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इंटरनेट मानक Disclosure to Promote the Right To Information Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public. “जान1 का अ+धकार, जी1 का अ+धकार” “प0रा1 को छोड न’ 5 तरफ” Mazdoor Kisan Shakti Sangathan Jawaharlal Nehru “The Right to Information, The Right to Live” “Step Out From the Old to the New” IS 6531 (1994): Canal Head Regulators - Criteria for Design [WRD 14: Water Conductor Systems] “!ान $ एक न’ भारत का +नम-ण” Satyanarayan Gangaram Pitroda ““IInnvveenntt aa NNeeww IInnddiiaa UUssiinngg KKnnoowwlleeddggee”” “!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै” Bhartṛhari—Nītiśatakam “Knowledge is such a treasure which cannot be stolen” IS 6531 : 1994 m*9 WFFJ Indian Standard CANALHEAD REGULATORS- CRTTERIAFORDESIGN (F irst Revision ) UDC 626.112-55 Q BIS 1994 BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002 April 1994 Price Group 5 Intake Structures Sectional Committee, RVD 11 FOREWORD This Indian Standard ( First Revision ) was adopted by the Bureau of Indian Standards, after the draft finalized by the Intake Structures Sectional Committee had been approved by the River Valley Division Council. Regulator provided at the head of canal offtaking from a river is termed as canal head regulator. It serves the following purposes: a) To regulate the supplies entering the canal: and b) To control silt entry into the canal. This standard was first published in 1972. The present revision has been made in view of the experience gained during the course of these years in the use of this standard. The important modifications made in the revision are given below: 1) Layout for curved channel head regulator in case of head works for spate irrigation system has been added. 2) Determination of value of C has been modified. 3) Design criteria for curved channel sediment excluder for spate irrigation headworks has also been included. For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS 2 : 1960 ‘Rules for rounding off numerical values ( revised )‘. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard. IS 6531 : 1994 Indian Standard CANALHEADREGULATOW- CRITBRlAFORDESIGN / First Revision ) 1 SCOPE respect to the axis of the diversion work. This may, however, be confirmed from model studies, This standard covers the criteria for the design of if necessary. A typical layout of the canal head canal head regulators. regulator is given in Fig. 2. 2 REFERENCES Layout of canal head regulator in case of head- The Indian Standards listed below are necessary works with sediment excluder is given in Fig. 3. adjuncts to this standard: 4 HYDRAULIC DESIGN IS No. Title 4.1 General 4997 : 1968 Criteria for design of hydraulic The hydraulic design of canal head regulator jump type stilling basins with consists of the following: horizontal and sloping apron 10430 : 1982 Criteria for design of lined a) Fixation of pond level ( including losses through structures ); canals and guidelines for selec- tion type of lining b) Fixation of sill level, width of sill and shape of sill; 3 LOCATION AND LAYOUT c) Fixa~tion of waterway, number and width 3.1 Location of spans and height of gate openings, The location of canal head regulator is inter- requirements of breast wall, etc; linked with the location of diversion work. The d) Shape of approaches and other component head regulator should be located as close to the parts; diversion structure as possible and preferably at the end of the outer curve ( convex bend ), if e) Safety of structure -from surface flow available, to minimize the sediment entry into consideration; the offtaking canal ( see Fig. 1A ). ) f Safety of structure from sub-surface flow 3.2 Layout consideration; and The canal head regulator should be properly g) Energy dissipation arrangements; terminal aligned so as to reduce silt entry into the canal structures. to ‘; minimum and avoid backflow and formation 4.2 Pond Level of stagnant zones in the pocket. To achieve this, the a& of canal head regulator may be located Pond level, in the under-sluice pocket, upstream at an angle of SO” to 110” ( SM Fig. 1B ) with of the camal head regulator should generally be UPSTREAM + CANAL Fm. 1A CANAL HEAD REGULATOR DOWNSTREAM A CONVEX BEND 1 SI 1356 : 4991 Q OF HEADWORKS Fra. 1B ALIGNMENTOFHEAD REGULATOR LOOSE APRON PERVIOUS FLOOR L - 2A lacipyT nalP fo daeH rotalugeR 2 IS6531:1994 SPACE FOR GATE GATE GROOVE HOISTING PLATFORM BREAST WALL -AX15 L’ HEAD BAFFLE BLOCK IMPERVIOUS FLOOR B2 lacipyT noitceS 70 daeH rotalugeR Fro. 2 LAYOUT OF CANAL HEAD REGULATOR \i MOF TOT- C.C. BLOCKS D/S LMMZHnni APRON U/S INVERTED FILTER U/S LAUNCHING APRON \ Y 31L-l EXCLUDER TUNNELS s x=I_ FLOW A3 lacipyT nalP fo daeH rotalugeR htiw tnemideS redulcxE obtained by adding the working head to the the full supply discharge in the canal at a speci- designed full supply level in the canal. The work- fied pond level. To obtain control on entry of silt ing head should include the head required for into the canal it is desirable that the sill of head passing the designed discharge into the canal and regulator should be kept higher than the sill of the head losses in the regulator. If under certain under-sluices, as much as possible, commensurate situations there is a limitation of pond level, the with the economic waterway and the driving full supply level should be fixed by subtracting head available. If a silt-excluder is provided, the the working head from the pond level. In regions sill level of head regulator should be determined of high altitude where there is a possibility of ice in conjunction with the design requirements of formation, a cover of ice of about 0.5 m may be silt-excluder. added to the working head. 4.3.1 The required head over the sill ff, for pass- 4.3 SZll Level ing a discharge Q, with an effective waterway L, should be worked from the following formula: Sill level should be fixed by subtracting from pond level the head over the sill required to pass Q= CL, ffe3’4 3 IS 6531 : 1994 t- AXIS OF HEAD REGULATOR .- MAX. POND LVL CEMENT CONCRETE LINW TPANSiTlON PORTION ______ -- ______ AAMOURED STEEL PLATE BOULDER SET FACING i I I I * *t * l I * j/ I PRESSWE RELiEF VALVE -S- ECTICW ._~ X -X GRANITE STONE ~L_E_ VEL VAF1IES 63 lanidutignoL noitceS fo lanaC daeH rotalugeR htiw tnemideS redulcxE Fra. 3 LAYOUT OF CANAL HEAD RECWLATOR WITH SEDIMENT EXCLUDER where C = a coefficient; Q = discharge in ms/s; L, = effective waterway in m; and HI and H, = total heads to the bottom and top C = a coefficient ( see 4.3.1.1 ); of the orifice. JS = effective waterway in m; and He = required head over the crest for passing 4.3.2 Width qf Sill a discharge Q, in m. Width of sill should be kept according to the 4.3.1.1 In the formula given in 4.3.1 the exact requirements of the gates, trash and stop logs value of C depends on many factors; such as head subject to a minimum of 213 He. over the sill, shape and width of the sill (W), 4.3.3 Shape of Sill upstream slope (51) and downw ard slope (&) of the sill, height over the upstre am floor (P) and The edges of sill should be rounded off with a roughness of its surface. Some values of C for radius equal to He. The upstream face should H generally be kept vertical and the downstream varied % and -G- for ungated flow and for sloped at 2 : 1 or flatter. & = 0, zz = 2 and 3 are shown in Fig. 4. The 4.4 Having decided upon the effective waterway, discharge reduction factor for varied submergence the total waterway between the abutments includ- ratios -zc be obtained from Fig. 5 [H* : depth ing piers should be worked out from the following formula: of tail wattr level above the crest 1. The values of Lt=L,+ 2(.7VKEc, + Ila)&+ W C be determined by model studies where values based on prototype observations on similar struc- where tures are not available. Lt = total waterways, But when the outflow is controlled by partly open L, = effective waterways, gates, the condition similar to sluice flow deve- JV= number of piers, lopes, The required head in this case may be computed by the following equation: K, = pier contraction coefficient ( see 4.4.1 ), K-, = abutment contraction coefficient Q = 2136 -2g.Le ( H18/a - H,sI= ) ( see 4.4.2 ), where H B = head over crest, and Q = discharge in ms/s; W = total width of all piers. IS 6531 : 1994 1.2 I I,- HORIZONTAL CREST I I I I Ha/w Fro 4 RECOMMENDATION FOR COEFFICIENT OF DISCHARGE FOR VARIED I&, P AND W 4.4.1 R .ecommended values of K, are as follows: )a For square nose piers with corners rounded with a radius equal to about 0.1 of the pier thickness: II, = 0.02 b) For rounded nose piers: K, = 0.01 c) For pointed nose piers: x, = 000 4.4.2 Recommended values of K, are as follows: a) For square abutments with head walls at 90” to the direction of flow: b) For rounded abutments with head walls a.t L_ 90” to the direction of flow for O-5 He > T > O-15 H, r K, = 0.1 --- 3 c) For rounded abutments where r > 0.5 He, 4.5 Shape of Approaches and Other Compo- and head wall is placed not more than 45O nent Parts to the direction of flow: The shape of approaches and other component where parts should preferably be fixed by means of =r abutment rounding radius. model studies. However, for works of medium