analysis on lucille clifton poem?

the mississippi river empties into the gulf

What a nice piece!
You’re generally on the right track with your sense of the overall meaning. With the techniques, well, you did a good thing by asking for some help
The personification you identify is somewhat off. Rivers do, in fact carry things. Barges, debris, etc. BUT, there’s a metaphor of rivers carrying things “on their white tipped backs.” Think about the metaphor being made here. What are the white tips literally? Figuratively?
One of the devices I picked up right away–because it’s so shocking–is the use of antithesis, using the negative to prove the affirmative. This technique is found at the last four lines, where a person is depicted meditating about the popular idea that we should only consider the present. Nothing else is important. The speaker uses the perhaps clumsy word “mistakenly” to show that this is not the case. The entire poem up to this point has shown this idea that history (like a river) is never ending, deep, and important. That’s the main metaphor. Another is the idea of the river as bloodstream of the gods. This suggests that history is the bloodstream of human culture. It is essential to even the most basic understanding.
I’ll let you work on the sound devices. Just listen carefully and repeatedly. If you’re in a rush, you’re unlikely to make any progress.
One final thing to consider here is the sexual imagery. Pools of water are often used as female symbols. Notice that the poem’s opening lines include a lot about things “entering” and “emptying” into other things. With the cycle of life, you have to have the force that creates life, too.
Best wishes!

Mississippi River Empties Into