In The Name Of GOD SEFIDRUD DAM DESILTATION OPERATION by M.H.Ranjbar Taklimy & E. Tolouie Sefidrud Reservoir desiltation committee, Gilan regional water board, Iran August 8-15,2005, Yichang,Hubei Province, China
LOCATION OF SEFIDRUD DAM AND CATCHMENT
SEFIDRUD RIVER SYSTEM
SEFIDRUD DAM Evacuating system:. 2 morning glory spillways, 3,000 m3/s. 2 auxiliary spillways, 2,000 m3/s. 5 power intakes, 160 m3/s. 5 bottom outlets, 980 m3/s. Total capacity, 6000 m3/s
SEFIDRUD DAM
Location, 250 km north west of Tehran Type, Buttress-gravity Max height, 106 m Crest length, 425 m Crest elevation, masl (metre above sea leavel) Main purpose, Irrigation (Mostly rice field) SEFIDRUD DAM
SEFIDRUD RESERVOIR
RESERVOIR SEDIMENTATION DATA
FEASIBILITY OF FLUSHING OPERATION Changing the rule curve
FEASIBILITY OF FLUSHING OPERATION Changing the rule curve
FEASIBILITY OF FLUSHING OPERATION Changing the rule curve
FEASIBILITY OF FLUSHING OPERATION Changing the rule curve
FEASIBILITY OF FLUSHING OPERATION Environmental impacts
MITIGATION OF NEGATIVE EFFECTS In order to mitigate negative environmental impacts, comprehensive studies on environmental aspects of sedimentation and desiltaion is carried out since 2003, we hope that the result of the studies will help us to achieve sustainable development in sefidrud river system.
RESERVOIR SEDIMENTATION DATA
FLUSHING WITH FLOW DIVERSION Diversion scheme Main features
FLUSHING WITH FLOW DIVERSION Diversion scheme Layout
FLUSHING WITH FLOW DIVERSION Diversion scheme Components (a) diversion dam (b) diversion(pilot)canal
FIELD OBSERVATIONS Types of erosion occurred along diversion canal
Outflow water vs outflow sediment
1:
Rehabilitation of reservoir capacity
CONCLUSION: 1- Flushing operation is a suitable tool to conserve and rehabilitate reservoir capacity, provided suitable outlet system is avilable. 2- Flow diversion to the flood plain is an effective and practical method to increase desiltation efficiency in flushing operation. 3- In sefidrud reservoir, flow diversion as a supplementary measure to flushing operation was proved to be very efficient in reducing trap efficiency of the reservoir, as presented below: trap efficiency (inflow sed.- outflow sed.) Inflow sed. during 17 years of normal operation=79%. trap efficiency during 3 years of flushing operation=37% trap efficiency during 7 years of flushing operation + flow diversion = - 96%.
PHOTOS
SEFID - RUD RESERVOIR DESILTATION Note: Foreset of deposited sediment is above power intake level
Different views of deposited sediment U/S of dam
Formation of main thalweg with in reservoir area
Sampling of suspended sediment
Qezel Owzan Diversion Dam during construction
View of Diversion Dam after completion
Digging pilot canal
Initial stage of diversion
Retrogressive erosion along pilot canal
Massive slide in unconsolidated deposit
Constructing fuse Plugg to create Hydraulic shock
Extensive erosion of new thalweg due to Hydraulic shock (dam break)
The End