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Web Services Documentation

Usage License

Data provided by the web services below is licensed under the Attribution 4.0 International (CC BY 4.0). Please credit the "Daily Erosion Project" of "Iowa State University".

The daily outputs generated by this project are provided on a per-HUC12 datum.  Presently, the various services only return the HUC12s for which DEP produces model results for.  The resulting coverage of these HUC12s is not necessarily spatially complete within the domain of interest.  For example, HUC12s that have no agriculture (ie urban areas) are not modeled.

The primary web-service endpoints emits GeoJSON and can be found here:

This service supports the following HTTP GET options.

GET OptionDescription
date=YYYY-mm-ddSpecify the calendar date you want data for.  This date is presently valid for the US Central Time Zone.
date2=YYYY-mm-ddOptional. If provided, this is a date inclusive range to provided summarized data for.
domain=XXOptional. Provide the result for the given state only, if a HUC12 covers multiple states, they are included as well.
callback=myfuncOptional. If provided, wraps the result in a JSON-P style response.

Here are some examples for the service above:

The GeoJSON response provides the following attributes

avg_lossAverage sheet and rill soil detachment.  This is not necessarily soil delivered to the bottom of the modeled hillslope. [tons per acre]
avg_deliveryAverage sheet and rill soil delivery to the bottom of the hillslope. [tons per acre]
qc_precipHUC12 averaged precipitation for the CST/CDT local day. [inches]
avg_runoffHUC12 averaged runoff.  The depth of water delivered to the bottom of the modeled hillslope. [inches]
tillcodeThis is a 0-6 value used within DEP to assign an increasing number of tillage operations to a given management.  The dominant tillage code for the HUC12 is provided.
avg_slp1This is the un-weighted average of bulk slope for all the DEP modeled flowpaths within a given HUC12.  The units are [1], so the ratio of change in elevation to flowpath length.

WEPP-Ready CLImate files

We are happy to share our WEPP climate files with anybody interested in using them.  Please be aware of a number of limitations.

  • The breakpoint precipitation data is always specified in US Central Timezone.
  • A climate file exists for each 0.1 by 0.1 degree lat/lon point within the contiguous US domain.  For locations where we run DEP and there is a flowpath being modeled, there is a climate file for each 0.01 by 0.01 degree lat/lon point.  This web service will return a CLI file for the nearest spatial point where we have a file existing.  The downloaded file will have a name with the lat/lon explicitly stated.
  • These files are a continuous work-in-progress and get daily reprocessing.  Please let us know of any issues you see with data quality.
  • Since WEPP needs to run for a full year, the files have data for the "future" to complete out the present year.  This future data is usually a simple copy/paste from the previous year.
  • Daily reprocessing of these files finishes at about 1:30 AM Central.  So if you request them after that time, they should have yesterday's data properly included.
  • Presently, the average wind direction is always zero.  This is due to the value generally not being used by WEPP and its value also being ill-defined.

The service is a simple call like so with the longitude expressed as degrees east:…