A question can be asked, if Noah reasoned such then why in verse 8 :6-12 did he send the Dove in order to know whether the flood waters had receded or not. Noah was not going to leave the ark until told to do so, so for what purpose did he send the dove ? It would have not made a difference anyhow ? I would like to propose , Bezrat Hashem, the following original answer: Noah was faced with a great destruction. The entire world as he had known it was destroyed by the flood. He needed to have a semblance of hope in his future. This is surely understandable, its human nature. A person needs to have hope and thus the will to continue living. But how was Noah to know? He needed a means to beseech G-d for mercy, so he send a dove as a means to signal G-d that he was in need of hope. Prayer can take on many different forms.

Noah, thereby, received his message in the form of an olive branch that the destruction was over and the waters are beginning to recede. Once Noah knew that the destruction was coming to its conclusion, he now knew that the reconciliation of the world after the destruction had begun. This gave Noah the hope he so desperately needed, so he waited for G-d's further instructions. The powerful message from the Torah is that we all need to have hope in the future. Similarly we find a most fascinating story at the end of Makkos 24a, as follows: "Once R.Gamliel,R.Elazar ben Azariah, R. Yehoshua and R. Akiva were coming up to Jerusalem.............When they came to the Temple Mount , they saw a fox emerging from the Holy of Holies. The Rabbis started to weep, but Rabbi Akiva was joyous. They asked him why he was joyous? Rabbi Akiva thereby explained his reasoning. It is written in Isaiah 8:2-- "I (G-d) summon trustworthy witnesses for myself Uriah the Priest and Zecharahu ben Yeverechua." By mentioning both these prophets together Scripture is making the prophecy of Zechariah dependent upon the prophecy of Uriah.Uriah prophesized the destruction of Jerusalem ("Zion will be plowed over like a field" Micah3:12), while Zechariah prophesized about its rebuilding ( "Old men and old woman will once again sit in the streets of Jerusalem"-- Zechariah 8:4) Now that the prophecy of Uriah had been fulfilled (fox), its certain that the prophecy of Zechariah will be fulfilled. The Rabbis thereby responded with, "Akiva, you have comforted us; Akiva, you have comforted us." (END OF QUOTE) (Please refer there for further details.) Rabbi Akiva knew that before the redemption can take place, the worst of the destruction had to be. He indeed comforted his worthy comrades. This is precisely what G-d had done for Noah by sending him the olive branch. We all need hope in the future. Have a good Shabbos