Chicago Lakefront Beach Swim Advisories Based on Predicted E. Coli Levels

Historical predictions of E. coli levels and resulting swim advisories for beaches along Chicago's Lake Michigan lakefront. The Chicago Park District issued advisories when predicted levels reached at least 235 Colony Forming Units per 100 ml of water. This dataset is historical-only, with a newer series beginning in 2017.

Use Cases

• Analyze the correlation between Predicted Level and Swim Advisory status to validate the 235 CFU threshold policy.
• Model the Probability of an advisory being issued based on Beach Name and Date to identify high-risk locations and times.
• Track temporal patterns in Predicted Level and Swim Advisory by Date for seasonal water quality assessment.
• Compare advisory issuance rates across different Beach Name entries to prioritize monitoring resources.

Strengths

• Includes key decision variables: Predicted Level, Probability, and resulting Swim Advisory.
• Linked to source data for predictions and later measurements via provided URLs.

Limitations

• Dataset is explicitly marked as historical-only, indicating it is not current.
• Unknown row count and temporal coverage limits assessment of statistical significance.
• Relies on predictions rather than solely measured E. coli levels.

Provenance

Source

Chicago Park District, published via data.cityofchicago.org.

Collection Method

Advisories issued based on predicted E. coli levels; prediction data sources are referenced.

Time Range

Historical period prior to 2017 (exact range unknown).

Freshness

Last updated metadata indicates 2026-04-03, but the data itself is historical-only.

Geography

Beaches along Chicago's Lake Michigan lakefront.