6/05/2017  |   11:00 - 11:15   |  301B

EXAMINING THE ECOSYSTEM SERVICE OF FECAL INDICATOR BACTERIA REMOVAL BY RIVER NETWORKS Rivers, estuaries, and beaches in the U.S. face persistent bacterial contamination. A better understanding of the mechanisms controlling bacterial contamination events would result in better management. Removal of fecal indicator bacteria (FIB) in river systems potentially attenuates downstream impairments and would represent an important ecosystem service to reduce microbial impairment of freshwater sources. We developed a module for routing FIB through river networks in the Framework for Aquatic Modeling of the Earth System (FrAMES) model to understand the fate and transport of E. coli, which is the freshwater indicator for fecal contamination. This study found that hyporheic exchange is important in removing E. coli. The water column and the hyporheic zone removed approximately 10-30% and 30-50% of E. coli input, respectively, in New England watersheds during the summer period. Watershed size, land use distribution, and hydrology interact to determine network-scale E. coli removal, but hydrology has the most significant impact. This study found that the ecosystem service of FIB removal reduces FIB levels at critical downstream water bodies, such as recreational lakes and estuaries. These results have important implications for managing bacteria contamination.

Tao Huang (Primary Presenter/Author), University of New Hampshire, th2018@wildcats.unh.edu;


Wilfred M. Wollheim ( Co-Presenter/Co-Author), University of New Hampshire, wil.wollheim@unh.edu;


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6/05/2017  |   11:15 - 11:30   |  301B

ALTERNATIVE ONSITE TREATMENT SYSTEMS INCLUDING CONSTRUCTED WETLANDS FOR TRACE ORGANIC CONTAMINANT REMEDIATION Trace organic contaminants (TOrCs) encompass a diverse group of chemicals not currently regulated in US waste or drinking waters which have been found to have ecotoxicological effects in aquatic ecosystems at extremely low levels. On a local scale, onsite treatment systems may have potent impacts on resources that are invaluable to residents, including surface and groundwaters. A Virginia Tech student completed a preliminary engineering report (PER) reviewing alternative treatment options to replace conventional septic systems for a small community with unusually high pharmaceutical consumption rates. Constructed wetlands were considered along with two proprietary systems: an aerobic styrene biofilter (EZ-Treat) and an aerobic treatment unit with a peat biofilter (Anua). The PER included findings from a literature review, a pilot study using real septic tank effluent from the community, and a cost analysis including capital and long term expenses. Although the wetlands exhibited excellent removal of nutrients and TOrCs, the Anua system had better removal of TOrCs and offered economic and strategical advantages over the compared options.

Chloe Greenberg (Primary Presenter/Author), Virginia Tech, chloefg@vt.edu;


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6/05/2017  |   11:30 - 11:45   |  301B

APPLYING THE SUSTAINABLE BOUNDARY APPROACH TO DEVELOP FLOW GUIDLINES IN THE UNREGULATED FLINT RIVER, GEORGIA Concerns over the ability to provide for public supply and support the requirements for aquatic biota are amplified in Georgia and the southeastern US by increasing population, increasing temperatures, and variable precipitation. Given uncertainty, there is need for systematic assessment of hydrologic change and evaluation of biological responses. We used the Sustainable Boundary Approach (SBA) to develop flow guidelines for 2 gauging stations on the Flint River. Substantial declines in growing season daily flows were apparent in the past 30+ years. Biological responses are undocumented, however several faunal groups (fishes, mussels, and crayfishes) are likely affected. The Flint River appears at risk for moderate to severe ecological degradation, for biota and ecological processes depending on growing season flow. Sufficient information exists to guide management and a monitoring network is in place to provide feedback. Challenges lie in engaging diverse stakeholders in a process leading to regional flows that sustain ecological structure and function. Actions could include more rapid responses to drought warning systems already in place, and enhanced conservation, particularly in the upper watershed.

Stephen Golladay (Primary Presenter/Author), Georgia Water Planning and Policy Center at ASU, steve.golladay@jonesctr.org;


Nicholas Marzolf ( Co-Presenter/Co-Author), J.W. Jones Ecological Research Center, nmarzolf@jonesctr.org;


Chelsea R. Smith ( Co-Presenter/Co-Author), The University of Alabama, crsmith5@crimson.ua.edu;


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