Suggest improvements for the highlighted problem areas:
The Mississippi River carries more silt than any other river does. Standing on the delta, the river slowly deposits some of this silt in the salty marshes. Thirty tons of silt arrive each second. When thoroughly laden, you can see the river choke the marshes with mud.
As the muddy delta grows, the river seeks a new path to the Gulf of Mexico often. The Mississippi has had seven deltas during the past five thousand years. The delta, therefore, is a collection basin for silt that is always changing.
- The Misplaced Modifier -
A final misplaced modifier is a phrase at the end of our opening paragraph:
The delta, therefore, is a collection basin for silt that is always changing.
Again the reader's mind allows for the possibility that the silt is always changing. Since this confusing possibility is obviously not intended, we should make the sentence clear with a rewrite:
The delta, therefore, is an ever-changing collection basin for silt.