[AussieConcreter]

We have a pond with a poor design - the outer margin is level with surrounding patio, and curves downwards into the body of the pond, encouraging soil and other debris to wash in with each rain event.

I want to do a small pour all the way around, to achieve a build-up of perhaps a ½", which will deflect most material away. Given this is outdoors (mid-Atlantic), what would be the right method for adding to the old concrete. Perhaps by drilling into it, and hammering in some spaced portions of rebar? The area of the pour is at grade and so is above the waterline. - Grant.

 

[SPS-1]

If I understand the situation correctly, you may wish to consider addind a curb to the outside of the concrete. You could either pour it, or use paving stones. If you want to get fancy, you might find an outfit that will extrude colored, decorative concrete shape curbing (I had that done around a flower bed).

 

[AussieConcreter]

Wow, thank you for the helpful ideas and drawing!

Attached - 3 pics that show the location of the pond amongst slate-in-concrete patio. As there's no easy way to build up around the perimeter (without cutting into the patio surface), I felt that a concrete-over-concrete addition was the way to go.

By the way, the wider shot gives a hint of a larger problem - the entire backyard is upslope of this terrace area, and apparently for years or decades, the soil has gradually washed downslope, undermining the retaining wall, and finally collecting in the pond. (there are many, many items on the ToDo List here!).

 

[dj3]

The "retaining wall" has failed. You need a new and effective retaining wall, with proper drainage, not a curb.

 

[huesmann]

Man that concrete surrounding the pond is in bad shape too. You have a lot of sediment in that pond.

Without a wider shot, I'd suggest (re)building the wall up higher, and putting in a gutter or swale at the top, to direct water from the hillside around the pond area.

 

[3onthetree]

What is the pipe for? And is the bottom of the bathtub the same limey concrete, aggregrate, or exposed soil?