2. →SPILLWAY GATE, ALSO CALLED STOP GATES, ARE
ADJUSTABLE GATES USED TO CONTROL WATER FLOW
IN RESERVOIR, RIVER, STREAM SYSTEMS.
→THEY ALSO ACTS AS BARRIER FOR THE STORAGE OF
ADDITIONAL WATER.
→BY THESE THE HEIGHT OF THE DAM WILL BE MORE
SUCH THAT LAND ACQUISITION WILL BE MORE.
→ GATES CAN BE PROVIDED TO ALL TYPES OF
SPILLWAYS EXPECT SIPHON SPILLWAY , BECAUSE
THE RAISE IN FLOOD LEVEL IS ALREADY SMALL
COMPARED TO THE OTHER TYPES OF SPILLWAYS
SPILLWAY CREST GATES
3. TYPES OF SPILLWAY GATES
DRIPPING SHUTTERS OR PERMENENT FLASH BOARDS
STOP LOGS AND NEEDLES
RADIAL GATE ORTAINTER GATES
DRUM GATES
VERTICAL LIFT GATES OR RECTANGLE GATES
4. DRIPPING SHUTTERS OR PERMENENT FLASH BOARDS
CONSISTSOFWOODEN PANELS
OF USUALLY 1.0-1.25m HIGH
HINGEDAT BOTTOMANDARE
SUPPORTEDAGAINSTWATER
PRESSURE BY STRUCTS.THE
SHUTTERS FALLS FLAT ONTHE
CREST WHENTHE
DOWNSTREAM SUPPORTING
STRUCTSARETRIPPED. HENCE
THEY ARE NOT SUITABLE FOR
CURVEDCRESTS.
THESE SHUTTERS CAN BE
RAISEDOR LOWERED FROM AN
OVER HEAD CABLEWAY OR A
BRIDGE.
VARIOUS AUTOMATICGATES
WHICH DROP
THEMSELVESHAVE BEEN DESIG
-EDTHESE DAYS.
5. STOP LOGS AND NEEDLES
STOP LOGS
→ THEY CONSISTSOFWOODEN BEAMS
OR PLANKS PLACED ONE UPON THE
OTHER AND SPANNING IN THE
GROOVES B/WTHE SPILLWAY PIERS .
→THEY CAN BE ROMED EITHER BY
HAND ORWITH HOISTING MECHANISM.
ITTAKES LOT OFTIME FOR REMOVING
THEM,IFTHEY BECOME JAMMED IN
SLOTS.
→LEAKAGE BW LOGS ISA BIG PROBLE
-M HENCETHEYARE USED IN MINOR
WORKS.
6. NEEDLES
NEEDLESAREWOODEN LOGS
KEPT SIDE BY SIDEWITHTHEIR
LOWER ENDS RESTING INA
KEYWAY ONTHE SPILLWAYAND
UPPER ENDS SUPPORTED BY A
BRIDGE.
IT IS DIFFICULTTO HANDLETHESE
ATTHETIMEOF FLOW HENCE
THESARE NOT USEDON ANY
MAJORWORKS.
THEY ARE SOMETIMESUSED FOR
EMERGENCY BULK HEADS,
WHERETHEY NEED NOT BE
REPLACED UNTILTHE FLOW HAS
STOPPED.
7. RADIAL GATE OR TAINTER GATES
RADIAL GATESARE ROTARY GATES
CONSISTINGOF CYLINDRICAL
SECTIONS.
THEY MAY ROTATEVERTICALLYOR
HORIZONTALLY.TAINTER GATESARE
AVERTICAL DESIGNTHAT ROTATES
UPTO ALLOWWATERTO PASS
UNDERNEATH.
LOWFRICTIONTRUNNION BEARINGS,
ALONGWITHA FACE SHAPETHAT
BALANCES HYDROSTATIC FORCES,
ALLOWTHIS DESIGNTO CLOSE
UNDER ITS OWNWEIGHTAS A
SAFETY FEATURE.
8. DRUM GATES
DRUM GATESARE HOLLOW
GATE SECTIONSTHAT FLOAT
ONWATER.THEY ARE PINNED
TO ROTATE UP OR DOWN.
WATER ISALLOWED INTO OR
OUT OFTHE FLOTATION
CHAMBERTOADJUSTTHE
DAM'SCREST HEIGHT.
THESEARE DESIRABLETO
LONGER SPANS IN ORDER OF
40 OR SOAND MEDIUM
HEIGHTS OF 10 OR SO.
9. VERTICAL LIFT GATES OR RECTANGLE GATES
RECTANGULAR GATESARE SPINNING HORIZONTALLY BWTHE
GROOVES MADE INTHE SUPPORTING SPILLWAY PIERS .
THE GROOVE S ARE LINEDWITH ROLLED STEEL CHANNEL SECTIONS
OF APPROPRIATE SIZE , SO ASTO PROVIDE SMOOTH BEARING
SURFACE HAVING SUFFICIENT BEARING STRENGTHANDARE KNOWN
AS groove guides .
RECTANGULAR GATES MOVE BW GROOVE GUIDES , AND CAN BE
RAISED OR LOWERED BY A HOISTING MECHANISM ATTHETOP.
THE GATESARE MADEOF STEELOR CONCRETEORWOOD .
THE FRICTIONAL RESISTANCE BW GATE AND DOWNSTREAMGROOVE
GUIDECAN BE REDUCED BY PLACING CYLINDRICAL ROLLERS BWTHE
BEARING SURFACE OFTHE GATE ANDTHE GUIDEGROOVES.
LARGEVERTICALS LIFT GATES MAY BE COUNTER BALANCED BY A
COUNTERWEIGHT BEAM ,WHICH IS LOADEDTO BALANCE SELF
WEIGHT OFTHE GATE, SO HOISTING FORCE IS REQUIREDTO BALANCE
THE FRICTIONAL RESISTANCE .