Comparison of a novel profile method to standard chamber methods for measurement of sediment oxygen demand.

A methodology is presented to determine the impact of flow rate upon sediment oxygen demand (SOD) based upon dissolved oxygen transport through the logarithmic boundary layer in stream systems. Previous work has used profile methodology to estimate atmospheric fluxes of pollutants from sediment, and similar principles are applied in this study. Chamber and profile SOD measurements were collected on July 21, 2009 in the Millstone River in Hillsborough, NJ and on July 22 and 28, 2009 in the Lawrence Brook in Milltown, NJ. The two systems were installed 2 meters apart laterally across the stream to measure SOD simultaneously. A total of 7 chamber measurements and 50 profile measurements were collected over 3 days. Chamber SOD measurements in the Lawrence Brook varied from 3.6 to 13.0 g/m(2)/day and had a mean of 5.0 g/m(2)/day. Concurrent profile SOD measurements varied from 1.3 to 13.5 g/m(2)/day and had a mean of 7.16 g/m(2)/day. In the Millstone River, the single chamber measurement was 4.6 g/m(2)/day while the profile measurements varied from 0.5 to 2.2 g/m(2)/day with a mean of 1.32 g/m(2)/day. The measurements made via the profile and chamber methods were found to be in relative agreement. A linear relationship between friction velocity and stream SOD was observed.