Table 6.  Applicable dates and parameter/method codes used to compile National Stream
Quality Accounting Network and Hydrologic Benchmark Network alkalinity, bicarbonate, and 
carbonate data on CD-ROM

[The assigned parameter/method codes reflect a coding of the data based on information from 
technical memorandum QW88_05 and records of national network protocols (memoranda QW84_16 
and QW85_19).  If an observation was unavailable for the indicated parameter code (column 4), 
the alternate parameter codes were searched for an available value according to the specified 
dates and parameter order.  In the CD-ROM data sets, these values were assigned their 
corresponding parameter and method codes in column 4]

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Constituent     Dates            Method of determination        Parameter &        Alternate 
                                                                method code     parameter codes
___________________________________________________________________________________________________
                            Data required by network protocols
___________________________________________________________________________________________________                        

Alkalinity   Before            Lab, fixed-endpoint titration1,     00417 A     00410, 00430, 00431,
               10-01-84                unfiltered samples.                     95430, 90410, 95410,
                                                                               00421
Alkalinity   10-01-84 -        Field, fixed-endpoint titration,    00410 A     00430, 00431
               09-30-85                unfiltered samples.             
Alkalinity   10-01-85 -        Field, fixed-endpoint titration,    39036 A     00410, 00430, 00431
               09-30-95                filtered samples.                  
Bicarbonate  10-01-85 -        Field, incremental titration,       00453 B     99440, 00450
               09-30-95                filtered samples.                  
Carbonate    10-01-85 -        Field, incremental titration,       00452 B     99445, 00447
               09-30-95                filtered samples.                  
___________________________________________________________________________________________________
                               Optional national network data                        
___________________________________________________________________________________________________
Alkalinity   Before            Field, incremental titration,       00419 B     99430
               10-01-85                unfiltered samples.           
Alkalinity   10-01-85 -        Field, incremental titration,       39086 B     99430, 00419
               09-30-95                filtered samples.                  
Bicarbonate  Before            Field, fixed-endpoint titration,    00440 A     
               10-01-85                unfiltered samples.                 
Bicarbonate  10-01-85 -        Field, incremental titration,       00450 B     99440
               09-30-95                unfiltered samples.           
Carbonate    Before            Field, fixed-endpoint titration,    00445 A
               10-01-85                unfiltered samples.           
Carbonate    10-01-85 -        Field, incremental titration,       00447 B     99445 
               09-30-95                unfiltered samples.           
___________________________________________________________________________________________________

     1  A limited number of field personnel may have conducted field determinations of 
alkalinity by fixed-endpoint titration.  These cases are coded as laboratory analyses.