Embed Size (px)
Citation preview
A HECRAS Sediment Transport Computational Study for Dam Removal
12/16/11Bishes Rayamajhi
Instructor: Dr. Hans Tritico
Goal of the Project
• To compute the additional sediment volume transported after the removal of a low head dam.
Project Area
• 33.518 river length of Mahoning River encompassing two Ohio counties; Trumbull and Mahoning meeting the Pennsylvania – Ohio state border at 11.838 RM.
• Crescent St Dam located at 23.023 RM to be removed under my project scope.
HECRAS parameters used:
• Transport Function – England and Hasen• Computational interval – 1 hour• Computational time period – Jan 1, 10 to Dec
31, 10• Grain size distribution – Normal
RESULTS
0.00 50.00 100.00 150.00 200.00 250.00 300.00 350.00 400.00
-1000.00
-800.00
-600.00
-400.00
-200.00
0.00
200.00
400.00
Time (days)
∆ M
ass
Out
(ton
s)
Change in mass outflow before and after removal at 23.073 RM
0.00 50.00 100.00 150.00 200.00 250.00 300.00 350.00 400.00
-500000
-450000
-400000
-350000
-300000
-250000
-200000
-150000
-100000
-50000
0
BeforeAfter
Time (days)
Long
itudi
nal C
umul
ative
Mas
s Cha
nge
(ton
s)
Longitudinal Cumulative mass changes before and after removal at 23.073 RM
0.00 50.00 100.00 150.00 200.00 250.00 300.00 350.00 400.00
-6000
-5000
-4000
-3000
-2000
-1000
0
1000
Time (days)
∆ M
ass
Bed
Cha
nge
Cum
ulat
ive
(ton
s)
Change in cumulative mass bed change before and after removal at 23.073 RM
0 500 1000 1500 2000 2500 3000790
800
810
820
830
840
850
860
870
880
890
1-Jan31-Dec
Station (ft)
Elev
ation
(ft)
Bed elevation change for RM 23.073 after dam removal
CONCLUSION
• 230,000 tons of sediment will be transported towards the dam’s downstream by the end of the year.
• This additional sediment will be accumulated in the upstream of Mahoning Ave Dam.
• Increased in sediment movement observed for high flow conditions.
• Pre-dam removal sediment transport studies will help the engineers and planners in solving the sediment transport management problem due to the removal.
