Evaluation of Mercury Release from Sediment and Dredging to Lahontan Reservoir Waters

Project ID: 22088
Principal Investigator: Daniel Deeds
Research Topic: Water Quality
Funded Fiscal Years: 2022 and 2023
Keywords: None

Research Question

Reclamation is responsible for managing water quality issues that could affect the reliability of water delivery that are a direct result of operations (FY 2022 SSIP). Sediment accumulation is an issue in nearly all Western US reservoirs maintained and operated by USBR and removal of sediment is a necessary part of ensuring optimal and efficient water storage and delivery. Lahontan Reservoir is part of the Carson River Mercury Site, listed on EPA's National Priorities List because of mercury contamination (EPA, 2018). The release of contaminants, including mercury, from the sediment/sediment-porewater compartment into overlying water during sediment excavation activities at Lahontan is of concern (Vicinie et al., 2011; Watson-Leung et al., 2017). In particular, this project will address the following questions:

1) Will dredging release RHg (an indicator of the bioavailable form that is converted into toxic methylmercury) into Lahontan reservoir's water column?

2) What is the sediment accumulation rate in Lahontan reservoir, and what is the likelihood that sediment-bound mercury is buried before it can be released to the overlying waters?

3) Does the oxidation of labile sulfide exacerbate mercury release from dredged sediments?

Need and Benefit

This proposal was coordinated with Jennifer Bountry, Sedimentation and River Hydraulics Group, and Rena Ballew, Water and Lands Specialist Supervisor, Lahontan Basin AO. The proposed work aligns with the Environmental Issues for Water Delivery and Management (EN); specifically, water quality and sediment management. Dredging of mercury-rich sediments in Lahontan Reservoir is a pressing need and the environmental impacts of dredging need to be understood for effective management.

Contributing Partners

Contact the Principal Investigator for information about partners.

Research Products

Please contact research@usbr.gov about research products related to this project.

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Last Updated: 6/22/20