..

I ii

UNITED STATES

DEPARTMENT OF TH [ INTERIOR

BUR EAU OF REC LA MAT ION

HYDRAULIC MODEL STUDIES OF TRAPEZOIDAL

DROP STRUCTURES FOR SAND HOLLOW

WASTEWAY--BOISE PROJECT, IDAHO

Hydraulic Laboratory Report No. Hyd. 250

RESEARCH AND GEOLOGY DIVISION

BRANCH OF DESIGN AND CONSTRUCTION

DENVER, COLORADO

MAY 19, 1949

Recommended design in operation at the maxbnum discharge

of 200 second-feet.

CONTENTS

S�y • • • • • • • • •. e e O,,, .� 0 • 0 • e • 0 • 0

Introduction • • • o • • • • • 0 • • • • • • • • •

Description and operation of model The investigation • • • • • • • • •

0 •

. . . . • •

Effect of notch discharge on stilling-

• • 0 •

e O • 0

basin performance • • • • • • • • • • • • •.• Stilling-basin tests • • • • • • • • • • • • • Tests on short basin • • • • • • • • • • • • • Tests· on long basin • ._ • • • • • • • • • • • Discussion of ·results of stilling-basin tests

Recommended design of drop structure . . . . . . . Table l - Results of tests on control notch . Table 2 Results of tests on short basin • • Table 3 - Results of tests on long basin . • •

• • • . . . 0 0 O

1

2

3 4-

5

5 6

7 8

9

lO l2 13

LIST OF FIGURES

Number

Frontispiece-1:6 scaJ.e model of recommended design

l . Location map 2o Profile and sections for drops 3 . OriginaJ. design 4. Mqdel drawin.s 'Of originaJ. design 5 . Head discharge curves 60 Control notches for Tests 2, 3, and 4 7 . Control notches for Test 5 and baffle piers of Tests 7 and 8 8. Plan drawings of 25- and 35-foot stilling basins 9� Baffle piers of Tests 9, 10, and ll

10. Fillet and false flat b.ottom on chute ll. Baffle piers of Tests 15, 16, and 17

.12. Location of baffle piers for Test.a 20-31 13 . RecommendeJ. design of drop 14. Flow conditions with notches of Tests l-4 15. Flow, conditions using notches of Tests 3-5 16. Flow conditions with baffle piers clogged 17 . Stilling-basin performance ·with and without baffle piers 18. Flow conditions with baffle piers of Test 2l installed 19 . Flow· conditions in the recommended stilling basin ·

UNITED STAT.ES DEPARTMENT OF THE INTERIOR

BURFAU OF RECLAMATION

Branch of Design and Construction Research and Geology Division

Laboratory Report Noo 250

HydrauJ.ic Laboratory

Denver, Colorado Date: May 19, 1949

Compiled by: L. J. Glasier and W . E. Wagner

Reviewed by: A. Jo Peterka

Subject: HydrauJ.ic model study of trapezoidal drop structures for Sand Hollow Wastewa.y (east branch)--Boiso Project, near Caldwell, Idaho .

SUMMARY

HydrauJ.ic model studies were made to develop a drop structure of trapezoidal cross section for use in a flow system, which wouJ.d (1) dissipate the energy in the water at the base of the drop, (2) provide uniform flow distribution across the entire trapezoidal section at th� enn. of the paved apron, and (3) provide � smooth water surface at the entrance to and in the lower canal. In addition, it was necessary to 5.evelop a control notch for use above the drop structure which wouJ.d provide a predetermined stage-discharge relationship up to a discharge of 200 second-feet . Tests indicated that the basin and the control are interrelated and that satisfactory operation of the basin is greatly dependent on the type of control used.

A 1:6 scale modei of the Sand Hollow Wasteway trapezoidal drop was constructed and tested in the laboratory, Figure 3 . Tests were made on five different controls, Figures 3, 6, and 7A, and on two different lengths of stilling basin, Figure 8. The effect of baffle piers on the stilling-basin performance was also studied.

The recommended design, Figure 13, was determined after considering not only the laboratory aspects but also the field limitations of the problemo

Laboratory tests showed that the recommended design performed satisfactorily for all conditions tested. The control consisted of two walls which formed a V-shaped notch located upstream from the drop, Figure 13 o The chute and stilling basin had sloping side walls and peaked bottoms. Baffle piers were installed near the upstream end of the basin to reduce the wave heights in the canal and to provide better distribution of flow in the stilling basin, Figure 18. However, the basin will perform satisfactorily, but with higher wavea, if for� reason the baffle piers become dalllB8ed or entirely destroyed; Figures l7A and Bo

mmorocTION

Drop structures of. trapezoidal cross< 1section which have be�q buil.t in the past have exhibited various undesirable characteristics.!/ In-­part this can be attributed to the tact that an inetticient liydraul.ic jump was :formed in the stil1fog·basin of the structure, and only a relatively small amount of the total. energy contained in the water was dissipated in the stilling pool.. This is evident :from observations of prototype structures in operation. In some cases a s'ingl.e current appeared to shoot through the basin in .an unstabl.e :fashion and ra11ed to spread out across the entire cross-sectional area of the basin. Because of this instability, waves were :formed on the surface of the canal. section below the drop and caused serious erosion of the canal. banks. At higher :flows strong side rollers formed Just below the structure· and water swept back in along the sides of the pool., causing erosion of the canal.banks and transition lining. At some :fl.owe an unstable whirl.pool formed in the stilling basin instead of the int�nded hydraulic Jump. Again, in other ranges of :flows, the Jump swept completely out of the stilling basin and formed in the ca.pal section below the drop.

The poor operation Just described is caused by the inherent tendency of the trapezoidal drop to concentrate _the :flow of water entering the pool into a,relativel.y narrow Jet which shoots al.ong the bottom of the pooi and fails :to spread out across the entire cross ... sectionaJ. area of the stilling pool, particul.arly in the tria.ngul.ar areas on each side bounded by the basin sides and the water surface. Despite the dif:ficul.ties encountered in the operation of previous trapezoidal drops it was decided that, if a structure of this tn>e cou1d be made to perform satisfactorily without expensive additions, savings in construction cost would be considerable. The major saving would.resul.t :from almost complete elimination of form work for placing, the concrete and a sizeable reduction in the quantity of reinforcing steel required in the conventional rectangular drop. In this study, a trapezoidal drop was constructed and modified to perform satisfactorily over the desired range of operating conditions, al.ways wlth the thought in mind that the aforementioned advantages of the trapezoidal shape should be maintained.

The Sand Hollow Wasteway (east branch) is located about 9 miles north of Cal.dwell, Idaho, on the Boise ProJect,.Payette Division. See Figure 1 for location map.

Y Hydraulic Laboratory Report No . 41, November 7, 1938, United States Department of the Interiori Bureau of Reclamation, "Model studies of the structures at St_ations 581/.00, '(iJ77foo, 738/.85, and the slope canal headworks on the Sun River Project, Montana."

2

Tb.ere a.re eight trapezoidal drop structures, all alike, located on the•wasteway, being so spaced that the control notch of one structure forms the tail-water control for the structure immediately above it . Each structure lowers the water 10 feet in elevation and is designed for a maximum flow of 200 cubic feet per second. Figure 2 shows the profile and Figure 3 the section drawings of the wasteway .

DE3CRIPI'ION AND OPERATION OF M'.)DEL

A 1:6 scale model of the original design of the trapezoidal drop structure was constructed according to the prototype drawings shown. on Figure 3. Model drawing, Figure 4, shows the relative location of the main features of the model .

Tp.e upper canal, the control, and a short section of canal before the drop were contained in the metal�lined head box and the chute, stilling basin, and lower canaJ. were contained in the tail box. The control was

· constructed of wood in all �ests except in the last phase of Test 3, in wh�ch a sheet metal control, for greater accuracy, was installed in the model . The original model was constructed of concrete except for the peaked bottom of the chute and stilling basin which were of plaster or. wood.

After Test 13 was concluded, the model stilling basin was lengthened to 35 feet and the canal section immediately downstream from the end of th.e concrete transition was lined with pea gravel to allow a study of possible erosion action on the canal banks.

Water was supplied to the model from an 8-inch portable pump and discharges were measured with an orifice-venturi meter. In starting a test, the model discharge, representing a desired prototype discharge, was set and the elevation of the water surface in the upper canal was determined by a hook gage, Figure 4. By use of the tail gate and the staff gage, the elevation of the water surface in the lower canal was set to correspond to the stage indicated on the stage-discharge curve for the particular f,low being used . The stage-discharge curve, Curve .IA, Figure 5, submitted to the laboratory by the design section indicates

. that the stage for arzy- given discharge is the same in the upper and lower canal sections .

To observe and measure the wave heights in the lower canal, reference lines corresponding to the proper tail-water depth for discharges of 200 second-feet and 50 second-feet were painted on the canal bankso These are shown in the Frontispiece as the elevation 5.5 and the elevation 2.95 foot lines, respectively . Wave heights were determined by noting at a wave measuring station the point on the canal bank to which the highest wave splashed and computing the vertical distance of this point above the tail-water reference line. This 'lllethod was used because comparative tests showed that wave heights determined in this manner were greater than those read on a staff gage in the channel. The locations of the various wave

3

measuring stations are given in the footnotes of T!3-bles 1, 2, and 3. A .line at elevation 6.o feet was also used to aid in visual comparison of wave heights at the max:imum design flow of 200 second-feet o For Tests 1-19, wave heights were measured only.for the 200-second�foot discharge but to aid in comparison of the various baffle pier designs of Tests 20-31_, wave heights were also measured at a flow of 50 second.­feet .

THE INVESTIGATION

The tests conducted in this model study were divided into two general classifications; the first to develop-a satisfactory control notch, Tests 1-5, and the second to develop a satisfactory stilling-basin design,' Tests 6-31.

· .

In the tests on the control notches, the resuJ.ts of which are shown in Table 1, Page 10, the pr:imary purpose was to develop a control at the upstream end of the drop structure which would maintain a predetermined stage-discharge relationship in the upper canal for a range of discharges up to 200 second-feet. The secondary purpose of this group of tests was to develop a notch having proper outflow characteristics, since the distribution of flow in the chute,had considerable effect on the hydraulic jump in the stilling basino

. The tests on the stilling basin were made to develop a stilling · basin which would operate satisfactorily when the recommended·control notch was installed in the model .

Control Notch ·re st s

In the first tests the main consideration given the control notch was that it provide the �roper stage-discharge relationship, but as the testing progressed it became apparent that the shape and location of the control structure had a great influence on the distribution of flow of water in the two valleys of the chute and consequently upon the action of· the hydraulic jump in the stilling basino -' Also, to secure uniform flow distribution in the basin it was, of course, necessary to divide the water evenly between the two valleys of the chute. Another factor affecting the practicability of the control was the susceptibility of the various control structures for becoming obstructed with floating weeds and debris.

Test l, Figures 3 and 14A, showed �hat the control pier of the originaJ. design did not maintain the desired water level in the canal. The control structores of Tests 2-5, Figures 6 and 7A, in all cases maintained the water surface Just slightly above the desired levelo The control notch 'designs of Tests 1, 2, and 5 were considered unsatisfact9ry because of the relatively greater possibility of becoming obstructed with trash and because the flow in the chute, particularly for flows 1ess than maximum, was not evenly distributed. The des.ign used in Test 4

4

had the same control notch as Test 3, but because it was located further downstream_it provided poor distribution of flow in the chute •

. Figures 14 and 15 show the model operation for a discharge of 200 second.­feet with the various control notches installed.

The control notch of Test 3 was selected as the control structure most nearly providing the desired performance. Figure 13 shows the reconnnend.ed design. Figure 5 shows the head-discharge curve obtained for the reconnnended notch and indicates that it maintained very nearly the desired water level in the canal above the drop for the desired range of discharges. Further, it was _considered least likely to be obstructed by floating trash and debris, and for all discharges tested the distribution of flow in the chute yalleys was satisfactory. The stae;e­discharge relationship shown 1n Figure 5 was made with the control notch accurately constructed of sheet metal.

Effect of notch discharge on stilling-b:":, .'_r1 performance. Although sufficient tests were not made to evaluate uach notch in terms of identical basins, certain characteristics of flow w0re noted, and provide a clue to the reasons for the successful operation of the notch of Test 3. In Tests 4 and 5, with a peaked bottom and a discharge of 200 second-feet, the flow was c9ncentrated on the outside slopes of the chute. As a result, the two jets were deflected by the basin sides, causing them to intersect about halfway down the basin length. This was evident when the tail water in the lower canal was lowered, Figure 15c.

In Tests 1, 2, and 3, the flow in general for 200 second-feet was weil. distributed in'the chute. For Tests l and 2, with a flat bottom, and for Test 3, with a short length of peaked bottom, the two jets intersected at the bottom of the pool somewhere near the lower end of the basin. Thus, for the notch of Test 3:, a m_ore uniform distribution of flow occurred in the chute and also throughout the length qf the stilling basin, Figure 158. Since it also maintained the desired stae;e­discharge relationship the notch of Test 3 was selected for use in the apron tests and ultimately for use in the reconnnended design.

Stilling-Basin Tests

With the recommended control of Test 3 installed i� the model, Tests 6-3i were conducted to develop a stilling-basin design which would produce, at ·a11 flows, a smooth evenly distributed flow of water in the basin and lower canal section. The stilling-basin length was 25 feet, in Tests 6-13, and was lengthened to 35 feet in Tests 14-31, F'igure 8. 'I'ht:) se groupings of tests will hereafter be referred to as tests on the short and long basin. Table 2, Pae;e 12, gives the results of the tests on the short basin, and Table 3, Pae;e 13, contains the results of the tests on the long· basin. It is to be noted that these two tables give the elevation of the highest wave for each test, and also describe the action in the pool and the charaoter of the canal surface.

5

After the proper control notch had been selected and the peaked bottoms installed in the stilling basin, it was found that the performance of the various stilling basins could best be evaluated by measuring and comparing the wave heights in the lower canaJ.o In practically every test the efficiency of the Jump and its ability to dissipate energy and provide uniform fiow was reflec�ed in the height of the waves which existed in the lower canal . For this reason the discussion of the stilling-basin tests centers around wav,e heightso However, the above-mentioned tables give a brief description of the· action in the pool and the photographs of the model in operation show the extent of the turbulent water in the model.

Tests on Short Basin

Tests 6-13 were conducted on the short basin, 25 feet longo Test 6, Figure 8A, was conducted with no baffle piers installed in_the basin . Tests 7, 8, 9, 10, and ll, Figures 7 and 9, were conducted to study the effect of different baffle pier designs. For Test 12, Figure l0A, a fillet was installed at the intersection of the chute and basin valleys. For Test 13, Figure l0B, a false floor of sheet metal was installed over the chute valleys t9 produce a flat chute bottomo

A comparison of the results.of Tests 7, 8, 9, 10, and ll, Table 2, Page 12, showed that the baffle pier designs of Tests 8 and 9 were most �ffective in reducing the wave heights in the canal section.downstream from the drop. For the maximum flow of 200 second-feet the waves splashed up to _about 600 feet for both tests, making the actual wave height above the normal water surface �bout one-half foot. The wave heights of Tests 7, 10, and ll were considerably higher, as shown in Table 2o

In Tests 7, 8, 9, and ll, the most effective location of the baffle piers, was determined by the following procedure: While th�model was operating at maximum design flow the baf'.fle piers, which were mpunted on sheet metal strips bent to fit _the floor of the basin, were inserted at the upstream end of the stilling basin and. slowly moved downstream _ to about the middle of, the basin. The wave heights were noted as th� baffle piers were moved and the location at which the waves were a minimum. was chosen as the most effectiveo

The piers of Test 10 were tested onJ.y at the location given in Figure 9B . The fillet of Test 12 and the flat chute bottom of Test 13 had onJ.y a sma.1.1. effect on the reduction of wave heights in the canal below the basin as shown in Table 2, Page 12 0

In Test 6, with the short basin and no baffle piers installed, the wave heights in the canal below the d:rop were about 1-1/2 feet. With the baffle piers of either Test 8 or 9 installed, the wave heights were reduced to about one-half footo This reduction of wave heights fully Justified the use of baffle piers in the basin .

(

6

For some installations, the short basin equipped with baffle piers, similar to those of Tests 8 or 9, Figures 7 and 9, might be considered ad.equate. However, since baffle _piers in the ,pro�otype structure might be damaged in various wa:ys, it was desired to develop, if possible, a stilling basin of economic proportions that would operate satisfactorily even if the baffle piers were destroyed completely. Accordingly, the stilling basin was lengthened to 35 feet and the tests on the long basin were iµade.

Tests on Long Basin

Tests 14�31, Table 3, Page 13, were performed on the stilling basin after it had been lengthened to 35 feet, Figure BB. Test 14, Figure BB, was made witp.out.baffle piers and Tests 15, 16, and 17, Figure 11, were conducted with various sizes of baffle piers installed in the basin. Tests 18 and 19, Figure 16, were performed to determine the effect on the action of the jump in the basin when the baffle piers of Test 16 were obstructed with trash. Tests 20-30, Figures l2A and B, were made to determin,e the most effective method of placing the baffle piers in two rows to reduce the possibility of their becoming obstructed with floating trash and debris. Test 3i, Figure 12C, was made to determine the effectiveness of an arrange­ment of baffle piers propos�d by the design section.

\

A comparison of the wave heights, Table 3, Page 13, of Test 14 with those of Tests 15, 16, and 17 showed that baffle piers reduce4 materially the height of waves in the canal section below the drop. Since sufficient reinforcing steel could be placed in the 7-inch wide piers of Test 16 to meet all structural requirements, this pier was selected for further tests. The distribution of flow in the,stilling basin apd a visual comparison of the height of waves in Tests 14 and. 16 are shown in Figure 17. Tests showed that small bits of debris and weeds introduced into the flow above the control would lodge on and between the piers spaced as shown in Test 16.

It is possible that during field operation of the prototype the baffle �lers will become completely obstructed with floating trash and debris. Consequently, for Tests 18 and 19, rags were fastened to the front of the baffle piers to assimilate the field conditions where the piers were completely obstructed, Figure 16A. In both tests the flow of water was deflected vertically upward over the piers and th� resulting pool surface was very rough, Figure 16B. Additional tests wer� then made to prevent clogging of the openings between the piers.

Tests 20-30 showed that there was an effective method of staggering the 7-inch wide piers into two rows to increase the clearance between the piers and yet provide 'a smooth water surface in the lower canal. By comparing the results of these tests in Table 3, Page 13, it was .apparent that the lo.cation of piers in Tests 21 and 22, Figure 12A, produced the most effective reduction of wave heights.· The location and arrangement of baffle piers of Test 21, is recommended by the laboratory because it is considered less likely to become obstructed with floating trash and debris. Figure 18 shows the operation of the model at a discharge of 200 second-feet using th9 piers of Test 21.

· It was evident that wave heights became progressively higher as the·

piers were moved downstream as a group; also that, in general, ·moving the

7

downstream row of piers downstream with the upstream row in a fixed position, gave progressively higher wave heights.

Discussion of Results of Stilling-Basin Tests

A study of the results of the tests on the short basin showed that the baffle pier designs of Te-sts 8 and 9 were most effective in reducing the turbulence and wave action in the canal section downstream from the drop . At the maximum design fJ.ow, the wave heights for the short basin without baffle piers were J. .5 feet compared to wave heights of one-half foot wh-en piers of the design of either Test 8 ·or 9 were installed in the basino If the canal banks were of a material abJ.e to withstand waves of this :magnitude the short·basin with properly designed baffle piers installE?d coul.d be used. There were no particularly undesirabJ.e hydraulic characteristics apparent on the modeJ. at lower fJ.ows in either Test 8 or 9 o

The fact that most of the flow was aJ.ong the sides of the pool at low flows was not considered serious, since harmful affects did not extend to the end of the apron.

Lengthening the stilling basin J.0 feet was thought -- to be justified for this particular installation on the Sand Hollow Wasteway since the long basin without baffle piers produced waves appreciabJ.y lower than those of the short basin, with no piers installedo Additional tests showed :that the wave heights could be further reduced by the addition of baffle piers to the long basin. With properJ.y pJ.aced piers in the long basin, the waves were reduced from 0o 9 feet to 0 . 3 feet higho The location of baffle �iers in Test 20 produced slightly more reduction of wave height� at the maximum design flow, but the J.ocation of baffle paers in Test 21 was recommended by the laboratory since tes�o �howed that this arrangement of piers was J..ess J.ikel.y to become obstructed with floating trash and debris .

At the request of the design section, the pier arrangement of Test 31 was tested in the model. This a.:tTangement differed from Test 21. in that the sma1.l outside piers of the upstream row were removed and the upstream row of piers were moved 6 inches farther downstream as shown in Figure 12C . The action in the pool and lower canal was Just as satisfactory· as tllat produced by the pier arrangement of Test 21, Figure 19. Further tests on the pier arrangement of Test 31. showed that the openings between the. piers would not become clogged with trash. _

For aJ.l flows tested, the pool and canal surfaces were relatively smooth and the fl.ow of water was evenly distributed at the end of the paved apron of the drop o There was no evidence of measurable erosion in the gravel-lined section of canal immediately below the drop.

Since the arrangement of piers for Test 31 performed satisfactoriJ.� they were adopted for use in the recommended structure.

8

RECOMMENDED· D]pIGN OF DOOF STRUCTURE

Based on the results of hydrauJ.ic model teets and on field l:1mitations, the structure recommended for prototype construction consisted of the long basin, Figure 8B, with the baffle pier arrangement of Test 31, shown in Figure 12c, and the control .aotch of Test J, Figure 6B. As a res.uJ.t of the tests made to reduce wave heights, it was possible to reduce the vertical. height of the stilling basin trom the origina.D.y proposed 10 feet to 9 feet. The entire structure is also shown on Figure 13, and an over-:all view of the model is shown in the Frontispiece.

9

TabJ.e J.

RESULTS OF TE3TS ON CONTROL NOTCH (TESTS J.-'5) Description

of test FJ.evation of* Desired Actual head Test desian Q hi&iliest wave · head** in modeJ. Remarks

J. See 200 605 1 5.50' 4. 5J.' ' Pronounced side Figure 3 rollers in pooJ. and , canaJ. surface very

rough. FJ.ow concentrated.in chute grooves. See Figure J.{+A . Two Jets intersect near end of basino '

J.00 -- 4. 02' 3-3J.' Pool. and canal surface rough. Flow do�n chute grooves tends to outside slo-oes of �ooves.

2 See 200 7.0 1 . 5. 5• 5 . G3 ' Pronounced side Figure 6A rollers. Pool and

canal. surface \ . extremely rough •

FJ.ow concentrated more on outside slopes of chute grooves. See Figure 14B. Two Jets intersect beJ.ow middle of -oooJ..

100 -- 4 . 02' 4028 1 Pool and canaJ. I

surface rough . - -F--l.ow shifted to

inside slopes of chute &Tooves.

*FJ.evation to whic� highest wave splashed on J.eft channel bank 8 feet downstream from end of transition.

**Desired head--Head from Curve A, Figure 5, corresponding to discharge for test.

J.O

Description of test

Test . desi..m Q. 3 See 200

Figure 6B

100

4 See 200 Figure 6c

100

5 See 200 Figure 7

100

Table l (Continued)

Elevation of Desired Actual head ili.!Zhest wave head in model.

6 . 25 1 5. 5' 5 . 66 1

-- 4.02' 4.14.'

6.75' 5 . 5' 5. 57'

-- 4.02 1 �4 . 13 I

6075' 5 . 5' 5062 1

4002 1 1j: o 45 I

ll

Remarks Side rollers in poolo

Pool and canal surface very rough. Peaked basin bottom seemed to straighten flow through poolo Distribution of flow down chute valleys uniform for different flows. See Figures l4C and l "lB •

Pool and canal surface rollilh.

Control notch of Test 3 moved to this position to spread flow of water onto outside slopes of chute valleys . Flow deflected back by side slopes of basin peak, two jets intersecting about center of basino Pronounced side rollers . Pool and canal surface very row:m. See Figure l4D.

Pool and canal surface rougho Flow of water still on outside slopes of chute valleys .

Pool and canal surface very rough . Pronounced side rollerso Flow·of water riding outside slopes of chute va.U..eys . Deflected back to center of pool by outside slopes of ba�ino Jets intersect about center of pool. See Figure 15 •

Pool and canal surface ro1who

Table 2

REBULTS OF T:ESTS ON "SHORT" STILLING BASIN Description Elev. of Distribu-

of test highest tion of Test desii:m Q wave* flow** Remarks

6 See 200 7.0' Poor Pool and canal surface v'ery rough, FiRure 8A pronounced side rollers.

7 See ' 200 6.25' Fair Pool and canal surface rough, side Figure 7B rollers in �pper pool .

50 -- Fair Flow mostly along sides of basin. Pool and canal surface roURh.

c3 See 200 6.0 1 Fair Pool and canal surface rough. Piers Figure 7c deflected jets of water up above

normal pool surface. Side rollers in upper pool.

50 -- Fair Pool and canal surface rough. Flow mostl.v along sides of pool .

9 See 200 6.0' Fair Pool and canal �urface rough. Piers Figure 9A deflected'jets of water up above

normal pool surface. Side rollers I in upper pool.

50 Fair Pool and canal surface rough. Flow --mostly along sides of pool.

10 See 200 6.5' Poor Pool and canal surface rough. Piers Figure 9B intercepted practically all incoming

flow, causing jets to shoot well above normal pool surface. Most of flow along surface of pool. (

ll See 200 6.5' Fair Pool and canaJ surface rough. Flow Figure 9c deflected to outsides of pool

eliminatiru;i: side roller. 12 See 200 6.5' Poor Pool and canal surface very rough.

Figure lOA �ottom fillet did not break up flow of incoming jets. Pronounced side rollers in pool.

13 See 200 6 . 5' Poor Pool and canal surface rough. Flow Figure lOB well distributed on chute bottom but

concentrated· into two jets by side slopes of peaked basin bottom and basin sides . Pronounced side rollers in 12001.

*Elevation to which highest wave .splashed on left channel bank 8 feet downstream from end of transition .

**At downstream end of transition.

12

Table 3

RESULTS OF TESTS ON ''WNG" ST.n.LJNG BASJN Description -

of test Elev. of Distribution Test desi.1m Q wave.a* of flow · Remarks

J);. See 200 6.4' Poor Pool and canaJ. surface fairly Figure 8B rough, side rollers on both sides

of stillinR pool . See Figure 17A. 15 See 200 6.1 Good Pool and canaJ. surface smooth.

Figure 1.lA SmaJ.l side rollers in unner pool . 100 -- Fair Flow mostly along sides of poolo

Pool and canaJ. surface smooth . 50 -- Fair Flow mostly along sides of pool o ' Pool and c·anaJ. surface smooth .

16 See 200 5. 9 Good Pool and canal surface smooth. '

Figure llB SmaJ.l side rollers in upper pool. See Figure l7B .

50 -- Fair Flow mainly along sides of pool. Pool and canal surface fairly smooth.

17 See 200 5o9 Good Pool and canal surface fairly Figure llC smooth . Side rollers in upper

pool o

50 -- Fair Flow mainly along sides of pool. Pool and canal surface fairly smooth.

18 See 200 6 .5 Fair Clogged piers deflected jet of Figure 16A on l·b water 3 feet up abo.ve normal

6. 1 pool surface . Rapid flow along on r b right bank, flow along left bank

slower and mostly on surface. 50 -- Poor Clogged piers deflected jet of

water 18 inches above normal pool surface . Very little flow along left banko

19 See 200 6.6 Poor Clogged_piers defleGted incoming - Figure 16B� both jets 3 feet above normal pool

banks surfaceo Pool and canal surface very rough . Flow mostly on surface of pool o See Fli?ure l6C .

*Elevation to which highest wave splashed on left bank 18 feet below end of transition for 100 sf. Elevation to which highest wave splashed on right bank 18 feet below end pf transition for 50 sf .

13

'

Description o:f test Elev.

Test des:1.� Q waves 50 --

20 See 200 5. e Figure 12A A=l. 5' 50 3.2 B=l. 5'

21 See �00' 5. 9 Figure 12A

A=l. 5' 50 3.15 B=3'

22 See 200 600 Figure J.2A A=l. 5' 50 3.25 B=4. 5 1

23 See 200 6.0 Figure 12A A=l.5' B=6 1

50 3.25

24 See 200 5. 9 Figure 12B A=l. 5' 50 3.3 B•l. 5'

25 See 200 6.0 Figure 12B A=l • .5 1 50 3.25 B=3.0 1

26 See 200 6. 0 Figure 12B A=l.5 1

B=4.5 1

50 3.25

of

Table 3 (Continued)

Distribution of flow Remarks Poor Clogged piers deflected inconiing

jets 18 inches above normal pool surface. Flow mainly on surface and alona sides� ipool.

Very good Pool and canal surface very smooth. Small side rollers in unner poolo

Good Pool surface smooth, flow of water unstable in center of pool just below piers O

Very good Pool and canal surface very smooth o

Small side rollers in upper pool. See Figure 18 0

Good Pool surface smooth but flow unstable in center·of pool just below piers.

Good Pool and canal surface smooth. Small side rollers in unner poolo

Good Pool and canal surface fairly smootho F1ow of water unstable in center of pool just below piers.

Good Pool and canal surface became rougher as second row of piers was moved downstream. Side rollers pecame larger.

Good Pool and canal surface became rougher as second row of piers was moved downstream. Unstable flow between rows of piers, center of pool.

Very good Pool and canal surface very smooth o

SmaJ.J: side rollers in unner pool. Good Pool and canal surface v&ry smooth.

No unstable area below pierso Good Pool and canal surface smooth.

Small side rollers in upper pool. Good Pool and canal surface fairly

smooth. No unstable flow below pier so '

Good Pool and canal surface became rougher as second row of piers was moved downstream. Side rollers became larger.

Fair Fluctuating horizontal roller formed between row of piers.

14

Description of test Elevo of

Test desi� Q waves 27 See 200 5 .9

Figure J.2A A=3' 50 3.2 B=l.5'

28 See 200 601 Figure 12A

A=3' 50 3.2 B•3'

29 See 200 600 Figure 12A

A=4.5 1 50 3.4 B=l.5'

30 See 200 6.0 Figure 12A

A=:4.5 1 50 3.3 B=3'

31. See 200 5 . 9 Figure 12C

50 3 . 15

Table 3 (Continued)

Distr;i.bution of flow Remarks

Very good Pool and canal surface smooth. Small. side rollers in mmer pool.

Good Pool and canal ·surface- fairly smooth. Fluctuating horizontal roller formed in center of pool just below lower_row of piers.

Good Pool and canal surface fairly smooth. Side· rollers in upper poolo

Fair Pool and canal surface became rougher as s,econd row of piers was moved downstream. Unstable horizontal roller formed in center of pool just below lower row of piers.

Good Pool and canal surface fairly smooth. Side rollers in upper pool.

Fair Pool and canal surface rather rougho Flow mainly along left side of pool.

Good Pool and canal surface fairly smooth. Side rollers larger than in Test 280

Fair Flow mainly along left side of pool. Side roller along right bank in upper three-fourths of poolo

Very good Pool and canal surface very smootho Small. side rollers in upper half of poolo See Fip:ure 19.

Good Pool and canal smooth but flow of water just below downstream row of piers unstable. _See Fip:ure 19 0

l5

9

'

F I G U R E

1 7 IG 15

10

2 3

2-, 2G

34 se 36 1

I

_ _ _ _ _ _ l. I

I

UN ITED STATES DEPA RT M ENT O F. "T H E. I N TE R IOR

B UR E A U O F R E C \... A M A'T IO N PAY E.TT.E DIV. - BOISE. PR OJ E C'T- IDAHO

LOC AT I O N MA P SAN D HOLLOW WASTE WAY(EAST BRANCH)

W I L LOW CR E E K WASTEWAY

2 5 0 0

<fl z Q I-

w ...J w

24 50

2400

2 5 5 0

IO

0

<{ > w _J w

2500

2450

FI G U R E 2

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140 150 STAT I O N S 160 170

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180

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STAT IONS

l-5•°_.l E A RTH SECT I O N

220

lW

230

SECTION d No. I 5 . 5

No.2 5 . 0 ll!o. 3 3. 1 8 No. 4- 3.1 1

H YDRA U LI C P RO P E R T I E S A

aa.oo 7 5.00 .%. 1 5

.;;>8

r n e..97 .025 2.71+ . 0 2 5 1 .88 . 0 2 5 2. 13 . 025

s V .00035 2. 2 . 00053 2.66 . 0039 5. 51+

. 002 l+.31+

U N I T E D 5, T A T E S

Q 200

2 0 0 2 00 2 00

D E P A R T M E N T O F' TH E INT E R I O R B U R E A U o r R E C L A M AT I O N

P A Y E T T E D IV \ 5 1 0 N ....., 80 1 .S E P ROJ ECT- I DA HO

P R O F I L E ( S E CT I O N S 5 A N O H O L L O W WAST E WA Y

(E A ST B RANCH )

O R A W N : _ ...fl, W tt, _ S U B M I TT E D : �...:..� - - - - - -

TRAC E D ;_fl_.W,,_R,_ R E C O M M E N D E D��- - _ _ _

CH EC K E. D :_yY.YJ.,..IS'L _ A P P RO V E D : _ ��"'- ".�.--

03- P-GSW CALDWELL, IOA H0 - 10- 16-47·

Top of cana l-·

Pier 45°4" !

Sta. A-- .,

0 -�

H A L F

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P L A N

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. ,

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S E C T I O N B-B

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S E C T I O N A - A

r/t

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S E C T I ON C-C S E C T I O N D-D

F I G U R E 3

S EC T I O N E- E S EC T I ON F-F S E C T I O N G·G SECTION H-H

0·

S C A L E OF F E E T

"

SAND HOLLOW WASTEWAY (EAST BRANCH)

TRAPEZO I DA L C O N CRETE D R O P S

V E R T I C A L F A L L 10. 0 ' D I S C H A R G E = 200 S E C O N D F E ET

O R I G I N A L D E S I G N

•

Sti l l ing well and hook gouge-. � --- 19'-o:--� Connecting tube used in model-. \ ;

Rock baffle---, '- • - \ ·

End of sti l l i n g basin apron - - - . ,.. _ _ _ ___ _ _ _ _ _ _ 4a'..-o' - --- - - - - - -,-, \ 1 r

/- --Control wheel for tailgate

', ! I r-- ·-- - ,. - -Ta i lgate

·.;,

-7 ' I

'

Water Inlet " Stoff Gouge-···-� .

)'

L H re: : r ..,, 1 f>'>/\¥40 � I ' ' I

I I ' I : : : : : : : :

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SCALE OF FEET (PROTOTYPE) 0 6 12 24 36 48

0 I 2 4 6 8 SCALE OF FEET (MODEL)

P L A N O F M O D E L

S AN D HO LLO W WA ST E WA 'Y

T R A P E Z O I D A L C O N C R E T E D R O P S

E X T E N T A N D L A Y O U T O F 1:6 S C A L E M O D E L

O R I G I N A L D E S I G N

_ _ .sondtrop

.,, Gl C ::0 [Tl

-I>

6.0

5.0

f-W 4.0 w u... z -0::

w f-<l: 3.0

3: u... 0

:r: f-a.. w 2.0

1 .0 j I

00

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;:--........ --- _,.. j

C u r v e 8- t:.---...... ' ' C u r v e A -_ .. __. '

j. .... -V" i:;...--/ �

.,, .... ,,,, "_/ V"

A/ ,,,,, / � ...... C urve A - D e s i r ed H ead - D i s c harge c u rve.

� ...... C a l c u l a t e d tor c a n a l s e c t i o n s b oth a b o v e

- '5/ ., a n d b e I o w d ro p . lj V

- ·· -T

., 1/ ; V _ C u r v e B - H e a d - D i s c h a r g e c u r v e obt a i n e d �

.,� f r o m m o d e l t e s t w i t h t h e c o n t ro l n otch . �" o f Test =lt: 3 i n s t a l l e d .

J :,," -

4� ,

,� )/'

I/

SAND H O LLOW WAST EWAY

H E A D - D I S C H A R G E C U R V E S

1 : 6 S C A LE M ,O D E L

..,, ---G> C ::a l'T1 01

10 20 30 40 so 6 0 10 so· 90 1 00 1 10 120 130 140 1so . 160 · 110 1 00 190 200 2 1 0 220

D I S C H A R G E I N _ C U B I C F E E T P E R S E C O N D

•

S EC T I O N A-A

� - --9.02�-->-: ' '

' ' -� �- 0.94'

S E C T I O N A - A ,

S E C T I O N A-A

F IGURE 6

Note , For location of Sto. A see F ig . 1 3 .

F loor Level

. A . T E ST 2. T WO N OTC H E S A N D O R I F I C E LOC A T E D 10' - 0" DOW N S T R E A M F R O M STA T I O N A .

A >

·-�

·8 "

• Bevel 4" . 45o

Fioor Leve l

> A

<l'. 0

B. TEST 3. R EC O M M E N D E D NOTCH D ES I G N W I TH O N E N O TC H AT STAT I O N A .

C . T EST 4 . SA M E N OTC H A S T E S T 3 E X C E P T N OTC H I S LOCATED 1 0' - 6" D OW N S T R E A M FROM STAT I ON A .

SA N D H O L L O W WAS T E WAY

T Y P E S OF CONT R O L NOTC H E S T E S T E D I , 6 SCA L E MODEL

•.

:*- 645'-·'"j 1/

'i' J

S E C T I O N A-A

,,

- 8 "�

··--Bevel 4''-45 °

Level

A. T E ST 5 T WO N O T C H ES LOCAT ED AT S TA T I O N A

/'/ Symmetrical a bout Ii. ------<·

B . B A F F LE P I E R DETA I L S U S E D I N T E ST 7

__:>l'.l'metrico l a bout i

C . B A F F L E. P I E R D E T A I LS U S E D I N T E ST 8

S A N D H O L LO W W A S T E WAY

CON T ROL NO T C H A N D T Y P ES O F _B A F F LE P I E R S T E S T E D 1 : 6 S C A L E M O D E L

FIG U R E 7

.. ;: I

,- Riprop trons,t,on ' Warp from 2d to l¼ , 1 ·

�I y

�- I r· - - -- - - - - -- - -2 5' - o·: __ - - ---- - - - -

·\

Level

F I G U R E 8

.,-Concrete transition : Warp from l ¾d to 2 d

,' �-.' . I

- - 10·- o�- - : I

:! �i ,:_ Control no -;:tc-;:-h --f-----..:._ ___ -t ____ .:.,_ ______ +--

' ' ' '

•o f Test 3

-±>I A

;.I '------:: :

�-- - - 10·-o·�- - -:.J

P LA N O F MOD E L

A . TEST 6 . SHO R T STI L L I NG BAS I N WITHOU T B A FF L E P I E RS

•• R iprop t rans i t i on / Warp from 2 • I

<X

d J. 1

V

I

I. Al

/ - '-Control nctch

of Test 3

�- I

�-I

1 I V r· - - - - - - -- -- -- ----35' -o"--- - - - - - --- - - - - - --- ---

P L A N O F MO D E L

Level

�.r

,,-concrete transition

Warp from 1( • to 2 • 1

� 1

B . TEST 1 4 . L O N G ST I LL I N G BASIN ' WIT H OUT B A FF L E PI E R S.

S A N D HO L LO W WAST E WAY

DETAI LS OF S T I LL I N G B A S I NS TEST E D

I • 6 SCALE MOD E L

F I G URE 9

A. T E ST 9 . B A F F L E P I E R D E TA I LS

�mmetrical about Ii.

8. T E ST 1 0. B A FF L E P I E R D E TA I L S

C. T E ST 1 1 . B A F F L E P I E R D E T A I L S

S A N D H O L L O W W A S T E W A Y

T Y P E S O F B A F F L E P I E R S T E S T E D

1 : 6 S C A L E M O D E L

\

FI G U R E 1 0

Sym met r i ca l about t··, .. ____ :\__ - - ---· - ---- ____ _,

H A LF PLA N OF M O D E L

S lope Dista n ce

A - 5' 6°

B - 3' o · C - 8 ' 6

°

o - 9' o ·

A. TES T 1 2 . F I LLET A T I N T E R SECT I O N OF. C H U TE

A N D STI L L I NG BAS I N FLOO R

' ' I ' '

Symmelricol about '1.··,

_2_:1_.,.. f

,-Folse bottom of sheet metal resti ng / on s ides and center peak of

/ chute bottom .

I ' '

!<- --3'-4f ,:.., _ _ _ _ _ _ _ _ __ _ _ _ 181

-6�---- - - - - - - - - - - - - �

H A L F P L A N OF M O D E L

B . T E ST 13 . FALSE F LOO R PLA C E D OVE R C H U T E V A L L E Y S

S A N D H O L LO W WAST E WAY

T E S T S TO I M P R O V E D I S T R I B U T I O N O F F L O W

I N S TI L L I N G BA S I N

1 ' 6 S C.A L E M O D E L

_ ___c:_:_Symmetr ica l about Ii.

• F L O W

_ -(· Symmetr i ca l about Ii.

F L O W

- - Symmetr i ca l about Ii. - � -,--------<

F L O W

•

A . T E S T 1 5 . B A F F L E P I E R D E TA I L S

B. T E S T 1 6 . B A FF L E P I E R D E TA I L S

/(" ,.:,. q,

C. T ES T . J 7. B A F F L E . P I E R D E TA I LS

S A N D H O L L O W W A ST E W A Y

T Y P E S O F B A F F L E P I E RS T E S T E D

1 • 6 S C A L E M O D E L

F IGURE 1 1

.. F L O W

A. T E S T S 20 · 2 3 A N D 2 7 - 30 . D E TA I L S OF B A F F L E P I E R S

. {. Symmetr ica l about i;_

FLOW

B. T E S T S 24 - 26. B A F F L E

.. . . Symmetr ical about It _L.-..:..'.___�- - - ----<

D E TA I LS OF P I E R S

C. T E S T 3 1 . D E TA I L S O F B A FF L E P I E R S

S A N D H O L L O W W A S T E W A Y

F I GURE 1 2

See Tobie ID for d i'mens ions A & 8.

See To b i e JII for d i me n s i ons A & 8.

T Y P E S A N D LOCAT I O N OF BAFFLE P I E R S T E S T E D

1 • 6 SC A L E M O O E L

i.J!9!.1Jiti2f1_!9..'.;, : or os directed �- - - - - - - - - - - - - - - - - - - - - - - -- - - - -- - --- - - -- - - _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ - - - - - - eo. oo' - - - - - - - - - - --- ------ - ------ - - - - - - - -' '

: Ar>- ' s·�� �-' '

- - � --· '

! I

--- - - - - - - --- - --- - - - - - ----«·>t 8 ->4 ,<--' - - -r- ,.-

!

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,,- Warp from 1 4: I slope _t r to 2: 1 slope ------

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Cutoff wall os direclu in sandy moferio/-,

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F I G U R E 13

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··· -f H ongit. @ B f

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SEC TION C-G

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y_ __j __

, l,j� Longit. bars @ef"atong

transv. bars. Bend 2 4 " into cuto f f

Top o f bank--, , .. ,,Level , .. 0 = 2 00 r- - - - - - - - - - - 1 1- 0 - - - -: - - - - - ""!<- - - - - - - - 15 - 0 - - - - - - - - --,..

- - -- I w. s---x : ,.--¥ -- : � " ='

m

C >-P L A N

Typical ground surface-.... ----,

' .. f, L ongit. bars @ 8 f along tronsv. bars

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SCALE OF F E E T

'- f, Longit.bors @ Bf olong lronsv. bars Bend into cu loft.

S C A L E O F F E E T

_";' � "' "' ._ - - - - - - - - - - - - -� ' ' ' s = '. oooJsl;

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S EC TION A-A Symmetricol about f

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LONGITUDINA L SEC TION ON f

' · . f9 Tronsv.

SEC TION D-·D

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SECTI ON E - E

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£/\Vt, �I �

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w. s.-) o = 200 ¥...=-� , ,

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..... PERSPE C TI VE

I ,- $ =,0003 5 SEC TION F-F

--Protection o s directed

E S TI M A T E D Q U A N T I T I E S Concrete _ _{.fpr_ pQ.e_sJry�fyr_e_o_njyJ _ _ _ _ _ __ _ ___ _ _ 5 9 Cu. Yds. Reinforcement steel (For_one_strucJure (Lnlv) _ _ 4600 L bs.

S T R U C TURE DA TA

S TA A EL EV. (]) ELEV. (g) E L EV. ® ELEV @) S TA . B · 22 5 + 0 0 2 5 2 7. 74 252 Z 65 2518 . 74 2 5 1 7. 7 1 224 + 20 2 1 1 + o o 25 1 7. 4 6 2517. 3 7 2508. 46 2507. 43 216 t 20 204 + oo 2507. 00 2506. 9 / 2498.00 2496.97 203 t 20 1 9 1 + oo 2496. 54 2496. 45 2487. 54 2486. 5 1 1 9 0 + 20 1 79 t 00 2486 . 12 2486.03 24 77. 12 2476 , 09 I 78 t 20 152 + oo 2475 . 53 2475 . 44 2466. 53 2 465. 50 161 t 2(' 1 4 5 + oo 2464.93 2465. 84 2455. 93 2454 .90 144 t 20 130 + oo 24 54. 40 2454. 3 / 24 4 5.40 2444.37 /29 +20

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N O T E S A ll reinforcement shall be placed so that the centers o f bars in

the outer toyer will be 2 f from face of concrete unless otherwise shown.

L op all bars 34 diameters of splices. Stagger splices. Entire structure to be placed _on undisturbed e arth or

thoroughly compacted fill.

UNITED STATE 5

DEPA R T M E N T OF THE INTE R I O R B U R E A U OF R E C L A M A TION

BO / Sc PR O J E C T - / Oil. H O

PAYETTE D I V I S I O N

S AND HOL LOW WASTEWAY ( EAST BRANCH )

TRAPEZOIDAL CONCRETE DROPS

F u /0.0' Q u ZO O

DENVER, COLORADO OCT. 3 , 19-4 7

Ao Test 1. Flow through notches using control of original design at Station A.

Test 3. Single notch at Station A . Note the even distribution of flow through the chute valleys.

Figure 14

. Test 2. SmaJJAr notches with orifice moved 10 feet downstream from Station A .

D. Test 4 . Single notch moved 10 1 6 11 downstream. Note th, water riding the outside slopes of the chute.

SAND HOLLOW WASTEWAY FLOW CONDITIONS WITH NOTCHES OF TESTS 1-4

Discharge--200 second-feet 1: 6 scale model

A o Test 5. Two notches without orif'ice located at Station A.

Figure l5

B. Test 3 . Single notch located at Station A. Note that Jets remain in the valleys through­out the basin length.

C o Test 4. Single notch moved 10 1 6 1 1 downstream f'rom Station A. Note the Joining of' the two Jets in the center of' the stilling basin.

SAND HOLLOW WASTE.WAY FLOW CONDITlONS USJNG NOTCHE3 OF TESTS 3-5

Discharge--200 second-feet l:6 scale model

A. Method used to clog ba.:f:fle piers for Test 19.

B. Test 19. Discharge of 200 second-feet with piers clogged as in A above.

SAND HOLLOW WASTJ!MAY FIDW CONDITIONS WITH PIERS CIDGGED

l: 6 scale model

Figure 16

Figure 17

A. Test 14 . No baffle piers. Stilling-basin operation satisfactory but turbulent with surges and waves extending into the canal..

B . Test 16. Baffle :piers installed . Stilling-basin .and canal water surface comparati�ely smooth.

SAND HOLLOW WASTEWAY STILLING-BASil PERFORMANCE WITH AND WITHOU T PIERS

Discharge--200 second-feet 1:6 scale model

"'

•

A. Test 2L Fl.ow cond.i tions in stilling basin with two rows of piers install.ed •

B. Test 2l. Waves aJ.ong the canal banks with same two rows of piers install.ed.

S.AND HOLLOW WASTE.WAY FLOW CONDITIONS WITH PIERS OF TEST 2l INST.AI.LED

Discharge--200- second-feet l:6 scale model

Figure 18

Figure l9

A . Test 31. Discharge 200 second-feet . Piers installed o Water surface in stilling basin and canal relatively smooth •

B o Test 31. Discharge 50 second-feet o Flow concentrated at side slopes of trapezoidal stilling basin. Waves negligible o

S.AND HOLLOW WASTEWAY FLOW IN RECOMMENDED STlLLJNG BASJN

l:6 scale model

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