While the rain does a good job of decomposing dog doo, a hose turned on high does not accomplish the same task nearly as neatly. Dog poop will be flung apart. It will clump. It will go places you didn't think it would. I am sure an engineer somewhere, possibly living here, would know this already and be able to chart said poop-power-washed antics. I am not an engineer and watching the rain at work, I assumed that this was a method superior to the plastic bag collection method I was using.
It was not, don't try it again.