1
Pierre Y. Julien
Reservoir Sedimentation
Department of Civil EngineeringColorado State University
Fort Collins, Colorado
Short CourseGadjah Mada UniversityYogyakarta, Indonesia
July 21, 2009
ObjectivesReservoir Sedimentation and Socio-Environmental Impacts:
1. Steep Mountain Channels and Sabo Dams; 2. Reservoir Sedimentation;3. Sediment Removal;4. Locks and Dams and Estuary Barrages;5. Effects Downstream of Reservoirs;6. Socio-Economic Impact.
1. Steep Mountains and Sabo Dams
2
Upper Basin: high-elevation snowpack; snowmelt runoff
Diverse Topography: highest mountains in Colorado – Elbert, Massive, Harvard, etc.
Lesser Himalayan Area
5
Bed Profile - 1988
250
270
290
310
330
350
370
0 10 20 30 40 50 60
Distance from Main Dam (KM)
Elev
atio
n (m
)
OGL,1967SURVEYED,1988SIMULATED,1988
Reservoir storage capacity of Sempor Dam
30
35
40
45
50
55
60
65
70
75
0 5 10 15 20 25 30 35 40 45 50
Volume (million m3)
Ele
vatio
n (m
)
197719811982198419942004
Volume (million m3)
Elev
atio
n (m
)
Imha reservoir
6
Barrier island loss due to hurricane Katrina, Mississippi RiverBarrier island loss due to hurricane Katrina, Mississippi River
July 2005July 2005
September 2005September 2005
11
CASC2D-SED Modeling 2004
4. Locks and Dams and Estuary Barrages
CASC2D-SED Modeling 2004
L&D No. 3
Locks and Dams
12
CASC2D-SED Modeling 2004
CASC2D-SED Modeling 2004
Sedimentation Problems Can Be Solved
CASC2D-SED Modeling 2004
Nakdong River and NREB Unsteady modeling for the upstream of NREB
13
CASC2D-SED Modeling 2004
Nakdong River Estuary Barrage
CASC2D-SED Modeling 2004
Quasi-steady state model
Upstream water level
Tide level
CASC2D-SED Modeling 2004
Quasi-steady state model (Model validation 2003 – with dredging)
4.8% (-0.32m)
2.9% (0.16m)
32.9% (0.27m)
5.9% (0.52m)
21.2% (0.17m)
14
CASC2D-SED Modeling 2004
5. Effects Downstream of Reservoirs
Hapcheon Re-regulation Dam
0
10
20
30
40
50
60
70
80
90
100
0 10 20 30 40 50 60 70 80 90 100
time (hr)
wat
er d
epth
(m)
Plan view from Main dam to Re-regulation dam
Main Dam
Re-regulation Dam
Main Power Station
Diversion Tunnel
119 m3/s during 3 hr per day
20 m3/s during 24 hr per day
Spillway
0
20
40
60
80
100
120
0 50 100 150 200 250Time ( hour, July 01 2005, 01:00 - July 10 2005, 24:00)
Flow r
ate
(m3 /s
)
Discharge at main damDischarge at re- regulation dam
15
Study Reach
Hapcheon Main Dam
Re-regulation Dam
Nakdong River
Study Reach = 45 km
Hapcheon city
Degradation and armouring
40 km
37
39
41
43
45
47
49
0 100 200 300 400 500 600
width (m)
bed
elev
atio
n (m
)
19832003
1 0 1 Kilometers
N
Sub-reach 1
Sub-reach 2
Sub-reach 3
Variation of Non-vegetated Active Channel Planform
1982
1993
2004
16
Variation of Non-vegetatedActive Channel Width
0
100
200
300
400
500
600
700
051015202530354045Distance from the confluence with the Nakdong River (km )
Active channel width (m)
1982199320041982_avg.1993_avg.2004 avg.
River changes below Hapcheon dam
2004
2007
1983
0.1
1
10
100
051015202530354045
Distance from the confluence (km)
Part
icle
siz
e, d
m (m
m)
198319932003
Median Bed Material Size (d50) along the study reach
Sub-reach 1 Sub-reach 2 Sub-reach 3
17
CASC2D-SED Modeling 2004
6. Socio-Economic Impacts: Case Study in Haiti
Example: Peligre Dam in Haiti
22
Could this be avoided?
CASC2D-SED Modeling 2004
Acknowledgments
Dr. Phil Combs (USACE-ERDC)Dr. Drew Baird (US Bureau of Reclamation)Dr. Marcel Frenette (U Laval)Dr. Sang-Kil Park ( PNU)Dr. Jose Luis Lopez (UCV)Dr. Y. Lan and D. Elsner (URS)Dr. Gigi Richard (Mesa State College)Dr. Un Ji (MJU)Dr. Z.Y. Wang (IRTCES)Dr. Chris Thornton (CSU – Hydraulics Lab.)Dr. Claudia LeonDr. Young Ho Shin (K-Water)
CASC2D-SED Modeling 2004
Erosion and River Mechanics Textbooks
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