Laboratory and Instream Nitrification Rates for Selected Streams

Abstract

Nitrification rate coefficients are predicted from biochemical oxygen demand tests for two rivers that are moderately deep but have some shoals and riffles. The two streams studied are notable for the lack of a thick benthic community and for the low flow velocities. Measured nitrification coefficients are compared to independently derived coefficients from calibrated first‐order, nitrification models of the Chattahoochee River in Georgia and the West Fork Trinity River in Texas. For the Chattahoochee River, the model calibration coefficient at 20 °C is 0.25/day compared to a laboratory measurement of 0.26/day. The model calibration coefficient is 0.52/day for the West Fork Trinity River compared to the laboratory measurement of 0.50/day. For both river studies, sufficient evidence is available to indicate that the nitrification models adequately separate nitrification from other processes that transform nitrogen.