STATSGO2-soil data

Step 1: Get soil data

Download state data from here: [1]

Download county or survey level data from here: [2]

Both sources should include a) tabular data b) spatial data c) Microsoft Access template

State data is spatially coarser than county or survey level data

Step 2: Soil Data Viewer

You need 1) Install ArcGIS 9.2 or later for soil data viewer 5.2 on a Windows XP system 2) Install soil data viewer version 5.2 [3]

Step 3: Prepare Access database

1) Open Access template 2) Enable macros 3) Type in full path name to tabular data 4) Import should run automatically

Step 4: Working with Soil Data Viewer in ArcGIS

1) Open ArcGIS - View > Toolbars > Soil Data Viewer Tools 2) Click on the Soil Data Viewer button 3) Browse to Access database 4) Choose the soil data layer to connect to the database

Soil data viewer online user guide is here: [4]

Step 5: Karl's method for estimating soil properties using SDV

Definitions:

a) Dominant Condition (DCD)

b) Dominant Component (DCP)

c) Weighted Average (WA)

d) All Layers (ACP)

1) Soil Physical Properties: Surface Texture

Useful for a) naming the soil .def file b) understanding depth to soil restrictive layer c) understanding ksat at surface

2) Soil Qualities and Features: Depth To Selected Soil Restrictive Layer (DtSSRL) & Depth to Any Restrictive Layer (DtARL

a) Generate Depth DCD, DCP, WA, ACP using both < and > for tie break rule with no cutoff (8 scenarios for DtSSRL and 8 scenarios DtARL)

b) Compare these to summer Landsat imagery and use expert judgment to determine the most accurate layer

c) Depth To Selected Soil Restrictive Layer (Lithic NOT Paralithic) results for Silver Fork: Tie break doesn't matter for all but ACP.

• ACP, < too shallow;
• ACP, > too shallow but deeper than ACP, <;
• WA, too shallow;
• DCP, bimodal (0 and 201) very shallow in upper basin;
• DCD, bimodal (0 and 201) deeper than DCP, >. Areas with zero depth to bedrock are those classified as un-weathered bedrock in Surface Texture

d) Depth To Any Restrictive Layer results for Silver Fork

• ACP, > 127,143,153 - not much spatial variability;
• ACP, < 0 - basically junk;
• WA - tie break doesn't matter, 17 for texture un-weathered bedrock;
• DCP - tie break doesn't matter, very shallow in upper basin;
• DCD, > zeros where surface texture is bedrock, 77,127,201
• DCD, < zeros where surface texture is bedrock, 77,127,201 but shallower than DCD, > (obviously)

3) Soil Physical Properties: Saturated Hydraulic Conductivity (RHESSys requires Ksat at surface)

-Plot for each 100cm

4) Soil Physical Properties: Percent Clay (used in RHESSys only for carbon cycling)

5) Soil Physical Properties: Percent Sand (used in RHESSys only for carbon cycling)

6) Soil Physical Properties: Percent Silt (used in RHESSys only for carbon cycling)