part i. reservoir sedimentation part ii. sediment...

1

Colorado State University

Training for Technical Planning of Small DamsDiponegoroUniversitySemarang, Indonesia

May 28, 2018

Part I. Reservoir Sedimentation

Part II. Sediment Management

3

Part II – Sediment Management

1. Sedimentation problems near dams

2. Density currents in reservoirs

3. Dambreak impact

4. Multi-objective dam operations

5. Socio-economic considerations

2

Reservoir sedimentation reduces flood control

L&D No. 3

Locks and Dams

Sediment can be Dredged

3

CSU Hydraulics Laboratory

Water

Sediment

4

Sediment can be Flushed

12




3. Dambreak impact



5

Discharge water through hydro power plant

13

/3714

Imha Reservoir has suffered from turbidity problems since 2002.

• Watershed area covers 1,361 km2

• Three major tributaries

In a deep reservoir, the density is determined by the result of solar heating of surface water which produces thermal stratification

15

(Imha Reservoir, July 2006)105

115

125

135

145

0 10 20

EL.m

O C

Temperature

997 998 999 1000kg/m3

Density

• Relatively warm, and• active mixing zone• Steep temperature

gradient zone

• Deep and cold zone

6

At IMHA BasinTyphoon Total

RainfallDuration

RUSA(8. 2002) 183㎜ 27hr

Meami(9. 2003) 185㎜ 31hr

Dianmu(6. 2004) 220㎜ 57hr

Ewiniar(7. 2006) 160㎜ 55hr

- Typhoon : triggered landslides and lots of sediment transport into reservoir

X

Plunge flow Underflow Inter flow

Plunge depth

Separation depth Interflow

depth

Plunge point

Separation point Interflow thickness

TE

W

Ti

Ti

TH

Epilimnion

Metalimnion

hypolimnion

17Discharge water through intake tower, 8/28/20068/28/2006

8/28/2006

18

II. Numerical Model

• Momentum (with Boussinesq approximation, non-hydrostatic ) :

)uux

U(

xdx

x

g

xg

x

P1g

x

UU

t

U

nsfluctuatioturbulentandforceViscous

3

1jji

j

i

j

gradientpressure'baroclinic'

ortionStratifica

z3

i0

gradientpressure'barotropic'

orsurfaceFree

i

gradientpressurechydrostatiNon

i

nh

0forceGravity

i

onacceleratiConvective

j

i3

1jj

onacceleratiLocal

i

• Scalar transport equation :

)ux

(x

)U(xt i

3

1j jj

3

1j jj

i

j

j

it x

U

x

U

it

x

3,2,1i:

t

tt Pr

0x

U

x

U

x

U

3

3

2

2

1

1

• Continuity :

7

/37

Inlet point0 km 4 km

Unit : kg/m3

/37

Inlet point0 km 4 km

Unit : kg/m3

21

Real-time gaging stations were installed at five stations to monitor turbid density currents propagating from each tributary into to the reservoir

Real-time monitoring system for Imha Reservoir; installed and has been operating by K-water since 2006

8

- Geomorphology and geological features of Imha Reservoir basin : Soil particles not easy to sink

Factors inducing turbid density currents

<Suspended Particle Sedimentation Test (After 48 hours)>

Other Site

DaeGok YongJunBanByeon

Imha Dam Basin

/3723

3-D Model simulation view at El. 141m

/37

0 10 200 10 20

0 200400 600800

0 10 20

24

July 11, 08:00 July 11, 12:00 July 11, 16:00 July 11, 18:00 July 11, 04:00

0 10 20

0 200 400600800 0 200 400 600 800 0 200 400 600 800

Observed

Simulated

105

115

125

135

145

0 200400600800

NTU

105

115

125

135

145

0 10 20

Temp.

Water Intake

9

/3725

26




3. Dambreak impact



ResultsResultsIV.IV.

27

38th Annual AGU Hydrology Days38th Annual AGU Hydrology Days

21 Mile Dam, Elko County, NV, Feb 8, 2017

How does the flood wave propagate downstream?

10

Bento Rodrigues Town,6 November 2015

Gesteira Town6 November 2015

Doce River at Governador Valadares City

11 November 2015, C ≈30,000 mg/l

Coast, 21 November 2015C ≈1,500 mg/l

Candonga Dam, 6 November 2015C ≈ 700,000 mg/l

28

Observed hydrographs in Doce River after the Fundão Dam break (ANA,2015).

29

Space and time steps: ∆x 500 , ∆t 900

Reservoir: The reservoir routing can be solved using the Level Pool Routing

→2

∆2∆

Where:

reservoirstorageasfunctionoftime; Inflow; Outflow;

30

Reach

S (m/m)

L (km)

W (m)

D (m2/s)

Manning n Ce (m/s)

A 0.0005 204 217 922 0.037 1.20

B 0.0005 133 377 531 0.032 1.04

C 0.0008 34 624 336 0.025 1.40

D 0.0002 108 725 328 0.020 0.60

11

31

The one-dimensional advection-dispersion equation is applied on the evaluation of transport ofsuspended load in open channels (Fischer et al., 1979; Julien, 2010).

Analytical solution for a constant spill in finite time interval is given by (Chapra,2008):

,2

Γ

2

Γ

2

Γ

2

Γ

2

Where: Γ 1 4 and

The error function complement, erfc, is equal to:

1 12

32

C is the concentration;is the flow averaged velocity; is the longitudinal dispersion

coefficient; is the settling rate.

33

12

34




3. Dambreak impact



/3735

Thank you!Questions?Sangju Weir, SK

from Hwayoung Kim

/37

Other Issues besides sedimentation

36

• It is hard to change reservoir operation rules for sedimentation problems because we have many other issues to deal with.

Flood control

Water supply

Turbidity

Stream ecology

Riverside environment

Hydropower

13

/37

10-3

10-2

10-1

100

101

0

0.2

0.4

0.6

0.8

164

|SC|Cobble

32|VCG

16|CG

8|MG

4|FG

2|VFG|Gravel

1|VCS

0.5|CS

0.25|MS

0.125|FS

0.0625|VFS|Sand

0.031|CM

0.016|MM

0.008|FM

0.004|VFM|Silt

0.002|CC

0.001|MC

0.0005|FC

0.00024|VFC|Clay

Tra

p ef

ficie

ncy,

TE, %

Fin

er (

%)

Grain size, ds (mm)

< LEGEND >Bed material dist.Suspended load dist.Trap efficiency curves

(Q=30 ,300 ,300m 3/s [L R])

64|SC|Cobble

32|VCG

16|CG

8|MG

4|FG

2|VFG|Gravel

1|VCS

0.5|CS

0.25|MS

0.125|FS

0.0625|VFS|Sand

0.031|CM

0.016|MM

0.008|FM

0.004|VFM|Silt

0.002|CC

0.001|MC

0.0005|FC

0.00024|VFC|Clay


(Q=30 ,300 ,300m 3/s [L R])

64|SC|Cobble

32|VCG

16|CG

8|MG

4|FG

2|VFG|Gravel

1|VCS

0.5|CS

0.25|MS

0.125|FS

0.0625|VFS|Sand

0.031|CM

0.016|MM

0.008|FM

0.004|VFM|Silt

0.002|CC

0.001|MC

0.0005|FC

0.00024|VFC|Clay


(Q=30 ,300 ,300m 3/s [L R])

10-3

10-2

10-1

100

101

0

0.2

0.4

0.6

0.8

164

|SC|Cobble

32|VCG

16|CG

8|MG

4|FG

2|VFG|Gravel

1|VCS

0.5|CS

0.25|MS

0.125|FS

0.0625|VFS|Sand

0.031|CM

0.016|MM

0.008|FM

0.004|VFM|Silt

0.002|CC

0.001|MC

0.0005|FC

0.00024|VFC|Clay

Tra

p ef

ficie

ncy,

TE, %

Fin

er (

%)

Grain size, ds (mm)


(Q=30 ,300 ,300m 3/s [L R])

64|SC|Cobble

32|VCG

16|CG

8|MG

4|FG

2|VFG|Gravel

1|VCS

0.5|CS

0.25|MS

0.125|FS

0.0625|VFS|Sand

0.031|CM

0.016|MM

0.008|FM

0.004|VFM|Silt

0.002|CC

0.001|MC

0.0005|FC

0.00024|VFC|Clay


(Q=30 ,300 ,300m 3/s [L R])

64|SC|Cobble

32|VCG

16|CG

8|MG

4|FG

2|VFG|Gravel

1|VCS

0.5|CS

0.25|MS

0.125|FS

0.0625|VFS|Sand

0.031|CM

0.016|MM

0.008|FM

0.004|VFM|Silt

0.002|CC

0.001|MC

0.0005|FC

0.00024|VFC|Clay


(Q=30 ,300 ,300m 3/s [L R])

Trap efficiency ( )

37

Q=30 m3/s

Q=300 m3/s Q=3,000 m3/s

Q=30 m3/s

Q=300 m3/s Q=3,000 m3/s

Low StageEl. 37.2m

High StageEl. 47.0m

avgTE = 77.9%

avgTE = 49.3%

/37

Sediment Yield & Reservoir Sedimentation

38

Time intervals (%)Mid-point

(%)delP Q (cms) C (mg/l) Q × delP

Measured load, qp (tons/yr)

qp/qt ratio(%)

Total load, qt (tons/year)

Avg. TE (%)

Res. Sed. (tons/year)

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11)=(9)*(10)

0 ~ 0.02 0.01 0.02 1,670 355 0.3 3,743 2% 91% 4,113 2% 37.8 1,555 1%

0.02 ~ 0.1 0.06 0.08 1,615 350 1.3 14,257 7% 91% 15,667 7% 38.2 5,991 5%

0.1 ~ 0.5 0.3 0.4 1,268 312 5.1 49,886 23% 91% 54,820 23% 41.3 22,654 17%0.5 ~ 1.5 1 1 678 232 6.8 49,576 23% 91% 54,480 23% 49.5 26,992 21%

1.5 ~ 5 3.25 3.5 263 148 9.2 42,840 20% 91% 47,077 20% 62.2 29,260 22%

5 ~ 15 10 10 104 95 10.4 31,218 15% 91% 34,306 15% 72.1 24,723 19%15 ~ 25 20 10 55 70 5.5 12,058 6% 91% 13,250 6% 76.2 10,103 8%

25 ~ 35 30 10 33 55 3.3 5,743 3% 91% 6,311 3% 78.3 4,942 4%

35 ~ 45 40 10 21 44 2.1 2,943 1% 91% 3,234 1% 79.4 2,569 2%45 ~ 55 50 10 13 35 1.3 1,435 1% 91% 1,576 1% 80.0 1,261 1%

55 ~ 65 60 10 7 27 0.7 640 0% 91% 703 0% 80.4 565 0%

65 ~ 75 70 10 3 18 0.3 167 0% 91% 183 0% 81.1 148 0%

75 ~ 85 80 10 1 10 0.1 29 0% 91% 32 0% 83.3 27 0%85 ~ 95 90 10 0 3 0 0 0% 91% 0 0% 94.5 0 0%

95 ~ 100 97.5 5 0 0 0 0 0% 91% 0 0% 100.0 0 0%

Total Naesung 214,534 100% 91% 235,752 100% 55.5% 130,790 100%

Yeong 44,331 82% 54,063 48.4% 26,193

Nakdong 128,310 94% 136,501 38.9% 53,042

Total 387,175 426,316 49.3% 210,025

FD SRC SEMEPP TE

Conventional FD/SRC method New approach

@Low stage

Sediment Yield: 426,000 tons/yr

Integrated Reservoir Sedimentation Estimation Procedure (IRSEP)

/37

Excavation Costs

39

Photos of excavationNakdong River Estuary Barrage

• Nakdong River Estuary Barrage (1990 – 2010)

• V = 13,678,000 m3 ( 43.2 million dollars)

• Unit cost = 6.31 USD/m3

Credit: K‐water

14

/37

Benefit and Cost AnalysisHydropower Revenues

• Capacity: 1,500 kW * 2 units

• 9.81

• Unit cost of sales = 0.13 USD/kWh

40

WeirProduction and benefit Unit cost of sales

MWh Benefit(106 KRW) benefit(103USD) KRW/kWh USD/kWhSangju 8,004 1,179 1,072 147.32 0.13

(Data: K‐water, 2014, 1 USD = 1,100 KRW)

/37

Hydraulic Thresholds

Open the gates above Q threshold = 620 m3/s

Operate the dam above H threshold = EL. 43.6 m

41

41 42 43 44 45 46 470

0.5

1

1.5

2

2.5

WS (El.m)

B/C

rat

io

WS threshold

/37

MCDA Optimization

[MCDA Characteristics]

• Decision making method to choose the best alternative

• Systematic process based on the familiar concept of an overall score

• Provides a way to document and audit decisions

42

• Main-Criteria and Sub-Criteria IdentificationSTEP 1

• Relative Importance Factors (RIF) Definition

STEP 2

• Constraints AnalysisSTEP 3

• Alternatives DevelopmentSTEP 4

• Rating method Determination and Modeling STEP 5

[MCDA procedure]

15

/37

Water Supply

Max. Reservoir Storage (V)

43

36 38 40 42 44 460

0.5

1

1.5

2

2.5

3x 10

7

Water stage (El.m)

Res

evoi

r st

orag

e (m

3 )

Maximum storage for water supply

Minimum storage for water supply (Pungyang intake facility)

Available storage

Intake pipe

/37

36 38 40 42 44 46 48 50 52 540

1

2

3

4

5

6

7

8x 10

7

Water stage (El.m)

Res

evoi

r st

orag

e (m

3 )

Maximum flood space

Top of banks

Current management storage (24.7 MCM)

Flood Control

44

Flood prevention space

Min. Reservoir storage (V)

/37

Stream Ecology & Riverside Environment

Max. GVSR(Good View Station Ratio)

45

36 38 40 42 44 46 48 50 520

5

10

15

20

25

30

35

40

45

50

Managing water stage (El.m)

Per

cent

of

pref

eren

ce f

low

wid

th r

atio

(%

)

16

/37

Stage (H) Constraints

46

0 2 4 6 8 10 12 1440

42

44

46

48

50

52

Distance from Sangju Weir (km)

Con

stra

int

wat

er s

tage

(E

l.m)

Pungyang(44.2)

Jukam(45.0) Hoesang(45.0) Maeho(45.0)

Drinking

Irrigation

Water Supply Constraints

Critical stage (El.45.0m)

* Irrigation duration: May‐September

Flood Drainage Constraints

Critical stage (El.46.1m)

0 2 4 6 8 10 12 1440

42

44

46

48

50

52

Distance from Sangju Weir (km)

Con

stra

int

wat

er s

tage

(E

l.m)

Maeho G4(46.1) Yaryong G5(46.1)

Flood drainage

* Flood season: June 21st – Sep. 20th

(Dam management Code, Mar. 1974)

/37

Discharge (Q) Constraints

• Hydropower production

Q > 50 m3/s

• Break‐even discharge

Q < 620 m3/s

• Turbidity limit Discharge

Q < 1,000 m3/s

47

/37

101

102

103

43

43.5

44

44.5

45

45.5

46

46.5

47

47.5

Q (m3/s)

Sta

ge (

El.m

)

h < EL 47.0 m (Flood control, Jun-Sep)

h < EL 46.1 m (Flood drainage, "Waryong", Jun-Sep)

h > EL 44.2 m (Drinking, "Pungyang")

h > EL 45.0 m (Irrigation, "Maeho", May-Sep)

h > EL 43.7 m (Break-even, B/C=1)

Q > 50 m3/s (Hydropower production)

Q < 620 m3/s (Break-even between HP and Sed.)

Q < 1000 m3/s (Turbidity downstream)

H and Q ConstraintsH range: EL. 44.2 ‐ 47.0mQ range: 50 m3/s – 620 m3/s

48

17

/37

Jan.1 Feb.1 Mar.1 Apr.1 May 1 Jun.1 Jul.1 Aug.1 Sep.1 Oct.1 Nov.1 Dec.1t Dec.3136

38

40

42

44

46

48

Month

Wat

er s

tage

(E

l.m)

Dringking water supply duration (Pungyang, El.44.2m)Irrigation duration (Maeho, El.45.0m)Flood drainage duration (Waryong G5, El.46.1m)Case1: High stage (El. 47.0m)Case2: Medium stage (El. 43.6m)Case3: Lowest stage (El. 37.2m)Case4: Seasonal stage control

Alternatives development

49

[Alt. 1]

High stage (El.47.0m)

[Alt. 2]

Medium stage (El.43.6m)

[Alt. 3]

The lowest stage (El.37.2m)

[Alt. 4]

Seasonal stage control

(1) Normal season (El.47.0m)(2) Flood season (EL.46.0m) ❸

❶

❹

❷

/37

07/17/2012 10/01/2012 01/01/2013 04/01/2013 07/01/2013 10/01/2013 01/01/2014 04/01/2014 07/01/2014 10/01/2014 12/31/201410

-2

10-1

100

101

102

103

104

Inflo

w &

dis

cha

rge

(m3 /s

)

Inflow and discharge

inflowtotal dischargedischarge for hydropowerQ threshold

07/17/2012 10/01/2012 01/01/2013 04/01/2013 07/01/2013 10/01/2013 01/01/2014 04/01/2014 07/01/2014 10/01/2014 12/31/201435

40

45

50

55

60

65

70

Wa

ter

sta

ge

at

Sa

ng

ju W

eir

(E

L.m

)

Water stages and movable gate opening at Sangju Weir

upstreamgate1 openinggate2 opening

Historical Operational Data

50

Water Stage is kept high according to the current rule

• Sangju Weir, July 2012 – December 2014 (2yrs)

/37

MCDA Rating (WAM)

51

Main Criteria (5)

Sub‐criteria (4)

Sub‐criteria (3)

Sub‐criteria (2)

Sub‐criteria (3)

Sub‐criteria (2)

Overall score and Ranking

Rating

18

52




3. Dambreak impact



Example: Peligre Dam in Haiti

Demographic Expansion

19

Lowland Slash and Burn

Subsistence Farming

Farming Uphill

20

Farming Hilltops?

Upland Degradation Causes Sedimentation

Sedimentation Reduces Flood

Control

21

Hurricane Impact

Emergency Spillway Operation

Citizens Blame their Government

22

Could this be avoided?

Summary and Conclusions

1. Sedimentation Problems near Dams

Flushing and dredging are possible in low-head dams

2. Density Currents in Reservoirs

Turbidity currents can be modeled and predicted

3. Dambreak Impact

Dam breaks impact rivers over long distances

4. Multi-objective Operations

Hydraulic thresholds and MCDA are useful for dam operations

5. Socio-Economic Considerations

Sedimentation can have a large socio-economic impact

Sediment Management References

1. Sedimentation Problems near DamsJi, U., P.Y. Julien and S.K. Park, “Case-Study: Sediment Flushing and Dredging near the Nakdong River Estuary Barrage”, J. Hydraulic Eng., ASCE, 137(11), 2011, pp. 1522-1535.

2. Density Currents in ReservoirsAn, S.D., and P.Y. Julien, “Case-study: Three-Dimensional Modeling of Turbid Density Currents in Imha Reservoir, South Korea”, ASCE J. Hydraulic Eng., 140(5), 2014,

3. Dambreak ImpactShin, Y.H. and P.Y. Julien, "Case-Study: Effect of Flow Pulses on Degradation Downstream of Hapcheon Dam, South Korea”, J. Hydraulic Eng., ASCE, 137(1), 2011, pp. 100-111.

23

Sediment Management References

4. Multi-objective OperationsKim, H.Y., and P.Y. Julien, “Case Study: Hydraulic Thresholds to Mitigate Sedimentation Problems at SangjuWeir”, ASCE J. Hydraulic Eng., 144(6), 2018, ISSN 0733-9429, 13p.

Kim, H.Y., D. G. Fontane, P.Y. Julien, and J.H. Lee, “Multi-objective Analysis of the Sedimentation behind Sangju Weir, South Korea”, ASCE J. Water Resources Planning and Management, 144(2), 2018, 12p.

5. Socio-Economic ConsiderationsLuis, J., Sidek, M.L., Desa, M.N.B.M. and P.Y. Julien, “Hydropower Reservoir for Flood Control: A Case Study on Ringlet Reservoir, Cameron Highlands, Malaysia”, J. Flood Engineering, 4(1), January-June 2013, pp. 87-102.

NEW 2018

69

Thank You!

Terima Kasih!

ACKNOWLEDGMENTSSangdo An, KICT, South Korea Marcos Palu, BrazilHwayoung Kim, K-Water, South KoreaMarcel Frenette, Québec, CanadaChris Thornton, CSU, USAPhil Combs, USACE, USANeil Andika, Indonesiaand apologies to those forgotten …

Terima kasih atasperhatian Anda!

part i. reservoir sedimentation part ii. sediment...

Documents