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TYPE OF SCHEMES

RUN OF RIVER

No storage.

The output is subject to instantaneous flow.

Reliability of discharge and geological conditions should be ensured.

CANAL BASED

Utilizes the fall and flow in the canals.

May be planned in main canal or in bye-pass canal.

Nearby drops should be clubbed in existing canals.

In canals under planning concentrated drops should be considered.

DAM BASED

Dam toe schemes are most common in India.

Water stored during monsoon is utilized for power generation.

PUMP STORAGE


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Upper reservoir

Lower reservoir

Pumped storage

power plant

Pumping

Generating

Pumped Storage Scheme Configuration


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Diversion and Intake structure

Desilting chamber

Water conductor system Forebay/balancing reservoir

Penstock

Surge tank

Power house

Turbine, generator and controls

Tail Race

Switchyard

COMPONENTS OF SMALL HYDROPOWER SCHEME


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INVESTIGATIONS

Investigation Stages

1. Reconnaissance level (preliminary/PFR)

2. Feasibility/Detailed level (pre-investment/DPR)

3. Execution


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RECONNAISSANCE LEVEL

At this level of investigations following should be

determined

Hydrological survey

Topographical survey

Geological survey

Power load demand assessment

Socio- economic survey

Head and discharge.

Technical feasibility of the project.

Identification of critical issues and their possible

solutions.


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FEASIBILITY/DETAILED PROJECT

REPORT-INVESTIGATIONS

Hydrological survey

Topographical survey

Geological surveyPower load demand assessment

Socio- economic survey

Meteorological survey

Environmental survey

Survey for construction material

Power Evacuation Line Survey


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DURING AND FOR EXECUTION

STAGE Sub soil exploration/geo-technical investigation for knowing

soil parameters for structural designs

Setting of the pillars with levels for controls of levels for

excavation and structure

Testing of construction material


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TOPOGRAPHICAL SURVEY


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DETERMINATION OF HEAD

By altimeter

By GPS

By Dumpy level

By total station


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Distances

Angles

Directions

Elevations

Coordinates

TOPOGRAPHICAL

SURVEYS


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RUN-OF-RIVER: River with rapids and

drops


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RUN-OF-RIVER: River with mild slope


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LAYOUT PLAN OF RUN-OF-RIVER

SITE


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L-SECTION OF RIVER


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DETERMINATION OF HEAD

By altimetervery approximate

By GPS approximate

By Engineering level reasonable

Theodolite and Total Station accurate

Map very rough

Water filled tube crude but accurate

O O OG S O A


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METHODOLOGIES FOR HEAD

ESTIMATION1. USING DETAILED MAPS

Detailed topographic maps are useful for locating potential sites andfor obtaining a rough estimate of head levels.


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2. WATER-FILLED TUBE AND ROD

METHOD

This method is suitable for low-head sites. It is reliable, reasonably

accurate and inexpensive.


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ENGINEERS LEVEL

A telescope mounted so that it can be levelled tomake the axis horizontal only


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3. VERNIER THEODOLITE

TOTAL STATION


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TOTAL STATION

Main Body


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CONTOUR MAP OF PROJECT SITE


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TOTAL POINTS COLLECTED


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Global Position System

HANDHELD

MOUNTED


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FLOW MEASUREMENT

Velocity-area method

Weir method


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RECTANGULAR NOTCH

Q = 1.8 (L-0.2H) H3/2

Where,Q is discharge in cumecs

L is the length of the rectangular notch.

H is the height of water in notch


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V - NOTCH

Q = 1.417 H5/2

Where,Q is discharge in cumecs

H is the height of water meters


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AREA VELOCITY METHOD


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FLOW MEASUREMENT OF

TURBULENT STREAM

InstrumentFlow Stream

RangeUpto 4000 l/s

Accuracy1% PrincipleConductivity of the water

Q = M/(K x A) cumec

M = Mass of salt (Kg)K = Conversion factor (Kg/m3/ohm-1)

A = Area under curve (ohm-1S)


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Time (Seconds)

Cond

uctivity

(10ohm

)

-6

-1

Area underCurve

Back ground Conductivity

SUITABILITY OF THE


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SUITABILITY OF THE

INSTRUMENT

SUITABLE TO MEASURE THE FLOW OFTURBULENT STREAM

MEASURE THE DISCHARGE OF THETURBULENT STREAM ACCURATELY ASCOMPARED TO OTHER METHODS

NO SITE CONSTRUCTION IS REQUIRED

SINGLE PERSON OPERTATION

SELECTION OF DISCHARGE


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SELECTION OF DISCHARGE

MEASUREMENTSECTION &

POURING POSITION Discharge measurement section should be

turbulent with no stagnant pools (water

velocity less than 0.1 m/s). The measuringposition should be in moving but not fast

flowing water

The pouring position should be at least 25 times

the width of stream at discharge measurement

section and the flow should be highly turbulent

for better mixing of salt solution.


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DETERMINATION OF QUANTITY

OF SALT Measure the Av. Width and Av. Depth of

the discharge measurement section and

multiply the two together.

Select the quantity of salt to use from the

Table.


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Table

Width (m) X

Depth (m)

Back Ground Conductivity

0-100 s 100-500 s 500-2000 s< 0.1 250 g 500 g 750 g

0.1 to 1.0 500 g 750 g 1000 g

> 1.0 1000 g 1500 g 1500 g


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Procedure for Discharge measurement

1. Choose a turbulent section for pouring salt solution2. Choose a measuring position. Check that the conductivity probe can be

submerged in the water without air bubbles being trapped by theprobe

3. Switch on the Flow stream

4. Find out background conductivity

5. Find out salt quantity and add to water in a bucket6. Pour the solution slowly in the stream but within 15 seconds.

7. Measure conductivity at measuring position

8. When test is completed get

Mass of salt

Elapsed time Background conductivity

Peak conductivity

Discharge in l/s.


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L 25 B>

POURING POSITION

MEASURING POSITION

FLOW


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GEOLOGICAL INVESTIGATIONS -

HYDROPOWER PROJECTS

STABILITY OF WEIRS

The foundation mass should be impermeable (non-jointed,

non-fractured and thoroughly crystalline igneous rocks,

claystones, massive sandstones and massive limestones) toavoid leakage.

Narrow river valley is suited most for construction of weir

Stable hillslopes attribute to the long life and stability of the

reservoir.

Sites should be selected carefully so as to be free from

defects which could result to leakage from reservoirs

Leakage may threat the safety and stability of the weir/dam.


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GEOLOGICAL STRUCTURES

Bed: A sedimentary layer whose thickness is more than acentimeter.

Dip: The maximum angle of inclination of a bed with the

horizontal.

Fault: A fracture along which it shows evidence of

relative movements.

Fold: Bends or curvature or undulations developed in the

rocks of the earths crust as a result of stresses to which

these rocks have been subjected from time to time.


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DEFECTIVE FEATURES


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SITE SELECTION

INTAKE

Should be at narrow valley. Bends should be avoided.

Banks should be stable.

No land slides.

Minimum turbulence in flow.


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DIVERSION WEIR AND INTAKE SITE


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DESILTING TANK AND CHANNEL

Flatter land.

Free from cross drainages.

No active slide zone.

Slopes should be stable.


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FOREBAY AND SPILLWAY

Flatter land.

Filling of land should be avoided.

Slopes should be stable. Natural stream should be nearby for spill water.


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PENSTOCK

Alignment should be along the ridge. Shortest length.

Minimum bends.

POWER HOUSE

Easy accessibility.

Flatter ground.

Above high flood level.

Stable slope.


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site selection, invesigations

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