The short answer
Read percent full as a storage measure and elevation as a surface-height measure. Compare dated values of the same metric; a percentage does not establish shoreline access.
Start with the unit
Elevation tells you how high the surface is relative to the source reference. Percent full describes stored water relative to conservation capacity. Neither number describes how much of a lake’s shoreline is accessible.
A practical reading sequence
Read the observation date first. Then note percent full, elevation and the difference from the conservation pool. Finally inspect the recent trend. One reading describes a position; a sequence reveals direction.
Why the numbers move differently
Reservoir shape matters: a foot of elevation does not represent the same water volume at every level or at another reservoir. TWDB uses reservoir-specific relationships. Do not convert elevation change into a storage percentage by simple division.
Use the comparison carefully
Our comparison keeps the covered Texas reservoirs on the same source family. Compare percentage-point changes with percentage-point changes and feet with feet. A lake with a higher percent full is not automatically better for a trip; check access and weather separately.
Your next steps
- Need a storage picture? Read conservation percent full.
- Need the surface height? Read elevation and its reference.
- Need a trend? Compare dated measurements of the same metric.
- Need access information? Check the managing authority.
Common questions
Why do two websites show different reservoir storage?
They may use different capacity curves or pool definitions. TWDB explains these differences; preserve each source and date.
Can I convert a one-foot rise into percent full?
Not with a universal formula. The relationship between elevation and storage depends on the reservoir’s shape and rating curve.
Sources and editorial record
Prepared with AI assistance from the linked sources. Independent human review pending. “Public Atlas Editorial” is a publication label. First edition: 2026-09-28. Scheduled source review: 2026-10-28. Data examples update with their source snapshots; the guide text is versioned separately.
Changes to this guide
- 2026-09-28 — First AI-assisted edition published with source links and review status disclosed.
- 2026-09-29 — Added focused reader questions and concise answers with source links; checked primary-source guidance and retained pending human review.