Brett Gerard

Senator George J. Mitchell Center and Maine’s Sustainability Solutions Initiative

My research is part of the “Safeguarding a Vulnerable Watershed (Sebago Lake)” project supported by Maine’s Sustainability Solutions Initiative. My research focuses on the condition of lowland tributaries within the Sebago Lake watershed which govern the flow of water, sediment, nutrients, and pollutants into the lake. I am interested in the lowland tributary network primarily because maintenance of lake water quality requires maintenance of this system. My primary interest is in the influence of climate and human modifications, both in-stream and on the landscape, on the flow regime and channel bottom conditions of these tributaries. Flow regime modification is considered one of the most serious threats to the integrity of riverine systems, and my interest in channel bottom conditions relates to the functionality of the hyporheic zone, a fluctuating zone beneath or adjacent to river systems where surface water and groundwater mix. Exchange between the river and the hyporheic zone can have a strong influence on a river’s thermal dynamics, nutrient cycling, and ecosystem integrity. For this research I primarily utilize a distributed watershed model coupled with the analysis of field data and observations.

Publications (Referred Journal Articles):

Gerard, B., Schwartz, B., and S. Schwinning (In Preperation). Effects of Environmental Parameters and Precipitation Dynamics on Infiltration and Recharge into the Trinity Aquifer of Central Texas.

Schwartz, B., Schwinning, S., Gerard, B., Kukowski, K., Stinson, S., and H. Dammeyer (2013). Using Hydrogeochemical and Ecohydrological Responses to Understand Epikarst Process in Semi-Arid Systems, Edwards Plateau, Texas, USA. Acta Carsologica, 42 (2-3), 315-325.

Publications (Non-referred):

Gerard, B. (2012). Effects of Environmental Parameters and Precipitation Dynamics on Infiltration and Recharge into the Trinity Aquifer of Central Texas. Master’s Thesis.

Presentations:

Smith, S., Gerard, B., Van Dam, B., and A. Reave. The Handprint of Hydrologic Interventions in Glaciated Terrain. American Geophysical Union fall meeting. San Francisco, California, December, 2013.

Schwartz, B., Gerard, B., Schreiber, M., and S. Schwinning. A Deeper Understanding of Processes Controlling Hydrogeochemical Fluxes Through Shallow Karstic Critical Zones (The Epikarst). American Geophysical Union fall meeting. San Francisco, California, December, 2013.

Stinson, C., Schwartz, B.F., Schwinning, S., Gerard, B.R., and P. Ramirez. Preliminary results from a multi-tracer epikarst recharge experiment: McCarty Cave, Texas, USA. Geological Society of America annual meeting. Denver, Colorado, October, 2013.

Gerard, B., Van Dam, B., and S. Smith. The Human Influence of Drainage in the Sebago Lake Rim Watershed. Maine EPSCoR State Conference. University of Maine, Orono, Maine. September 2013.

Gerard, B.R. and S. Smith. The Drainage Density of Sebago Lake. Soil to Sea Conference. Johns Hopkins University, Baltimore, Maryland. May 2013.

Gerard, B.R., Schwartz, B.F., and S. Schwinning. Modeling the precipitation threshold required for recharge in a karst aquifer of central Texas. Geological Society of America annual meeting. Minneapolis, Minnesota, October, 2011.

Schwartz, B.F., Gerard, B.R., Tobin, B.W., Ramirez, P., Hutchins, B., Schwinning, S., and M.E. Schreiber. Hydrogeochemical responses at in-cave sites as indicators of epikarst processes: “Cave Without a Name”, central Texas, USA. Geological Society of America annual meeting. Minneapolis, Minnesota, October, 2011.

Gerard, B.R., Schwartz, B.F., Ramirez, P., Stinson, C.L., Tobin, B.W., Timmins, G., Hutchins, B., and S. Schwinning. The influence of barometric pressure fluctuations on cave drip rates. Geological Society of America South-Central section 46th annual meeting. Alpine, Texas, March, 2012.

Schwartz, B.F., Nowlin, W., Hutchins, B., Hardy, T.B., Ramirez, P., Timmins, G., Gerard, B.R., and K. Hoesel. Geochemical trends and storm responses at San Marcos Springs, Texas: New perspectives and new questions. Geological Society of America South-Central section annual meeting. Alpine, Texas, March, 2012.

Stinson, C.L., Schwartz, B.F., Tobin, B.W., Gerard, B.R., Ramirez, R., Timmins, G., Hutchins, B., and S. Schwinning. Trinity Aquifer epikarst study using δO18 and δD stable isotope analysis, Cave Without a Name, South-Central Texas. Geological Society of America South-Central section annual meeting. Alpine, Texas, March, 2012.

Tobin, B.W., Schwartz, B.F., Gerard, B.R., Ramirez, P., Timmins, G., Hutchins, B., Stinson, C.L., and S. Schwinning. Autogenic vs. allogenic recharge: Searching for the source of the stream in Cave Without a Name, Boerne, Texas. Geological Society of America South-Central section annual meeting. Alpine, Texas, March, 2012.

Gerard, B.R., Schwartz, B.F., Nowlin, W., and S. Schwinning. Modeling the precipitation threshold required for recharge in a karst aquifer of central Texas. 17th Annual Biology Student Colloquium. San Marcos, Texas, March, 2012.