Effects of benthic activities on stream oxygen balances are often overlooked in municipal wasteload allocations (WLAs). To improve dissolved oxygen (DO) concentration predictions for the central Scioto River in Ohio, benthic oxygen flux (BOF) rates were incorporated into the QUAL-2e water quality model, by measuring the BOF rates in situ with opaque and translucent hemispherical chambers under the low-flow conditions of late September, 1985.

The average light and dark chamber BOF rates were 6.46 g O₂/m²·d and −2.74 g O₂/m²·d, respectively. The net BOF rate applied to the model was 1.74 g O₂/m²·d, corrected for water column demands. Measurements conducted during variable weather conditions showed a strong influence of cloud cover on BOF rates. The inclusion of the BOF term in the calibrated model resulted in a predicted DO increase as high as 1.15 mg/L in some stream segments, compared with 0.08 mg/L for planktonic photosynthesis. The BOF rates used in the QUAL-2e WLA model improved the DO predictions for the Scioto River.