Looking for a particular stream restoration detail (grade control)

[beej67]

I've worked on stream restoration projects in the past for previous firms where we called out a grade control structure that was basically a big log that crossed the realigned creek perpendicular, with a notch cut in the log and two other logs behind it benched in at 45 degrees to hold the primary log in place. The purpose was to create a small stilling basin upstream of the log and riffle/habitat downstream of the notch, and allow us to flatten the stream's grade between logs. It worked great in the project, but for the life of me I can't remember what the dang things are "called."

Anybody know what those things are called, and if so where to find a detail of them? I can whip a detail up from scratch, but if there's an official name for them that'd help.

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[zabrab]

I haven't seen them in a while, but I know them as a "log drop structures" or a "log weirs."

 

[onealexis]

Look for anything Rosgen has written.

Here's a link:

http://www.wildlandhydrology.com/assets/cross-vane.pdf

Details are included, though not truly construction details, but at least something you can work with.

 

[fishstunts]

We used a thick rip rap mat at a steep slope with a plunge pool at the end for grade control on one project and used a gabion basket with rip rap plunge pool on another. Both are still working well with no failures and stopped the head cutting of the channel. I don't have a copy of the details, but the details are easy to draw.

 

[UtilScott]

Resource agencies in the Pacific NW discourage full span structures for grade control. The problem has been that over time the downstream reach erodes/downcuts leaving a jump height over the full spaning log weir that exceeds fish passage requirements. Agencies prefer a roughened channel reach that includes boulders and LWD to control grade and velocities while allowing fish passage. Enviros like it because it looks less "engineered."

 

[beej67]

This project is pretty small, and the basin is less than a hundred acres, so I'm not extremely worried about fish passage.

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[cvg]

full span could be done with rock or concrete, just design with a trickle channel notch. eroding and down cutting is due to poor construction or inadequate design of the plunge basin. the intent of the structure is to reduce erosion and downcutting and riprap or concrete should be used to stabilize the basin. not sure how a trickle channel could easily be done with logs spanning the creek.

Urban Drainage and Flood Control District in Denver has a good manual prepared by McLaughlin Water Engineers (1986) with numerous designs