Some years back, I was in a training session developed by hydrologist Dr. David Rosgen. He showed us on one of his field trips a system to remove sediment from a moderate size stream. The sediments removed were mostly sands to gravel sizes, perhaps even small cobbles. The structure name began with the word Vortex. From what I can remember, the structure was approximately a 1 meter in diameter corregated metal culvert, with a slit in the top along the channel width so sediments could enter. The pipe was buried in the channel with a slight gradient, and angle in crossing the channel. The pipe extended to a constructed pit constructed in the floodplain. As sediment discharged and partially filled the pit, it would have to be removed with some regularity. The water washed sediments could be sold as fairly clean materials for construction or other uses, or removed to suitable fill storage locations. If one were to fail to remove the pit sediments with enough frequency, eventually the fill would back up into the pipe and plug it full of sediment, negating its function. Rosgen has published on many of his experiences and ideas about channel types, hydrology and sediment, and I am not sure if he has published about the structure he showed us. The angle and gradient of the structure across the channel developed a vortex that moved and delivered sediment to an off channel pit. It worked and even there was some particle size separation in the pit, with coarser materials settling first near the discharge. You can find more information about Rosgen and his work at wildlandhydrology.com.

Another option is to develop an ongoing dredging program near the reservoir inlet to remove sediments in a maintained channel or lake pit, before and well away from the hydraulic structures. Be aware, that sediment removal from a stream system can create a clean water effect to downstream areas that can accelerate erosion in moving waters. Dr Matt Kondoff and others has published on this due to the effects of instream mining on downstream and upstream erosion. Land use and instream practices can accelerate erosion and sediment sources. Recognizing and addressing these sources can also be used to help reduce sediment problems. Braided streams are a natural result of too much sediment in low gradient systems, resulting in channel filling, frequent adjustments, flooding and higher than normal water table, resulting in some wildlife beneficial habitats, but conditions that some landowners would not want. Controlling and understanding rivers and sediment would be helpful in addressing your problem.

My last sentence could be misinterpreted. Especially the word controlling. The excessive modification and control of streams can sometimes be the problem. Other authors exist that have studied river behavior and excess sediment such as Dr Luna Leopold. If you find any authors you appreciate, also look through their references. I however do not remember any papers addressing your specific issue relative to hydraulic structures, but there must be some hydroelectric companies that have had to address the issue to keep their generators operational, such as diversion wire mesh screens.

Dear Mr. Hansen,

I appreciate sharing your experience with me on the subject-matter.

Best regards,

Zafer

Dear Zafer,

I think the most comprehensive book on sediment transport is "Sedimentation Engineering: Processes, Measurements, Modeling, and Practice" Edited by Marcelo Garcia, Ph.D., P.E. wich is a quite recent second edition. Unfortunately I do not have access to it, so I cannot say if it deals with your specific question. My guess, but it is only a guess is that it does not but if you manage to get a hold of the book you can check for yourself.

The structure that Mr. Hansen describes seems to be a kind of Tyrolean Weir. As it name suggests this kind of intake was developed in the Alps more than 100 years ago to help remove sediments on mountain environments.

Some literature on the, can be found here:

http://open_jicareport.jica.go.jp/pdf/11737046_08.pdf

http://etd.lib.metu.edu.tr/upload/12618706/index.pdf

A recent development is the so called "Coanda Weir". Here you will find some design guidelines:

http://www.reseau-cicle.org/wp-content/uploads/riaed/pdf/R-2003-03.pdf

Other than these two type of structures there are mainly two other forms of managing sediments:

- sediment diversion structures and

- sediment detention basins

For the later one here is one short descrption:

http://www.transportation.alberta.ca/Content/docType372/Production/12GuidelinesDsgnSediCntnment.pdf

If you have some further questions I will be glad to help.

Dear Rafael,

Many thanks for taking your time to suggest several publications.

I will go through them definitely. One thing though, tyrolean weirs are themselves intake structures, used in mountain environments like you said. Their function is to receive sediment-free water directly by separating water from the sediment laden flow. My goal is just the opposite. I want to trap (catch) the sediment from the flowing water in a river and let the water flow as a clean water to enter the intake structures of a small power plant located downstream.

Best regards,

Zafer

Dear Zafer,

what William means, is called vortex tube, which withdraws bedload, but not suspended load. Submerged vanes is another technik to divert sediment entering into the (damless) intakes.

The Monograph of IAHR from M. Bouvard (2017) Mobile Barrages and Intakes on Sediment Transporting Riverscould can be pretty helpful

https://books.google.de/books?id=yJY4DwAAQBAJ&lpg=PT269&dq=damless%20intakes&hl=de&pg=PT268#v=onepage&q=damless%20intakes&f=false

Many years ago I read a book on intakes , I think the title of the boook was "damless river intakes". I found it very helpful book with practical design aspects.

you may also use the short chapter draft and the literture in the following script:

http://www.eolss.net/Sample-Chapters/C07/E2-07-05-04.pdf

or just search in internet for "river intakes" you find for example the following book: River intakes and diversion dams:

https://duckduckgo.com/l/?kh=-1&uddg=https%3A%2F%2Fwww.amazon.com%2FRiver-Intakes-Diversion-Developments-Engineering%2Fdp%2F0444873155

For fine sediments I know only design of settling basins.

I hope that these could help.

Regards

Hassan

Bed-load removal can be done by using a sill to separate the clean upper part of the water for the diversion, which is why side weirs have an elevation higher than bed level. You could also use bottom inlet with racks, any sediment that is not trapped on the trash racks and comes along with the flow can be managed the following way: you can have a pond or stilling basin with a side and bottom outlet: the side outlet will be used to the power plant usage, the bottom outlet will be used to flush the accumulated sediments at suitable intervals. Usually a percentage of diverted water will have to be lust for continuous flushing (around 10%). You could also use mechanical dredging of the sediment ponds with moving cranes, etc.