Nineteen sub-watersheds were calibrated using the NWS River Forecast System (NWSRFS). The NWSRFS includes the Sacramento Soil Moisture Accounting model, unit hydrograph analyses, a snow accumulation and depletion model, reservoir operations and routing schemes, and channel routing. The channel and reservoir/lake routing routines use both hydrologic and dynamic routing methods.
Dynamic routing of each sub-watershed hydrograph into Lake Champlain was completed using the NWS FLDWAV model. Sub-watershed lateral inflow is routed through Lake Champlain to the Richelieu River. The use of the dynamic routing technique allows for a forecast water level at other points of interest in the lake, including Burlington. Hydrologic Engineering Centerís River Analysis System (HEC-RAS) was used to develop the backwater profile along and through the controlling sections at Saint Jeanís Shoal.
Wind effects can have a significant impact on lake levels. An inland version of the Sea, Lake, and Overland Surge from Hurricanes (NWS-SLOSH) is in the development stage and is being coupled with the National Center for Environment Prediction (NCEP) Aviation (AVN) model for its forecast wind data. This model output will be used to refine the hydrologic/hydraulic model output for Lake Champlain levels in the short-term.
Forecasts were available throughout Spring 2001 when a significantly above average snowpack occurred in the basin. Available products allowed emergency managers in both the United States and Canada to monitor the potential for serious flooding in the basin.