Form Approved
REPORT DOCUMENTATION PAGE
OMB No. 0704-0188
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1. AGENCY USE ONLY (Leave blank)
2. REPORT DATE
3. REPORT TYPE AND DATES COVERED
July 1999
4. TITLE AND SUBTITLE
5. FUNDING NUMBERS
A Synopsis and Comparison of Selected Snowmelt Algorithms
HEC-96-030
6. AUTHORS
CWIS 31578
Rae A. Melloh
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)
8. PERFORMING ORGANIZATION
REPORT NUMBER
U.S. Army Cold Regions Research and Engineering Laboratory
72 Lyme Road
CRREL Report 99-8
Hanover, New Hampshire 03755-1290
9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)
10. SPONSORING/MONITORING
AGENCY REPORT NUMBER
Office of the Chief of Engineers
Washington, D.C. 20314-1000
11. SUPPLEMENTARY NOTES
For conversion of SI units to non-SI units of measurement, consult ASTM Standard E380-93, Standard Practice for Use of the
International System of Units, published by the American Society for Testing and Materials, 100 Barr Harbor Drive., West
Conshohocken, Pennsylvania 19428-2959.
12a. DISTRIBUTION/AVAILABILITY STATEMENT
12b. DISTRIBUTION CODE
Approved for public release; distribution is unlimited.
Available from NTIS, Springfield, Virginia 22161
13. ABSTRACT (Maximum 200 words)
One-dimensional snowpack algorithms in major operational snowmelt models used in the United States (HEC-1,
SSARR, NWSRFS, SRM, and PRMS) are reviewed and contrasted with two U.S. Army Cold Regions Research
and Engineering Laboratory (CRREL) algorithms (SNTHERM and SNAP) that are candidates for use in distrib-
uted operational models. In contrast to current operational models, the CRREL algorithms provide more detail
in snowpack processes and require no calibration. The CRREL algorithms also include a full surface energy bal-
ance that requires more meteorological data than most operational models. Simpler surface energy balances
could be used with the CRREL models. In future modeling systems, it would be preferable for the surface
energy balance algorithms to be made independent of the internal snowpack process algorithms, so that avail-
able meteorological data can be used to drive a snowpack model of choice. Improvements are needed in the
way that forest canopies and other groundcovers are accounted for in the surface energy balances of the CRREL
models.
14. SUBJECT TERMS
15. NUMBER OF PAGES
24
Algorithms
Hydrological models
Runoff
Snowmelt
16. PRICE CODE
17. SECURITY CLASSIFICATION
18. SECURITY CLASSIFICATION
19. SECURITY CLASSIFICATION
20. LIMITATION OF ABSTRACT
OF REPORT
OF THIS PAGE
OF ABSTRACT
UNCLASSIFIED
UNCLASSIFIED
UNCLASSIFIED
UL
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Standard Form 298 (Rev. 2-89)
NSN 7540-01-280-5500
Prescribed by ANSI Std. Z39-18
298-102
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