Field notes / California water / 03

How full
is full?

A reservoir can be above average and still have plenty of room. Three numbers tell three different stories about the same water.

Shasta · July 30, 2025 · 3,258,792 acre-feet. Seasonal comparisons use 30 eligible observations for this calendar date in water years 1991–2020. Rounded for this opening.

A lake can look reassuringly blue while a water chart asks a more precise question. How much space is left? How does this date compare with other years? And what can one reservoir tell us about drought?

Historical edition · observations through September 30, 2025 · retrieved September 5, 2026. These are six selected reservoirs, not all California storage.