I'm with CTKen on this one. I'm curious what the concentration of the bleach is to the water in the ditch. Earlier this year I had to disinfect my well, and used bleach to do the job. I had to run water until the chlorine smell went away but there was still small traces when I tested before drinking any. And any of us who have swam in a public pool knows how bad the pool water tastes but have surely swallowed very small amounts. And we're still kicking. If the smell is overwhelming, poison control is probably a very good idea. And I'd also take a close look at the plants in and around that ditch. If the chlorine is in high enough levels it may affect the vegetation which in turn my affect the ducks..