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"