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CLOSE THIS BOOKPlanning of Water and Hydropower Intake Structures (GTZ, 1989, 122 p.)
VIEW THE DOCUMENT(introduction...)
VIEW THE DOCUMENTAcknowledgements
VIEW THE DOCUMENTPreface
1. Hydrological bases
2. Planning of the intake structure
3. Hydraulic operation and calculations
4. Necessary proofs of stability
5. Sand trap
Appendix
VIEW THE DOCUMENTList of symbols
VIEW THE DOCUMENTBibliography

List of symbols

A

= area


= branch of a river


= buoyancy in kN


= cross-section of flow


= runoff during an observed period of time T

AE0

= precipitation area


= total catchment area surface in m² or km²

Ai

= partial area of a partial catchment area in m² or km²

A1,2..

= partial area of station 1, 2 . .

a

= aerated area between tail water and top of the weir crest


= calibrated parameter for current meter (given by manufacturer of the instrument)


= height of the sluice opening


= inside width between trash rack / sluice bars


= coefficient dependent upon particle diameter

B, b

= width of weir, canal

b

= calibrated parameter for current meter (given by manufacturer of the instrument)


= width of trash rack / screen

C

= concentration of suspended matter

Cs

= content of suspended matter

c

= correction coefficient


= coefficient of resistance of particles

D

= equivalent diameter (4 F / U = 4 ·B ·h / (B +2h))

d

= distance between the trash rack / screen bars


= particle diameter

E

= catchment area

F

= cross-sectional area


= Froude's number

Fi

= individual surface fractions

fv

= velocity area

fvm

= mean velocity area

G

= weight of the structure in kN

g

= acceleration due to gravity = 9.81 m/s²

H

= horizontal forces


= main stream, main river

HHQ

= highest discharge

HQ

= flood discharge

HQ100

= 100-yearly flood

HW

= high-water level

h

= depth of water at the vertical lines of measurement


= elevation of water surface


= impounding head


= water level

hA

= runoff rate of the AEO during a certain period of time (T) in mm

hE

= energy head

hN

= height of precipitation above AEO during a certain period of time (T) in mm


= heavy precipitation

hR

= retention rate in the AEO during a certain period of time (T) in mm

hV

= evaporation height in the AEO during a certain period of time (T) in mm

hm

= mean weir head

hü

= weir head

hüe

= head of diversion weir

hüs

= head of retaining weir

I

= slope, gradient

iN

= intensify of precipitation in mm/hour

k

= correction factor

kS

= roughness coefficient

L

= length of structure


= length of trash rack / screen

l

= length of transition area (sand trap)

MMQ

= mean monthly discharges of all years observed

MQ

= mean monthly discharges of one year

MW

= mean water level

mG

= bed load movement

niG

= bed load transport

mGf

= bed load

mSf

= suspended matter load

rnSf

= suspended master transport

N

= precipitation

NG

= area precipitation

NNW

= lowest low-water level

NQ

= low discharge

NW

= low-water level

Ni

= precipitation of the station i

N1,2..

= point precipitation of station 1, 2 . . .

n

= correction coefficient


= number of events


= number of revolutions per unit of time


= pore volume proportion

ni

= number of potential steps in flow direction up to the point i being sought

nS

= number of potential lines


= number of potential steps

o

= index for headwater

PG

= bed load pressure

PSi

= seepage water pressure at a specific point i

Pu

= tail water pressure

Q

= discharge

QA

= discharge in the branch of a river


= design discharge

QH

= discharge in the main river

Qü

= discharge capacity over the weir

R

= retention in the catchment area during T (interception, infiltration)

Re

' = Reynolds' number

rhy

= hydraulic radius

S

= seepage water pressure

s

= height of end sill


= length of measurement section


= density of particles due to density of water

T

= time, unit of time


= recurrence interval

TK

= time of concentration in hours

TN

= duration of precipitation

TR

= duration of precipitation

t

= water depth

tan j

= friction coefficient

td

= time of passage

ts

= settling time, sinking time

U

= wetted perimeter


= tail water pressure

u

= index for tail water

V

= evaporation above the catchment area during T


= vertical forces

VQ

= estimated discharge

v

= flow velocity

vA

= flow velocity in the diversion canal

vE

= flow velocity in, the settling basin

vz

= flow velocity in the inlet canal

vd

= flow velocity in the settling basin

vi

= individual velocity values

vm

= mean flow velocity

vS

= settling/sinking velocity of particles

vS'

= mean settling/sinking velocity of particles

WG

= height of the amount of bed load

WH

= horizontal water pressure

WH1e

= horizontal water pressure in the headwater

WHr

= horizontal water pressure in the tail water

WV

= water surcharge on the structure

We

= height of diversion weir

WS

= height of retaining weir

w

= weir crest height


= dynamic buoyancy due to turbulent flow

x

= calibration factor

a

= angle of curvature / bend


= velocity coefficient

b

= angle of inclination

gF

= specific weight of solid matter particles

gG

= specific weight of bed load

gS

= specific weight of particles / grains

gW

= specific weight of water

D

= difference

DZel

= difference of energy heads

d

= contraction coefficient

m

= discharge coefficient


= weir coefficient

mX

= reduced weir coefficient

j

= retardation coefficient

n

= kinematic viscosity of the water

nG

= stability against sliding

y

= runoff coefficient, discharge coefficient

l

= loss coefficient

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