Jeff Deacon Casey Lee Julia Norman David Reutter 2017 The data are contained in 9 comma delimited files Science Base U.S. Geological Survey https://doi.org/10.5066/F73777K4 The National Water Quality Network (NWQN) for Rivers and Streams includes 113 surface-water river and stream sites monitored by the U.S. Geological Survey (USGS) National Water Quality Program, National Water-Quality Assessment (NAWQA) Project. The NWQN includes 19 large river coastal sites, 44 large river inland sites, 30 wadeable stream reference sites, 10 wadeable stream urban sites, and 10 wadeable stream agricultural sites. In addition to the 113 NWQN sites, 3 large inland river monitoring sites from the USGS Cooperative Water Program are also included in this annual water-quality reporting Web site to be consistent with previous USGS studies of nutrient transport in the Mississippi-Atchafalaya River Basin. This data release provides streamflow, nutrient, pesticide and sediment data collected and analyzed by NWQN and other historical water-quality networks from 1963-2016. Data from this release are presented at the USGS Tracking Water Quality page: http://cida.usgs.gov/quality/rivers/home. The U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Project characterizes the status and trends of water quality and aquatic ecosystems by monitoring ambient water-quality and ecological conditions through the newly established National Water Quality Network (NWQN) for Rivers and Streams. The NWQN is the primary source of data for the systematic annual reporting of ambient conditions nationally. Primary objectives of the NWQN are to: • determine the status and trends of loads and concentrations of contaminants, nutrients, and sediment in the Nation's large rivers, including loads to selected major estuaries; • determine the status and trends of concentrations of contaminants, nutrients, and sediment for selected wadeable streams in selected land-use and environmental settings; and • determine trends in ecological condition in relation to trends in contaminants, nutrients, sediment, and streamflow alteration for selected wadeable streams in selected land-use and environmental settings. In an effort to meet these objectives, the USGS Tracking Water Quality webpage (http://cida.usgs.gov/quality/rivers/home) is being updated with nutrient and pesticide concentration and load data collected from the NWQN. These metadata describe 9 data tables that are part of this data release. This publication supercedes a previous data release "Nutrient and pesticide data collected from the USGS National Water Quality Network and previous networks, 1980-2015" (https://dx.doi.org/doi:10.5066/F7BK19GZ) 19631001 20160930 ground condition Complete Annually -185.16601562163 -58.095703126298 72.328996908904 6.4458829858152 USGS Thesaurus nutrient content sediment transport pesticide and herbicide contamination streamflow water quality river systems USGS Metadata Identifier USGS:595e6b16e4b0d1f9f05702fd Getty Thesaurus of Geographic Names United States None, however, acknowledgment of the U.S. Geological Survey would be appreciated in products derived from these data Although there are no restrictions or legal prerequisites for using the data, users are advised to read the data set's metadata thoroughly to understand appropriate use and data limitations. Casey Lee USGS mailing and physical

4821 Quail Crest Place

Lawrence KS 66049 USA 785-832-3515 cjlee@usgs.gov A wide variety of tests were developed and implemented for these data. These tests verified that data had reasonable minimum and maximum values, that the correct data were contained within each column, and that columns matched between data frames among other things. These tests can be found here: https://github.com/USGS-CIDA/nar_data In addition the streamflow and nutrient data are plotted and can be reviewed on the following site: http://cida.usgs.gov/quality/rivers/home. Much of the pesticide data will be available to review on this site in August 2017. As stated in the attribute accuracy report: "A wide variety of tests were developed and implemented for these data. These tests verified that the data had reasonable minimum and maximum values, that the correct data were contained within each column, and that columns matched between data frames among other things. These tests can be found here:https://github.com/USGS-CIDA/nar_data Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. No formal positional accuracy tests were conducted No formal positional accuracy tests were conducted U.S. Geological Survey National Water Information System 2016 Obtained via webservices U.S. Geological Survey - National Water Information System; http://dx.doi.org/10.5066/F7P55KJN USGS http://dx.doi.org/10.5066/F73777K4 streamflow and water-quality data 19631001 20160930 http://dx.doi.org/10.5066/F73777K4 USGS NWIS The raw data for everything contained herein Process Step 1 Process description: Refers to aflow.csv. Annual flows in this file are reported for each site and water year. Annual flows were computed by converting daily flows (available here: http://waterdata.usgs.gov/nwis/dv/?referred_module=sw and computed in Process Step 3), reported in cubic feet per second, to acre-feet per day. These data were then summed for each respective combination of site and water year. 20170703 Process Step 2 Process description: Refers to aloads.csv. Annual loads in this file are reported for each site, constituent and water year from 1963-2016. Data from 1963-1992 are only included for sites reported in Aulenbach and others (2007). Annual loads were computed from discrete water-quality data presented in the discqw.csv file and daily flows in the dflow.csv file. Loads were computed using the LOADEST program (Runkel, 2004) implemented via the rloadest package in the R statistical environment (https://github.com/USGS-R/rloadest). The MODTYPE field in this file provides more information on the type of load model used to compute load values. Values in this field include “COMP” indicating the data was computed using composite method developed by Aulenbach and Hooper (2006). “CONTIN” indicates that loads were computed through the use of continuous nitrate data, which can be found for a specific site at the USGS NWIS daily water quality page (waterdata.usgs.gov/nwis/dv/?referred_module=qw); “DAILY” indicates that data were computed using daily values (SSC only, found for a specific station at waterdata.usgs.gov/nwis/dv/?referred_module=sw); REG indicates models were computed using a 5-year moving window (see http://cida.usgs.gov/quality/rivers/technical_information#TechnicalInformationandGlossary-LoadEstimation for full details); “REG_2; REG_3; REG_4” indicates models were computed using regression methods with 2, 3, or 4-year moving windows (respectively) as opposed to a 5-year moving window; “REG_PRELIM” indicates that a model was developed using data collecting during the initial 2-4 years in which a site was sampled; models at these sites will continue to be updated until 5 years of data are collected; and “REGHIST” indicating that models were historically computed according to procedures described in Aulenbach and others (2007). Note that one additional site indicated as "GULF" in the SITE_ABB, SITE_QW_ID, and SITE_FLOW_ID fields is included to represent cumulative loading to the Gulf of Mexico. These loads are the sum of constituent loads from the Atchafalaya River at Melville (SITE_QW_ID of 07381495) and the Mississippi River at St. Francisville (SITE_QW_ID of 07373420). Details regarding load computation methods are available at: http://cida.usgs.gov/quality/rivers/technical_information#TechnicalInformationandGlossary-LoadEstimation. Aulenbach, B.T., Hooper, R.P., 2006. The composite method: an improved method for stream-water solute load estimation. Hydrol. Process. 20, 3029-3047. Aulenbach, B.T., Buxton, H.T., Battaglin, W.A., and Coupe, R.H., 2007, Streamflow and nutrient fluxes of the Mississippi-Atchafalaya River Basin and subbasins for the period of record through 2005: U.S. Geological Survey Open-File Report 2007-1080, http://toxics.usgs.gov/pubs/of-2007-1080/index.html Runkel, R.L., Crawford, C.G., and Cohn, T.A., 2004, Load Estimator (LOADEST): A FORTRAN Program for Estimating Constituent Loads in Streams and Rivers: U.S. Geological Survey Techniques and Methods Book 4, Chapter A5, 69 p. 20170703 Process Step 3 Process description: Refers to dflow.csv. Daily flows in this file are reported for each site and date from 1968-2016. Daily flows are obtained for each site from the USGS NWIS surface water page: http://waterdata.usgs.gov/nwis/dv/?referred_module=sw. In a few cases, small gaps (1-10 days) in daily flow data are interpolated to allow for load computations. Because zero and negative flow values cannot be used in the load computation process because of log-transformation, these data are converted to 0.01 cubic feet per second. This step is deemed appropriate because negative flows are extremely rare throughout the network, and because when they do occur, they represent a small percentage ~<1% of cumulative annual flows. 20170703 Process Step 4 Process description: Refers to discqw.csv. Discrete water-quality data in this file are reported for each site and date from 1963-2016. Data from 1963-1992 are only reported for sites reported in Aulenbach and others (2007). The USGS NWIS system (http://nwis.waterdata.usgs.gov/usa/nwis/qwdata) is the source of data in this file. These data underwent additional processing steps before publication which are detailed here: http://cida.usgs.gov/quality/rivers/technical_information#TechnicalInformationandGlossary-Water-QualityAnalyses Aulenbach, B.T., Buxton, H.T., Battaglin, W.A., and Coupe, R.H., 2007, Streamflow and nutrient fluxes of the Mississippi-Atchafalaya River Basin and subbasins for the period of record through 2005: U.S. Geological Survey Open-File Report 2007-1080, http://toxics.usgs.gov/pubs/of-2007-1080/index.html 20170703 Process Step 5 Process description: Refers to mflow.csv. Monthly flow values reported in this file are reported at each site and water year for sites in the Mississippi River Basin from 1963-2016. These data are published exclusively for sites in the Mississippi River Basin; monthly water-quality loads to the Gulf are used to predict the extent of the hypoxic zone in the Gulf of Mexico, see http://toxics.usgs.gov/hypoxia/mississippi/oct_jun/ for more details. Monthly flows were computed by converting daily flows (see Process Step 3), reported in cubic feet per second, to acre-feet per day. These data were then summed for each month and water year at each site. 20170703 Process Step 6 Process description: Refers to mloads.csv. Monthly water-quality load values are reported for sites in the Mississippi River Basin from 1969-2016. Monthly loads have been historically published in the Mississippi River Basin in part because they are used to predict the extent of the Gulf hypoxic zone, see http://toxics.usgs.gov/hypoxia/mississippi/oct_jun/ for more details. Other than the difference in time span, processing steps for this file are the same as those described in step 2 (aloads.csv) 20170703 Process Step 7 Process description: Refers to pestlong.csv. This file is used to link abbreviated pesticide names to more detailed names, chemical abstract service numbers, and USGS parameter codes. The USGS NWIS system parameter code page (http://nwis.waterdata.usgs.gov/usa/nwis/pmcodes) is the source of this data. 20170703 Process Step 8 Process description: Refers to pestsamp.csv. This file presents pesticide results from samples collected at NWQN sites. Beginning in 2013, NAWQA began using a new analytical method developed by the USGS National Water Quality Lab (Sandstrom and others, 2015) to analyze water samples for current use pesticides and pesticide degradates. Before 2013, different analytical methods were used to measure a subset of these pesticides in water. To enable consistent comparisons of pesticide occurrence among NWQN sites through time, only those pesticides that were analyzed throughout the NAWQA Project--before and after 2013--are presented on this website. A number of additional data preparation steps detailed below are implemented to ensure the consistency and comparability of pesticide data presented on this website. The following data preparation steps were taken with discrete water-quality data obtained from the USGS NWIS database: 1. An initial retrieval of water-quality data for NWQN sites from NWIS was limited to 227 pesticide compounds analyzed in Sandstrom and others, 2015, including compounds common to this method that were previously analyzed by other methods. 2. All internal or proprietary samples or results were removed. 3. Results duplicative among different USGS water science centers were narrowed to only one result. 4. Quality assurance data (i.e. spikes, blanks or duplicates) were removed. 5. Results that are identified as contaminated (with a REMARK code of “V”) and results in which concentrations are equal to or less than zero (which is inconsistent with laboratory reporting protocols) were removed. These data are likely not accurate. 6. Only results from analyses conducted at the USGS National Water Quality Laboratory were retained. 7. Analyses with unknown or potentially incorrect method codes were removed. 8. We randomly selected among values collected at the same site within a single hour as these results were presumed to be from replicate sampling. 9. Units for pesticide concentrations were converted to be reported in micrograms per liter so that all results share common units. 10. Laboratory reporting limit data provided by the USGS National Water Quality Laboratory were assigned to pesticide sample results. 11. Selected pesticide concentrations with "raised reporting levels" are removed. Raised reporting levels may occur for various reasons, including interference in the sample matrix, inability to accurately quantify the pesticide concentration, changing laboratory instrument sensitivity, dilution, and (or) blank contamination (Shoda and others, in-press). Pesticide results with raised reporting levels were deemed highly uncertain and were removed if they met the following criteria: - If the result is reported as a censored value (REMARK_CD of "<"), the concentration (RESULT_VA in the USGS NWIS results) field is less than the NWQL interim reporting level, and if the value qualifier code reported from the USGS NWIS (VAL_QUAL_CD_TX) system is not populated. - If the result is reported as a censored value (REMARK_CD of "<"), the concentration (RESULT_VA in the USGS NWIS results) field is less than the NWQL interim reporting level, and if the value qualifier code reported from the USGS NWIS (VAL_QUAL_CD_TX) contains a "v" (indicating that the analyte was detected in a laboratory blank), or if the lab comment field (RESULT_LAB_CM_TX from the USGS NWIS) is reported as "contamination". - If the result is reported as a censored value (REMARK_CD of "<"), and the concentration (RESULT_VA in the USGS NWIS results) field is greater than the calibration standard reporting level. The calibration reporting level is defined by Shoda and others (in-press) refers to the value of the first calibration standard higher than the highest commonly-observed laboratory reporting level. See Shoda and others (2017) for more details. Removing such results with raised reporting levels is consistent with practices historically used by NAWQA for assessing pesticides in streams (Gillion and others, 2006). 12. Pesticide sample results are only reported for Coastal River, Large Inland River, Urban Indicator, and Agricultural Indicator sites because pesticide analyses typically aren't collected at reference sites. 13. Pesticide sample results are only reported for sites in which a complete year of data were collected in 2016. 14. Pesticide data are only reported since the inception of the NAWQA program, and thus are reported from 1993-2016. Sandstrom, M.W., Kanagy, L.K., Anderson, C.E., and Kanagy, C.J., 2015, Determination of pesticides and pesticide degradates in filtered water by direct aqueous injection liquid chromatography tandem mass spectrometry: U.S. Geological Survey Techniques and Methods book 5, chap. B11 Shoda, M.E., Nowell, L.H., Bexfield, L.M., 2017, National Water-Quality Assessment Project replicate surface water and groundwater pesticide data analyzed by the USGS National Water Quality Laboratory schedule 2437, Water Years 2013-15: U.S. Geological Survey data release, https://doi.org/10.5066/F75H7DS8. 20170703 Process Step 9 Process description: Refers to NWQN_sites.csv. This file provides a list of National Water Quality Network sites and cooperative program sites for which streamflow and water-quality data are collected. Site names and drainage area are obtained from the USGS NWIS system: http://nwis.waterdata.usgs.gov/nwis/. 20170703 aflow.csv The annual flow transported past each NWQN site, in acre-feet USGS National Water Quality Assessment Program - National Water Quality Monitoring Network "SITE_ABB" A text abbreviation of the site name, primarily for use within the National Water Quality Program. Producer defined This code is typically the first four characters of the site location. For example, the SITE_ABB for the site "Red River at Alexandria" is "ALEX". SITE_QW_ID Unique USGS station number indicating location where water-quality samples are collected. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN USGS station numbers represent either a geographic location, represented by latitude and longitude of 15-digits, or an 8-digit or more network sequence number. SITE_FLOW_ID Typically a unique USGS station number indicating location where streamflow data is recorded. In some instances these data are obtained from outside sources, in those cases an abbreviation of the collection agency and site number (if available) are displayed. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN USGS station numbers represent either a geographic location, represented by latitude and longitude of 15-digits, or an 8-digit or more network sequence number. In cases where streamflow is collected by an outside entity the rationale behind the indicator is unknown. WY A numeric identifier of the water year in which data were recorded. Producer defined 1963 2016 years FLOW A numeric identifier of the volume of water transported for a given water year, in acre-feet. U.S. Geological Survey - National Water Information System; Surface water; http://dx.doi.org/10.5066/F7P55KJN 0 805000000 acre-feet aloads.csv The annual water-quality load transported past each NWQN site, in tons. USGS National Water Quality Assessment Program - National Water Quality Monitoring Network SITE_ABB A text abbreviation of the site name, primarily for use within the National Water Quality Program. Producer defined This code is typically the first four characters of the site location. For example, the SITE_ABB for the site "Red River at Alexandria" is "ALEX". SITE_QW_ID Unique USGS station number indicating location where water-quality samples are collected. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN USGS station numbers represent either a geographic location, represented by latitude and longitude of 15-digits, or an 8-digit or more network sequence number. SITE_FLOW_ID Typically a unique USGS station number indicating location where streamflow data is recorded. In some instances these data are obtained from outside sources, in those cases an abbreviation of the collection agency and site number (if available) are displayed. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN USGS station numbers represent either a geographic location, represented by latitude and longitude of 15-digits, or an 8-digit or more network sequence number. In cases where streamflow is collected by an outside entity the rationale behind the indicator is unknown. CONSTIT A character abbreviation indicative of the water-quality constituent being reported. Producer defined TN Total nitrogen Producer defined SSC Suspended-sediment concentration Producer defined NO3_NO2 Nitrate plus nitrite Producer defined TP Total phosphorus Producer defined MODTYPE A character indicator of the type of model used to compute water-quality loads. Producer defined REG Load computed using LOADEST with 5-year sampling window Producer defined REG_4 Load computed using LOADEST with 4-year sampling window because 5-years of data weren't available. Producer defined REG_3 Load computed using LOADEST with 3-year sampling window because 4-5-years of data weren't available. Producer defined REG_2 Load computed using LOADEST with 2-year sampling window because 3-5 years of data weren't available. Producer defined DAILY Load computed by summing daily sediment loads published on NWIS Producer defined REGHIST Historically computed load (using LOADEST) published by the USGS at: http://toxics.usgs.gov/hypoxia/mississippi/flux_ests/index.html Producer defined REG_PRELIM Preliminary load computed using LOADEST that will change as future water-quality data are collected Producer defined COMP Load computed using the composite method (Aulenbach and Hooper, 2006) Producer defined CONTIN Load computed from continuously-monitored nitrate data Predefined TONS Annual water-quality load, measured in tons Producer defined 0 282000000 Tons per year TONS_L95 Lower 95 percent confidence interval about the annual water-quality load. Producer defined 0 226000000 Tons per year TONS_U95 Upper 95 percent confidence interval about the annual water-quality load. Producer defined 0 351000000 Tons per year FWC Flow-weighted constituent concentration, in milligrams per liter per year Producer defined 0 15600 milligrams per liter per year YIELD Water-quality constituent yield, defined as the load divided by the upstream drainage area of the water-quality site. Yields are not computed (and are listed as NA) for Mississippi and Atchafalaya River sites downstream from the Old River diversion because drainage area cannot be accurately defined. Producer defined 0 5560 Tons per square mile dflow.csv The daily flow at each NWQN site, in cubic feet per second U.S. Geological Survey - National Water Information System; Surface water; http://dx.doi.org/10.5066/F7P55KJN SITE_ABB A text abbreviation of the site name, primarily for use within the National Water Quality Program. Producer defined This code is typically the first four characters of the site location. For example, the SITE_ABB for the site "Red River at Alexandria" is "ALEX". SITE_QW_ID Unique USGS station number indicating location where water-quality samples are collected. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN USGS station numbers represent either a geographic location, represented by latitude and longitude of 15-digits, or an 8-digit or more network sequence number. SITE_FLOW_ID Typically a unique USGS station number indicating location where streamflow data is recorded. In some instances these data are obtained from outside sources, in those cases an abbreviation of the collection agency and site number (if available) are displayed. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN USGS station numbers represent either a geographic location, represented by latitude and longitude of 15-digits, or an 8-digit or more network sequence number. In cases where streamflow is collected by an outside entity the rationale behind the indicator is unknown. DATE Date, defined as YYYY-MM-DD Date Date Date FLOW Streamflow, in cubic feet per second. Values are primarily positive, but may be negative at sites influenced by tidal flow. U.S. Geological Survey - National Water Information System; Surface water; http://dx.doi.org/10.5066/F7P55KJN 0 2350000 cubic feet per second WY A numeric identifier of the water year in which data were recorded. Producer defined 1963 2016 water year discqw.csv Discrete water-quality results from samples collected at NWQN sites U.S. Geological Survey - National Water Information System; Water quality; http://dx.doi.org/10.5066/F7P55KJN SITE_ABB A text abbreviation of the site name, primarily for use within the National Water Quality Program. Producer defined This code is typically the first four characters of the site location. For example, the SITE_ABB for the site "Red River at Alexandria" is "ALEX". SITE_QW_ID Unique USGS station number indicating location where water-quality samples are collected. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN USGS station numbers represent either a geographic location, represented by latitude and longitude of 15-digits, or an 8-digit or more network sequence number. SITE_FLOW_ID Typically a unique USGS station number indicating location where streamflow data is recorded. In some instances these data are obtained from outside sources, in those cases an abbreviation of the collection agency and site number (if available) are displayed. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN USGS station numbers represent either a geographic location, represented by latitude and longitude of 15-digits, or an 8-digit or more network sequence number. In cases where streamflow is collected by an outside entity the rationale behind the indicator is unknown. CONSTIT A character abbreviation indicative of the water-quality constituent being reported. Producer defined TN Total nitrogen Producer defined SSC Suspended-sediment concentration Producer defined NO3_NO2 Nitrate plus nitrite Producer defined TP Total phosphorus Producer defined DATE Date, defined as YYYY-MM-DD Date Date Date WY A numeric identifier of the water year in which data were recorded. Producer defined 1963 2016 water year CONCENTRATION Water-quality constituent concentration in milligrams per liter U.S. Geological Survey - National Water Information System; Water quality; http://dx.doi.org/10.5066/F7P55KJN 0 32000 milligrams per liter REMARK Character qualifier of concentration values U.S. Geological Survey - National Water Information System; Water quality; http://dx.doi.org/10.5066/F7P55KJN "" No qualifier U.S. Geological Survey - National Water Information System; Water quality; http://dx.doi.org/10.5066/F7P55KJN "<" The result is less than the value reported in the CONCENTRATION field U.S. Geological Survey - National Water Information System; Water quality; http://dx.doi.org/10.5066/F7P55KJN "E" The result is estimated U.S. Geological Survey - National Water Information System; Water quality; http://dx.doi.org/10.5066/F7P55KJN mflow.csv May flow transported past NWQN monitoring sites, in acre-feet USGS National Water Quality Assessment Program - National Water Quality Monitoring Network SITE_ABB A text abbreviation of the site name, primarily for use within the National Water Quality Program. Producer defined This code is typically the first four characters of the site location. For example, the SITE_ABB for the site "Red River at Alexandria" is "ALEX". SITE_QW_ID Unique USGS station number indicating location where water-quality samples are collected. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN USGS station numbers represent either a geographic location, represented by latitude and longitude of 15-digits, or an 8-digit or more network sequence number. SITE_FLOW_ID Typically a unique USGS station number indicating location where streamflow data is recorded. In some instances these data are obtained from outside sources, in those cases an abbreviation of the collection agency and site number (if available) are displayed. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN USGS station numbers represent either a geographic location, represented by latitude and longitude of 15-digits, or an 8-digit or more network sequence number. In cases where streamflow is collected by an outside entity the rationale behind the indicator is unknown. WY A numeric identifier of the water year in which data were recorded. Producer defined 1968 2016 Water years FLOW The volume of water transported past the site in May, in acre-feet. Values are primarily positive, but may be negative at sites influenced by tidal flow. U.S. Geological Survey - National Water Information System; Surface water; http://dx.doi.org/10.5066/F7P55KJN 39 129000000 acre-feet mloads.csv The May water-quality load transported past each NWQN site, in tons USGS National Water Quality Assessment Program - National Water Quality Monitoring Network SITE_ABB A text abbreviation of the site name, primarily for use within the National Water Quality Program. Producer defined This code is typically the first four characters of the site location. For example, the SITE_ABB for the site "Red River at Alexandria" is "ALEX". SITE_QW_ID Unique USGS station number indicating location where water-quality samples are collected. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN USGS station numbers represent either a geographic location, represented by latitude and longitude of 15-digits, or an 8-digit or more network sequence number. SITE_FLOW_ID Typically a unique USGS station number indicating location where streamflow data is recorded. In some instances these data are obtained from outside sources, in those cases an abbreviation of the collection agency and site number (if available) are displayed. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN USGS station numbers represent either a geographic location, represented by latitude and longitude of 15-digits, or an 8-digit or more network sequence number. In cases where streamflow is collected by an outside entity the rationale behind the indicator is unknown. CONSTIT A character abbreviation indicative of the water-quality constituent being reported. Producer defined TN Total nitrogen Producer defined NO3_NO2 Nitrate plus nitrite Producer defined TP Total phosphorus Producer defined WY A numeric identifier of the water year in which data were recorded. Producer defined 1969 2016 Water year MODTYPE A character indicator of the type of model used to compute water-quality loads. Producer defined REG Load computed using LOADEST with 5-year sampling window Producer defined REG_4 Load computed using LOADEST with 4-year sampling window because 5-years of data weren't available. Producer defined REG_3 Load computed using LOADEST with 3-year sampling window because 4 or 5 years of data weren't available. Producer defined REGHIST Historically computed load (using LOADEST) published by the USGS at: http://toxics.usgs.gov/hypoxia/mississippi/flux_ests/index.html. Producer defined COMP Load computed using the composite method (Aulenbach and Hooper, 2006) Producer defined CONTIN Load computed from continuously-monitored nitrate data Producer defined REG_PRELIM Preliminary load computed using LOADEST that will change as future water-quality data are collected. Producer defined TONS The May water-quality load transported past each NWQN site, in tons USGS National Water Quality Assessment Program - National Water Quality Monitoring Network 0.0056 1180000 Tons TONS_L95 Lower 95 percent confidence interval about the water-quality load. Producer defined 0 1060000 Tons TONS_U95 Upper 95 percent confidence interval about the water-quality load. Producer defined 0.0139 1310000 Tons pestname.csv Linkages between pesticide abbreviations, long names, USGS parameter codes, and chemical abstract service (CAS) numbers U.S. Geological Survey - National Water Information System; Pesticide Organics, Parameter Code Definition; nwis.waterdata.usgs.gov/nwis/pmcodes CONSTIT An abbreviated name for the pesticide being reported. Producer defined Names are derived from full pesticide names reported by the USGS under Organics, pesticide at: nwis.waterdata.usgs.gov/usa/nwis/pmcodes. For example, Simazine, water, unfiltered, recoverable, micrograms per liter is "Simazine" in this file. LONGNAME The full pesticide name as reported in the U.S. Geological Survey National Water Information System. U.S. Geological Survey - National Water Information System; Pesticide Organics, parameter codes; nwis.waterdata.usgs.gov/nwis/pmcodes A text description of the various pesticide names reported PARM_CD U.S. Geological Survey 5-digit parameter code for the respective pesticide U.S. Geological Survey - National Water Information System; Pesticide Organics, parameter codes; nwis.waterdata.usgs.gov/nwis/pmcodes Five digit USGS parameter code for pesticides reported in this dataset CAS_NUM The Chemical Abstract Service (CAS) number for pesticides reported in this dataset U.S. Geological Survey - National Water Information System; Pesticide Organics, parameter codes; nwis.waterdata.usgs.gov/nwis/pmcodes Chemical abstract service numbers assigned to each pesticide pestsamp.csv Results from pesticide analysis of discrete water-quality samples collected at sites in the USGS National Water Quality Network U.S. Geological Survey - National Water Information System; Water quality; http://dx.doi.org/10.5066/F7P55KJN SITE_QW_ID Unique USGS station number indicating location where water-quality samples are collected. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN USGS station numbers represent either a geographic location, represented by latitude and longitude of 15-digits, or an 8-digit or more network sequence number. DATETIME The date and time of sample collection, formatted as "YYYY-MM-DD HH:MM:SS" U.S. Geological Survey - National Water Information System; Water Quality; http://dx.doi.org/10.5066/F7P55KJN Date and time of sample collection WY A numeric identifier of the water year in which data were recorded. Producer defined 1993 2016 water year CONSTIT An abbreviated name for the pesticide being reported. Full names can be obtained from linking this name to the "pestlong.csv" file. Producer defined An abbreviated name for the pesticide being reported. Full names can be obtained from linking this name to the "pestlong.csv" file. PARM_CD U.S. Geological Survey 5-digit parameter code for the respective pesticide U.S. Geological Survey - National Water Information System; Pesticide Organics, parameter codes; nwis.waterdata.usgs.gov/nwis/pmcodes USGS 5 digit parameter code METH_CD USGS laboratory method code U.S. Geological Survey - National Water Information System; Method Codes; help.waterdata.usgs.gov/method_cd Alphanumeric USGS method codes CONCENTRATION Pesticide concentration in micrograms per liter U.S. Geological Survey - National Water Information System; Water quality; http://dx.doi.org/10.5066/F7P55KJN .0000083 140 micrograms per liter (ug/L) REMARK Character qualifier of concentration values U.S. Geological Survey - National Water Information System; Water quality; http://dx.doi.org/10.5066/F7P55KJN "" No qualifier U.S. Geological Survey - National Water Information System; Water quality; http://dx.doi.org/10.5066/F7P55KJN "<" The result is less than the value reported in the CONCENTRATION field U.S. Geological Survey - National Water Information System; Water quality; http://dx.doi.org/10.5066/F7P55KJN "E" The value reported in the CONCENTRATION field is estimated U.S. Geological Survey - National Water Information System; Water quality; http://dx.doi.org/10.5066/F7P55KJN ">" The result is greater than the value reported in the CONCENTRATION field. Concentration values with a ">" are treated in any computations as though the REMARK code is "" U.S. Geological Survey - National Water Information System; Water quality; http://dx.doi.org/10.5066/F7P55KJN LRL The pesticide laboratory reporting level Producer defined .001 2.7 micrograms per liter (ug/L) NWQN_sites.csv NWQN sites, site names, locations, and drainage area U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN SITE_QW_ID Unique USGS station number indicating location where water-quality samples are collected. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN USGS station numbers represent either a geographic location, represented by latitude and longitude of 15-digits, or an 8-digit or more network sequence number. SITE_QW_NAME Unique USGS station name indicating where water-quality samples are collected. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN Unique USGS station name indicating location where water-quality samples are collected. DA Drainage area upstream from the water-quality sampling location in square miles. Drainage is displayed as NA at two sites on the Lower Atchafalaya River downstream where the river bifurcates. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN 2.35 1131100 square miles QW_LAT Latitude where water-quality samples are collected U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN 20.97 62.35 decimal degrees QW_LONG Longitude where water-quality samples are collected. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN -162.89 -70.98 decimal degrees SITE_FLOW_ID Typically a unique USGS station number indicating location where streamflow data is recorded. In some instances these data are obtained from outside sources, in those cases an abbreviation of the collection agency and site number (if available) are displayed. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN USGS station numbers represent either a geographic location, represented by latitude and longitude of 15-digits, or an 8-digit or more network sequence number. In cases where streamflow is collected by an outside entity the rationale behind the indicator is unknown. SITE_FLOW_NAME Unique USGS station name indicating where streamflow associated with water-quality samples are collected. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN Unique USGS station name indicating location where streamflow associated with water-quality samples is collected. FLOW_LAT Latitude of site where streamflow data associated with the water-quality sampling was located. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN 20.97 62.35 decimal latitude FLOW_LONG Longitude of site where streamflow data associated with the water-quality sampling was located. U.S. Geological Survey - National Water Information System; Site Information; http://dx.doi.org/10.5066/F7P55KJN -162.89 -70.97 decimal degrees SITE_TYPE Character representation of the type of monitoring site Producer defined Coastal rivers Coastal River Site Producer defined Large Inland Rivers Large Inland River Site Producer defined Reference Reference site Producer defined Urban Urban indicator site Producer defined Agriculture Agricultural indicator site Producer defined U.S. Geological Survey - ScienceBase mailing and physical

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