dams and reservoirs in civil engineering

types, advantages disadvantages etc

1. Dams

E Definition of Dams

E Advantages and Disadvantages of Dams
E Classification of Dams

E Types of Dams

3. A dam is a structure built across a stream,
river or estuary to retain water.

Dams are made from a variety of
materials such as rock, steel and wood.

5. al aay

"MTS =)

7. Upstream side

Downstream side

Parapet walls Spill way

MWL (inside dam)

Max. level

Normal Water Level

Free Board

Gallery

a

thecivilengg.com

8. Heel contact with the ground on the upstream side
Toe contact on the downstream side

Abutment Sides of the valley on which the structure of the dam rest
Galleries small rooms like structure left within the dam for checking
operations

Diversion tunnel Tunnels are constructed for diverting water before the
construction of dam This helps in keeping the river bed dry

Spillways It is the arrangement near the top to release the excess water
of the reservoir to downstream side

Sluice way An opening in the dam near the ground level, which is used
to clear the silt accumulation in the reservoir side

9. Dams gather drinking water >>>
for people.

Dams help farmers bring Dm
water to their farms.

Dams help create power D>
and electricity from water.

Dams keep areas from Dm
flooding.

Dams create lakes for people =>=>

to swim in and sail on.
Do

Flood Control

10. "Dams detract from natural settings, ruin nature's work

#Dams have inundated the spawning grounds of fish

#Dams have inhibited the seasonal migration of fish

s Dams have endangered some species of fish

sDams may have inundated the potential for
archaeological findings

Reservoirs can foster diseases if not properly
maintained

"Reservoir water can evaporate significantly

mSome researchers believe that reservoirs can cause
earthquakes

11. Main dam section at Sandeuping

Ship lift
Direction >

of flow

13. Le

Work began:

Due for completion: 2

Power generation

Power capacity: 18

will be

14. Sluice Gates

N

2
SS
Qt
LA |
vi x A
|
Je)

ik

PES; bat VE

18. Bhumibol Dam
The Largest Concrete Arch Dam in Thailand

Name humi Jam

Location On Ping river at Sam Ngao di in

Type E t if r tila vi
Size 154 met I and 486 meters Irr «++

Year Completed

Storage Capacity 13,462 million cubi
Electricity Generating Capacity

Annual Energy 1,200 GWh

19. Sirikit Dam

Name irikit Dam

Location On Nan River at Tha Pla district, Utt

Type Earth fill dar

Size 113.6 meters high and 800 meters long at the c

Year Completed

Storage Capacity 510 million cu
Electricity Generating da 50

Annual Energy 1,000

20. Srinagarind Dam

Name
Location

Type och jam with
Size
Year Completed

Storage Capacity

?

Electricity Generating Capacity

Annual Energy

21. Vajiralongkorn Dam

Name Vaji
Location
Type

Size
Year dit

Storage Capacity
Electricity Generating aa

Annual Energy

22. Lam Takong Dam
tS
Name L Takor

Location On Lam Takong ri

Type

Size 9
Year Completed

Storage Capacity nillion cubi
Irrigation Command Area 100,000 rai

23. Classification based on function

u Diversion Dam |
= Coffer Dam
= Debris Dam

25. Tha Thung Na Dam

Maeklong Dam

26. Classification based on hydraulic design

a Non-Overflow Dam
“Classification based on material of construction

‘a Non Rigid Dam

27. “Classification based on structural behavior

= Buttress Dam
a Embankment Dam

28. Gravity dams are dams which resist
the horizontal thrust of the water
entirely by their own weight.

Roadway

Concrete gravity dams
are typically used to
block streams through

narrow gorges. Concrete

Concrete gravity dam

29. width

span

=

crest —”

pr ore
upstream face 7

ma
width
l
A
downstream face

downstream face

== abutment

gl

ad Material of Construction:

Concrete, Rubber Masonry

foundation

30. An arch dam is a curved dam
which is dependent upon arch
action for its strength.

Arch dams are thinner and
therefore require less „,,.,.
material than any other
type of dam.

Arch dams are good for sites
that are narrow and have
strong abutments.

Concrete

31. span

— width —

„le
crest
a “+
toe.

— foundation central angle)

upstream face

reservair
width

“ight

downstream face
heel

Material of Construction:

Concrete

32. Buttress dams are dams in which the
face is held up by a series of

supports.
„ Buttresses
Roadway
Buttress dams can take many
forms - the face may be flat or
curved. Fist slab

Flat slab buttress dam

33. upstream face buttress head

sei

heel ul toe buttress | abutment

foundation, downstream face

Material of Construction:
Concrete, Timber, Steel

34. P Embankment dams are massive

dams made of earth or rock.

They rely on their weight to
resist the flow of water.

Homogeneous dam free water surface
Meter surface Sr seepage line

Dam with a drainage blanket

water surface tree water surface

‚greinage blanket

35. Plain View

downstream face

crest

upstream face

upstream
height re

Le

width

a

foundation

Material of Construction:
Earth, Rock

36. in vr Jarro j
MISE SEMI Bar
mA Wide Valley : Embankment Dam

37. Geology and Foundation Condition

aSilt and Fine Sand Foundation :
<

aNon-Uniform Foundation :

38. PT ds Pr dam

Environmental considerations
mEarthquake zone

mOverall cost

General considerations

40. # Gravity or weight of dam
Hydrostatic force

a Uplift force

mice force

#Earthquake forces

42. # Gravity or weight of dam

When

W

Weight of dam
Specific weight of material
Volume of dam

43. Hydrostatic Force

|. Horizontal hydrostatic force

al
ll. Vertical hydrostatic force

44. a Uplift Force

a 109

Dance trom hee! of dam ın per cent of tase wath

Uplift Force

45. alce Force

Ice thickness, ft

o 2 4 6 5,10 „12 m 19
Thrust, 1000 1b/lin ft

46. s Earthquake Force
E, =m(0.5g tol .0g)

E, = 0.555kY,h*

48. e have vertical US face
e constant extrados radii for U-shaped valley
e suitable to install gates at the US face

st le arch dams
® for V-shaped valleys
@ have curved US face
e no possibility for gate installment

49. i
di
13
!

i
!

midi

50. Constant-radius arch dam

Constant-angle arch dam

51. Y =k — 0
2Sin(0 / 2)

52. pt

Crest lengtr e

Om al
Crest length 143m
L ' Tim
Belengih el Archer 6 radivs to
foce ot cres!
asus 35m 85m
‘At mid height >. a
mak, thickness
rc A =
DAM PROFILE - "26m

LE GAGE France (1953) TOLLA Corsica (1959)
(strangthened later)

54. du <a

ps à

55. Earth Dams
are the most simple and economic (oldest dams)

Types:

1 Homogeneous embankment type
2 Zoned embankment type

3 Diaphragm type

56. Impervious foundation
Completely homogeneous dam

57. Rock Fill

Pervious Rolled Fill

Pervious Rolled Fill Original Surf
Approximate Rock Line ss

59. Rock fill Dam with RC facing

60. Tension Cratks
(partially water fited)

Circular Sup Failure

Phreabe

Surface

i no
H

Horizontal Alter

62. Buttress Dam
: is a gravity dam reinforced by structural supports.

Buttress
:a support that transmits a force from a roof or wall to another
supporting structure.

This type of structure can be considered even if the foundation
rocks are little weaker.

68. A coffer dam during the
construction of locks at
the Mongomery Point
Lock and Dam.

69. Tailing Dam at Aznalcollar Mine, Spain
o

April 25, 1998: the tailings dam at the Aznalcollar
mine near Sevilla, Spain failed. This has had BIG
societal implications — the toxic waste has killed
many fish and birds and flooded thousands of
hectacres of farmland.

February 26, 1999 marks the 27th anniversary of the failure of another
tailings dam on Buffalo Creek, West Virginia 125 peoople were killed
and 4,000 were left without homes. The dam failure was compounded
by the fact that it was waste that was escaping; the waste caught fire
and an explosion eventually occured.

70. Concrete 11%

Rockfill 3%

Other 16% Earthfill 58%
Timber Crib 2%

71. Teton Dam, Idaho

June 5, 1976: the failure in the Teton Dam led to flooding in the
cities of Sugar City and Reburg in Idaho. The dam failure killed 14
people and caused over $1 billion in property damages.

The dam failed because the bedrock was not strong enough to
support the structure. Currently the dam is once again used for
hydroelectric power,

72. Folsom Dam, USA

July 17 1995: a spillway gate of Folsom Dam failed, increasing
flows into the American River significantly The spillway was
repaired and the USBR carried out an investigation of the water
flow patterns around the spillway using numerical modelling

No flooding occured as a result of the partial failure, but flooding
is still a major concern for this area It seems that the Folsom Dam
may be due for a height increase as an answer to this concern

73. 4

Master Program of Exvircontal
engineering and Climate

Cane 7. Dams

* Dam Basics
- Purposes of Dams
- Components of Dams
- Types of Dams
- Dam Operations
+ Benefit-Cost Analysis
* Impact of Dams
« Dams and Locks for Navigation
Ea

74. Chattahoochee
Blountstown
Weve ahitchka
Mile 35

Apalachicola River

Coosawarier

River
CARTE

Oostananla 2

River Rome

Coosa River

CLAIBORNE

Mobile
River

RS

HARRIS

Alabama River

Choctaw Bluff

Barry Steam
Plant

Tallapoosa River

75. Master Program of Enviromental
engincering and Climate change

Purposes of Dams

e Amanagement tool used to control, regulate, and
deliver water for a variety of purposes:
Store water for dry periods
» Prevent flooding

» Increase river depth to aid navigation
e Stock watering and irrigation
» Fish farming

76. Master Program of Enviromental

Water

2 Set
Fire and Farm Ponds Irrigation
: supply

Other
Undetermined
Hydroelectric

Flood Fish and Wildlife

res Mining (tailings)

Debris control
Navigation

Recreation

Figure 7.1 Primary purposes eg" the United States.

77. 1970-1979

1960-1969

1950-1959

2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000 20,000
Number of dams

Figure 7.2 Age of dams in the aies tates.

78. Figure 7.3 Principal parts of a;

|

of Enviromental
‘and Climate change

79. Types:
+ Gravity Concrete Dam
» Buttresses
Concrete Arch Dam
Earthfill Dam
+ Core of large rocks
+ Clay cutoff walls
+ Stone surface (rip rap)
Storage (pools):
+ Dead Pool (not PC...)
+ Inactive Pool

+ Conservation Pool
+ active or joint-use

+ Flood Pool

+ Surcharge Pool

e Freeboard

Master Program of Enviromental
engineering and Climate change

+ Other Terms:

Face: Exposed surface of dam
Abutments: sides of dam
Appurtenances: pipes, gates, etc.
Dam Crest: Top of dam

Toe: base of dam

Parapet wall: along top

Spillway: for emergency releases
Outlet Gate: Adjustable spillway
Firm Yield: dependable capacity

Powerhouse: location of
generators

Headrace: Canal leading up to
powerhouse

Tailrace: Canal leading away from
powerhouse

80. of the earthen embankment dam MER erosion from waves.

81. MOE”

Master Program of Enviromental
| engineering and Climate change

Maximum water surface

Surcharge capacity

Emergency
spillway

Active storage
Minimum pool level

Dead storage

Principle
outlet

Figure 7.5 Classification of principle storage zones in a cross section of a
multipurpose reservoir. SEN

82. Bottom of Conservation

Dec

1

Nov

1-Mar tApe 1-May Tun het tug Sop

‘Feb

tion

83. Be A
Figure 7.6 Notice the cement blocks that are being poured during
construction of Hoover Dam and \petiegendous width of the structure at its
base.

84. Figure 7.7 The dramatic concrete arch design of Hoover Dam securely
holds the impounded waters of LM o.

85. Grand Coulee Dampigsgegipvity concrete dam.

86. Figure 7.10 Hydroelectric turbias aalerand Coulee Dam.

87. = ab e Et |
—
Workers inspect a hydroelectric turbine runner blade at Fort Loudoun Dam,
near Lenoir City, Tennessee.

88. Master Frogram of Enviremental
engineering and Clin

Benefit - Cost Study

+ Costs + Benefits
e Land Purchase + Cheaper electricity
e Dam Construction + Fewer floods
+ Dam Operation + More irrigation water
« Power lines + More recreation
» Irrigation systems + Easier navigation
» Navigation aids + Increased property
+ Environmental impacts values

89. enefit - Cost Analysis
© Benefit - Cost Ratio:
» Ratio of Benefits to Costs: r= B / C
er >1means more benefits than costs
© Net Value:
» Benefits minus costs: NV = B - C
+ NV > o means more benefits than costs
+ Rate of Return:
+ Discount rate that makes B(rr) = C
+ rr> market rate is a good investment

90. Muster Program of Enviromental
engineering and Climate change

Issues:

+ Time-Value of Money
« Today's Costs vs. Tomorrow’s Benefits
+ Must Discount the value of future benefits
e The Discount rate is like the interest rate

» Incorporates the risk of the project, and the alternative
uses of the money, such as investing the money
somewhere else.

91. Muster Program of Environmental
engineering and Climate change

mpacts of Dams
e Barriers to fish and boat movement
+ Salmon in the west, Shad in the east
+ Must build locks to move boats around dams

° Sediments build up in reservoir

« Farmland along the Nile and Mississippi Rivers
depended on these for soil improvement, and the
Delta needs these to keep the ocean out

° Many cities, farms, and people must be relocated

92. "Wr

Master Program of Enviromental
engineering and Clsanie change

_ SS

RC Relicensing

+ The Federal Energy Regulatory Commission (FERC)
regulates private dams (such as Georgia Power
dams).

In order to get or renew a permit, the operator has
to explain how the dam benefits the public.

+ FERC can give the original permit to anyone.

° When renewing a permit, FERC can give it to the
builder, or to anyone else they choose.

+ Many Georgia Power dams must have their permits
renewed, and are finding ways to improve their
performance so they can pet their permit renewed.

93. Figure 7.12 This scene in Wanxian, the largest of the relocation cities
affected by Three Gorges Dam, S 1 Ba in China (San meaning
“three,” Xia meaning “Gorge,” and: aning “Dam”).

94. gure 7.13 This tributary of the Yangtze River flows through the narrow

canyon called Xiao Sanxia (Less Gorges) and will be flooded after
completion of the Three Gorges Rn

%

95. Master Program of Enviromental
engineering and Climate change

Dams and Locks for Navigation

» Problem with dams blocking rivers
» Historical use of rivers by boats to transport goods.
+ With a new dam in the way, the barge operators are put
out of business.
» Protests build for providing a way around the
obstruction.

96. o Master Program of Enviromental
m — engineering and Climate change

Figure 7.14 Main-river dams form a staircase of reservoirs that stretch the
entire length of the Tennessee Ri

EM

100. Figure 7.15 Chickamauga Lock and Dam, located on the Tennessee River
near Chattanooga, Tennessee, is EEE lock in the TVA navigation system.

102. hine) - Danube Canal: Elevations on thé section

from Wúrzburg to Passau going through 53 stepwise
locks

103. Master Program of Enviromental
— engineering and Climate change

Interesting Websites
e Panama Canal Video
* Canal Video

104. 4 2 Allatoona

105. Bottom of Conservation

Dec

1

Nov

1-Mar tApe 1-May Tun het tug Sop

‘Feb

tion

106. A A 1-Apr Amaya Indul Au 158 100 1-Nov___1-Dec

107. Muster Program of Envirgmental
engineering and Climate change

Athens Poultry Industry

e Employs
» 150 workers per shift (three shifts) at about $10/hr
» Several dozen supervisors at about $20/hr
+ This is a payroll of over $15,000,000 per year
e Water Use
» They process about 200,000 birds per day
« This requires about 7 gallons per bird
e Which is 500 million gallons per year
e Water value
* is 3 cents per gallon
+ not counting taxes agglggilger community benefits.

108. | Atlanta, Georgia

“the fastest-spreading human
settlement in history"

Time Magazine

March 22, 1999

109. Carter’s Lake

Lake Allatoona

Lake Lanier

Atlanta

111. j Yee"

à Master Program of Envire
—— — nd Clon
a

hake. Allatogna and Cherokee Counties

Created by U.S. Army Corps of Engineers
Filled in December 1950

Watershed area is 1,110 mi?

Lake volume is 367,500 acre-feet

Lake area is 12,010 acres

Maximum depth is 145 ft

112. Lake Purposes

Saya wr Er

Flood control

Navigation

Hydroelectric power generation
Water supply

Water quality

Recreation

Fish and wildlife management

Master Program of Enviromental
engineering and Climate change

117. DD

Master Program of Enviromental

engineering and Climate change

* Lake Sedimentation
- Reduction in storage capacity
— Impairment of
* navigation
* recreation
* aquatic habitats
+ Regulatory Controls
- Stormwater regulations
- Erosion and sediment laws

118. Suspended Solids Concentration, mg/l

1,000

100

10

West Fork Little River near Clermont
à Chestatee River near Dahlonega

+ Chattahoochee River at Cornelia

* Chattahoochee River at Norcross

10 100
»Q/ Qo

119. +E. coli
— Total coliform

120. Sediment Bound Hg (ppb)

300 E

D
&

n
8

150

100

a
[=]

7 © % Clay vs. Stream Bed Hg
& % Clay vs. Stream Bank Hg
South Flat Cr. El % Clay vs. Lake Bed Hg
(urban) A % Clay vs. Upland Soil Hg
— Regression Line
95% Prediction Interval
Chestatee River

<r
A

10 20 30 40 50 60
Percent Clay (<2 um)

70

122. Master Program of Enviromental
— = engineering and Climate change

Lake Allatoona Tributaries

1000 © Noonday Creek y= 16.681 y=6,8339x""""
e Little River R? = 0.6987 + R? = 0.5872
+ Etowah River

Turbidity, NTU
8

3

Runoff, cfs / mi?

123. Muster Program of Environmental
engineering and Climate change

Sediment Budge

° Annual sediment loads, et bedload
e Etowah River: 25,300 tons
Little River: 10,000 tons
+ Noonday Creek: 1,100 tons
+ Blankenship Sand
+ Operates on the Etowah and Little Rivers
+ Removes over 120,000 tons of sand and silt

+ 85% are sand product
+ 15% are silt materials

126. Master Program of Enviromental
engineering and Climate change

Sand Removal

Each semi load contains:
23 tons of sediment
98% sand
2% clays
253 pounds of organic matter
10 pounds of nitrogen
5 pounds of phosphorus
2 pounds of regulated metals (mostly Ba, Cr)

This frees up almost 4000 gallons of storage

128. Master Program of Eavircontal
engineering and Chmaie chan

Silt Removal

Each semi load contains:

23 tons of sediment
35% sand
55% silt
10% clays
2600 pounds of organic matter (10x sands)
50 pounds of nitrogen (5x sands)
12 pounds of phosphorus (2.5x sands)

12 pounds of regulated metals (5x sands)

129. WEL”

Master Program of Enviromental
engineering and U lmate change

Reservoirs

» À reservoir is an artificial lake called man-made reservoir. It can be
formed by building a dam across a valley, by excavating the land or
by surrounding a piece of land with dykesand diverting a part of the
river flow into the reservoir. The water is stored in the reservoir
and can be used for irrigation, hydro-power or as a water source for
domesticor industry use. Man-made reservoirs are also very
effective constructions to control unexpected floods (see also
stormwater management).

A reservoir is fed by precipitation, rainwater runoff or from a
constant flow of a river. Water loss can occur due to evaporation
(especially in arid regions) and depending on the reservoir bottom
due to percolation (small reservoirs are often lined). Sediments
from rivers or surface runoff can reduce the storage volume of a
man-made reservoir significantly (FAO 1992).

130. HAPE”

Master Program of Enviromental
engineering and Climate change

131. Reservoirs

Master Program of Enviromental
engineering and Climate change

Water stored in a valley usually has a higher level than the valley
bottom downstream of the dam. Because of this difference in level,
the valley can be irrigated by a gravity system or other distribution
systems. Water can be taken from the reservoir via a concrete or
steel pipe.

This pipe connects the reservoir to an irrigation canal downstream.
A valve is usually located on the upstream end of the pipe to
control the discharge of water into the canal (FAO 1992). The
kinetic energy of reservoirs is often used to produce electricity (see
also hydropower small-scale and hydropower large-scale).

132. Comparison of the riverbed landscape between upstream and
downstream reaches of the Yasugawa Dam in the Yasu River in central
Japan. The dam is as old as 53 years and the distinctive riverbed
armouring can be observed. White part of rocks indicates thick
accumulation of organic matter originated from the reservoir. Source:
TAKEMON (2006)

133. WIE”

Master Program of Enviromental
engineering and Climate change

Reservoirs

+ Where no such water-body previously existed the presence of a
reservoir in a drainage basin and the abstraction of significant water
amounts for storage upstream significantly impacts the watercourse,
the flora and fauna, and the human inhabitants in the drainage basin.

» These potential impacts should be identified and thoroughly examined
prior to reservoir construction, in order to comprehensively assess the
total value of the reservoir project.

» Procedures to identify and properly evaluate potential environmental,
social and economic consequences of reservoir construction involve so-
called ‘Environmental Impact Assessment’ (EIA). Such an assessment is
now obligatory by law in many countries for all new dam constructions

(UNEP 2000).
EE

134. Master Program of Enviromental
engineering and Climate change

Reservoirs

» Ecological impacts of reservoir dams have been reported from
various aspects such as barrier for migratory animals like
anadromous fish, eutrophication of reservoirs by plankton
blooming, decreasing flow volumes in tail waters, stabilisation of
flow regimes by flood peak cut, changes in thermal regimes of river
water, river bed degradation and increase in substrate grain size by
sediment trapping, etc. (TAKEMON 2006).

Furthermore big dams and extraction of water (e.g. for spate
irrigation) can create riparian conflicts (see water conflicts). Also
read the paragraph “Impact on Environment” in the rivers
factsheet.

135. sic Design Principles
Adapted from UNEP (2000)

» Like lakes, reservoirs range in size from pond-like to very large
water-bodies (e.g. Lake Powell, U.S.A.). The variations in type and
shape, however, are much greater than for lakes. The term
‘reservoir’ includes several types of constructed water-bodies
and/or water storage facilities:

Master Program of Environ
engineering and Climate change

1. Valley reservoirs - created by constructing a barrier (dam)
perpendicular to a flowing river.

2. Off-river storage reservoirs - created by constructing an
enclosure parallel to a river, and subsequently supplying it with
water either by gravity or by pumping from the river.

136. = Z Program of Enviromental
A englncering and Climate change

137. Master Program of Enviromental
engineering and Climate change

sic Design Principles

Adapted from UNEP (2000)

The latter reservoirs are sometimes called embankment or bounded
reservoirs, and have controlled inflows and outflows to and from
one or more rivers.

In addition to single reservoirs, reservoir systems also exist, and
include cascade reservoirs - consisting of a series of reservoirs
constructed along a single river, and inter-basin transfer schemes -
designed to move water through a series of reservoirs, tunnels
and/or canals from one drainage basin to another.

138. WIE”

Master Program of Enviromental

gi

mping from a Reservoir
Irrigation

» The fields located around the reservoir upstream of a dam or surrounding a
natural lake are higher than the reservoir or lake's water table. Here
irrigation is only possible with the help of pumping stations, manual or
motorised pumping.

» The water level in the reservoir is usually highest at the end of the rainy
season, and lowest at the end of the dry season or the irrigation season.
Pumps installed at reservoirs and lakes must be able to handle these
fluctuations, which are not only vertical, but even more pronounced
horizontally, because the water recedes back to the lowest parts of the
reservoir.

» A dead branch of a river can also be made to function as a reservoir. The
branch is filled with water during the wet season and closed off during the
dry season so that the stored water may be used. Due to the low water
level, pumps are normally needed to irrigate fields from such a reservoir.

139. A small reservoir in the hills of Tepoztlán (Morelos, Mexico), which is mainly filled
by precipitation catchment. The water is extracted by gravity and is protected by a
fence to avoid contamination from animals or unauthorised use. The reservoir is
sealed with an impermeable liner. Source: B. STAUFFER (2009)

140. WEL”

Master Program of Enviromental
engincering and Climate change

ae u ne
peration and Maintenance

+ Because reservoirs are man-made water-bodies, they are more amenable to
artificial operation and regulation than lakes. As previously noted, operational
possibilities unique to reservoirs include the ability to discharge known
volumes of water at predetermined times, and selective discharge of water from
different water layers within the reservoir. This must be planned carefully as it
directly impacts the environment as described above. Also read the document
“Reservoir Operations and Managed Flows” (WMO and GWP 2008).

* Dams, especially the very large ones, must be checked regularly to ensure their
stability and security. Furthermore, many man-made water reservoirs are
affected by high sedimentation rates.

+ The accumulation of sediments in the reservoir reduces the main reservoir
asset i.e, its volume capacity. Moreover sediments can negatively affect
pumping and hydropower equipment. Therefore the designers should
consider the soil erosion and sediment transport (CHANSON and JAMES
1998). There are several approaches to minimize or deal with sedimentation.

141. MEI”

Master Program of Enviromental
engineering and Climate change

peration and Maintenance

» When a reservoir serves different functions it is nearly impossible to operate
each function at its maximum level. For example, a reservoir that provides
irrigation, power generation (see small scale and large scale hydropower), flood
control, and recreational use may cause conflicting demands by its users
(WATERENCYCLOPEDIA 201).

+ Health Aspects

+ Faecal pollution and other contamination of reservoirs has to be prevented by
wastewater treatment and buffer zones in case of non-point sources of
pollution (see also the factsheets on lakes or invalid link). If the reservoir is also
used as a source of drinking water, please also check water purification as a
measure to protect human health.

© It should also be considered, that surface water sources can lead to mosquito
breeding..