SEDIMENT FINGERPRINTING IN THE CLEAR LAKE, CALIFORNIA, WATERSHED: DETERMINING SOURCES OF NUTRIENTS AND SEDIMENT

Presented by: Dr. Charles Alpers, Research Chemist

Dr. Alpers will discuss a sediment fingerprinting study that has the goal of determining sources of particulate nutrients from Clear Lake tributaries and land uses. The nutrients nitrogen (N) and phosphorus (P) are a concern because they can stimulate frequent harmful algal blooms. Understanding and controlling sources of nutrients to Clear Lake is a high priority for managers who intend to improve water quality. In this study, nine of the largest tributaries to Clear Lake are being sampled. Results of the study will be used to inform other watershed modeling efforts.

THE FUTURE OF FINE-SEDIMENT DISCHARGE IN THE HUMBOLDT BAY-EEL RIVER REGION, CALIFORNIA

Presented by: Jennifer Curtis, Research Geologist

The Eel River is a major river in northwestern California. The river provides groundwater recharge, recreation, and industrial, agricultural, and municipal water supply. In this project, the future of fine-sediment discharge in the study region was assessed using a combination of empirical and statistical models and future climate projections. Streamflow was simulated using a deterministic water-balance model, and fine-sediment discharge from river and tributary sources was computed using statistical sediment-transport models. In this presentation, Ms. Curtis will discuss this research.

WATER-QUALITY MODELING OF THE CLEAR LAKE, CALIFORNIA WATERSHED: GEOLOGICAL AND ANTHROPOGENIC INFLUENCES ON NUTRIENT AND SEDIMENT TRANSPORT

Presented by: Dr. Joseph Domagalski, Program Chief of Biogeochemistry and Contaminants

As stated above, nutrients are a concern in Clear lake because they can stimulate frequent harmful algal blooms. Dr. Domagalski’s presentation will discuss a dynamic version of the SPARROW (Spatially-Referenced Regression on Watershed attributes) model that is being developed to understand Clear Lake nutrient and sediment sources. SPARROW models can predict loads and sources of nutrients at the sub-watershed scale based on climatic and landscape features. The SPARROW model being developed will be calibrated using three years of stream water-quality monitoring along with landscape features including rainfall, runoff, soil types, groundwater recharge, fertilizer use, cattle grazing, and urban density.

 

GEOCHEMISTRY AND MINERALOGY OF MINE WASTE AT SULPHUR BANK MERCURY MINE, LAKE COUNTY, CALIFORNIA

Presented by: Connor McVey, Geologist

The abandoned Sulphur Bank Mercury Mine on the shores of Clear Lake has been designated as a "Superfund Site" by the U.S. Environmental Protection Agency (EPA). This means that the EPA has determined that the area is contaminated by hazardous waste and requires cleanup. To support EPA’s efforts, the USGS is characterizing the geochemistry and mineralogy of mine waste. In his presentation, Mr. McVey will discuss the collection and analysis of mine waste samples. Sample analysis includes total metals, metals by 5-step sequential extraction, arsenic (As) and mercury (Hg) bioaccessibility, Hg isotopes, sulfur isotopes, and mineralogy.