Field Estimates of Oxygen Balance Parameters

Field studies of oxygen balance in the Merrimack River, Massachusetts, were conducted during the period 1962-1963. Streeter-Phelps equations, extended to include addition of BOD from bottom deposits, removal of BOD by settling, production of dissolved oxygen by photosynthesis, and longitudinal mixing by tides, indicated 50% to 80% of BOD by settling and approximately two-thirds of oxygen furnished by algae in photosynthesis. The atmospheric reaeration rate constant, k₂, was found to be considerably less than expected; the algae was found to be essential to pollution control. Extreme variations in the temperature and dissolved oxygen at river stations indicated the desirability of mixing several samples continuously collected at each river station, the recording of temperature and dissolved oxygen in mixture, and compositing of BOD light- and dark-bottles from mixture, with recording of dissolved oxygen and temperature in each bottle incubated in river water. Field measurements of BOD from bottom deposits are recommended.