STATSGO2 lookup table

[Kremena]

Hello all,

I downloaded DEM, NLCD 2001 land use and STATSGO2 data for the state
of Colorado from the USDA Geospatial Data Gataway. I imported the DEM
and the landuse into SWAT without any problems. However I am having
problem with the STATSGO2 data. There is not "stmuid" key in this
dataset; instead the key is called "musym". My question is: how do I
create a lookup table for the data? I tried to search the STATSGO
documentation for a description of the musym key values and their
match to the soil categories so I can create a custom lookup soil
table but I could not fine any documentation.
Any suggestion will be greatly appreciated.

Thanks,
Kremena

[Rosie Records, CA Cooperative Fish & Wildlife Research Unit]

Hi Kremena,

I always find STATSGO and SSURGO challenging to work with. I have
done a lookup before with SSURGO data, and looking back over my
STATSGO downloads I think it would work the same way.

The problem I found with this before was that one map unit symbol can
relate to many soil series, because one polygon often contains a group
of soils too spatially variable to break out into smaller polygons.
So you would need a method to decide for each map unit symbol which
soil group would be used to determine soil properties (whichever
series made up the greatest percentage of the association, perhaps?).
I couldn't think of a good way to write a query for this and didn't
want to do it by hand, so just ended up going with the SWAT-supplied
soil database.

Here is how I have found lookup data before for SSURGO/STATSGO:

1. When you download your STATSGO data, does it give you the
soildb_CO_2003 or similarly named MS Access file?

If yes, try opening this file and enable the macros contained. When I
do this, a box pops up with a list of map unit symbols in that state
download.

2. Try switching to Table view in Access and opening the Mapunit and
the Component tables.
The first column in Mapunit ("Mapunit Symbol") should contain your map
unit symbols that you see in your polygon's attribute table as MUSYM.
In the "Component" table, you will find a column called "Mapunit key"
that is also in the polygon attribute table as MUKEY.

In ArcMap, you can perform a join and/or relate between the polygon
and these tables in Access, based on either of these columns mentioned
above. Keep in mind that one MUKEY record in your polygon attribute
table may have multiple records with the same MUKEY in the "Component"
table and tweak your type of join and/or relate accordingly.

3. You can then export the attribute table with the joined/related
data from the Access table, open the .dbf in Excel, and modify as
needed to make a lookup table. Remember that sometimes the joined
table will show as blank in ArcMap, but will actually be populated
with data once you export it and open it in Excel.

I hope this helps. The SSURGO documentation has pretty detailed table
and field descriptions, which should be similar to STATSGO-2's:
http://soildatamart.nrcs.usda.gov/documents/SSURGOMetadataTableColumnDescriptions.pdf

Cheers,

Rosie

[Soil Database Manager]

Allow me to jump in to this conversation and explain a few issues.
1st. ARCSWAT is using the old Soils Database Structure and soils data
- pre 1995. If you use the built-in STATSGO layer keep in mind it is
dated and very old. The ARCSWAT programmers are aware of this issue
and are working on rebuilding the soils layer to the current data
structure. I have had several conversations with them encouraging
them to update the SWAT soils database model. The SSURGO and STATSGO2
data can be downloaded from the Soil Data Mart http://soildatamart.nrcs.usda.gov

2nd. The stmuiid was a concatenation of the state code and the map
unit symbol and used as a unique identifier for a map unit in the old
data structure. That identifier in the current data structure for the
STATSGO2 and SSURGO is the mukey. It is the mukey that joins the
mapunit to the component and the spatial to the attribute. It is the
cokey that joins the component to the horizon tables. Aggregation of
the soils data is critical in development of any modeling processes.

3rd. The STATSGO2 map unit can contain UP TO 21 soil components.
Seriously think about that when attempting to aggregate data to use in
the ARCSWAT model. This is not a simple process and you must
understand that those are the types of soils found in that 1500 ac
minimum delineation. STATSGO is created on a 1:250K scale. SSURGO is
created at a 1:12K or 1:24K scale depending on the location in the
country. SSURGO typically contains between 1 and 3 components and
occasionally up to 5. It is county level detailed data for general
land use planning whereas STATSGO2 is generalized data for REGIONAL
land use planning. Please pay attention to this fact and make sure
you are using the appropriate data layer for the model run.

4th. I have a SQL that can be used to extract the soil properties
used by ARCSWAT (same one I provided to the programmers). Just email
me or reply and I will forward it to you.

I am not a SWAT user but I am the expert on the soils databases.
Unfortunately I get many questions asking how to use current soils
data structure in an old model.

Paul R. Finnell
paul.f...@lin.usda.gov

On Nov 8, 4:10 pm, "Rosie Records, CA Cooperative Fish & Wildlife

> and field descriptions,  which should be similar to STATSGO-2's:http://soildatamart.nrcs.usda.gov/documents/SSURGOMetadataTableColumn...

[Soil Database Manager]

I came across this thread in the forum and found it interesting. I
knew it was only time before someone came up with a solution to the
soils database issue.

http://www.bae.ksu.edu/watershed/ashesh/swatiotools.html

It seems this is a solution that allows ARCSWAT users to utilize the
new soils database structure.

On Nov 17, 8:04 pm, Soil Database Manager <am20...@gmail.com> wrote:
> Allow me to jump in to this conversation and explain a few issues.
> 1st.  ARCSWAT is using the old Soils Database Structure and soils data
> - pre 1995.  If you use the built-in STATSGO layer keep in mind it is
> dated and very old.  The ARCSWAT programmers are aware of this issue
> and are working on rebuilding the soils layer to the current data
> structure.  I have had several conversations with them encouraging
> them to update the SWAT soils database model.  The SSURGO and STATSGO2

> data can be downloaded from the Soil Data Marthttp://soildatamart.nrcs.usda.gov

> paul.finn...@lin.usda.gov