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Surface Water Supply Index (SWSI) Maps and Data from USDA/NRCS, Montana

Abstract: The Surface Water Supply Index (SWSI) was developed by Shafer and
Dezman (1982) to complement the Palmer Index for moisture conditions
across the state of Colorado. The Palmer Index is basically a soil
moisture algorithm calibrated for relatively homogeneous regions, but
it is not designed for large topographic variations across a region
and it does not account for snow accumulation and subsequent
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Description: Access to SWSI maps and documentation
Geographic Coverage
Spatial coordinates   
  N: 49.0   S: 45.0   E: -104.0   W: -116.0

Data Set Citation
Dataset Originator/Creator: Shafer and Dezman
Dataset Title: Surface Water Supply Index (SWSI)
Dataset Release Date: 1982
Dataset Publisher: USDA/NRCS
Online Resource:
Temporal Coverage
Start Date: 1994-01-01
Data Set Progress
Data Center
Natural Resources Conservation Service-Montana, U. S. Department of Agriculture Supplemental Info
Data Center URL:

Data Center Personnel
Phone: (406) 587-6991
Email: rkaiser at
Contact Address:
USDA Natural Resources Conservation Service
10 E. Babcock, Room 443
City: Bozeman
Province or State: Montana
Postal Code: 59715
Country: USA
Distribution Media: ftp, www
Fees: none
Shafer, B. A. and L. E. Dezman, 1982. Development of a Surface Water
Supply Index (SWSI) to assess the severity of drought conditions in
snowpack runoff areas. Proceedings of the Western Snow Conference,
pp. 164-175.
Extended Metadata Properties
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Creation and Review Dates
Last DIF Revision Date: 2017-08-24