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Upcoming Webinar Series on "Mercury in Reservoirs"

   01 February 2018

The U.S. Geological Survey (USGS), in collaboration with the California Water and Environmental Modeling Forum (CWEMF), will present a series of free webinars on mercury in reservoirs.

Scientists will present a series of webinars on mercury in reservoirs, with the goal of informing stakeholders in the State of California's Statewide Mercury Control Program for Reservoirs. Stakeholders include reservoir owners and operators (including federal, state, and local agencies, and irrigation districts), water-quality regulators, and the scientific community.

Topics will include mercury sources from historical gold mining, mercury methylation and bioaccumulation in food webs, management tools, and current scientific studies in California and elsewhere in the western U.S. that are addressing mercury issues. Seven webinars will be given from February 14 through May 2, 2018.

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Webinar Series on Mercury in Reservoirs
February – May 2018
Presented by the U.S. Geological Survey (USGS), in collaboration with the
California Water and Environmental Modeling Forum (CWEMF)

Weds. Feb. 14 – Mercury transport and bioaccumulation in California reservoirs affected by historical gold mining

(C. Alpers, R. Stewart, J. Fleck, M. Marvin-DiPasquale)

Information was presented on mercury in California reservoirs as it relates to historical gold mining. Case studies from the Yuba and Bear River watersheds in the northwestern Sierra Nevada were used as examples. Data from USGS studies at Englebright Lake, Camp Far West Reservoir, and Lake Combie were discussed. Lessons learned from these studies were considerd along with possible management options to control methylmercury formation and bioaccumulation in reservoirs, and to maintain reservoir capacity.

Weds. Feb. 28 – The biogeochemical cycling of mercury within Lake Powell, Glen Canyon National Recreation Area, Utah-Arizona

(M. Marvin-DiPasquale, D.L. Naftz, D.P. Krabbenhoft, G. Aiken, E.S. Boyd, C.H. Conaway, J. Ogorek & M. Anderson)

Elevated Striped-bass mercury concentrations found in the downstream portion of Lake Powell resulted in a 2012 fish-consumption advisory for the lower ~100 km of the reservoir. The USGS conducted two detailed reservoir sampling events (late spring during high-flow conditions, and late summer during stratified, low-flow conditions) to collect chemical, physical, and biological data needed to test hypotheses associated with a conceptual model developed to explain the observed spatial gradient in fish mercury concentration. This presentation details the major findings of that study.

Weds. Mar. 7 – The Hells Canyon Complex mercury study, Snake River, Idaho-Oregon, USA

(D. Krabbenhoft, C. Eagles-Smith, A. Baldwin, B. Poulin, M. Marvin-DiPasquale, R. Myers, J. Naymik, & R. Harris)

The Hells Canyon Complex (HCC) Mercury Study was initiated in 2014 following an initial pre-study that revealed elevated levels in game fish. The HCC is a relatively unusual setting in that it consists of three reservoirs (Brownlee, Oxbow, and Hells Canyon) in series over about a 100-mile section of the Snake River along the Idaho-Oregon border. During summer, the two largest reservoirs (Brownlee and Hells Canyon) exhibit strong thermal and chemical stratification, which carries well into the fall and early winter periods. Elevated levels of methylmercury accumulate in the hypolimnion of these reservoirs, and an important goal of this project is to resolve the key factors controlling mercury methylation and the fate of methylmercury during the fall destratification period. This large, multi-disciplinary project has eight guiding hypotheses, all of which point the effort toward understanding how reduced methylmercury production and bioaccumulation might be achieved.

Weds. Mar. 21 – Mercury bioaccumulation and food web studies in lakes and reservoirs

(C. Eagles-Smith, J. Ackerman, R. Stewart, R. Harris)

Weds. Apr. 4 – Mercury isotopes – an emerging tool for science and management in reservoirs

(D. Krabbenhoft)

Weds. Apr. 18 – Mercury studies at Lahontan Reservoir, Carson River, Nevada

(E. Morway, M. Marvin-DiPasquale, C. Thodal, D. Krabbenhoft)

Weds. May 2 – Synthesis of mercury case studies in reservoirs – matching study design to research and management questions

(J. Fleck, M. Marvin-DiPasquale, C. Eagles-Smith, R. Stewart, C. Alpers, R. Harris, D. Krabbenhoft)


There is no cost to participate.

Start time: 10:00 am Pacific Time; Planned duration of presentations: 60 minutes, followed by up to 30 minutes of discussion

Call in information: 703-648-4848, code 89789#

Two options for screen-sharing:

1) GS-Talk (Avaya Aura): Link will be the same for each webinar.

2) Skype for Business Web App — download at:

Second Webinar — Weds. Feb. 28:

Link will be updated for each webinar.

Please RSVP for each session by contacting Gabe Lopez (, 916-278-3026)

For additional information, contact: Charlie Alpers (, 916-278-3134) or Shyamal Chowdhury (, 916-417-5256)

Contact Information

Laurel Rogers
Media, Outreach, Special Events
(619) 225-6104
cell: (619) 980-6527

Gabriel Lopez
Requests for USGS data and reports
(916) 278-3026

Other Resources

California Water Science Center


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* DOI and USGS link and privacy policies apply.