Why was there a need for a global flood?

This is the sort of assertion I have a hard time wrapping my head around. If God is omniscient and knows the future, then even before he made Adam, he would have known about this necessity. He would have known that he would need to effectively start over with his little "humanity" experiment.Now, when a human sets up a prototype or an experiment, and after running it for a while, finds that there is a problem, or the design wasn't as good as they would have liked, it is quite logical to take what seems to be working, throw the rest out and try again. In fact, that's the way most of our great inventions came about.I don't think we can say the same thing about an omniscient god, however. It's sort of the same as our inventor making something he knows won't work, spending time on it, but not doing anything to effectively fix the error, and letting it run until it starts to set his house on fire. It would definitely make sense, at that point, to toss the invention out and start again, but I would hardly blame the invention for starting a fire, when it was obvious to the inventor that that was a distinct possibility. When you add in the fact that God KNEW for certain how his experiment would go, it seems to me that the blame for the wickedness of humanity rests solely at his feet, and all those lives that were brought into the world only to be snuffed out are a serious breach of ethics on his part.

I understand this, I use the word "future" because it is the colloquial word we use in our temporal existence. So, we're left with two possibilities:1) God, seeing what is happening at one time, can change something in another time in order to make a bad situation not happen, or2) God can't affect what we call the future because it's all happening at the same time to him.If option one is right, then we're still stuck with the situation that God knew wickedness would overrun the planet, requiring a global flood, and yet he did nothing to try and change that outcome, thereby consigning all those people to death. In my mind, that is highly unethical. We don't even let clinicians do human trials if there is a possibility of harm to the people involved.If option two is right, then we're left with an impotent God. One who created because he had to, and has to no way to affect the creation. In other words, we have a purely Deistic Universe, where God winds the clock and then things play out according to Natural Laws. This is hardly the God of the Bible. Ok, if that was his Plan, then it was a success. People chose not to be with God. But apparantly God wasn't happy with that outcome, so he wiped everything out and hit the 'Reset' button. So, he's OK with post facto deck stacking, but not changing the intial conditions so he wouldn't have to destroy all those lives, both human and animal. Again, that leaves us with what I would consider an unethical God.