber the water passes through a 30-inch circular steel conduit, 722 feet in length, to the pivot valve _and thence to the stilling basin.
The hydraulic m 1odel tests discussed in this report were confined to studies of the entry of the jet from the valve into the stilling basin, the stilling basin performance, and the flow into the canal.
As originally designed, the outlet works control and regulation was accomplished with a 14-inch hollow-jet valve. During the course of the stilling basin studies, an economic analysis by the designers brought forth that considerable savings could be realized by the use of a 14-inch butterfly valve. Accordingly, the laboratory was requested_ to develop a stilling basin that would be satisfactory for this type of valve. Still later developments increased the maximum discharge from.60 to 100 second feet, and since the 14-inch butterfly valve could not pass this quantity at the available head, it was necessary to use a larger valve. An 18-inch pivot valve was found to be available and was specified for use. Before the type of control valve to be used was definitely decided, the prototype construction schedules made it necessary for the designers to issue drawings of the stilling basin outline to the contractor. The stilling basin developed for the 14-inch butterfly valve was recommended for construction since its performance was satisfactory, and it was believed that it could be made satisfactory if another type valve were used. Tests from this point on, therefore, used the recommended basin outline and changes were confined to the valve hood ..
THE MODELS
The 1 :4. 67 model. A 3-inch hollow-jet valve and sections of 3-inch pipe were both available in the laboratory. Therefore, a scale ratio of 1 :4. 67 was selected for the model studies. This model of the outlet works consisted of a straight section of 3-inch steel pipe~ the
3
3-inch hollow-jet valve representing the 14-inch prototype valve~ the stilling basin, and a section of the· canal. Figure 3 shows the model lay-out.· giying the actual model dimensions.
Water was supplied directly to the 3-inch pipe by a laboratory pump through a Venturi orifice meter for accurate.measurement of discharge. On·e diameter upstream from the valve a piezometer was installed to measure the head on the valve.
The connectio·n between the straight pipe and the valve was constructed so that wedge-shaped shims could be installed to depress the valve from the horizontal to 10° in increments of 2-1/2°
The hollow-jet valve was accurately machined from brass stock and constructed so that it could be opened and closed in a manner similar to the prototype valve.
The trajectqry apron under the valve and the transition leading to the canal section were of concrete screeded to sheet metal tem:.. plates. The stil~ing basin and canal section were constructed of wood lined with galvanized sheet :JD.etal. The canal section was molded in pea gravel about 3 inches thick. as shown in Figure 3.
The tailwater elevation was measured by a staff gage in the canal section and controlled by a tail gate installed at the lower end of the canal section. The tailwater elevations for the discharges used in this study are shown in Figure 29.
The 1 :6 model. The stilling basin outline had been submitted for field construction and the 1:4. 67 model dismantled when the laboratory was informed that an 18-inch pivot valve had been specified to meet increased discharge requirem·ents. As a result of this informa-
. tion. the stilling basin model was rebuilt for further study and a scale · of 1 :6 selected so that a 3-inch model pivot valve could be used.
The second model was constructed similar to the 1:4. 67 model with the exceptions that the trajectory floor under the valve was of wood covered with sheet metal and one side of the basin was made of glass panels, Figure 15.
The valve was constructed with a transparent plastic barrel with machined-brass leaf and operating mechanism. from drawings furnished by the valve manufacturer. Figure 16. The hood or discharge guide was constructed of galvanized sheet metal and was part of the lab-oratory development. Piezometers connected to open-tube glass manom-eters were placed in both the valve and discharge guide, Figures 16 and 23.
4
THE INVESTIGATION
1 :4. 67 fy.fodel, Hollow-jet Valve Stilling Basin Studies
For all studies ~ad~ to develop a stilling basin for use with the hollow-jet valve, ·a maximum discharge of 60 second feet at reser-voir elevation of 5430 was used, resulting in a head of approximately 200 feet at the valve which was the maximum expected head. This combination of head and discharge provided the severest operatipg condition. The tailwater elevation at this discharge was 5225. O. /
For each stilling basin the model was operated at the above discharge; then on a basis of visual observations confirmed by photographs,· measurement of the magnitude of the surges and waves, and from the movement o1 the rip rap in the canal section, the effectiveness of the basin, and the probable changes needed to improve the basin ·were determin·ed.
Preliminary basin. The control valve for the preliminary design was a 14-mch hollow-jet valve that could be depressed from the horizontal to 10° in 1 increments of 2-1/2°. The _stilling basin was 111 feet long and 6 feet wide, with a depth of 13. 5 feet. Under the valve was a parabolic trajectory floor 60 feet long, Figure 7. Figure 3 shows the preliminary basin with model dimensions.
- The model was operated for this design with the valve in a horizontal position and depressed 2-1/2°, 5°, 7-1/2°, and 10°. In each of the valve positions, the flow spread uniformly on the trajectory, but the hydraulic jump formed on. the lower part of the trajectory apron: There were excessive disturbances in the form of large boils in the upstream portion of the jump, causing surges in the pool and movemep.t of the riprap in the canal section. In the downstream part of the stilling basin, all of the flow was in the upper 2 to 3 feet of the pool making the surface velocity excessively high, Figures 5 and 6.
It was apparent. that the basin in this form was not satisfactory, primarily because the jet from the valve did not penetrate sufficiently deep into the basin to obtain good energy dissipation.
Basin No. 2. For Basin No. 2 the preliminary basin was altered so that there was a deeper pool for energy dissipation and the valve was moved close to the water surface so that the jet could penetrate the pool. This was accomplished by lQwering the floor of the basin 2 feet and_ the center line of the valve 1. 4 feet Figure 7. The para-bolic tra~ectory under the valve was changed to a straight line slope of about 10 below horizontal. The O. 6-=-foot relative change in elevation of the valve and the basin floor combined with the changes in the trajectory floor increased the total length of the stilling basin by 2 feet. Other features of the stilling basin and the canal remained unclianged. The axis of the hollow-jet valve was depressed 10° from the horizontal, Figure 7.
5
. The appearance of the stilling action for 60 second feet was not improved with this basin. The outflow was still confined to the upper 2 to 3 feet of the pool and the surges were even more pronounced than for the previous basin, Figure: 8. The surges in the stilling pool caused waves of a choppy nature that e:xt~nded down into the canal section, and in a short period of time, moved the riprap on the banks of the. canal for several feet downs.treani.
· The trajector~ apron under the valve was removed, and with the'Valve depressed 10°, the jet was allowed to plunge into the pool. With 1¥.s arrangement the jet did not penetrate into the pool but skipped along the ~urface of the water with no energy dissipation. This high velocity of flow extended down into the canal section causing considerable damage to t~e rip rap banks.
. The valve was then depressed 30°. At this angle the jet plunged into the pool but the width and depth of the pool w.as not adequate to absorh the energy, with the result that the jet struck the floor of the basin and was ,deflected back to the pool surface causing large boils and surges with some of the flow near. the surface directed back toward the valve.
· The return flow interfering with the jet from the valve resulted in ari even greater amount of surging accompanied by large quantities of splashing aild spray that covered a considerable area around the model. The mist and spr,:y occurring with this operation was an additional undesirable feature that could not be tolerated in the prototype structure, indicating a definite need for improvement. However. it was noticed that in the extreme downstream end of the basin the flow had become nearly uniform, and the wave action in the canal was smoothe~ than for the previous tests; It was · concluded that this type of energy dissipation might perform satisfactorily with a wider and deeper stilling pool.
Basin No. 3. Since it was felt that a wider basin would dissipate more energy, the model was altered so that the sides of the basin diverged from a width of 6 feet at the valve, to a width of 12 feet iri a
· length of 37 feet. The basin was 12 feet wide for a length of 55 feet and then had a 20-foot transition leading· to the canal. The floor of the diverging section was sloped about 10° below horizontal. The valve was depressed 10° but the elevations of the valve and the basin floor were the same as in Basin. No. 2, Figure 7.
The model was operated with this design but the jet did not penetrate the pool. The flow skipped along the surface of the pool, creating cc;msiderable spray and disturbance, Figure 9. Since there was no improvement over Basin No~ 2 and since the jet from the valve did not penetrate the pool, the valve was depressed below 1 d0 •
The method of depressing the valve was made simpler by using a section of fle~ble rubber hose in place of the pipe upstream from the valve. With ·a tilt slightly greater than 10° the jet penetrated the pool to a greater depth and the· energy from the jet seemed to be better dissipated, but the trajectory floor was too flat and the valve could not be
6
depressed much below 10°. Therefore. the trajectory floor. was removed and the jet allowed to plunge directly into the pool. This arrangement resulted in better stilling action. but the elevation of the valve was too low and it became submerged at all flows.
The valve and connecting pipe were raised to eliminate this submergence. The model was then operated at a discharge ·of 60 second feet with the valve depressed at several different angles to determine the most satisfactory angle of depression. For 24° the jet dived under the water surface and resulted in the best stilling pool action observed so far. However. due to ·the entrained air and the concentration of the jet in a small area, large boils and unsymmetrical flow prevailed in the basin. Figure 9-C. The boils and unsymmetrical flow were confined to the upstream portion of the stilling basin and the flow had become more or less stable by the time it entered the canal section, although the surface velocity was still too great.
Basin No. 4. During the previous tests it was observed that most of the stilling action was confined to the upstream portion of the basin with very little use being made of tlie downstream half. Also1 the stilling action that did occur was not thorough arid the flow in the downstream part had a high surface velocity that carried over into•the canal section, causing damage to the riprap. Therefore. it was decided that with · a deeper pool a more complete dissipation of energy could occur
. and the length of the stilling basin could be shortened. On this basis1 for Basin No. 4, Basin No. 3 was made 4. 5 feet deeper and shortened by 18. 62 feet. Figure 7.
. The model was operated at 60 second feet with the valve de-pressed 24°. The stilling action was much improved, there was better distribution of the flow, but large surges and waves were still present
· indicating that the jet was not penetrating to the bottom of the pool. The waves extended down into the canal section and caused some movement of the riprap banks.
HOOD S·TUDIES
Deflectors. The best stilling action· obtained so far had been with the jet plunging directly into the pool. However. the energy dissipation had not been complete, indicating that there might not be sufficient penetration and spreading of the jet into the pool. It was thought that a device which protected the jet from the tailwater until the jet was close to the floor of the sti]).ing basin would provide the penetration necessary to distribute the flow evenly and to obtain a more thorough energy dissipation.
A flat sheet, the f~ll width of the diverging section of the basin. called a deflector, was placed over the valve and parallel with the angle of tilt of the valve. The deflector ext~nded to within 2 feet of the floor
7
of the pool. For a discharge of 60 second feet, the stilling action was greatly improved over the previous tests. However, the flow from under the deflector was not eve~y distributed and rose to the ·surface of the pool in surges that shifted from one side of the basin to the other. This action was reflected in waves that carried down into the canal section causing movement of the rip rap banks.
The deflector was then extended to within 13 inches of the stilling basin floor. ·The deflector then exerted more control ovE!r the jet from the valve, and consequently the dist.ribution of the flow emerging from under the deflector was more evenly distributed across the basin. The surges were dampened to the extent that the waves resulting from the surges caused only a slight movement of the riprap banks in the canal section. Wh~reas the improvement in the stilling action was noticeable, it was still 1not sufficient to give the best_ possible energy dissipation.
Discharge guide. Since there was a definite improvement with the use of a· deflector over the top of the valve, it seemed likely that better control of the jet could be obtained by using a device that would confine the jet entirely until it had penetrated to the floor of the basin.
The first device tried was an 8-inch-diameter pipe, representing a 37-inch-prototype pipe, placed so that Uie jet discharged directly into it and was carried to the bottom of the pool. It was apparent that this device was not adequate. At the 60-second·-foot discharge there were large boils and surges that shifted from one side of the basin to the other. producing unsymmetrical flow in the basin and damage to the riprap in the canal. At flows less than 60 second feet, the jet did not force the flow out of the lower end of the pipe. Consequently, the _water backed up in the pipe and flowed out of the upper end with considerable splashing.
The next devtce tried was a transition box 28 feet long., with the upstream opening 13 feet 10. 67 inches square and the downstream opening l foot 2 inches high by 6 feet 3 inches wide. The box was inclined the same as the valve and was placed directly in front of, but not touching, the valve. The performance of the basin with this type of guide was very p·oor. The concentrated jet was not distributed across the basin and therefore rose to the surface in a series of shifting surges with very little energy having been dissipated. When the height of the downstream opening of the chute was reduced to .7 inches., the stilling action was improved for the larger flows; however, for the lower flows, the water backed up in the guide and flowed out the upstream end.
14-INCH BUTTERFLY VALVE -
At this point in the study it was decided to use a 14-inch butterfly valve instead of the hollow-jet valve because of the economies which
8
could be realized, since a butterfly valve may be obtained commercially where the hollow-jet valve must be made to order.
Prelimina~ studies. During the initial studies the butterfly valve without a ood or gu_ide was used in conjunction with Stilling Basin No. 4.
The flow from the butterfly valve was entirely different than the flow from the hollow-jet valve. Where the flow from the hollow-j et valve was annular in shape at all heads and valve openings. Figure 11-A. the flow from the butterfly valve consisted of two jets whose pattern varied considerably with either a change in head or degree of opening. Figure 11-B. The two jets from the butterfly valve issued from the upper and lower part of the valve and were separated by the leaf. Figure 10. When the leaf was closed in a counter-clockwise manner. Figure lp-A, the upper jet formed a large fin that arched high above the basin and extended far down into the canal section. When the valve w~s turned s<:> that the leaf closed in a clockwise manner. Figure 10-B, the large fin was directed into the stilling pool and the part of the jet that now was on top fell well within the stilling basin. However. in neither position 'Was the,re appreciable stilling action or dissipation of the jet energy .. The jet struck the surface of the pool and skipped along the surface creating a high surface velocity in the canal section accompanied by large waves that destroyed the rip rap banks.
The valve was then depressed 30° and allowed to plunge direc-. tly into the pool; The jet was now confined in the stilling basin, but there was not enough penetration into the pool due to the wide divergence of the jet. and consequently all of the flow was along the surface.
Basin No. 5. All of the previous tests showed that a deep basin cannot be fully utilized if the jet does not penetrate the water. Since in the last test the jet had not penetrated to the bottom of the pool, two possible solutions were proposed; eith~r a device to carry the jet to the bottom of the basin could be developed or the floor of the basin raised so that the ordinary penetration of the jet without a protecting device would reach the floor.
The latter solution was the most economical so it was tried first. The floor of Stilling Basin No. 4 was raised to elevation 5215. 5 by placing a wooden false floor 4. 5 feet above the existing floor.
When the model was operated the extreme dispersion of the jet at small openings prevented appreciable penetration into the pool. and at the larger openings the depth was not adequate for energy dissipation. This basin was also tried with two types of deflectors on the valve. Figure 13. These tests are described in greater detail in the section under "Hood Studies. 11 Briefly. however. the stilling action was very inadequate for valve openings of one-third or less, making it apparent that the deeper basin was necessary.
9
When the false floor was removed to revert to the deeper basin, the side rails that supported the false floor were not removed. When some of the earlier tests were repeated to obtain photographs, it was noticed that the stilling action was improved. Further investigation showed that the rails assisted ·in turning under the boils which formerly had risen to the surface next to the walls. Figure 12 shows a comparison of the flow appearance with and without the side rails. This feature was ·incorporated in the basin with tpe addition of 450 fillets on the top and bottom of the rail to facilitate field construction, since tests had shown that the fillets did not reduce the effectiveness of the rails. Stilling Basin No.' 5 consists of Stilling Basin No. 4 with the addition of the side rails.
Recommended basin outline. At this point in the investigation, it became necessary to submit a stilling basin outline to the field so that the first stage concrete ·could be poured and the basin used for diversion purposes. However, the type of valve to be used had not definitely been decided and consequently the f~l basin could not be recommended. The investigation had shown, however, that some type of hood would be neces·sary on the valve and that the basin as developed to this point had the proper over-all dimensions. Since the performance of Stilling Basin No. 5 :was satisfactory, it was submitted to the designers.
The recommended basin outline had a valve chamber 6 feet wide and 8 feet long, a diverging section 37 feet long with the maximum width 12 feet,· a 12-foot-wide section 36 feet 4 inches long, and a 19-foot transition leading to the canal section. The floor of the pool was at elevation 5211. 0,- with the low~r e_dge of the rails 2 feet 10 inches above this. The rails started 3 feet upstream from the end of the trajectory and were each 34. 6 fe.et long, Figure 4.
Tests from here on had to be made using the basin outline which was now under construction. Therefore, all changes and additions had to be compatible with this design.
HOOD STUDIES
Deflec_tors. Because of the extreme divergence of the jet of the butterfly valve at partial openings, it was apparent that in order to obtain the desired stilling action it would be necessary to develop a guide to carry the flow to the bottom of the stilling pool for the most effective energy dissipation. For all of the following tests the valve was depressed 30°. .
TJ;ie rfirst type of guide tested was a semicircular hood 3. 5 feet long, fastened over the top of the valve, Figure 13, Deflector No. 1. This hood caused the jet to plunge into the basin, but the jet divergence was- such that the penetration was not sufficient, and
10
consequently there were large boils and surges in the stilling basin causing wave action in the canal section that moved the riprap from the banks.
A curved deflector, the width of the stilling basin, was then developed to attempt to confine the divergence of the jet, Figure 13, Deflector No. 2. With this design the operation in the stilling basin was good at the larger discharges. For a valve opening of one-third or less the jet's divergence was so great th.at its energy was diminished to the extent that the jet did not penetrate into the pool but hit the surface of the water and caused a considerable amount of spray and splashing to be present. This spray backed up over the valve, causing the valve to be partially submerged intermittently, resulting in very poor basin operation. Side walls were placed under the deflector to further control the divergence of the jet at the small openings, but th~re was no improvement in the stilling action, so further study on this type of hood was discontinued.
. Discharge guides. Deflectors No. 1 and 2 as described above were of the same general type, but differed in size and in the method of attaching them to the stru.ctuire. Whereas .neither of the deflectors were entirely satisfactory, some features ,of both showed p~omise that warranted further development. It was believed that if the jet could be carried to the bottom of the pool as by Deflector No. 2, bu~ at the same time be fastened directly to the valve as Deflector No. 1, better control of the jet could be obtained and consequently a better stilling action.
The first discharge guide developed along this line consisted of a length of 14-inch pipe bolted to the downstream flange of the valve. The pipe was 11. 67 feet long and inclined 30° below the horizontal.
The operation with this type of guide was exceptionally good; the energy dissipation was accomplished with no disturbances in the form of visible surges, boils, or wave action, although some eddies were noticeable. However, this lack of a visible stilling action can be explained as follows: .In fastening the guide directly to the valve it was not possible for the valve to receive air, and consequently there was no air carried into the stilling basin as in all of the previous tests. The lack of air, however, caused subatmospheric pressures in the pipe and valve, and the use of this device could not be recommended.
Two air vents, about 5 inches in diameter, were then placed in the sides of the guide, directly downstream from the flange. With air provided, the turbulence in the basin increased considerably. Also, part of the flow from the valve was discharged through the vents, causing objectionable spray and splashing. To eliminate this feature a pipe 18; 67 inches in diameter was used in place .of the 14-inch pipe. The larger pipe was fastened to the valve in the same manner as the smaller pipe, and two air vents, the same size and location, were also provided. The larger pipe provided the additional area needed to prevent flow out of the air vents, but the circular pipe did not exert enough control over
11
the dispersion of the jet and the flow in the basin· was unsymmetrical with large shifting boils and surges~ · ·
To obtain better dispersion, a circle-to-rectangle transition, 11 feet 9 inches long, was used in place of the circular pipe. The upstream end· of the transition was circular, 18. 6 7 inches in diameter. and fastened directly to the valve by a flange. Air vents were provided immediately downstream. from the flange. The lower end was rectangular. 5. 1 7 inches high and 4 feet 5 inches wide. giving the same area at the entrance and exit of the transition, Figure 14.
With the valve fully open, the transition helped to provide good operation in the stilling pool; however, as·the valve was closed, shifting boils caused excessive waves, in the transition and canal.
To eliminate the poor stilling basin appearance at the smaller discharges, . two methods of reducing the area at the end of the transition were tried. For the first a wedge-shaped divider, 8. 17 inches wide and 23. 35 inches long, was placed ·in the center of the rectangular opening. This split the jet and-directed the two parts against-the basin walls. The reduced area resulted in better stilling action but tQe splitting of the jet and its consequent striking of the walls with considerable force made the use of the dividing .wedge undesirable.
'
The area was then reduced byr an amount equal to the wedge by reducing the·height of the rectangular opening to 4. 2 inches. When the
-model was operated with this arrangement. the action in the stilling pool-was improved with the jet plunging sufficiently deep into the pool to give thorough energy dissipation. ·
At this point in the model studies the testing was discontinued because there was still considerable doubt as to tl~e type and size of control valve that was to be used in the outlet works; and therefore it was not pi:actical to develop a final discharge guide until a definite decision was made.
1:6 MODEL--COMMERCIAL PIVOT VALVE
Introduction. The model studies were resumed after a lapse of several months. An 18-in.ch copi.mer~ial pivot valve had been selected for the .outlet works; the 18-inch ·valve had become. necessary when· the maximum discharge requirements had been in~re~sed to 100 second feet.
i .
The pivot valve is similar in performance· to the butterfly valve in that the flow issues from the valve in two jets whose characteristics vary considerably with both head and degree of opening. At small openings the jet diverges, with the smallest openings giving the greatest divergence, Figure 11-C; at the larg~r openings the jets are concentrated and diffic~lt to spread. These features made the control of the
12
jet a problem similar to that encountered with the butterfly valve .. Consequently, the same manner of overcoming the difficulty was used ..
Several months had elapsed since the model studies were discontinued and the 1:4. 67 model had been dismantled to make room for more active studies; The model was rebuilt to a scale of 1:6 so that a 3-inch model of the pivot valve could be used. The recommened basin, Figure 4. was rebuilt to this scale in the same manner as in the 1:4. 67 model, with the exception that in one side of the 1:6 model, glass panels were installed. Figure 15 shows the model installation. · With the panels it was possible to see how deep the jet was penetrating and the effectiveness of any device used to obtain a better dispersion of the jet.
The model valve was constructed of brass and transparent plastic. The valve leaf and operating mechanism were machined from brass stock, and the barrel molded in transparent plastic, Figures 16, and 17. Piezometers were installed on the invert of the valve barrel.
The prototype stilling basin had already been accepted and constructed in the field; therefore, any changes necessary to obtain proper operation would have to be made with a hood or discharge guide used in conjunction with the valve.
In the preliminary tests the pivot valve was depressed 30° and discharged directly into the basin, Figure 17-A. The jet did not penetrate the pool, and as a result there were large boils and shifting surges in the basin, with high velocity surface flow and large waves in the canal. Figures 18 and 19 show the action at two different discharges and reservoir elevations. It was apparent from this test that a hood or discharge guide was necessary to enable the jet to penetrate the pool for any effective energy dissipation.
HOOD STUDIES
Preliminari hoods. To provide information to determine the type of discharge guide that was necessary for the pivot valve, the hood that had been used on the 1:4. 67 scale model, Figure 14, was fastened to the pivot valve, Figure 17-B. The 4-inch-diameter entrance of the model hood when scaled up for the 1 :6 model represented a 24-inchdiameter opening on the prototype. This entrance was sHghtly larger than the diameter of the valve, but flanges on the valve and hood were matched so that they could be fastened together concentrically. Two 6-inch-diameter air vents. one on each side of the hood immediately downstream from the flange, provided ventilation 'for the valve.
Operation with this hood was satisfactory with the air vents open. The stilling pool operation was adequate with the stilling action well distributed throughout the basin., Figures 20 and 21. Pressure measurements
13
obtained in the valve and hood for several discharges were all above atmospheric. When the air vents were closed, the appearance in the stillin~ pool was much better since there was no entrained air, but pressures in the valve and hood dropped to below atmospheric, which increased the discharge. This was. an '!ndesirable feature, and because of the comparatively small openings for the air vents, it was possible that at some time they might become closed off in the prototype structure.
Because of this uncertain ventilating factor and because of possible damage to the valve from vibration in the hood, it was decided to position the hood in such a way that the hood _and valve would not be attached. - : - --- · ,. - ,_
The same hood was used, but instead of being fastened to the valve it was fastened to the side walls and floor of the stilling basin. There was a 4-1/2-inch clearance between the valve and hood. This arrangement was satisfactory at the larger discharges, but as the valve was closed and the jet began to disperse, part of the jet did not enter the hood, showing a need for a larger entrance to the hood.
Another hood was constructed with the entrance diameter increased to 30 inches and the rectangular exit dimensions increased to 7 inches high by 4 feet 10 inches wide. The length was increased to 12 feet 6 inches, Figure 22. This hood was also placed 4-1/2 inches from the valve and parallel to the- sloping basin floor.
Operation with this design was satisfactory at all flows. The jet penetrated to the bottom of the stilling basin and there was good dissipation of the jet energy. However, there were still some boils and · surges present in the lower end of the stilling basin and they had a tendency to shift from one side of the basin to the other.
Two alterations to the hood were made in an attempt to reduce the slightly _unstable flow in the basi,z:i. __ For the first alteration a sheet metal slide gate was placed on the rectangular exit. The gate could be raised or lowered by means of a threaded crank while the model was in operation. It was anticipated that the unstable condition in the lower end of the stilling basin might be controlled if the flow emerged from the hood through a smaller area. At a discharge of 60 second feet the unstable condition had been most prevalent. Therefore, the model was operated at this discharge, and the slide gate slowly closed. The gate could be closed only three- eighths of an inch before the water backed up in the hood and started coming out of the entrance. It was decided to accept the original 7-inch height for this opening in order to provide for any inconsistencies between the model and prototype.
The second alteration was to increase the length of the discharge guide by 6 feet in order to bring the jet closer to the floor of the pool before releasing it. This did not improve the stilling action and there was a tendency for the water_to -choke -Up in the hood, although none came
14
out the entrance. Since these alterations did not improve the flow conditions, neither was incorporated in the recommended design.
Recommended hood. The hood recommended for prototype construction is shown in Figure 23. The slight differences between this hood and that, shown in Figure 22 were made to eliminate sharp corners where there was flowing water and for ease of prototype construction. A 1 :6 model was construeted of the recommended hood and installed for further testing.. The model hood installation is shown in Figures 4 and 17-C.
The model was operated over the full range of discharges at reservoir elevations 5340 and 5430. Three features: (1) stilling basin appearance, (2) wave action and its effect in the canal section, and (3) pressure measurements in the hood, were then checked for a final evaluation of the design.
Stilling Basin Appearance
The model was operated at discharges ranging from 5 to 100 second feet at reservoir elevatiQns of 5340 and 5430. The appearance of the flow in the basin was satisfactory. The water surface in the . basin at 100 second feet was comparatively rough, but since it was an infrequent operating condition, the basin was believed to be adequate. For a flow of 15 second feet at reservoir elevation 5430, the jet leaving the valve and entering the hood was dispersed to such an extent that it tended to choke up the hood, causing some water to splash back into the valve chamber; however, the amount of the water splashed back was small enough that a -1/8-inch drain hose could keep the chamber siphoned dry while the model was operating, and therefore the splash was not considered dangerous. {This backflow was also encountered dur_ing the prototype tests. see Appendix. )
The hood did not choke up at any of the other discharges. indicating that it was a specific head and valve opening that caused the jet to disperse and would occur in the prototype only under the same conditions. ];i'igures 25, 26, and 28 are photographs showing the appearance of the stilling basin for several different operating conditions. Figure 3 of the Appendix shows the prototype stilling basin at a discharge of 30 second feet. ·
Wave Heights
The wave heights in the canal section were measured by means of a staff gage located about 2 feet downstream from the end of the concrete transition. · The wave height was determined by recording the maximum and minimum water surface that occurred in a period of 1 minute. · Several such readings were obtained and averaged for the height that has been tabulated in the table below.
15
The wave heights were measured at four discharges for . . the recommended stilling basin both with and without the side rails.
The wave heights at 15 second feet were negligible under both conditions. At all other discharges except 100 se.cond feet, the waves were 1ess in magnitude with the rails in place; at 100 second feet the rails seemed to lose their dampening effect. ·Figures 26 and 27 are a comparison of the appearance in the stilling·basin with and without the side rails:.
, I
WAVE HEIGHTS IN CANAL SECTION
30 60 60.
, 00 . 00
100
5430 5340 5430 5430
. 22 foot • 28 foot . 25 ,foot • 63 foot
. 10 foot
. 19 foot
. 07 foot
. 66 foot ''
Wave heights obtained during the prototype tests showed that at 15 second feet the wa\res were about o. 05 foot in magnitude, and at 30 second feet were 0.1 foot in magnitude both of which compare favorably with the model measurements.
Pressure Measurements
Thirty-two piezometers w~re placed in critical areas on
,,
the model hood, Figure 23. Pressure Ill,easurements obtained from f
these piezometers at discharges of 15, 30, 45, and 60 second feet / with reservoir elevations of 5340 and 5430 were atmo·spherfc or aboile · at every discharge with one exception. When the discharge was 30 :i second feet at reservoir elevation 5340, the pressure at Piezometer 1
No. 7 was O. 4 foot of water below atmospheric. Since this pressur~i was. not excessively low nor the others too high, the hood design wa~; considered adequate. Figure 29 is a graphical representation of thei pressure ,readings. .. 1
The prototype structure has 12 piezometers that corresponll to the following numbered model locations: Nos. 2, 3, 6, 8, 11, 13:
11
16, 18, 21, 23, 27, and 30. .Figure 24 shows the location and instal:lation of the prototype piezometers. Pressure measurements made on the prototype structure were all higher than corresponding pres-1 sures de~ermined from the model. The tailwater elevations during the prototype tests were about 1-1/2 feet higher than the tailwater used for the model tests. which might account for the discrepancy. i Figure 2 of the Appendix is a comparison of the prototype and modE/1 pressure readings. ·: . I
16
VALVE STUDIES
Dischar!e characteristics. To determine the discharge characteristics o the pivot valve, tests were made on the 1 :6 model valve.
The information thus obtained was used to determine the coefficient of discharge, c0 , for. the valve at any opening and to determine the discharge. in cubic feet per second for any valve opening and pressure head at the valve, Figures 30 and 31.
The model discharge was measured by an orifice Venturi meter and the pressure head at the valve was measured by a piezometer placed 1 diameter upstream from the 30° bend.
Two approach conditions were used for the tests; in the first the valve and a short section of the approach pipe were depressed 30° to represent the prototype. arrangement; for the second condition the valve and approach pipe were horizontal.
For the first condition the maximum c0 is O. 658 occurring at a valve opening cif 89. (3 percent; for larger valve openings the coefficient decreases rapidly.
For the second condition c 0 was the same for valve openings up to 75 percent; for openings greater than 75 percent c0 was larger than it had been for corresponding openings under the first condition. The maximum c0 with the horizontal approach was O. 63 and was attained when the valve was 82-percent open; for valve openings greater than 82 percent the c0 decreased, but not as rapidly as under the first condition, Figure 30.
Tests with the valve and a short section of the approach pipe depressed 30° showed that the maximum required discharge can be obtained a:t normal reservoir elevations with this valve. The discharge in second feet for valve openings at 10-percent intervals has been plotted against pressure head in Figure 31.
The coefficient of discharge was obtained for the two discharges used during the prototype tests, see Appendix. For both discharges the prototype coefficient was smaller than the coefficient determined from the model studies. This difference cannot be explained at the present time.
Pressures.. Four piezometers were placed in the valve so that pressure measurements could be obtained under the most common operating conditions. These piezometers were located on the bottom of the valve, two on each side of the invert, Figure 16. Since this was not a comprehensive study of a ptvot valve, no piezometers were placed in the gate leaf or operating stem housing.
17
Pressure readings were taken for discharges of 30 and 60 second feet at reservoir elevations of 5340 and 5430. No subatmospheric pressures were found for these discharges .. On Figure 16 the pressure readings at each piezometer location :are shown in tabular form. ·
18 latfflor .. QedamatloD • O.anr, Coto.
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R.aaw. .. .... R.81 w. R.80W. R.79W. R.78W. R.77W. R,71W. R. 7SW. R.74W R. 71W. R.72W. R.71 W. R.TOW. R.69W.
UNITl!O STAT I! II Ol!NltTMntr OI' n,a INTl!ltlOlt
•ulll!AU OI' lll!CLAltl,ITIO#
COLORADO Ille THOlll,-SON PRo.Jta:r • COLO.
HORSETOOTH RESERVOIR LOCATION MAP
"6Mv•1t, CO&.OIMOO. ,.a.a,;, ,._
"70 "70~===t===t===r=~::;;~,==+==~F=3===i====f==-~~ 80
t I I I ~t I I I I I I 50
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STATIONS
60
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40
30
20
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0 10~ 1or 2.'.E_ SCALE OF FEET
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_____ G_ro~und surface---,, ~------------------------- ...__ ~ Rock surface-----
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NOTES PROFILE ON £ SOUTH CHANNEL CROSS SECTION OF CHANNEL P57 Indicates Test Pit
A~~.6·1 Indicates Auger Hole
5060 5360
P54 ~ - '--11 --- . ., 50 50 - - - " II ---.....
Ground surface----- D<«- ~ "- / ' '-40 40
/ ~'I.' / " --y 4'c-,,W,V "\. 7 '- \ P51 30 30
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10 10
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STATIONS 60>00 70•00 ao-oo 00-00
0300
PROFILE ON £ NORTH CHANNEL
RESERVOIR AREA ANO CAMCITY TABL.E
ELEVATION AREA CAPACITY ACRES ACRE FEET
5440 2009 166,718
35 1938 156 850 30 1873 147322
5425 1806 138 124 20 1742 129 254 15 1676 120 709 10 1625 112456 05 1569 104471
5400 15/J 96 761 95 1457 89386 90 1399 82246 85 /343 75 449 80 1282 68885
5375 1222 62 624 70 1162 56659 65 1107 50987 60 1045 45 607 55 977 40 549
5350 9/J 35 825 45 837 JI 445 40 757 27460 J5 700 23 814 JO 635 20,475
5325 580 17 437 20 525 14 675 15 471 12 184 10 419 9 959 05 372 7 982
5300 322 6 247 95 270 4768 90 220 3 544 85 176 2555 80 132 I 784
5275 96 1183 70 75 754 65 47 448 60 JO 255 55 19 132
5250 ff 58 45 4 19 40 I 5
5235 0.3
FIGURE 2
DlkE
LOCATION MAP
UNITED STATES
DEPARTMENT OF THE INTERIOR
8/JREAIJ OF RECLAMATION
COLORADO BIQ THOMPSON PROJEGT - OOL.o.
HORSETOOTH RESERVOIR GENERAL MAP 01' RESERVOIR Alfl!A
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SECTION C-C
SOLDIER CANYON DAM OUTLET WORKS
PRELIMINARY STILLING BASIN 1: 4.67 SCALE MODEL
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SECTION C-C
SOLDIER CANYON DAM OUTLET WORKS
PRELIMINARY STILLING BASIN 1: 4.67 SCALE MODEL
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SECTION G-G SECTION H-H
Ar'i( -TTIIITT7--,//l.mYA
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SECTION D-D
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SECTION C-C SECOND STAGE CONCRETE NOT SHOWN
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SECTIONAL ELEVATION 8-8
I () 5 10
SCALE OF FEET
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1 E 15221 (-:1::;t:: :: :;.~~~-~:::::-_:::;:::~:::::_-_-_-_-_; _-_-::_-_:;~~~:::::-_-_tr~-~ - -20+~----------r ; : Slopefper fooQ"'~jl.;,:'.i...-+ _;... __
SECTION F-F SECTION E-E
f (Inside face
Chamfer-·-
(]{; :rf r . ro:, °/,_:;;:i:-L- t?:t)\:7') ;,-_ ~' -··,-,--" ___ 4 Metal seal-No_24 gage------ ~-'--'-'-"'- __ , - ___ _ 1;:: ' ___ ,:.,.•- .:ti Paint projecting half --~::;_:; :!-f·-~-'; ,-:;,- • _-.-_.:,,;_-'.-:-_. of seal with asphalt before ',-__ o_ :;, <-:~::.o
-o:-:~-:~-- pouring adjacent concrete - - - ," - -- -- f Chamfer--/
FLOOR WALL
;§ ':' .... ..
CONTRACTION JOINTS 0 I 2
SCALE OF FEET
NOTE Chamfer all exposed corners[ unless otherwise noted_
REFERENCE DRAWINGS VALVE HOUSE -CQNCRETE OUTLINE _________________ 24rD-3155
PLAN.PROFILE, AND SECTIONS _____________________ 24r0-3080
STILLING BASIN-REINFORCEMENT ________________ z45-D-!Jl5!1
UNITED STATES DEPARTMENT OF THE IN TERI DR
BUREAU OF RECL.AMATION
COLORADO-SIG THOMPSON PROJECT- COLD
H0RSET00TH RESERVOIR
SOLDIER CANYON DAM OUTLET WORKS
STILLING BASIN -CONCRETE OUTLINE
~t :::~-_::~~-:~:~;.-_-_-_-_--_-_-_-:::..:::;;;-:§~~:_-_--_-_-~, • CHECKED4~-----------APPROVEO_____ ~----
-ii DENV R, CDLORAD, AP ILi I 45-0-3158,
A. Basin, No Flow Valve tilted 5°
B. Discharge 60 cfs Valve Horizontal
SOLDIER CANYON DAM Outlet Works
1:4. 67 scale model Stilling Basin Studies Preliminary Basin
c. Discharge 60 cfs Valve tilted 2½0
l%j ..... (IQ i::: '"l Cb
i:.n
A. Basin, No Flow Valve tilted 5°
. B. Discharge 60 cf s Valve Horizontal
SOLDIER CANYON DAM Outlet Works
1:4.67 scale model Stilling Basin Studies Preliminary Basin
c. Discharge 60 cfs Valve tilted 2½0
"zJ .... ~ '1 (I)
UI
A. Valve Tilted s0 B. Valve Tilted 7½0
SOLDIER CANYON DAM Outlet Works
1 :4. 67 scale model Stilling Basin Studies·
Preliminary Basin Discharge 60 cfs
c.
"%J .....
~ (D
en
Valve Tilted 10° "
A. Valve Tilted 5° B. Valve Tilted 7½0
SOLDIER CANYON DAM Outlet Works
1:4. 67 scale model Stilling Basin Studies
Preliminary Basin Discharge 60 cfs
C. Valve Tilted 10°
l'%j ..... O"Q ~ 'i (1)
0)
#f--i,_____ __ I i~-f [ l -3t- l~l --- ___________ . _____________________________________ 111_ 00 ___ .. __ • _______________ • ________ .-.-::.-::·~-~~~---_J !-"e~o'-+-- -- --- -- ------37~0·- --- -----------+------ ------;~;~::-----55'-o'---- ------- -------------+------20"0'-- -----j
PLAN ' PLAN
SECTION ALONG t
PRELIMINARY BASIN
# I J~ I -- i ::3l-~-a:o:+----- -- ---------39'-o~ -- ---------- -----:------------- --- ---46°0~ ------ - ------------+------20·-o~---· ---,- ___ i_ ~. ·-····-····----·-------------·-··· ------------- -.113' d' • -------- --- · ----- ------ ----- --------- --·- --------------~
PLAN
-El.5231.0
·Et521'-5 El.5217.~) __ _
:·'.;{: :-·~_::;:~·.:::,'!::,·-·., •: ·:.o. ·,·:,. ··::_&!·::-:..·: .'·:F·:"
SECTION ALONG i
BASIN NO. 2
I
•El.5231.0
SECTION ALONG t, BASIN NO. 3
---'1,"-------,,.--j_ i_---- ---- __, ___ _
l i : ; : ! : . t-e ~ -----------3r-_ff ________________ ;;ck' ··---·--364" ----·--·-----··-·..;.. ----- i9-0' ·----i
El.5226.0)
. }VO:fob,e t'irt ..... 0'-30'
PLAN
-·El.5231.0
El.5215,~_i', •••.
·El.5211.0
SECTION ALONG t BASIN NO. 4
I SOLDIER CANYON DAM
OUTLET WORKS STILLING BASIN OUTLINES
1:4.67 SCALE MODEL T.J. R. 7-14-50 "' .....
Dry Model Discharge 60 cfs
SOLDIER CANYON DAM Outlet Works
1 :4~ 67 scale model Stilling Basil?, Studies
Basin ~o. 2
"%.1 ..... ~ '1 ~
00
Dry Model
SOLDIER CANYON DAM Outlet Works
1:4. 67 scale model Stilling Basin Studies
Basin No. 2
Figure 8
Discharge 60 cfs
A. Dry Model Valve depressed 100
B. Discharge 60 cfs Trajectory Apron in place Valve depressed 100
SOLDIER CANYON DAM Outlet Works
1:4. 67 scale model Stilling Basin Studies
Basin No. 3
C. Discharge 60 cfs Trajectory Apron Removed Valve depressed 24°
t'%j
~-'i (!)
co
A. Dry Model Valve depressed 100
B. Discharge 60 cfs Trajectory Apron in plac.e Valve depressed 100
SOLDIER CANYON DAM Outlet Works
1 :4. 67 scale model Stilling Basin Studies
Basin No. 3
C. Discharge 60 cfs Trajectory Apron Removed Valve depressed 24°
1-rj I-'•
~ 'i (1)
co
,-.-----------------------------------------------n
FLOW ---->-
PO SI TI ON 11A11
LEAF CLOSES IN A COUNTERCLOCKWISE DIRECTION
' T.J. R. 2-14-50
FLOW >-
SOLDIER CANYON. DAM OUTLET WORKS
_14• BUTTERFLY VALVE
POSIT 1ON "a" LEAF CLOSES IN A
CLOCKWISE DIRECTION
-~ C ~
-0
Figure 11
A. HOLLOW-JET VALVE Operating at a small opening and large head, note symmetry of the jet.
B. BUTTERFLY VALVE Operating at a small opening and large head, note the large fin on the top of the jet, also the extreme divergence.
C. COMMERCIAL PIVOT VALVE Operating at a small opening and large head, note the divergence of the jet.
SOLDIER CANYON DAM Outlet Works
Model Studies Flow patterns for three types of control valves.
Figure 11
A. HOLLOW-JET VALVE Operating at a small opening and large head, note symmetry of the jet.
B. BUTTERFLY VALVE Operating at -a s.mall opening and large head, note the large fin on the top of the jet, also the extreme divergence.
C. COMMERCIAL PIVOT VALVE Operating at a small opening and large head,_ note the divergence of the jet.
SOLDIER CANYON DAM Outlet Works
Model Studies Flow patterns for three. types of control valves.
Figure 12
Without side rails With side rails
Without side rails
Discharge 45 cfs Reservoir elevation 5430
Discharge 60 cfs Reservoir elevation 5430
With side rails
SOLDIER CANYON DAM Outlet Works
1 :4 .. 67 scale model Stilling Basin Studies
Basin with and without side rails
Without side rails · With side rails
Without side rails
Discharge 45 cfs Reservoir elevation 5430
Discharge 60 cfs Reservoir elevation 5430
SOLDIER CANYON DAM Outlet Works
1:4. 67 scale model Stilling Basin Studies
Basin with and without side rails
With side rails
Figure
I I
/ I
/
T.J.R. 7-27-50
. I ~ . I
A . ··· I --------------------3'- &"-----------------~
• ~I
~'1, I
I I
I I
I I
I
SECTION ALONG l
·~ , ,204l/' --- it, I ,,, .i ----c.. . / _,,_,_ ----¥-- '
SECTION A-A
DEFLECTOR NO. I
/ /
I I
/
--~ ~"" I
/I
El.5215.5
I
/ I
I
DEFLECTOR NO. 2
/
SOLDIER CANYON DAM OUTLET WORl<S
14• B!JTTERFLY VALVE
DEFLECTORS
FIGURE 13
FIGURE 14
~--·--- .. -. ---.-----11. 1 911--- .. ------- .---------~
I . j : <78 I : - -----f I
Ar> I I I
I I =,-----~ I ..,_ I ~ I ID -------- I _, I
1 ____ 1;_:-______________ J _I A~ ~ -~
_____ i PLAN
-c.i B
k- - - - - - - - - - - - - - - - - - - - 11 1 9 II - - - - - - - - - - - - - - - - - - - -Jlol I -~ I
x-.---1· :..;, : = =• I I ....
to H--l I~ ID - - If
-..!, ,:f II -f t-i ___ A->le.,&.. ~ -,
·,,AIR VENT I ONE ON EACH SIDE
~-1!6.6~ I I I I I I I I I I
SECTION ALONG i
!:::::::
~--- -- 41-511---- - - - ->i 'f
I I __ '{
SECTION A-A SECTION B-B
T. J. R. - 2-23-51
SOLDIER CANYON DAM OUTLET WORKS
HOOD FOR BUTTERFLY VALVE
1:4.67 SCALE MODEL
/, •• 3• PIVOT VALVE
=' ~
"'
! io : !.!_.. ~ l _: I I I : L.en I a, : I I II I I I I -!. I !'"'----------3-tl ---------,-; 1<--------2'-e"-------~ : :
I : I I ~---~ ½ I I I - I 1 1-~--------t---------i r-------2'- &"-- · ---- .:.C--------------------6' .2 !"----- ----- --------'4c---------------------&1-o". -- - -----------------~----------- 3'-411 ------ ·*------- ----101 o" - --------,-.c.-----2'0"-----~ ! . : ~------------------- - - --- -------------------- ---------------- -- --------------281 · 0 t" --------- ----- -------·- -- -- -- . ----------- ----- -· ----------------- ----- _______ -,.J
PLAN
A.-> .-----.--~-----+r ------:-----71 --r.i-~----:~ I ~ . ! ; ""'"~~·~-·=------ I------, ~ J---- ----
I
B.->-
' 2
I 1 Q -.., ' =~ -.!.. -· = i 1't=============I=========:::::;~ "'!" I •t:.l. : I : .. I : l·----: ·f-,- I =I
t _________________________________ f~--- EL. 9211.0 (PROTOTYPE) :..,~ \ i
J-c.----- -21-0N- -- -~ rt"" l~O··r+o•J
i •' -IN ,., ·' ,.,
I
! ' ' I :
Ii~
:i.·-'-'---+----'
SECTION A-A
-A'->-
SECTION ALONG t
SOLDIER CANYON DAM OUTLET WORKS
RECOMMENDED STILLING BASIN 1:6 SCALE MODEL
a->-
SECTION B-B
.••• -·TAIL GATE
, .. ..I '·SAND 7-~~j
:!I m·
f! -T.J.R. 7-26-50 UI
.RGUII •
T'
SECTION ON l END VIEW
DISCHARGE PIEZ # I PIEZ 2 PIEZ 3 PIEZ 4
T.J.R. 2- 7-51
PRESSURES FEET OF WATER
RESERVOIR ELEVATION 5340
30 G.F.S. 60C.F.5. 86 FT. 24 FT. 43 FT 8. 7 FT. 84 FT. 21 FT. 45 FT. 9.4 FT.
5430 30·C.F.S. 60 C.F.S.
1.76 FT. 112 FT. 70 FT. 59 FT.
173 FT. 108 FT. 77 FT. 61 Ft
SOLDIER CANYON DAM OUTLET WORKS·
18-INCH COMMERCIAL PIVOT VALVE PIEZOMETER LOCATIONS AND PRESSURES
1:6 SCALE MODEL
A. Model of commercial pivot valve installed in model.
B. Hood designed for Butterfly valve fastened directly to pivot valve. Note piezometers in hood, and side rails in basin.
SOLDIER CANYON DAM Outlet \\brks
1 :6 scale model Hood Studies
Pivot valve and Hoods
C. Recommended hood installed 4-1/2-inches in front of valve
l'%j ..... ~ '1 (1)
.... --1
A. Model of commercial pivot valve installed in model.
B. Hood designed for Butterfly valve fastened directly to pivot valve. Note piezometers in hood, and side rails in basin.
SOLDIER CANYON DAM Outlet W>rks
1:6 scale model Hood Studies
Pivot valve and Hoods
C. Recommended hood installed 4-1/4-inches in front of valve.
l:tj I-'•
~ 11 CD ..... -.J
Figure 18
Reservoir Elevation 5430
Reservoir Elevation ·5340
SOLDIER CANYON DAM Outlet Works
1:6 scale model Hood Studies
Performance of 18-inch Pivot valve without hood
Discharge 30 cf s
Reservoir elevation 5430
Reservoir elevation 5340
SOLDIER CANYON DAM Outlet Works
1 :6 scale model Hood Studies
Performance of 18-inch Pivot valve without hood
Discharge 30 cfs
Figure 18
Reservoir elevation 5430
Reservoir elevation 5340
SOLDIER CANYON DAM Outlet Works
1 :6 scale model Hood studies
Performance of 18-inch Pivot valve without hood.
Discharge 60 cfs.
Figure 19
Figure 19
Reservoir elevation 5430
Reservoir elevation 5340
SOLDIER CANYON DAM Outlet Works
1:6 scale model Hood studies
Performance of 18-inch Pivot valve without hood.
Discharge 60 cfs.
Figure 20
Reservoir elevation 5430
Reservoir elevation 5340
SOLDIER CANYON DAM Outlet Works
1:6 scale model Hood Studies
Performance of 18-inch Pivot valve with preliminary hood.
Discharge 60 cfs
Reservoir elevation 5430
Reservoir elevation 5340
SOLDIER CANYON DAM Outlet Works
1 :6 scale model Hood Studies
Performance of 18-inch Pivot valve with preliminary hood.
Discharge 60 cfs
Figure 20
Reservoir elevation 5430
Reservoir Elevation '5340
SOLDIER CANYON DAM Outlet Works
1:6 scale model , Hood Studies
Hood as designed for Butterfly valve fastened to 18-inchPivot
Valve. Discharge 60 cfs.
Figure 21
Reservoir elevation 5430
Reservoir elevation 5340
SOLDIER CANYON DAM Outlet Works
1 :6 scale model Hood Studies
Hood as designed for Butterfly valve fastened to 18-inchPivot
Valve. Discharge 30 cfs.
Figure 21
FIGURE ll
!-< ·------------------12'- 611 ------------------- >t I · ~·e I . 1 I - T
A l I r> : I _"'!., ___ - I
: =' =' 0 U)
-,---- I
N ~ I I I I I I J___ I
ACL::,.-:-.;..._-------------------J __ t ...::J B
PLAN
I II . I t<--------------------12-6------------------>i I I
: I -,.;--- I : I
= I U> I I I
~ L_i I _'{_ ___ ..__ __________________________ ! -
I
SECTION ALONG G.
t<------4' - I o!.!..----->j I ~~
r--,____ ________ __._l_
SECTION A-A SECTION B-B
T. J. R. 2 - 26-51
SOLDIER CANYON DAM OUTLET WORKS
PRELIMINARY HOOD FOR PIVOT VALVE
P6 SCALE MODEL.
FIGURE l3 1-< . - . . - - . . - . - - •. . 12. ·45.i.'. .. - . - - . . .. . . - -1
I 8 ~I a I . -~
Ar -'-" . l . I
. - I
1---- --2'-o'!..----2'-d~"'~-~2'-o'~>-k---2!..o'!..~--2'-o'!..->-l : _, ; -~ .. I .I. I I I .1 I I . ,. I I I - OI
'. . '4· 1 9 ;14 . ,19 j4·1 --;
1::- -~ ' 25 ·7 . _'i._A_~ 2 . -~ 2: i
6 II _ _.__, 1
16 21 ____ i_ 2lJa ·
PLAN
. ==-------------~---~--=-8 8A. 13 13A 18 23
--------:. T ..... ---+-----t-----. ----:r.__ I?
• . ~- -----JL_ 99
. . . ~
SECTION C-C
-
30-
29 +
I I" I r-c·------4-11 ~2 _ _;_ _____ >;
3~R-~j . . ~ 1i~R
SECTION A-A s ECTIO N a-a
SOLDIER CANYON DAM OUTLET WORK-S
RECOMMENDED HOOD FOR PIVOT VALVE
S H OW I N G PI E Z OM ET ER LO CAT I ON S
1:& SCALE MODEL.
T.J.R .. .,.2-2.1.,.51.
fr---,~,--d'~--~:----;;,..--~•~~--~-;;-~~---.--;;----------;-, ' ' " , ff,~ Stilling basin
·:".··.·~A·
l Discharge-guide---------..
© Indicates piezometer number and· is stamped at pipe top
PART PLAN
~ ,-,a .. ..---~ •· . w Il y:-k __ ·:y ~h:~ I.ill f I -
SECTION A-A
SCALE' a, ,rrT
' ' \ ( 1· Half coupling '--l 1'-9o•Street elbow
I 1"-90• Screwed elbow I_ 1• Pipe cap
f I' Half coupling ----~ 1"-90•Screwed elbow
l 1° Pipe cap
,-1• Std. gal. steel ·' pipe
A ....,A
·:~ .. ::_•:1 ··.,o.
·-<~·-=· ··.•:·
DE TAIL B TYPICAL PIPE SUPPORT
d--r··-1' Std. pipe
I' Half coupling~: __ ffl ···-W•lld
~ { Drill--•
TYPICAL PIEZOMETER CONNECTION
~2· n~· (i) @ @
,,Floor
~-oo·:·
® ® ® BEND IN FLOOR OF DISCHARGE GUIDE
(REFER TO SECTION A•A)
REFERENCE DRAWINGS VALVE HOUSE-CONCRETE OUTLINE . _245-D-3155 STILLING BASIN- CONCRETE OUTLINE _____ 246- D- 5158
VALVE HOUSE- DISCHARGE GUIDE----·-··-------245-D -4620
NOTE• All fittings malleable iron
UNITED STATES DEPARTMENT OF THE INTERIOR
BUREAU OF RECLAMATION
COLORADO-BIG THOIIPBON PRO,ECT -COLO. HORSETOOTH RESERVOIR ..
SOLDIER CANYON DAM OUTLET WORKS
PIEZOMETER TIPS AS INSTALLED DRAWN __________________ SUBMITTED _____________________________ _
TRACED.J.i...Q0f1,, ___________ RECOMMENDED. ___ .................... _____ .............. ..
CHECKED--- __________ ---APPROVED- __________________________ _
2 21.2 - 30 I FORT COLLINS COLO. DEC. 2, 1948 I
;; = ,., ~
Reservoir elevation 5430
Reservoir elevation 5340
SOLDIER CANYON DAM Outlet Works
1 :6 scale model Hood Studies
Recommended stilling basin and hood. Discharge 30 cfs
Figure 25
Figure 25
Reservoir elevation 5340
Reservoir elevation 5430
SOLDIER CANYON DAM Outlet Works
1: 6 scale model Hood Studies
Recommended stilling basin and hood. Discharge 30 cf s
Figure 26
Reservoir elevation 5340
Reservoir elevation 5430
SOLDIER CANYON DAM Outlet Works
1: 6 scale model Hood Studies
Recommended stilling basin and hood. Discharge 60 cf s.
Reservoir elevation 5340
Reservoir Elevation 5430
SOLDIER CANYON DAM Outlet Works
1: 6 scale model Hood Studies
Recommended stilling basin and hood. Discharge 60 cfs.
Figure 26
Reservoir elevation 5340
Reservoir elevation 5430
SOLDIER CANYON DAM Outlet Works
1:6 scale model Stilling Basin Studies
Recommended Basin with side rails removed. Discharge 60 cfs.
Figure 27
Reservoir elevation 5
Reservoir elevation 5430
SOLDIER CANYON DAM Outlet Works
1:6 scale model Stilling Basin Studies
Recommended Basin with side rails removed. Discharge 60 cfs.
Figure 27
Figure 28
Reservoir elevation 5430
SOLDIER CANYON DAM Outlet Works
1 :6 scale model Stilling Basin Studies
Recommended Basin and Hood. Discharge 100 cfs
Reservoir elevation 5430
SOLDIER CANYON DAM Outlet Works
1 :6 scale model Stilling Basin Studies
Recommended Basin and Hood. Discharge 100 cfs
Figure 28
25
28
o:20 L&J
.. m ~ ..
•. z.
e'j 15 1-L&J 2 0 N•
.L&J
.a::10
-5
...
I I I
I ,. ! \ I i I
I / I
~ 1/ '1 ' r /
I
I I I I
I \ I I \\ I I I I \, I
~
I
V 27
o:21 L&J m ::i!! ::)
z o: 16 · I!! L&J 2 0 N L&J ii: II
6
I I
)~ .1 I ~ I
I
I I I' I I
!A
1i
I f lj ,.
o:22 .__.__._.,___.....,__,__...._. L&J m 2 ::)
z ffi_ 17 ~--U-..;..!----4--l
lL&J 2 2 L&J ii::12~-rl,ll~-+--
/~ ~ : IJ \ ' lo 2-1 0
215
2 4
0: L&J m 2 ::) z 0:
·L&J 1-L&J 2
·2 L&J ii:
19
I
9
I ! I I I I
i I I/ I
I
/: ?' I ,i
Ii I t I I I
"' \ ', l '
+2
25 I I I I I I :
26 I
I I
I
/ -- /J
iii ,v m I :E I
::) !} z 0:1 L&J I f I-L&J : I :E 0 ~ I N
~10
' I I I I
5 \ .
~ I '\ I
I lj
+4. +6 +2 +4 +6
i ~
(
1·,.
PRESSURE-FEET OF WATER FOR RESERVOIR ELEVATION 5430
27
0:2 L&J m 2 ::) z
I
a: 16 L&J 1-L&J :E
2 ~I I
6
2
I ,
/~9 I 1/ JI I I I I
: I;
I J
I ii I
I
fl
2 9
2 B
a: 2 L&J m 2 ::) z a: I L&J 1-L&J 2 0 N
7
~· 2
7 '
1 . 5
+4 +6
I I I
I . I I
~'I' I I I I I I I
I f ~I
/ ,, I }; ' I I
fJ J
~ ,' \. o +e +4. +8 o +e +4 +8 ·-1 0 +2 +4 . +6 _-I O +e +4 +6
TAILWATER ELEVATIONS DISCHARGE
15 C.F.S. 5D • 45 • 60 •
-100 •
P F E 2-20-111
ELEVATION 5225.5 5224.1 5224.6 5225.0 5225.B
0 PRESSURE-FEET OF WATER FOR RESERVOIR ELEVATION 5340
SOLDIER CANYON DAM OUTLET WORKS
PRESSURES IN REC()MMENDED HOOD 1:6 SCALE ·MODEL
29
50
a:25 L&J m 2 ::) z
ffi 18 1-L&J
~13A N L&J ii: 13
BA
8
I
\ I \ i I
I
iL I J
I I I
I J
\ I i
I ' I I\ I)"
, /.
FIGURE 29
\ ., 1
/ 1/ I
~
9 2
3
0: 2 L&J m ~ z
ffi I 1-L&J
3
. ~13A
ii
+2 +4 +6
\ I I I
I \ I
,'I I ~I
I /1
/ ,~; I r .' : ' : / / I i
N L&J ii: I
\ l 3 'l
/-... B
!\,., ' B!j V ,1
..,'r o +e +4 +a
KEY 60 - SEG0ND -FEET 46 • SEG0ND-FEET 30- SEG0ND - FE ET 15- SEG0ND- FEET
O.T
0.6
0.5
Q 0
111
~4 C X () (I)
0 I&. OQ3
IL l&I 0 0
0.2
0.1
_ l.---' 0
'
i
..
/
l/ ,,,,
~/ .....
i,...,--
10 20
-
.. -
..
J ~,r
/,,.
/ l/
.v ,/
V
/" v., .J V '"t-
/"
.J / j v"'
tC --t ~
30 40 50 60
% GATE OPENING
Maximum . .Pl Coefficient= 0.658- .,
' ..---~ - 1 ~ ... I v~ .,.;, 'i -.. ~ _,J-- '-~ /. , . . '
' Straight · '-30° Bend _ ~I
Approach .... -~~ V in Approach Pipe --- Pipe --
.... V·
-~ ~ ~/
~/
~ /
~ /
SOLDIER CAN YON DAM ..
OUTLET WORKS COMMERCIAL PIVOT VALVE
COEFFICIENT OF DISCHARGE CURVE ... R.A.S. B-18-49.
~ -Gl C ~
'" g_
70 80 90 100
FIGURE 31 200 I I I I 190 l---l--l--+----1------1---1~-H--+---lj ~-t--/++---+-----t-t-,-t------t-----"1
180
I I I I 1701-----+--+---+-+-+-+---++---++/--+---++/-+----+-. --+-+-/ -------t--i__,.....,.// 160 ~1----1---1--~---+1--I--_ --+---If-, _-+-----+-+1--+---+--t-t-
1 v-r--1
150 1----11--1--1---4---4----l~--+----lf--+--++--+------fl--+---t----#""1*"-:----1
e / I # <l 140 l----l'----+-+--+-+----l--+---+--f+---j-+----+--+--+----+-+--+--+-+-r-t---:----1 : ~ / / / ·/;' 8 130 -~~----+-+----+-__,__-+--__,/ _____ /-+-----+-;------h-,-------: 120 - ~1----+-+----++---.+-+-+----+/--,---,------+-/J-//'--#---t--+-----t I 110 CD+---'+--+---+-----+-+---+--------j,ft------+--t-+--/--t------i#-r----t--t-----1
~ 100---~ ___ , __ ,....,.___G ___ -+-lr'----_i_._"' ___ ;_,_i ______ q,_9/2-+-l.j _l/_-t--------t----,__,/
~ I I I I/ ~jl 0 90 l----f---+-----11-+------+-1--f---+--+----+-~-+----+,f+---+--+--.:+-+-------i
: I / . / / /,'I I ~ 80
~ II I I /I I 1u 70i-----+--+t------+--t---t ____ --t--+---+-----------t----r-, ___ -------1
~ I I ,' JV JV ~ &oi---.----++----t----+-+----t-----+--+---+-----+-+--+--.....,..._-t--------t----------1
f I I I .f ./ 50l---+-+4---1---"---4---Jl--...........+-----+--l-¥----1-----A----+---i-----+------I
j , / / 11 / V : // // / ~-, / . '' I 'I ; j' AQ ~ / SOLDIER CANYON DAM
I • , .,/ OUT.LET WORKS 20 / / I/ 1.Jr / COMMERCIAL PIVOT VALVE
I · //1~ ~,,, ./r DISCHARGE CURVE I/ ~- R.A •. S. e- 19-49
~ VJ_/~~~ 0 "'-'-'1iilo ~:;:(20=---J30l----=4l.o ____,5Jo _____ _J.&o~---=70L----=ebo-J90:---.J,o-=-o -----:-:11~0 _1J20~130
DISCHARGE IN c.f.a.
Field Trip Report No: 1191 ·.
To: Chief Engineer
.. . .
:oec,ember 19,/ 19.51
:,Through: C~ieJ. Engineering . , 'Laboratories :Branch . · .. _,,'._ : . '. ..
From: Engin~.~r. Ben R .. Blackwe.ll
Subject: . ~ield Trip. to obtain hydraulic mea~ureJ,nents.---S.oldier Canyori Outlet W6rks--C:plorado-~ig ':rhoµipson Project
Introduction ·,: '
1. September 2(:L°and 27, 1951, were spent at Soldier Canyon Outle.t Works obtaining hydraul~c measurements utilizing special equipment installed in the discharge guide during construction. The very best of cooperation was received from L. · R. Fossett,· Mainte~ nance Superintendent, ably assisted by H. J. Barber and G. H. Burkard, all of the Loveland, Colorado office. These men adjusted the outlet works dis~harge as required by the test schedule.. they assi~ted 'in :running levels. arid. did everything in. their power to bring the test.Ing program to ~ succes~fµl co_nclusion. · ··
Purpose. of the Trip
2, The pridtary ·purpose of the trip was~,to 6btain pressure measurements in the discharge guide of the Soldier Canyon Outlet Works and compare these pressures with those predicted from hydraulic model studies. Secondary purposes include (1) partial calibration of the 18-inch pivot valve, (2) wave height observations in the canal downstream from the stilling basin, (3) observations on the sev~r.tty of the. eje_ction pf water out .of the upstream end of the dischar.ge'guide into.the valve house. and (4) observations' on the hy-draulic performance (;>f the stilling' basin. . .. . . . .
'. • •· • !, •
Thi.s study is of spe<::ial interest due to the departure from standard .design practice by havirig the valve discharge into a submerged.discharge guide •.. T.he purpose of this guide is to convey the water from the valve to the bottom of the. stilling ha.sin where max-imum ·energy dissipation isrpossible with~ minimum length of basin. . This new design concept wc:1.s discussed in detail in the paper "Progress
- .. } . . •' .
in New Designs for Outlet Works Stilling Basins" by A. J. Peterka and H. W. Tabor which was presented at the Fourth International Congress on Large Dams at New Delhi. India. in Februa~y 1951.
Operating Range of the Outlet Works
3. Tb,e outlet works was designed for a maximum capacity of 100 cubic feet per second. This capacity anticipates greatly expanded deliveries in the Fort Collins area. At the present tune the capacity of the outlet works is limited by the capacity of the available canal system. A 2-foot Parshall flume limits the flow to College Reservoir to about 30 cubic feet per second while the canal to Dixson Reservoir · will handle approximately 8 cubic feet per second. Model data were obtained at discharges of 15, 30, 45, 60, and 100 cubic feet per second. At the time of the tests the head on the valve was approximately 130 feet while the maximum available head. when Horsetooth Reservoir is full, will be about 203 feet. Model data were obtained for heads of 35, 75, 113, _ 160, and 203 feet prototype. The actual model heads were one-sixth of these values.
Model Pressure Measurements
4. Model data were obtained from a 1 to 6 _scale hydraulic model in the Denver Hydraulic Laboratory. Model pressures were measured on a manometer board. Since one of the purposes of the model tests was to evolve a design for the discharge guide without negative pressures. the low point of the surge in .1be. manometers was recorded ~s the pressure in the discharge guide. Neither the average pressure nor the magnitude of the pressure surge as shown by the manometer was recorded. Apparently the _surge was not large enough to give concern.
Prototype Pressure Measurements .
5 .. Prototype pressure measurements were obtained at discharges. of 15 and 30 cubic feet per second at the 12 piezometer locations in the discharge guide shown in Figure 1. The reservoir for these tests was at elevation 5358. 8 feet, resulting in a head of approximately 130 feet on the valve. Two te~hniques were used in obtaining the pressures. namely. (1) an electric "well" gage. and (2) a gas pressure system. · The tops of the 1 . ..:inch vertical pipe leads from the piezometer openings were all apprec~ably above the hydraulic gradient in the discharge guide, thereby permitting the use of the pipes as manometers~ The .well gage probe was used ·to locate the water surface in the opaque pipes. Both of these methods of measuring pressures indicate the average pressure at the piezometer since most of the pressure fluctuations. are absorbed in the large volume iri the 1-inch riser pipes in conjunction with the small 1/8-inch piezometer openings.
2
Comparison of Model_-PrOtPtW. f-r,~_ssures , .. ,• .. , ,. ( ... ·.-. .
6. In addition to the fa,c;ft¥(0the prototype dat~ indicated
average pressures and the mq:del 4~ta indicated a minunµm pressur~. the prototype tailwate:z:; elevations were about _1. 5Jeet higher than those tested in the model.· Both of these factors tend·to result in high,er protptype p_re,ssuresJ~n we.re ~dicated by.t,h~ mod.el. The ~o,del d~ta:{or .tiie pfototype J1e~d tes-teq w~:r~ obta;i,ned from a cro~~fpl.ot ofth~. i;nQdelresults. The fµial results showing·(t) model data. · (:2) .p~ot.c;>(ype':data· u~iilg .the: ·w:~11 · g!:l,ge. · and ( 3) prot_otype data using· the.'lNl ga_s setup is. ln~lud~:d. i.n this report as Figure 2. From an ex;ilili~tio,.:~fof this fig~re # ~ay be--·clearly seen that the prototype pressures are consistently ;higher_'t~an. the µiodel p:ressur:es extended. to the prototype level. ·· ·.
Backflow out of the Discharge Guide . . . .
7. .In both the ~odel and the prototype .Small .a.mounts of Water were ejected ll.ack out .. Qf the tippEfr. end· of the_ discluirge guide into · the valve house area.· In both. tJJ.e m~.del and _the pr<:>totype this action was more se:y~re at· 15 cubic f~_et pe~·seconq tllan af ihe higher dis"'.' . charges. At 15. cul;>ic· feet per secoµd in th~ prototype: the ejected · water· was sufficient to wet the· valve house· fioe>.r ~ediately above the valve. No damage was done. · · · · · '
Stillie« Basin Operation
8. Model and prototype stilling basin 'operation were both similar and satisfactory. The energy 'of the water was· dissipated within the confines of t~e bas.in an<;t wav-e. height,s in the canal. as discussed elsewhere in this report, were ·small. Figure 3 shows the prototype .operation at.1,5 and .30.~ecoqd fe.et an4 the model operation at 30_-·second feet. --Due to the high ta.P-wa_ter elevation in the field., caused by the backwater from the 2. 0 foot Parshall_ tlume downstream from the outlet works, there 'was some now back over __ the_head.wall_ at the upstream end of the stilling basin into _the _yaJ,ve house structure., Figu~e s·. ~ the prototype, as well as in the model, the' energy dissipating boils· shifted from side to side as well as long!tudinally within _the :confines of the stilling basin. , · · · · · '
Wave Action in the Canal
9 .. Wave action in the canal downstream from the outlet works was_ o}?ser"yed in both the_ mo_~el llhd: in the prototype. These observations were· lll:ade aboµt_5_0 feet dovm.s.tream froni'the end of the stilling basin. Model wave 'heights e:,cpressed in prototype feet were as follows:
3
Discharge · 15 c. f. s. 30c.f.s. .60 c.f.s.
. 100 c~ f. s.
Wave. Heights · Negligible
o·. 1 feet o. 2 feet o. 7 feet
Prototype observations µidicated wave heights of less than 0...05 feet at 15 cubic feet per second and less than o. 1 feet at 30 cubic feet per second. This prototype wave action· at the lower discharges compares favorably with. predictions from ·the model studies. The model studies, however, indicated greatly increased wave action below the stWing basin for the higher flows. This increased wave action at the higher flows should be carefully checked in the prototype.
Calibration of the Pivot Valve-·
.10. A careful calibration of the pivot valve.was made in the hydraulic laboratory on a 1 to 6 scale model. The laboratory coefficient curve together with the two. prototype calibration points are shown in Figu~e 4~~e_ proto.type discharges were measu~ed through a 2-f oot Parshall\ (lume., while the gate opening was obtained from measure~ents of the _valve stem. travel. ·T'1e coefficient of discharge was· obtained from .the formula
Q = CAV,2gh.
where A • area of an 18-inch circle and h • totai head at the ·valve in feet
The calibration data are summari~ed in the following table:
Dischar·ge · ·Gate QfeninC 15 .c. f •. a. 21,- · · 3~ c. f. s. . 43o/o· · !
-'i '
Proto.· ;Coeff. 0.09 0.19
Model Coeff. 0.117 0.226
The protot~e cc;,efficients ar, 77o/o and. 84o/o respectively of the model results. Thi$ differe11ee between model and prototype, much gr~ater than would nQnn;aJiy: .... ~eol•d, cannqt be e~lained at the present time. Further study will be pven to this problem in order to locate the cause of the discrepancy.
Future Tests
11. Since the present tests were limited to the lower range of discharges,. at some future date when field collditions are appropriate., application wW be made for another field trip to the Soldier Canyon
Outlet Works for obtaining more data at higher heads and discharges. At this time average pressures will be obtained in the outlet1 works discharge guide as was- done in the tests discussed in this report and the results will be compared with the model study test results. In addition to these tests an effort will be made to obtain data on pressure surges in the discharge guide using a pressure cell with suitable electronic recording equipment. The tests should be made at discharges approaching the maximum capacity of the outlet works. Experience has shown that in some cases the pressure surges in hydraulic structures must be given primary d~sign consideration when the average hydraulic pressures may be of minor importance.
/S/ Ben R. Blackwell
5
t Discharge guide----~----,
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© Indicates piezom~er number ani is stamped at pipe top
PART PLAN
-.
.
SECTION A-A
&CALE OF FEET
£1'' Pipe, capu::k:--·:u
' ' I ( 1' Half coupling 1-~ 1'-90• Street elbow
I 1'-90• Screwed elbow I_ 1' Pipe cap
..JA
,-,·Std.gal. steel ' pipe
1(·~:r--:: .,: .. .-,.1,
DETML B TYPICAL PIPE· SUPPORT
,•·1' Sid. pipe
I" Half coupling···-,>-Weld
{Drill<,
TYPICAL PIEZOMETER CONNECTlbN
,,Floor
~2· 4~'
© @ ® ~-00'
© ® ®
BEND IN FLOOR OF DISCHARGE GUIDE (REFER TO SECTION A-A I
REFERENCE DRAWINGS VALVE HOUSE- CONCRETE OUTLINE_.; __________ :,_ 245-0 -3155 ST1LLING BASIN-CONCRETE OUTLINE ____ _,,45- D- 3158 VALVE HOUSE - DISCHARGE GUIOE_ ______________ 245 - D -4620
NOTE.• All fittings malleable iron
UNITED STATES DEPARTMENT OF THE INTE.RIOR
BUREAU OF RECLAMATION COLORADO•BIG THOIIPBON PROJECT •COLO,
HORSETOOTH RESERVOIR
SOLDIER CANYON DAM OUTLET WORKS·
PIEZOMETE~ TIPS AS INSTALLED
::::::~~~~~~====~=-===~=:;::::::~~~~~-~-=====~~~~~~--~~~~~~~~;-1 221.2-30 FORT COLLINS COLO. DEC.2,1948 .. .;..
FIGURE 2.
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BOTTOM OF GUIDE
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DISCHARGE 15 C,F.S.
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PIEZOMETER NUMBERS BOTTOM OF GUIDE
EXP.LANATION : l!> MODEL STUDIES
In PROTOT.YPE .. WELL GAGE
A.PROTOTYPE--· N2 SETUP
DISCHARGE 30 C.F.S.
SOLDIER CANYON DAM
OUTLET WORKS DISCHARGE GUIDE
FTR 1191
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4 6 8 10 ~EZOMETER NUMBERS RIG HT SIDE OF GUIDE
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4 6 8 10 P~ZOMETER NUMBERS
RIGHT SIDE' OF GUIDE
12
NOTE: PIEZOMETER LOCATIONS ARE SHOWN IN FIGURE I.
MOOEL .. PROTOTYPE PRESSURES
Prototype Basin Discharge 30 cfs. Reservoir elev. 53 58. 8 Tailwater elev. 5225. 7
Model Basin Discharge 30 cfs. Reservoir elev. 5340 Tailwater elev. 5224. 1
Figure 3
Discharge 15 cfs. Reservoir elev. 5358. 8 Tailwater elev. 5224. 9
Discharge 30 cfs. Reservoir elev. 5358. 8 Tailwater elev. 5225. 7
SOLDIER CANYON DAM Outlet Works Stilling Basin
Model-Prototype Photographs
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Maximum .n Coefficient= 0.658- ,,
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SOLDIER CANYON DAM OUTLET WORKS
COMMERCIAL PIVOT YALVI COEFFICIENT OF DISCHARGE CURVE
R.A.S. 8-18-49
70 IO 90
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