Precipitation at Hetch Hetchy – 2019
A new water year (WY) starts every October. The graph charts cumulative precipitation at Hetch
Hetchy Reservoir as the WY progresses. Precipitation is shown as a percentage of average, and
curves for the current year and past year are shown. Cumulative precipitation curves for both dry
and wet years are also shown, as well as a median. Why 1977? – It is the driest year on record.
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Why 1983? – It is the wettest year on record.