COLUMN_NAME DESCRIPTION LEGAL_VALUES UNITS PUBLICATION_DATE Date the dataset was published to the NARS site NA NA UID Unique identifier for the site/visit NA NA SITETYPE Site type (probability-based or hand-picked) used in the NLA survey design PROB | HAND. PROB for sites from probability survey. Usually HAND for hand-picked lakes. NA NA UNIQUE_ID Unique site ID based on location that does not depend on year sampled or any other factor. Form is NLA_ss_nnnnn where ss state and nnnnn is number that starts at 10001. Includes both PROB and HAND lake types NA NA DOC_MDL Method detection limit of dissolved organic carbon NA NA DOC_RESULT Analyte value: dissolved organic carbon NA NA SULFATE_MDL Method detection limit of sulfate NA NA SULFATE_RESULT Analyte value: sulfate NA NA ANC_RESULT Analyte value: acid neutralizing capacity NA NA CHLA_MDL Method detection limit of chlorophyll-a NA NA CHLA_RESULT Analyte value: chlorophyll-a NA NA ANC_MDL Method detection limit of Acid Neutralizing Capacity (ueq/L) NA NA ANC_NARS_FLAG "Flag assigned by NARS for Acid Neutralizing Capacity. ND = Non-detect, L = Estimated, Q = Quality-related issue, S = Shipping time exceedence, H = Holding time exceedence" NA NA DOC_NARS_FLAG "Flag assigned by NARS for Dissolved Organic Carbon. ND = Non-detect, L = Estimated, Q = Quality-related issue, S = Shipping time exceedence, H = Holding time exceedence" NA NA SULFATE_NARS_FLAG "Flag assigned by NARS for Sulfate. ND = Non-detect, L = Estimated, Q = Quality-related issue, S = Shipping time exceedence, H = Holding time exceedence" NA NA NTL_RESULT Result for Total Nitrogen (mg N/L) NA NA NTL_MDL Method detection limit for Total Nitrogen (mg N/L) NA NA NTL_NARS_FLAG "Flag assigned by NARS for Total Nitrogen. ND = Non-detect, L = Estimated, Q = Quality-related issue, S = Shipping time exceedence, H = Holding time exceedence" NA NA PTL_RESULT Result for Total Phosphorus (ug/L) NA NA PTL_MDL Method detection limit for Total Phosphorus (ug/L) NA NA PTL_NARS_FLAG "Flag assigned by NARS for Total Phosphorus. ND = Non-detect, L = Estimated, Q = Quality-related issue, S = Shipping time exceedence, H = Holding time exceedence" NA NA CHLA_NARS_FLAG "Flag assigned by NARS for Chlorophyll a. ND = Non-detect, L = Estimated, Q = Quality-related issue, S = Shipping time exceedence, H = Holding time exceedence" NA NA CYLSPER_RESULT Result for Cylindrospermopsin (ug/L) NA NA CYLSPER_MDL Method detection limit for Cylindrospermopsin (ug/L) NA NA CYLSPER_NARS_FLAG "Flag assigned by NARS for Cylindrospermopsin. ND = Non-detect, L = Estimated, Q = Quality-related issue, S = Shipping time exceedence, H = Holding time exceedence" NA NA MICX_RESULT Result for Microcystin (ug/L) NA NA MICX_MDL Method detection limit for Microcystin (ug/L) NA NA MICX_NARS_FLAG "Flag assigned by NARS for Microcystin. ND = Non-detect, L = Estimated, Q = Quality-related issue, S = Shipping time exceedence, H = Holding time exceedence" NA NA ATRAZINE_RESULT Result for Atrazine (ppb) NA NA ATRAZINE_MDL Method detection limit for Atrazine (ppb) NA NA ATRAZINE_NARS_FLAG "Flag assigned by NARS for Atrazine. ND = Non-detect, L = Estimated, Q = Quality-related issue, S = Shipping time exceedence, H = Holding time exceedence" NA NA MMI_BENT Benthic MMI score NA NA TROPHIC_STATE Trophic state (Oligotrophic/Mesotrophic/Eutrophic/Hypereutrophic) |OLIGOTROPHIC|MESOTROPHIC|EUTROPHIC|HYPEREUTROPHIC NA ECOLI_DETECT E. coli Detection Detected|Not Detected|Not Assessed NA ECOLI_EPA_COND E. coli condition based on EPA benchmark Above Benchmark|At or Below Benchmark|Not Assessed NA BENT_MMI_COND_2017 Condition class based on 2017 updated benthic MMI scores Good|Fair|Poor|Not Assessed NA ACID_COND Acidity condition class Good|Fair|Poor|Not Assessed NA CHLA_COND "Condition for Chlorophyll a indicator, based on CHLX" NA NA CYLSPER_DETECT Cylindrospermopsin Detection Detected|Not Detected|Not Assessed NA CYLSPER_EPA_COND Cylindrospermopsin condition based on EPA benchmark Above Benchmark|At or Below Benchmark|Not Assessed NA MICX_DETECT Microcystin Detection Detected|Not Detected|Not Assessed NA MICX_EPA_COND Microcystin condition based on EPA benchmark Above Benchmark|At or Below Benchmark|Not Assessed NA NTL_COND Condition class based on total nitrogen Good|Fair|Poor|Not Assessed NA PTL_COND Condition class based on total phosphorus Good|Fair|Poor|Not Assessed NA DRAWDOWN_COND_2CAT_2017 "Drawdown condition, specifially for 2017 survey" Not Large|Large|Not Assessed NA LITCVR_COND Shallow water habitat condition class Good|Fair|Poor|Not Assessed NA LITRIPCVR_COND Lake habitat complexity condition class Good|Fair|Poor|Not Assessed NA RDIS_COND Lakeshore disturbance condition class Low|Medium|High|Not Assessed NA RVEG_COND Riparian vegetation condition class Good|Fair|Poor|Not Assessed NA DIS_O2_CLS Dissolved oxygen condition class High (>=5 Ppm)|Moderate (>3-<5 Ppm)|Low (<=3 Ppm)|Not Assessed NA MEAN_METAL_PEC_Q "Mean metal probable effect concentration quotient (PEC-Q) calculated as the sum of up to seven individual metal PEC-Q values (i.e. As, Cd, Cr, Cu, Pb, Ni, Zn) divided by the number of metal classes used (i.e., 1 to 7). This group of metals have reliable PEC values. One-half (0.5x) the reporting limit was substituted for nondetect values. Values are unitless." NA NA MEAN_PEC_Q Mean probable effect concentration quotient (PEC-Q) calculated as the average of Total_PAH13_PEC_Q and Mean_Metal_PEC_Q. Total PCBs were excluded due to the high percentage of censored data. Values are unitless. NA NA NLA_SCI_STATUS "Sediment Contaminant Index condition assignment for NLA 2017 based on sediment contaminant thresholds of Mean_PEC_Q <=0.1 is Least Disturbed, Mean_PEC_Q > 0.1 and Mean_PEC_Q < 0.6 is Moderately Disturbed, and Mean_PEC_Q >=0.6 is Most Disturbed. " NA NA TOTAL_PAH13_PEC_Q PAH13 probable effect concentration quotient (PEC-Q) calculated as Total_PAH13 divided by the Probable Effect Concentration (PEC) value of 22800 ng/g dw. Values are unitless. NA NA ATZ_DETECT Atrazine Detection Detected|Not Detected|Not Assessed NA ATZ_EPA_COND_10 Condition based on Atrazine concentration and 10 ppb benchmark At or Below Benchmark|Above Benchmark|Not Assessed NA ATZ_EPA_COND_15 Condition based on Atrazine concentration and 15 ppb benchmark At or Below Benchmark|Above Benchmark|Not Assessed NA ATZ_EPA_COND_3.4 Condition based on Atrazine concentration and 3.4 ppb benchmark At or Below Benchmark|Above Benchmark|Not Assessed NA ZOOP_MMI_COND_2017 Condition class based on 2017 updated zooplankton MMI scores (following tow volume corrections) Good|Fair|Poor|Not Assessed NA E_COLI_NARS_FLAG NARS flag NA NA E_COLI_PRESENT Present/Absent NA NA E_COLI_RESULT Most Probably Number - E. coli NA NA BFXHORIZDIST_DD horizontal distance to drawdown zone using horiz_dist_dd (mean(horiz_dist_dd)) NA NA BFXVERTHEIGHT_DD vertical height to drawdown zone using vert_height_dd (mean(vert_height_dd)) NA NA LitCvrQc3OE NLA 2012 Shallow water habitat condition indicator NA NA LitRipCvrQc3OE NLA 2012 Lake habitat complexity condition indicator NA NA RDis_IX NLA 2012 Lakeshore disturbance condition indicator NA NA RVegQc3OE NLA 2012 Riparian vegetation condition indicator NA NA B_G_DENS Cyanobacteria cell density NA NA AG_ECO3 "NARS 3-level reporting region (2015), based on aggregating AGGR_ECO9_2015 reporting regions. No missing values allowed." EHIGH|PLNLOW|WMTNS| NA AG_ECO9 "NARS 9-level reporting region (2015), based on aggregated Omernik Level III ecoregions. No missing values allowed." CPL|NAP|NPL|SAP|SPL|TPL|UMW|WMT|XER| NA AREA_CAT6 Lake area categories (6) used in most NLA survey designs. HAND sites also assigned area category. Based on AREA_HA. No missing values allowed. "(0,1]| (1,4]| (4,10]|(10,20]| (20,50]| >50|" NA EPA_REG EPA Region. No missing values allowed. Region_01|Region_02|Region_03|Region_04|Region_05|Region_06|Region_07|Region_08|Region_09|Region_10| NA FRAME07 Lake is included or excluded from sample frame for the NLA 2007 survey design. Blank values are not allowed or NA for missing Exclude|Include| Not Present| NA FRAME12 Lake is included or excluded from sample frame for the NLA 2012 survey design. Blank values are not allowed or NA for missing. Exclude|Include| Not Present| NA FRAME17 Lake is included or excluded from sample frame for the NLA 2017 survey design. Blank values are not allowed or NA for missing. Exclude|Include|Not Present NA HUC2 Watershed Boundary Dataset Level 2 Hydrologic Unit Code where lake is located (based on NHDPlusV2 use of HUCs). No missing values allowed. H01|H02|H03|H04|H05|H06|H07|H08|H09|H10|H11|H12|H13|H14|H15|H16|H17|H18|H19|H20 NA HUC2_NM Watershed Boundary Dataset Level 2 Hydrologic Unit Region Name where lake is located. No missing values allowed. Arkansas-Red-White Region|California Region|Great Basin Region|Great Lakes Region|Lower Colorado Region|Lower Mississippi Region|Missouri Region|Mid-Atlantic Region|New England Region|Ohio Region|Pacific Northwest Region|Rio Grande Region|Souris-Red-Rainy Region|South Atlantic Region|Tennessee Region|Texas Region|Upper Colorado Region|Upper Mississippi Region| NA LAKE_ORGN "Lake origin, based on evaluation on map or in field" MAN_MADE|NATURAL|UNCERTAIN|UNKNOWN NA LAT_DD83 "Latitude (based on NAD83 datum) assigned to lake during site selection from NHD-based sample frame. Generally, but not always, represents centriod of lake polygon in NHD. No missing values allowed." NA NA LON_DD83 "Longitude (based on NAD83 datum) assigned to lake during site selection from NHD-based sample frame. Generally, but not always represents centriod of lake polygon in NHD. No missing values allowed." NA NA MAJ_BAS_NM Major USGS Hydrologic Basins derived from NHDPlus names Text of 16 basin names Arkansas-White-Red Region|California Region| Great Basin Region|Great Lakes Region|Lower Colorado Region|Lower Mississippi Region|Mid Atlantic Region|Missouri Region|New England Region|Ohio-Tennessee Region|Pacific Northwest Region|Rio Grande-Texas-Gulf Region|Souris-Red-Rainy Region|South Atlantic Gulf Region|Upper Colorado Region|Upper Mississippi Region| NA MAJ_BASIN Major USGS Hydrologic Basins derived from NHDPlus codes Text of 16 basin codes from 01 to 18 with 05_06 and 12_13 combined preceeded by letter H H01|H02|H03|H04|H05_06|H07|H08|H09|H10|H11|H12_13|H14|H15|H16|H17|H18 NA MISS_BASIN "Within Mississippi Basin or outside, based on MAJ_BAS_NM values" MISSISSIPPI_BASIN|NOT_MISSISSIPPI_BASIN NA PSTL_CODE "State two letter postal code for site sampled. 50 state postal codes plus AS, MP, GU, PR, VI for American Samoa, Commonwealth of Northern Marianas, Guam, Puerto Rico and Virgin Islands. No missing values allowed." NA NA SITE_ID "The NLA Site ID for the study and year sampled. Preferred form is NLAnn_MM-xxxxx where nn is current cycle year (07, 12, 17, etc), MM is two letter state code, and xxxxx is between 10001 and 99999. No missing values allowed." NA NA TNT_CAT NLA target status assigned based on lake evaluation for use in national assessments Target|Non_Target|None NA URBN_NLA07 Lake identified as an urban lake using 2007 definition of Urban. No missing or blank values allowed Urban|Non-Urban| NA URBN_NLA17 Lake identified as an urban lake using 2017 definition of Urban. No missing or blank values allowed Urban|Non-Urban| NA WGT_TP NLA adjusted weight for lake when want estimates to be for the Target Population. Includes weight adjustments to account for sites with unknow status and when lake status is known to be target but not sampled. Note: >0 or 0 if site is not to be used for target population estimation NA NA XCOORD x-coordinate from US Contiguous Albers Equal Area Conic projection EXCEPT Hawaii or Alaska lakes which are calculated from Hawaii or Alaska Albers Equal Area Conic projectionNo missing values allowed. NA NA YCOORD y-coordinate from US Contiguous Albers Equal Area Conic projection EXCEPT Hawaii or Alaska lakes which are calculated from Hawaii or Alaska Albers Equal Area Conic projection. No missing values allowed. NA NA YEAR Year site was evaluated that determined the evaluation status (IND_GROUP = EXTENT) for the lake within a DSGN_CYCLE of a STUDY. NA NA VISIT_NO Sequential number of visit to site |1|2 NA MMI_ZOOP_2017 Zooplankton MMI score based on 2017 revision and tow volume corrections. NA NA DO_SURF Mean DO in upper 2 m NA mg/L