A reason is because when it floods it waters all their plants and it's one of their only water sources :)
He proposed the Fugitive Slave Act in 1850, which was to send back runaway slaves from which who escaped from the southern states to the north. As this was a add onto the older laws this law punished officials who did not capture runaway slaves and bring them back to the southern states. In 1855 was found unconstitutional and was Nullified