Hydrologic and Temperature Indicators of Surface Water Groundwater Exchange, Sandia Canyon Wetland, Los Alamos NM

Reid, Kevin

Hydrologic and Temperature Indicators of Surface Water Groundwater Exchange, Sandia Canyon Wetland, Los Alamos NM

Monday, February 26, 2018: 3:20 p.m.

Kevin Reid, PG , TerranearPMC, Los Alamos, NM

Tanner Bonham, BS , TerranearPMC, Los Alamos, NM

Armand Groffman, Ph.D. , Los Alamos National Laboratory, Los Alamos, NM

Jeffrey M. Heikoop, Ph.D. , Los Alamos National Laboratory, Los Alamos, NM

Thaddeus Kostrubala, MS, PE , Los Alamos National Laboratory, Los Alamos, NM

Dea Musa, BS , Los Alamos National Laboratory, Los Alamos, NM

Steve Veenis, BS , Los Alamos National Laboratory, Los Alamos, NM

Amanda White, Ph.D. , Los Alamos National Laboratory, Los Alamos, NM

The Sandia Canyon wetland is approximately 16,000 m² and largely sustained by year-round NPDES permitted outfall water from the Los Alamos National Laboratory. From 1956 to 1972 the wetland received effluent containing hexavalent chromium resulting in elevated chromium concentrations in the sediment and alluvial groundwater. Reducing conditions within the wetland favor chromium to exist as the more stable and less toxic valence state of Cr(III). Due to the low solubility of Cr(III) most of the inventory is thought to be adsorbed to sediments or organic material. In addition to outfall discharge, the wetland receives storm water runoff from an impervious developed landscape in response to precipitation events. Understanding the hydrologic pathways through the wetland is important for analysis of the geochemical stability of the chromium inventory within the wetland sediments. Particularly how groundwater-surface water exchange could potentially transport chromium out of the wetland downstream to receptors. Within the wetland there are twelve alluvial wells installed in four transects of three wells each and three surface water gage stations. Water levels and discharge were measured continuously. Geochemical samples were collected quarterly. Nine of twelve alluvial wells show water level responses to runoff events. Two of twelve wells show temperature responses to runoff events. These results indicate there is connectivity of the surface water and alluvial groundwater. The set of three wells which did not have as strong correlation were located in the widest section of the wetland where flow is more dispersed within ponded and highly vegetated areas. Although there is connectivity of surface water and alluvial groundwater, the geochemical monitoring results show chromium remains stable as Cr(III) within the alluvial system. LA-UR-17-27384

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Kevin Reid, PG, TerranearPMC, Los Alamos, NM

Kevin Reid is project manager with TerranearPMC in Los Alamos, New Mexico where he supervises staff conducting environmental investigations at Los Alamos National Laboratory. Mr Reid has over ten years of experience in the field of hydrogeology and holds a MS degree in Watershed Sciences from Colorado State University. Mr. Reid is a PG with the state of Idaho.

Tanner Bonham, BS, TerranearPMC, Los Alamos, NM

Tanner Bonham is a graduate of Colorado State University. He supports the groundwater sampling program at Los Alamos National Laboratory. Additionally Mr. Bonham conducts vegetation surveys and runs the water level program for wetland monitoring.

Armand Groffman, Ph.D., Los Alamos National Laboratory, Los Alamos, NM

Hydrologist, Los Alamos National Laboratory

Jeffrey M. Heikoop, Ph.D., Los Alamos National Laboratory, Los Alamos, NM

Dr. Heikoop is an isotope geochemist with research interests including 1) the use of nitrogen, carbon, chlorine, oxygen, deuterium and sulfur isotopes as geochemical tracers of pollution; 2) contaminant dynamics in complex surface and subsurface environments; and 3) reconstructing paleoclimate records from the lake sediments, bogs, corals and tree rings. He has a Ph.D. degree in geology from McMaster University and is currently a Project Leader in the LANL Water Stewardship Program.

Thaddeus Kostrubala, MS, PE, Los Alamos National Laboratory, Los Alamos, NM

Thaddeus has a Chemical Engineering B.S. from Colorado School of Mines and a Civil Engineering Master’s Degree from Colorado State University Fort Collins and a registered Professional Engineer registered in New Mexico. Thaddeus has worked for over 15 years in the field of environmental engineering on remediation and reclamation projects in the west. Thaddeus currently works for the Los Alamos National Laboratory in the Surface Water Protection program on issues associated with storm water quality and historic releases of industrial materials.

Dea Musa, BS, Los Alamos National Laboratory, Los Alamos, NM

Scientist, Los Alamos National Laboratory

Steve Veenis, BS, Los Alamos National Laboratory, Los Alamos, NM

Storm Water Program Manager, Los Alamos National Laboratory

Amanda White, Ph.D., Los Alamos National Laboratory, Los Alamos, NM

Hydrologist, Los Alamos National Laboratory