Nick Graham

Graham, N., Monohan, C., Matiasek, S., and Brown, D., 2017. Metal-Based Coagulant Effect on Sediment Slurry for Lake Combie Reservoir Sediment and Mercury Removal Project. California State University, Chico. Summer 2017. 


This study was conducted to assist Nevada Irrigation District (NID) in the analysis of a sediment and mercury removal treatment process at the Lake Combie Reservoir, Grass Valley CA. Part of the removal process consisted of administering metal-based coagulants to promote the sedimentation of fine grain materials. Field-scale tests resulted in process effluent below regulatory criteria for total metal concentrations including mercury (Hg), chromium (Cr), iron (Fe), magnesium (Mg), molybdenum (Mo), nickel (Ni), and zinc (Zn). Additional sediments from future sites (Combie Lake and Greenhorn Creek) and alternative coagulants (LBP-2101 and Clar+Ion 5057) were tested in the sedimentation process. Furthermore, prediction models for continuous real time total mercury (THg) and filtered mercury (fHg) concentrations during the sedimentation treatment process are presented. The models use the parameters; total suspended solids (TSS), total dissolved solids (TDS), and ultraviolet absorbance (A254) as proxies for THg and fHg concentrations. The multivariate regression models had R2 values of 0.97 and 0.85 for the prediction of THg and fHg, and p-values <0.0001. Continuous monitoring of these proxies at pre- and post-treatment locations coupled with the predictive capabilities of the models suggest that full scale implementation of the sediment and mercury removal process at Lake Combie Reservoir can operate within regulatory criteria with the ability to identify an exceedance before effluent is released.

Student Bio

Nicholas Graham, M.S., completed his undergraduate studies in 2013 (B.S., Hydrology) and his graduate degree in 2017 (M.S., Hydrology and Hydrogeology) from California State University, Chico. Before joining The Sierra Fund, Graham spent three years with the United States Geological Survey (USGS) Biogeochemistry Group and as a Hydrologic Technician and Hydrologist including collaborative work with NASA in developing Real-Time Monitoring Networks to ground truth satellite-based remote sensing and Ameriflux in deployment and maintenance of GHG flux monitoring stations. As TSF’s Environmental Scientist, Graham leads and coordinates TSF forest, meadow, and river restoration projects, installs and maintains stream and groundwater measurement equipment, collects environmental samples, leads and coordinates fieldwork with graduate students, and gathers and processes water quality data on real-time continuous monitoring networks. Additionally, Nick is a developing programmer in RStudio/RMarkdown environments and a geospatial analyst using ArcGIS pro.