Thursday, June 8, 2017
14:00 - 15:45

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14:00 - 14:15: / 305B COMPARATOR SITE SELECTION FOR SCREENING-LEVEL CAUSAL ASSESSMENTS

6/08/2017  |   14:00 - 14:15   |  

COMPARATOR SITE SELECTION FOR SCREENING-LEVEL CAUSAL ASSESSMENTS Sites in poor ecological condition require causal assessment to determine appropriate follow-up steps. A key component of this process – though one that lacks standardization - is to identify a series of ecologically similar sites used to assess potential stressors at the impaired site. A good set of comparators should: 1. Be capable of supporting similar biota to the impaired site; 2. Comprise a gradient of biotic condition; and 3. Contain enough sites to assess variability. We propose a quantitative approach to select sets of comparators from a large pool of potential sites in Southern California using expected biological similarity. Expected biological similarity was measured as Bray-Curtis dissimilarity values (BC) calculated from the expected taxa lists produced by a predictive biotic index of stream health. We were able to select more than 100 comparators for all but 1 of 15 case study streams at a BC <0.1. Sets of comparators have many possible applications for bioassessment monitoring programs, but will be particularly useful for deriving evidence for causal assessment. DISCLAIMER: Views expressed are the authors’ and not views or policies of the U.S.EPA

David Gillett (Primary Presenter/Author), Southern California Coastal Water Research Project, davidg@sccwrp.org;


Raphael Mazor ( Co-Presenter/Co-Author), Southern California Coastal Water Research Project, raphaelm@sccwrp.org;


Susan Norton ( Co-Presenter/Co-Author), U.S.Environmental Protection Agency, norton.susan@epa.gov;


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14:15 - 14:30: / 305B RAPID DERIVATION OF EVIDENCE FOR CAUSAL ASSESSMENT

6/08/2017  |   14:15 - 14:30   |  305B

RAPID DERIVATION OF EVIDENCE FOR CAUSAL ASSESSMENT Causal assessment is a recommended follow-on effort when biological monitoring results indicate that stream condition is degraded. However, these assessments can be resource and time intensive. We demonstrate how groups of comparator sites identified based on expected biological similarity can be used to quickly derive evidence for causal assessments. Sets of comparator sites were created for 15 demonstration sites in poor condition from Southern California. We evaluated two common types of evidence for four example stressors – total nitrogen, ammonia, specific conductivity, and bifenthrin – as candidate causes of the poor biotic condition at each site. Elevated conductivity was the most frequently supported cause, although ammonia, total nitrogen and bifenthrin were also indicated at some sites. Evidence also suggested that each of these stressors was an unlikely contributor at least one site. Our approach could be adapted for any bioassessment program with a large amount of sample data and an associated predictive index of biotic condition, and lays the groundwork for developing more rapid causal assessment methods. DISCLAIMER: Views expressed are the authors’ and not views or policies of the U.S.EPA.

Susan Norton (Primary Presenter/Author), U.S.Environmental Protection Agency, norton.susan@epa.gov;


David Gillett ( Co-Presenter/Co-Author), Southern California Coastal Water Research Project, davidg@sccwrp.org;


Raphael Mazor ( Co-Presenter/Co-Author), Southern California Coastal Water Research Project, raphaelm@sccwrp.org;


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14:30 - 14:45: / 305B STREAMLINING CAUSAL ASSESSMENT USING AN R-BASED SCREENING APPLICATION

6/08/2017  |   14:30 - 14:45   |  305B

STREAMLINING CAUSAL ASSESSMENT USING AN R-BASED SCREENING APPLICATION The number of impaired waterbodies in the U.S. is rising as monitoring programs expand to include more locations and more possible sources of impairment. Moreover, few impaired waterbodies are affected by a single source, making it difficult to determine the cause or causes of biological impairment. EPA’s Causal Assessment/Diagnosis Decision Information System (CADDIS) provides a thorough approach to causal assessment but is time-consuming and data intensive. Consequently, there is a need for a tool capable of rapidly screening impaired waterbodies to help understand the likely causes of impairment, rule out unlikely causes, identify data gaps, and prioritize additional monitoring effort. We have developed a Causal Assessment Screening Tool as an R-based application and have demonstrated its utility using stream sites in southern California. The tool uses a combination of statistical techniques to select comparator sites, identify candidate causes, evaluate stressor-response relationships, and incorporate stressor-specific diagnostic tools. Its output can provide stakeholders with sufficient information to tailor next steps for an impaired waterbody, including filling critical data gaps, conducting more in-depth causal analyses, or developing appropriate restoration plans.

Ann Roseberry Lincoln (Primary Presenter/Author), Tetra Tech, Inc., Ann.Lincoln@tetratech.com;


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14:45 - 15:00: / 305B UNDERSTANDING VARIATION IN STREAM TEMPERATURE AND DISSOLVED OXYGEN RESPONSES TO SMALL DAMS

6/08/2017  |   14:45 - 15:00   |  305B

UNDERSTANDING VARIATION IN STREAM TEMPERATURE AND DISSOLVED OXYGEN RESPONSES TO SMALL DAMS Many of the estimated 2 million dams in the U.S. are small structures with highly variable impacts to water quality. Some studies have reported increased temperature and decreased dissolved oxygen (DO) downstream of dams, whereas other studies have shown no impact. Given this observed variability, we examined the role of landscape context (e.g., percent forest, drainage size), dam characteristics (e.g., reservoir volume, dam height), and flow in explaining spatial and temporal variation in stream temperature and DO responses to dams. Downstream temperatures were warmer (0.2–5.3C) at 14 of 18 sites, with greater thermal impacts in forested vs. urban watersheds. Temperatures decreased with increasing distance downstream of the dam at 26 of 31 sites, with shorter dams and sites with higher forest cover showing faster recovery. DO was lower in the impoundment compared to upstream reaches at nine of the 12 sites, but that only translated to lower downstream DO at 6 sites. These results can help to identify which unmanaged dams might provide the greatest water quality benefits from dam removal.

Peter Zaidel (Primary Presenter/Author), Massachusetts Cooperative Fish and Wildlife Research Unit, University of Massachusetts Amherst, pzaidel@umass.edu;


Allison Roy ( Co-Presenter/Co-Author), U.S. Geological Survey, Massachusetts Cooperative Fish and Wildlife Research Unit, University of Massachusetts Amherst, aroy@eco.umass.edu;


Keith Nislow ( Co-Presenter/Co-Author), Northern Research Station, U.S.D.A. Forest Service, University of Massachusetts Amherst, knislow@fs.fed.us;


Ben Letcher ( Co-Presenter/Co-Author), U.S. Geological Survey, bletcher@usgs.gov;


Beth Lambert ( Co-Presenter/Co-Author), Massachusetts Division of Ecological Restoration, beth.lambert@state.ma.us;


Kristopher Houle ( Co-Presenter/Co-Author), Massachusetts Division of Ecological Restoration, kris.houle@state.ma.us;


Christopher Smith ( Co-Presenter/Co-Author), U.S. Environmental Protection Agency, Region 1, chris.r.smi@gmail.com;


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15:00 - 15:15: / 305B STREAMFLOW MECHANISMS AND WATER CHEMISTRY USING OPEN SOURCE WIRELESS TECHNOLOGY

6/08/2017  |   15:00 - 15:15   |  305B

STREAMFLOW MECHANISMS AND WATER CHEMISTRY USING OPEN SOURCE WIRELESS TECHNOLOGY High freshwater salinity (measured as total dissolved solids, TDS) is toxic for many fish and macroinvertebrates. Salinity levels are often the strongest indicators of stream degradation below mountaintop mining and valley fill (MTM/VF) operations throughout central Appalachia. Unfortunately, there are no standard technologies to cost-effectively control TDS loadings to streams at remote mine sites. However, a promising experimental technology (“hydrologic isolation,” HI) to remedy this was implemented at a MTM/VF site in eastern Kentucky. Our goal is to evaluate the effectiveness of this HI methodology in maintaining downstream water chemistry. We will identify and characterize source water contributions to streamflow using salinity measurements (conductivity, a proxy for TDS) to determine how HI affects surface water-groundwater interactions and identify the dominant flowpaths contributing to streamflow. Using a wireless sensor network to collect surface water and groundwater chemistry data, we pair continuous rainfall data with continuous discharge and flow-weighted conductivity to evaluate the seasonal relationship between rainfall-runoff and streamflow and conductivity levels. Dynamic end-member mixing analyses will be used to quantify contributions to stormflow from different streamflow generation mechanisms. The wireless sensor technology will be described and preliminary results will be presented.

Stephanie Fulton (Primary Presenter/Author), University of Georgia, sgfulton@charter.net;


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15:15 - 15:30: / 305B RESHAPE 1% OF THE LAND, GENERATE 50% OF REGIONAL ION FLUX

6/08/2017  |   15:15 - 15:30   |  305B

RESHAPE 1% OF THE LAND, GENERATE 50% OF REGIONAL ION FLUX By dismantling and redistributing 100s of meters of bedrock to mine coal from the surface, mountaintop mining with valley fills has dramatically changed catchment hydrology and biogeochemistry over more than 5,000 km2 in Central Appalachia. Throughout this expansive coal region, mining operators deposit tens of millions of m3 of crushed bedrock into headwater valleys, creating valley fills, which have substantial subsurface water storage potential. Streams draining mines have reduced peakflows, elevated baseflows, and lower event runoff ratios on average. The water percolating through valley fills drives the dissolution and oxidation of pyrite into sulfuric acid which reacts with carbonate-rich materials to rapidly weather out a suite of elements including Ca2+, Mg2+, K+, SO42-, HCO3-, exporting 45-times more total dissolved solids. These exceptionally high weathering rates and elevated baseflow mean that mountaintop mines control water chemistry well downstream of their impacts. Here we model elemental flux from mined landscapes through large river networks (the Ohio and its sub-watersheds). Despite occupying less than 1% of the land surface area they may contribute as much as 50% of weathering derived solutes to these major rivers.

Matthew Ross (Primary Presenter/Author), Duke University, matt.ross@duke.edu;


Fabian Nippgen ( Co-Presenter/Co-Author), Duke University, fabian.nippgen@gmail.com;


Brian McGlynn ( Co-Presenter/Co-Author), Duke University, brian.mcglynn@duke.edu;


Emily Bernhardt ( Co-Presenter/Co-Author), Duke University, ebernhar@duke.edu;


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