Identification of gas supersaturation sources in the upper Colorado River, USA

Atmospheric gas saturation levels were monitored throughout a 40-km reach of the upper Colorado River during the summer and fall of 1995 to identify possible sources of gas supersaturation in the river. Gas saturation data from seven fixed sampling points and 40 random sampling points were analyzed using analysis of variance (ANOVA) and multiple regression methods. The lowest total gas saturations (ΔP=−27) were found at the bottom release of Williams Fork Reservoir. The highest total gas saturations (ΔP=77) were found at the spillway release of Windy Gap Reservoir and the confluence of Willow Creek and the Colorado River. Spacial and temporal effects were determined to be significant contributors to gas saturation levels. Gas supersaturation in the study area originated from both man-made and natural sources. Water discharged from the spillway of Windy Gap Reservoir was found to be the main source of man-made supersaturation, while photosynthetic activity of aquatic plants was determined to be the natural source of supersaturation in the study area. Copyright © 1999 John Wiley & Sons, Ltd.