Dataset Title

Arizona Soil Moisture Infiltration Index 30m version 1

Authors

• Ryan E Lima (Northern Arizona University, 0000-0002-5352-7215) Ryan.lima@nau.edu
• Temuulen T. Sankey (Northern Arizona University, 0000-0002-7859-8394 )
• Abraham E. Springer (Northern Arizona University, 0000-0003-4826-9124)

Description

This raster data layer was created to assist in mapping suitability for groundwater recharge potential throughout the State of Arizona.

The Soil Moisture Infiltration Index is a custom index created to discern where on the landscape water is likely to infiltrate into the soil, it is a weighted linear combination of Topographic Relative Moisture Index (TRMI) and Soil Saturated Hydraulic Conductivity (sKsat).

30m Resolution

The SMII layer, and the input layers can also be found on ArcGIS Online:

TRMI [https://nau.maps.arcgis.com/home/item.html?id=8f916b72b9f4432aace904a3c8786342] sKsat [https://nau.maps.arcgis.com/home/item.html?id=de8eee9cc2714956b134114456ee439f] sksat (reclassified)[https://nau.maps.arcgis.com/home/item.html?id=f4711aa26ad24354a1077f8e7bd4a4eb] SMII [https://nau.maps.arcgis.com/home/item.html?id=339798eab3cc473d9771223f6e200baf]

additionally TRMI data and its documentation can be found on hydroshare:

Lima, R., A. E. Springer, T. Sankey (2025). Arizona Topographic Relative Moisture Index (TRMI), HydroShare, http://www.hydroshare.org/resource/6cc17c1cf6e0445a93d78b065e102d41

Geographic Coverage

• Latitude: [30.5162255350522, 37.8474133318948]
• Longitude: [-115.428691746036, -107.349953619422]
• CRS: EPSG:4269, NAD83 Geographic Coordinate System (degrees)

• Easting (m): [74,884.55, 850,317.80]
• Northing (m): [3,381,660.51, 4,198,137.36]
• CRS: EPSG:26912, NAD83 UTM Zone 12N (meters)

Temporal Coverage

• N.A. generated 2025 using TNM dem data

File Descriptions

| File Name | Description | Format | Size | |-----------|-------------|--------|------| |SMII/SMII_reclass10.tif|8bit unsigned int raster of SMII using classes 1-10, no data = 0|TIFF 30m Raster |618,443 KB| |SMII/WLC_TRMI_sKsat.tif|result of raster calc weighted linear combination of sKsat and TRMI|TIFF 30m Raster |618,443 KB| |SoilKsat/Soil_saturated_hydraulic_conductivity_reclass_10.tif|DESCRIPTION |TIFF 30m Raster |724,640 KB| |TRMI/Topographic_Relative_Moisture_Index_reclass_10.tif|DESCRIPTION |TIFF 30m Raster |890,822 KB|

Methodology

These layers were combined using the raster calculator in ArcGIS Pro using the following specifications and weights: "Topographic_Relative_Moisture_Index_reclass_10.tif" * (0.67) + "Soil_saturated_hydraulic_conductivity_reclass_10.tif" *(0.33)

Though a custom python program with more functionality can also be used if you prefer: see https://github.com/Ryan3Lima/create_WLC_indices.

TRMI

see: Lima, R., A. E. Springer, T. Sankey (2025). Arizona Topographic Relative Moisture Index (TRMI), HydroShare, http://www.hydroshare.org/resource/6cc17c1cf6e0445a93d78b065e102d41

sKsat

This layer represents spatial estimates of saturated hydraulic conductivity (Ksat) for soils across the AZHU8 boundary, derived from the gNATSGO_CONUS 2024 release. The data was processed in ArcMap 10.8.3 using the Soil Data Development Toolbox and symbolized using standard Ksat class limits. The final output was exported and saved as an ESRI layer file and then shared via ArcGIS Pro and ArcGIS Online.

Saturated hydraulic conductivity (Ksat) refers to the ease with which pores in a saturated soil transmit water. The estimates are expressed in terms of micrometers per second. They are based on soil characteristics observed in the field, particularly structure, porosity, and texture. Saturated hydraulic conductivity is considered in the design of soil drainage systems and septic tank absorption fields. For each soil layer, this attribute is actually recorded as three separate values in the database. A low value and a high value indicate the range of this attribute for the soil component. A "representative" value indicates the expected value of this attribute for the component. For this soil property, only the representative value is used. The numeric Ksat values have been grouped according to standard Ksat class limits.

The classes are:

• Very low: 0.00 to 0.01
• Low: 0.01 to 0.1
• Moderately low: 0.1 to 1.0
• Moderately high: 1 to 10
• High: 10 to 100
• Very high: 100 to 705

Units of Measure: micrometers per second Aggregation Method: Weighted Average; Tiebreak rule: Fastest Top horizon depth: 0; Bottom horizon depth: 200 Component Percent Cutoff: 0%

Methodology References

Soil Survey Staff. 2023. Soil Survey Geographic (SSURGO) Database. United States Department of Agriculture, Natural Resources Conservation Service. https://websoilsurvey.sc.egov.usda.gov/

Soil Data Development Toolbox. 2013. Version 3.1. United States Department of Agriculture, Natural Resources Conservation Service. https://www.nrcs.usda.gov/resources/data-and-reports/soil-data-development-toolbox

Quality Control/Limitations

• visually inspected
• Limitations: there are significant areas of missing data within this dataset particularly in stream channels, this is due to a lack of soils data for those areas.

Licensing

CC BY-NC 4.0 https://creativecommons.org/licenses/by-nc/4.0/

Citation

Please cite this dataset as:

Lima, R.E., Sankey, T.T., Springer, A.E. (2025). Arizona Soil Moisture Infiltration Index 30 meter raster v1 , 2025 [Dataset]. HydroShare. https://doi.org/10.xxxx/xxxxx

Related Publications

• Lima et al., (In Review). Mapping landscape suitability for thinning to reduce evapotranspiration and enhance groundwater recharge in semi-arid ponderosa pine forests. Journal of Hydrology: Regional Studies.

Funding

Arizona Board of Regents for funding this research through the Technology and Research Initiative Fund (TRIF) through the Arizona Tri-University Recharge and Water Reliability Project (ATUR)