Know the boundaries.
A useful environmental hub makes its evidence, methods and uncertainty visible.
What this hub does
AlgalBloom is an independent environmental information project. It combines a focused lake-data explorer with broader educational guides. It is not an EPA service, and no agency endorsement is implied.
Coverage and freshness
The 2026 CSV contains three waterbody identifiers: cunliff, mashapaug and rwp zoo. The README describes Lake Archer and Mashapaug Pond. This discrepancy is disclosed rather than silently assigning unverified names or coordinates. Lake Archer is not present as an identifier in the current 2026 explorer.
The explorer currently uses the 2026 provisional CSV from the EPA research repository. The record count includes source rows with valid dates, including records without numeric values. Charts use numeric records only. The latest observation date is 2026-10-18. A daily source check is distinct from daily sampling.
How summaries are calculated
Source records are grouped by collection date, waterbody, variable, units, device, site and depth. Each plotted mean is the sum of numeric values divided by their count. Minimum, maximum, count and count of records carrying QA notes accompany the mean. Field duplicates and laboratory replicates are retained. Sampling frequency is not normalized, and these summaries are not time-weighted or lake-wide averages.
Quality control and units
The source reports checks against historical ranges and sensor detection limits. A QA note is not automatically evidence of an invalid measurement. Values are not silently clipped, removed or converted. RFU fluorescence must not be treated as a measured toxin concentration. Conductivity, oxygen saturation and oxygen concentration must be interpreted in their supplied units.
What the data cannot establish
A limited set of study waterbodies cannot represent national conditions. These observations do not establish toxin presence, water safety, regulatory exceedances, climate attribution or a bloom forecast. No generic danger score is computed. Follow locally issued official advisories for decisions about water use.
Refresh and failure handling
A daily WordPress task downloads the current-year CSV over HTTPS, validates its columns, computes a checksum and replaces the stored snapshot only after successful parsing. Failed checks preserve the last successful data. The Daily Updates page retains the latest 365 check outcomes. An hourly Hostinger server cron triggers WordPress scheduling independently of visitor traffic. The dataset tasks run daily; NOAA observations are published monthly.
Source and reuse
The EPA repository publishes these research data under the Creative Commons Zero Public Domain Dedication. They remain provisional and may change. The EPA seal and logo are not used. Named research references appear in plain text throughout this site.
Accessibility and privacy
Navigation, filters and topic accordions support keyboard use. Data tables provide an alternative to the trend chart. Filters run in your browser. This theme adds no advertising, tracking pixels, map embeds or third-party font requests.