Algal Influences on the Assimilative Capacity of the Red River, 1997 Biological Sciences Symposium Proceedings
The Red River begins in New Mexico and flows through Texas, Oklahoma, Arkansas and Louisiana. The River carries a substantial sediment load and can be characterized as being extremely turbid. Secchi disk readings are on the order of less than 6 inches. Weyerhaeuser has conducted wasteload allocation studies on the River for their Valliant, Oklahoma Mill and have found that the River has a significant algal contribution to the dissolved oxygen (DO) in the River. During River water quality surveys, diurnal DO, chlorophyll a, light and dark bottle measurements, algal identification, and algal biomass have been measured. The River DO saturation has been found to be greater than 95 percent during all seasons of the year with diurnal DO measurements ranging from 1 to 2 mg/L. Chlorophyll-u measurements have ranged from about 9 to 20 mg/L. The Algae have been identified as blue-green and green algae with the dominant algae genuses being the blue-green algae Oscillatoria and Merismopedia, and the green algae Rhizoclonium. QUAL2E model runs were made to simulate DO in the River accounting for the algae influence. Although the turbidity of the Red River would lead one to believe algae should not be a factor in this River, the turbulence in the River evidently presents the algae the opportunity to be exposed to sunlight on a frequent basis. The model results indicate that the algae for all practical purposes have the equivalent of nearly distilled water due to the River turbulence. Model projections with and without the algae are projected.