To determine if current water conditions are typical, this dashboard evaluates live gage data against a rolling 30-year baseline of historical seasonal percentiles for the current month.
How the Data is Analyzed:
Modern Baseline Pool: Rather than using raw 100-year old records, we analyze a rolling 30-year historical window for each station, grouped by calendar month. This matches the standard "Climate Normals" framework used by organizations like NOAA.
Urbanization & Climate Shifts (Why 30 Years?): Using century-old data assumes weather and land use remain unchanged. However, rapid urban growth across the Madison area has increased stormwater runoff, while climate shifts have brought larger, more intense rainfall events over recent decades. A rolling 30-year window accurately captures this modern, higher-volume water cycle along with current lock-and-dam operating rules.
Normal Range (Green): Conditions sitting between the 25th and 75th percentiles represent typical historical baselines for that specific month.
Above/Below Normal (Blue/Orange): Values shifting beyond this normal 25-75% corridor highlight unusual high-flow cycles or seasonal low water.
