Page History

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1. Download Nutrient Data (Starting with HUC-08 Lower Mississippi River for documenting steps; will combine sites from other HUCs into one document for trend analysis)
   1.  other HUCs are 05,06,07,08,10,11 ; then clip to HTF state boundaries if needed.

   2. HUC08Data<-readWQPdata(huc="08", characteristicType="Nutrient", siteType="Stream")
      
      

   1.  Nitrate plus Nitrite, the CharacteristicName is "Inorganic nitrogen (nitrate and nitrite)"
      1. Remove Composite Samples, field observations and quality control samples (the two types we want are "Sample-Routine" and "Sample")

         1. SampleRoutine<-filter(HUC08Data, ActivityTypeCode == "Sample-Routine" | ActivityTypeCode == "Sample")

      2. Also want to remove preliminary values
         1. ResultStatusIdentifier = "Preliminary"
      3. select parameters to harmonize

         1. Inorganic nitrogen (nitrate and nitrite) ; Inorganic nitrogen (nitrate and nitrite) as N ; Nitrate ; Nitrate as N ;

            1. filter/group by site + date + time time
            2. (Here we are following procedures and assuming that parameters/fractions can be combined into longer dataset in the same way that was done in the USGS report)
            3. look to see if "Inorganic nitrogen (nitrate and nitrite)" is available at a particular site. 
               1. If so, is there more than one entry for that date and time at the site?
                  1. If yes, keep the data that indicates filtered (dissolved) in column "ResultSampleFractionText"
                  2. if no, keep the unfiltered or total
               2. If Inorganic Nitrogen not available, go through the same procedure as above for: Inorganic nitrogen (nitrate and nitrite) as N; Nitrate and Nitrate as N; Nitrate. All can be combined to make a longer record if needed.
            4. Check to see if there are "ResultDetectionConditionText" qualifiers - (Not detected or below detection Limit. .... Figure out what to do with thoseStill need to figure out how to deal with these properly)

               1. > count(finalResult$ResultDetectionConditionText)
                  
                  x freq
                  
                  1 *Non-detect 9
                  
                  2 *Present <QL 9
                  
                  3 Below Detection Limit 6
                  
                  4 Detected Not Quantified 7
                  
                  5 Not Detected 15050
                  
                  6 Not Present 1
                  
                  7 Not Reported 11
                  
                  8 Present Above Quantification Limit 9
                  
                  9 Present Below Quantification Limit 1749
                  
                  10 <NA> 15107

            5. Determine if units are as N or NO3, change to "as N" when necessary. Want units to be "mg/l as N" in column "ResultMeasure.MesaureUnitCode"Select Parameter of Interest and Harmonize Data 
               
               1. divide reported as NO3 by constant to get "as N"
      4. Once the the list of sites is complete, then look at the length of record, and clip to have it be with records from 1979 - 2017 (including 2018-2020 if they're available)
      5. look at frequency of measurements and data gaps
      6. do gauge matching process.