- Use your own concentration data to estimate annual load in your watershed -

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  • Column 1: Date[yyyymmdd]
  • Column 2: Time (24-hour clock; If you do not have the time of sampling, use 1200 in all rows )
  • Column 3: Concentration (select units)
    Note that LOADEST requires 12 or more nonzero observations (LOADEST User's Guide, p. 17)

Date     Time     Concentration

Parameter Name
Target Concentration

If you prefer, you may
(File must be in .csv or .txt format)

If the dataset has a negative value,        

If you have flow data, you may enter it (or upload file). Otherwise select "USGS Gage Location Tool" to identify a gage and automatically pull in flow data.

  Date             Flow
(Currently unavailable)

If the dataset has a negative value,        
Site Name  
Watershed Area from the USGS Station sq. mi
The value will be valid,
if the "USGS Gage Location Tool" is used.
Watershed Area (above monitoring site) 
If you do not know the watershed area, use the 

Output Load Unit :  

Optional : Aggregated by season
(output file download only)
If you wish, you may define seasons
for aggregating output load in the column at right

Season 1: -
Season 2: -
Season 3: -
Season 4: -

Optional : Set Model Number
Model number "0" is default, makes an appropriate selection.
(LOADEST User's Guide, p. 12)

Developed by the Agricultural and Biological Engineering Department at Purdue University
Contact Dr. Jane Frankenberger for more details if you need any help for this "Web-based Load Calculation using LOADEST" tool.
Programmed by Youn Shik Park, Kongju National University