Tree nurseries and greenhouses within the USDA red imported fire ant (RIFA) quarantine zone are required to incorporate insecticides into their potting media to prevent artificial spread of RIFA. Bifenthrin and fipronil are two common insecticides that are incorporated into potting media. During irrigation and stormwater events, there is potential for insecticides to leach from nursery pots, resulting in the contamination of nearby surface waters. In this study, occurrences of insecticides in simulated nursery runoff were compared with two irrigation strategies and two types of containers in single pot leaching and field runoff simulations. In addition, toxicity of pot leachate to the aquatic invertebrate, Hyallela azteca, was measured, and removal efficiencies of insecticides from bioretention cell media were evaluated. Overhead irrigation resulted in significantly higher concentrations than drip irrigation, and RootMaker pots allowed more leaching as compared to standard slick-wall pots. However, in all tests, the average concentration of bifenthrin during 15 days of leaching in both pot and field simulations was greater than 200 ng/L; more than 100-fold greater than the LC₅₀ for H. azteca. Toxicity studies confirmed this level of toxicity. Higher amounts of compost, 20 and 40%, in bioretention cell media resulted in greater percent reduction of both bifenthrin and fipronil. This study determined that management techniques may be able to limit the amount of insecticide that leaches from pots and runs off to receiving water bodies. Specifically, the selection of appropriate pot types, irrigation strategies, or filtering runoff through bioretention cells may reduce contamination loads. Thus, further best management strategies such as the use of bioretention cells are needed in nursery and greenhouse facilities to prevent surface water runoff from transporting toxic insecticides.

BSLDEM10M Mean drainage-basin slope CANOPY_PCT Percentage of forest-canopy cover CONTDA Contributing drainage area CSL10_85FM 10-85 stream channel slope GIS Geographic information system GLS Generalized least squares IACWD Interagency Advisory Committee on Water Data IMPNLCD01 Percentage of impervious cover LC01CROP Percentage of drainage area with crop cover LPIII Log-Pearson Type III LOWESS Locally weighted scatterplot smoothing NWISWeb National Water Information System Website ODOT Oklahoma Department of Transportation OK_HIPERMA Percentage of drainage area on the High Plains aquifer OLS Ordinary least squares OUTLETELEV Outlet elevation

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For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment-visit http://www.usgs.gov or call 1-888-ASK-USGS.For an overview of USGS information products, including maps, imagery, and publications, visit http://store.usgs.gov.Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. AcknowledgmentsThe Canadian River alluvial aquifer study was conducted as a part of the U.S. Geological Survey (USGS) Cooperative Water Program in cooperation with the Oklahoma Water Resources Board (OWRB). The authors thank the board members of the OWRB for their support of this study and the OWRB technical studies section, who provided datasets and field assistance.The authors thank USGS employee Lynette Brooks for her help in conceptual flow model analysis and design. The authors thank Mike Fienen for support with parameter estimation (PEST) settings, singular value decomposition, and regularization. Additionally, the authors thank the Wisconsin and Nebraska Water Science Centers for use of their high-performance computing networks to perform the PEST calibration for the two groundwater-flow models. The authors also thank USGS employee Kevin Smith for his extensive field work and site data collection. Finally, the authors thank the many landowners who provided access to their land and groundwater wells, without whose assistance this study would not have been possible. DatumVertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88).Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).Altitude, as used in this report, refers to distance above the vertical datum. AbstractThis report describes a study of the hydrogeology and simulation of groundwater flow for the Canadian River alluvial aquifer in western and central Oklahoma conducted by the U.S. Geological Survey in cooperation with the Oklahoma Water Resources Board. The report (1) quantifies the groundwater resources of the Canadian River alluvial aquifer by developing a conceptual model, (2) summarizes the general water quality of the Canadian River alluvial aquifer groundwater by using data collected during August and September 2013, (3) evaluates the effects of estimated equal proportionate share (EPS) on aquifer storage and streamflow for time periods of 20, 40, and 50 years into the future by using numerical groundwater-flow models, and (4) evaluates the effects of present-day groundwater pumping over a 50-year period and sustained hypothetical drought conditions over a 10-year period on stream base flow and groundwater in storage by using numerical flow models. The Canadian River alluvial aquifer is a Qua...

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