Data sources

Lake pages identify the exact station, series, parameter, statistic and water-surface reference used for their measurements. Source identity and reuse were reviewed before inclusion.

United States Geological Survey

The cohort contains 91 USGS series. USGS Water Data APIs supply provider daily means. Approved, provisional and revised qualifiers are retained; estimates and other excluded qualities do not silently become measured values.

US Army Corps of Engineers

Nine series use the CWMS Data API. These daily observations retain their provider convention and are not relabelled as daily means or assigned an invented USGS approval status.

Reuse and attribution

Verified agency observations are made available with their source attribution and provenance in per-lake CSV downloads. No government agency endorses this site. Provider data may be corrected or incomplete; consult the linked original series for agency context.