COLUMN_NAME LABEL LEGAL_VALUES INDEX_SITE_DEPTH Depth at the index site CLEAR_TO_BOTTOM Lake clear to the bottom |Y|N DISAPPEARS Depth at which secchi disk disappears REAPPEARS Depth at which secchi disk reappears 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." 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." 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. No missing or \blank\"" values allowed.""" DATE_COL Date of sample collection VISIT_NO Sequential number of visit to site |1|2 PUBLICATION_DATE Date the dataset was published to the NARS site SAMPLE_TYPE Code identifying sample type UID Unique identifier for the site/visit NARS_COMMENT "Comment explaining NARS_FLAG or other qualifying information, if applicable." NARS_FLAG "Flag assigned by NARS: ND = Non-detect, L = Estimated, Q = Quality-related issue, S = Shipping time exceedence, H = Holding time exceedence, NR = No lab result for analyte"