Surface Water Supply Index
 
 
select a region on the map to view a graph that shows that regions corresponding SWSI
 
 
 

The SWSI is designed for areas that rely on snow melt as the primary source of surface water. The SWSI accounts for snowpack, mountain precipitation, streamflow, reservoir storage, and soil moisture conditions. The SWSI has been available in Montana since February of 1990 and is used to evaluate current and seasonal surface water supplies. It is typically used by irrigators, fisheries personnel, recreationalists, and others who utilize surface waters.

*definition provided by NRCS - national resources conservation service (montana).