Hello Ebissa. I am not sure what you mean by 'controlling' sedimentation. If you mean reducing sedimentation at source before it enters a reservoir or a channel, that will be challenging since sedimentation is a result of solids carried into the waterways by precipitation run-off. In Canada one method that was used in a run-of-river hydro-electric power station (Forrest-Kerr) was to design de-sanding bays to reduce the velocity of water to allow precipitate to settle before entering the actual reservoir and turbine. The challenge at that point was to determine the rate of siltation since the de-sanding bays must be dredged to remove the precipitated solids. But in general all reservoirs and riverways are going to silt up. So the issue becomes one of monitoring the rate of siltation and then determining the optimum time to dredge to remove those solids. For monitoring, the classic method was to perform periodic bathymetric surveys using either single-beam or multi-beam echosounders mounted on a vessel and operated by skilled technicians. These instruments are increasingly being mounted on unmanned surface vessels which are quite small and can now be man-carried to reservoirs, even those that are normally inaccessible for a larger watercraft. However these surveys are periodic and do not account for sudden changes in condition occurring after storm events. There is also the cost of deploying the sensor, the watercraft, and the technicians to operate the equipment and analyze the data. Another method is to use permanently installed sensors at the dam face to monitor the rate of siltation over time. Siltation at the dam face is problematic not only due to reduction of reservoir capacity, but due to the added mechanical loading on the dam structure itself which could eventually lead to failure. One advantage of these sensors is they measure the rate of change of depth over time, making remediation planning easier. Also, the same system set-up can be used on the discharge side to monitor scour, or at the turbine inlet to monitor the increase in tramp debris where objects such as logs and other garbage can clog the inlet or even enter the system and cause damage.
I would be happy to put you in contact with Ms. Aziah North and also refer you to Northwest Hydraulic Consultants. Aziah works for Kongsberg Maritime Canada (Ltd) out of our Port Coquitlam office (greater Vancouver, Canada) but is responsible for dam applications globally. The closest specialist for bathymetric applications in the Mediterranean basin is Mr. Simone di Giacomo of Kongsberg Maritime AS (office in Rome but lives in Norway). Northwest Hydraulic Consultants have over 200 engineers and are also based in greater Vancouver, but have offices in Asia and engage in projects globally. Their website is https://nhcweb.com/
and a good person to contact is Dr. Andre Zimmermann, who is also an Adjunct Professor at University of British Columbia Faculty of Engineering. Dr. Zimmermann has worked with Aziah on a few different applications. https://nhcweb.com/staff/andre-zimmermann/
Finally, there is a White Paper written on Reservoir Sedimentation which may be informative - the list of authors and stakeholders is quite extensive. (File uploaded; URL is https://www.friendsofreservoirs.com/wp-content/uploads/2019/05/National-Res-Sed-White-Paper-2019-06-21.pdf)
I hope this was of some assistance. Yours truly, Konrad Mech
P.S. I hope all is improving in Addis Ababa. One of my classmates Marian Miszkiel P.Eng. is managing the campus construction project for the UN in Addis.
Konrad Mech P.Eng
Director, Sensors and Robotics Channel Management
Kongsberg Maritime AS
Port Coquitlam BC
Sent: 01-28-2022 02:47 PM
From: Ebissa Gadissa
Subject: Reservoir and Channel Sedimentation
How can we control Reservoir and channel sedimentation? What are the most economical techniques to control sedimentation? Is there any new finding regarding to this issue?
Ebissa Gadissa S.M.ASCE