What are the possible advantages disadvantages to the organisms using estuaries for these purposes?

Advantages:
-fertile soil for agriculture
-the deltas can trap pollutants before they flow into the gulf
-sediment that is deposited in the delta does not become turbidity in the gulf
-they create wildlife habits
-deltas are a perfect location to send the homeless to

Disadvantages-
-upstream erosion is required to produce a delta
-can cause upstream flooding
-can impede ship/barge traffic
-the homeless tend to congregate near and around deltas