Examination of physical, chemical, and microbiological water quality parameters in the Lower Van Duzen River Basin

Thesis (M.S.)--Humboldt State University, Natural Resources: Wastewater Utilization Program, 2009The purpose of this study is to provide chemical, physical, and microbiological water quality baseline data for the lower Van Duzen River Basin mandated by California Regional Water Quality Control Board. Water quality data were collected from October 2006 to April 2008, and included temperature, dissolved oxygen, pH, conductivity, total suspended solids, turbidity, and fecal coliforms. Data were collected from monitoring sites on five tributaries (Wolverton Gulch, Yager Creek, Cummings Creek, Hely Creek, and Grizzly Creek) and two sites on the mainstem Van Duzen River. All sampling parameters were measured using approved Environmental Protection Agency standard methods. Water temperature exceeded water quality standards during the warm summer months in Yager Creek and the Van Duzen River. Fecal coliform concentrations exceeded standards of less than 200 CFU/100 ml at Wolverton Gulch, Yager Creek, Grizzly Creek, and the Van Duzen River during significant rainstorms. However, levels were never exceeded during warm summer months when United States Environmental Protection Agency full body contact standards would most likely occur. Water quality standards for dissolved oxygen, pH, and conductivity levels were met at all sampling sites. The analysis of turbidity data will be used to assist the North Coast Regional Water Quality Control Board in determining baseline conditions required for development of water quality standards. Levels of total suspended solids exceeded water quality standards following rainstorms, but did not exceed standards during periods of no rainfall. Water quality monitoring in the lower Van Duzen River Basin should continue to focus on analysis of suspended sediment to determine the duration and frequency of events when levels are exceeded. Tributaries to the lower Van Duzen River should continue to be managed as coldwater refugia for aquatic species during the warm summer months