CONTROLS ON METHANE EMISSIONS FROM US RESERVOIRS DERIVED FROM A NATIONAL-SCALE MEASUREMENT CAMPAIGN

Following guidance from the Intergovernmental Panel on Climate Change, methane (CH₄) emissions from U.S. reservoirs are included in the Inventory of U.S. Greenhouse Gas Sources and Sinks. U.S. reservoirs are estimated to emit 1,094 kt CH₄ y^-1 and are the sixth largest anthropogenic CH₄ source in the country. However, this estimate is based on default emission factors—making the accuracy of this estimate uncertain. To improve the inventory estimate, we measured CH_4­ emissions at 108 reservoirs using a spatially balanced survey design across the conterminous U.S.  Ebullitive and diffusive emissions were measured at 15-25 locations in each reservoir during a 48-hour period between June 1 and September 15, 2018-2023.  All reservoirs emitted CH₄, with a mean emission rate of 134 mg CH₄ m^-2 d^-1 (Inter Quartile Range: 18-110 mg CH₄ m^-2 d^-1). These data, along with those from an additional 39 U.S. reservoirs where we measured emissions using identical methods, comprise the largest inter-reservoir GHG dataset ever assembled using consistent measurement methods. Initial data analysis suggest that emission rates are related to watershed properties (soil erodibility), reservoir morphology (water depth), productivity (chlorophyll a concentration), and regional effects such as sulfate concentrations in the Great Plains. We anticipate our analysis will identify drivers that can be used to estimate emission rates at unsampled locations for inclusion in EPA’s U.S. Greenhouse Gas Inventory.    

Presentation Preference: Oral

Primary Presenter: Jake Beaulieu, United States Environmental Protection Agency (Beaulieu.Jake@epa.gov)

Authors:

Bridget Deemer, U.S. Geological Survey, Grand Canyon Monitoring and Research Center, Southwest Biological Science Center, Flagstaff, AZ  (bdeemer@usgs.gov)

Ken Forshat, U.S. Environmental Protection Agency, Office of Research and Development, Ada, OK  (forshay.ken@epa.gov)

Natalie Griffiths, Oak Ridge National Laboratory, Oak Ridge, TN  (griffithsna@ornl.gov)

Lilian Herger, U.S. Environmental Protection Agency, Region 10, Seattle, WA  (herger.lilian@epa.gov)

Jeff Hollister, U.S. Environmental Protection Agency, Office of Research and Development, Narragansett, RI  (hollister.jeff@epa.gov)

Scott Jacobs, U.S. Environmental Protection Agency, Office of Research and Development, Cincinnati, OH  (jacobs.scott@epa.gov)

Peter Leinenbach, U.S. Environmental Protection Agency, Region 10, Seattle, WA  (leinenbach.peter@epa.gov)

Rachel Pilla, Oak Ridge National Laboratory, Oak Ridge, TN  (pillarm1@ornl.gov)

Stephen Shivers, U.S. Environmental Protection Agency, Office of Research and Development, Narragansett, RI  (shivers.stephen@epa.gov)

Avery Tatters, U.S. Environmental Protection Agency, Office of Research and Development, Gulf Breeze, FL  (tatters.avery@epa.gov)

John Walker, U.S. Forest Service  (John.Walker3@usda.gov)

Katie Buckler, U.S. Environmental Protection Agency, Office of Research and Development, Ada, OK  (buckler.katherine@epa.gov)

Russell Neill, U.S. Environmental Protection Agency, Office of Research and Development, Ada, OK  (neill.russell@epa.gov)

Aleksandra Djurkovic, U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, NC  (djurkovic.aleksandra@epa.gov)

Joseph Corra, U.S. Environmental Protection Agency, Office of Air and Radiation, Washington D.C.  (corra.joseph@epa.gov)

Payton Goodwin, Pegasus Technical Services  (goodwin.payton@epa.gov)

Leah Juilfs, Pegasus Technical Services  (juilfs.leah@epa.gov)

Casey Langstroth, Utah State University, Logan, UT  (casey.langstroth@usu.edu)

Brent Richmond, U.S. Environmental Protection Agency, Region 10, Seattle, WA  (richmond.brent@epa.gov)

Thomas Sabol, U.S. Geological Survey, Grand Canyon Monitoring and Research Center, Southwest Biological Science Center, Flagstaff, AZ  (tsabol@usgs.gov)

Jeremy Schroeder, U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, NC  (schroeder.jeremy@epa.gov)