Average year supply is the average annual supply of a water development system over a long period. For this report the SWP and CVP average year supply is the average annual delivery capability of the projects over a 70-year study period (1922-91). For a local project without long-term data, it is the annual average deliveries of the project during the 1984-1986 period. For dedicated natural flow, it is the long-term average natural flow for wild and scenic rivers, or it is environmental flows as required for an average year under specific agreements, water rights, court decisions, and congressional directives.
Drought year supply is the average annual supply of a water development
system during a defined drought period. For this report, the drought period
is the average of water years 1990 and 1991. For dedicated natural flow, it
is the average of water years 1990 and 1991 for wild and scenic rivers, or
it is environmental flows as required under specific agreements, water rights,
court decisions, and congressional directives.
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