### Appendix 2-D(2) Comparison of SAM Outputs to Monitoring Data from Monitoring Sites in Scioto River Basin, OH This appendix, the second of three spreadsheets, is provided in support of the comparison of model outputs with measured data in Section 2.4 of the SAP documentDevelopment of a Spatial Aquatic Model (SAM) for Pesticide Assessments. As a part of the model evaluation for SAM, this appendix provides a comparison of estimated daily atrazine concentrations for 2000- 2014 to monitoring data from the Atrazine Ecological Exposure Monitoring Program (AEEMP), Atrazine Monitoring Program (AMP), and Heidelberg University's National Center for Water Quality Research (NCWQR) at the Scioto River. Monitoring data and descriptions can also be found in Appendix 2C.
The table to the right describes each tab linked to the monitoring sites found in the Scioto River test basin. Figures 1 and 2 (below) shows the locations of the test sites. Each basin is identified both by the original study ID and by the NHDplus (version 2) comid for the catchment that is associated with the monitoring sampling site (pour point).
Figure 1: Location of Test Basin Areas for SAM Model Development and Evaluation.

### Figure 2: AEEMP and AMP Monitoring Sites in the Scioto River (OH) Test Basin Area.Worksheet Tab Contents SummaryByYear Summary of annual (2000-2014) total mass lost, total runoff, maximum atrazine concentrations and comparisons with monitoring for each test basin site. Includes graphs comparing estimated concentrations with monitoring data.
OH-04_3483775_basin Results for AEEMP site OH-04 (NHD+ comid 3483775) OH-10rvr_5214753_basin Results for AMP site OH-10 river (NHD+ comid 5214753) OH-11res_5213585_basinResults for AMP site OH-11 reservoir (NHD+ comid 5213585) HU_SR_3486865_basin Results for Heidelberg U. NCWQR monitoring site for Scioto River (NHD+ comid 3486865) Monitoring Monitoring data for each of the test basin sites (used for graphs) Each basin tab includes the following fields: Field Description/source Date Daily dates from scenario, 1/1/2000 - 12/31/2014 Est. Conc (ug/L) Estimated daily concentrations generated using aggregated scenarios (soils grouped by WQI criteria) Rmass (kg) Daily pesticide mass flux lost in runoff generated using aggregated scenarios (soils grouped by WQI criteria) Runoff(m) Daily runoff volume using aggregated scenarios (soils grouped by WQI criteria) RConc(ug/L) Daily runoff concentration using aggregated scenarios (soils grouped by WQI criteria) TotalFlow(m3) Total flow estimate in stream mixing cell, based on NHD+ data baseflow(m3) Base flow estimate for stream mixing cell (see Section 2.1) MassAppl Daily mass applied based on pesticide application rate, corn area, length of application window (50 days) Cumul. Mass Appl. Cumulative mass of pesticide applied in watershed (summing MassAppl)Cumul. Runoff Loss, Aggreg Scenarios Cumulative pesticide mass lost in runoff (summing daily Rmass values)

Year Year of simulation Mass(kg) Sum of daily pesticide mass loss by year for soils aggregated by WQI scenarios Runoff(m) Sum of daily runoff volumes by year for soils aggregated by WQI scenarios
Max conc Maximum annual concentration in water for soils aggregated by WQI scenarios

Max runoff conc Maximum annual concentration in runoff for soils aggregated by WQI scenarios CornArea(m2) Corn area, based on watershed recipe files for 2010-2014 CDL
CornFrac Corn as a fraction of watershed area, based on watershed recipe files for 2010-2014 CDL Applied(kg) Total kg of pesticide applied by year, based on application rate, area in corn

FracLoss Fraction of pesticide lost to runoff by year: ratio of annual mass runoff loss to amount applied