WMS:HEC-HMS Meteorological Model

The HMS Meteorological Model dialog for the "Standard Project Storm" method.

• Precipitation Data – Method selected for precipitation simulation.
  • Index Precipitation: – Probably maximum index precipitation. Represents the total precipitation depth of the storm. Values available from HYDROMET Report 33. It can also be estimated from plates contained in EM 1110-2-1411 (US Army Corps of Engineers)
  • Storm Area: – The total drainage area at the point where the standard project flood is to be estimated.
  • Temporal Distribution: – Drop-down choices
    • Standard – Distributes the precipitation according to the criteria outlined in EM 1110-2-1411.
    • SWD – Distributes precipitation according to the Southwestern Division criteria (table 3.1 of the HEC-1 reference manual).
  • Subbasin – Column containing all subbasins included in model.
  • Transposition Factor – Can range from 0.80 to 1.40 and is multiplied by the index precipitation to determine the mean areal precipitation. The transposition factor can be determined from the SPS isohyetal pattern contained in EM 1110-2-1411 and a map of the watershed.