Replacing pond spillway 1

[larryalgot]

Please advise on methods of replacing a washed out concrete
spillway on a dam made of sand. The old spillway was undermined and collapsed in on itself. It was 12 ft. wide
and 4 ft. high and held back about one acre pond with an
average depth of 4 ft. My inclination is to put in two
four ft. dia. pipes extending into the pond with clay soil
in the middle and large stone on the pond side. The spillway/overflow will have to support light vehicle traffic.
I would appreciate any advice or guidance.

Thanks,
Larryg

 

[cvg]

More data would assist, such as:

Why did the spillway wash out? Was it due to
a) piping
b) erosion at downstream end
c) insufficient capacity
d) structural failure due to truck traffic

Does the dam have a clay core?

you probably won’t get as much capacity from the two pipes as you did with 4 feet of flow over the 12 foot wide spillway.

Current practice for structures within dam embankments is to provide a filter diaphragm around them, rather than clay. This controls internal erosion to prevent piping.