The effects of pollution on water quality - Escambia River and Bay, Florida were investigated during a period of low Escambia River discharge (1,068 cfs) in September and October, 1969. The tidal circulation and bottom sediment characteristics of the bay were reported. Further circulation and more extensive sediment characterization studies were made in June, 1970, at much higher river flows (59,533 cfs). The report presents these results and compares them with those of the 1969 study. Both studies show that Escambia Bay sediments are highly organic and tidal circulation in Upper Escambia Bay is poor. Because of these conditions, sediment disturbances--such as result from dredging--can cause severe oxygen depletion. Massive fish kills could result.