Public data index › USGS streamgage revision ledger

What did USGS publish for daily streamflow—and what changed later?

Nationwide baseline sealed 2026-08-09 from the official USGS Water Services interfaces.

On 2026-08-09, this ledger sealed 9,834 active streamgages and 58,963 daily mean discharge observations across 52 U.S. states and jurisdictions. Revision count: not measurable yet. The archive has 1 dated seal. A zero would be false: there is not yet a second copy of the same observation to compare.

Coverage receipt. All 104 of 104 expected source fetches succeeded. The source window is the prior seven days; this archive cannot recover a value that appeared and disappeared between daily seals.

Why keep a dated ledger?

USGS daily values can carry provisional qualifiers and can be revised after their first publication. A current API response answers what USGS serves now; it does not, by itself, preserve the exact response we read on an earlier date. Each collection therefore seals the raw response before parsing it, stores the content hash, and retains the observation identity, value, unit, qualifier, source URL, and collection time. A difference is counted only when the same identity exists in two or more seals.

This is useful to utility operations and compliance teams that need to close a dated question: what was published for one gage during a review window, and did a later read disagree? It is evidence of our observations of the public interface, not a replacement for a certified USGS record.

Coverage by state and jurisdiction

Counts below come from the latest sealed site inventory and daily-value response. If either source receipt for a jurisdiction is unreadable or unsuccessful, the page says unknown rather than showing a convincing zero. Unknown or unavailable evidence stays labeled unknown.

Method and provenance

1. Query active stream sites with daily discharge data.
2. Query the seven-day daily-value window for parameter 00060 and mean statistic 00003.
3. Seal every raw response and its SHA-256 hash before parsing.
4. Verify every row and the batch seal byte-for-byte.
5. Compare only identical observation keys across dated seals.
6. Count a revision only when value, qualifier, or no-data state differs.

Observation date: 2026-08-09. Collected at: 2026-08-09T10:24:47+00:00. Batch seal: 126fd88404d709f8b01281b4759ed2758af368350f02b897f8b2e2e1e6fb2621.

Official sources: USGS site service, USGS daily values service, and USGS Water Services documentation. The source agency remains authoritative for current streamgage values.

Limits that matter

• The ledger begins on the first snapshot date shown above; it does not reconstruct earlier publication history.
• The seven-day rolling window means observations can leave the source query before a later seal.
• A qualifier change is a published-record change, not proof that the underlying river physically changed.
• This page is informational and is not flood guidance, engineering advice, or a compliance determination.

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