×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Spillway Detail

Spillway Detail

Spillway Detail

(OP)
I've come across an interesting situation, let me give some background.

Three 48" road culverts convey upstream flow between two private lots before reaching the river.  The soil characteristics are sandy silt with little cohesive strength.

The drainage shed is approximately 130 acres, with a current 100 year flow of about 180 cfs (recently experienced).  The future build out upstream will increase that flow to about 400 cfs.

The channel between the two lots is experiencing extreme erosion, much to the chagrin of the two owners.  We will propose a concrete or armored channel for the majority of length between the culverts and river.

However, there is one area which coincides with the historic 100 year WSE of the river, where a large drop off is evident.(see picture attached)  The picture is a bit misleading, the drop from top to bottom is about 25 feet.

We will have some fill brougt in to raise the bottom and begin the channel, however I plan on designing a spillway from the top to toe at this drop area.

Can anyone refer me to some standard details for spillways.  I was thinking maybe an ogee spillway design with a trapeziodal channel at each end.  Or, perhaps just a linear channel down the slope, but I am worried about the hydraulic jumps where the flow will likely go from sub-super-sub critical.

Anyway, I am looking for a detail of a spillway.

RE: Spillway Detail

GoldDredger;
You may want to consult FHWA's HEC 14 for energy dissipators.  I deal with similar situations quite often.  I have prepared counter measures using concrete and riprap/gabions.  The extent of the structure is dependant on the topography and hydraulic charateristics.  Typically, I would design a spillway with an energy dissipator at the bottom. Looks like a great project.

RE: Spillway Detail

You could check in the BOR Small Dams Manual for some spillway designs.

 

RE: Spillway Detail

Bureau of Reclamation Engineering Monograph No. 25, "Hydraulic Design of Stilling Basins and Energy Dissipators"

RE: Spillway Detail

Curious as to who is paying for the fix?  The reason I ask is I had a similar situation that was being addressed by the City.  Turned out to be cheaper to buy one of homes and knock it down rather than construction a substantial conveyance structure.

RE: Spillway Detail

(OP)
Thanks for the posts.  They put me on track with some research and I found even more information.

I could not find information on 'BOR small dams manual', what does BOR stand for?

As far as paying for this fix, it appears it will be the homeowners association.  They are the ones who own the drainage easement and are responsible for it's maintenance.  It will be an expensive proposition for them unfortunately, but I don't believe as expensive as buying the homes would be.

RE: Spillway Detail

BOR = Bureau of Reclamation - more commonly shortened to USBR

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources