Answer:
The Poem is a symbol of life. The brook's journey from its origin till its joining the brimming river is man's journey of life from birth to death. Whatever happens to it on the way is similar to what man encounters through his life. The brook's noisy flow is similar to mans struggling and fretting and fuming against the odds of life. The brook slips, slides, glooms and glances. So does man. It makes its way forcefully against odds, so does man as he struggles through many problems. The brook carries many things with it as it flows. So does man-he meets people - builds relationships - carries memories, collects materialistic things as he goes through life.
The only difference between man and the brook is that man's life comes to an end. Where as the brook lives on and on forever.