I need to guide water flow at the end of my driveway (see this question). My plan is to put in a concrete curb or hump to guide the water. I've gone all over the map in thinking of how to build it, but right now my plan is as follows:
Set short (8"?) rebar pieces vertically into the ground, with the top ends bent at 90° about 2" above the ground
Have one long rebar piece wired to the vertical pieces
Hand-shape concrete (probably good ol' Quikrete) into a 4" tall by 6" wide curb, centered on the long rebar piece
This is an approximate cross-section of the curb, where the sloped side will be guiding the water:
I'm not heavily invested in this shape; I wouldn't mind if it ended up just a rounded hump. I just want it to be durable, to guide the water, and to not look too awful from a distance.
I've been going back and forth on whether I'll need to build a form to hold this shape while the concrete sets. Right now my plan is to have a single board define the vertical rear edge of the curb. and then use hands and trowels to mold the concrete against the board and around the rebar.
So, the question: will I be able to mold this, or will the concrete slump? (Any other tips would be welcome.)