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

  • 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

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.

Optional Modules
The module is recommanded if the datasets have much differences in their period.
The module is strongly suggested prior to use of the "Problematic Dataset Check" module.
The module identifies issues in the abnormality dataset that might cause errors in the following steps. Issues in the dataset that will be detected are :
1) water quality data without streamflow data,
2) streamflow that is a negative number,
3) dataset without any water quality or streamflow data (i.e. only date).
The dataset can be fixed manually or by the module.
LOADEST uses logarithm streamflow,
therefore the streamflow of 0 will cause error.
The streamflow of 0 can be converted to the specific valu below.
If streamflow is 0, change it to cfs.

Developed by the Agricultural and Biological Engineering Department at Purdue University - 2011
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, Purdue University Research Assistant