Buzzards Bay Baywatchers Long-Term Trends

Recreates the violin + GAM trend plots described in Rachel Jakuba's (Buzzards Bay Coalition) "Baywatchers long-term analysis" email: for each water-quality parameter, the annual distribution of values (violin) overlain with a GAM smooth trend curve, colored by periods of statistically significant change (red = increasing, blue = decreasing, gray = not significant).

Parameters covered: water temperature, ammonium (NH4), chlorophyll-a, and Secchi depth.

Data

Buzzards Bay Coalition Baywatchers water quality monitoring program, 1992-2023 (~116k QC'd samples, 414 stations). See data/README.md for how to fetch the source spreadsheet from the MBL/WHOI Data Archive.

Layout

• analysis/load_data.py — loads and caches the raw spreadsheet.
• analysis/trends.py — GAM trend fitting, bootstrap significance testing, and static matplotlib figures (python analysis/trends.py, writes to figures/).
• notebooks/baywatchers_trends_hvplot.ipynb — interactive version (hvplot/holoviews/panel): a station map, the four violin+trend plots with pan/zoom/hover, and a dropdown dashboard.
• figures/ — static PNG output of analysis/trends.py.

Setup

pip install pandas numpy scipy matplotlib openpyxl pyarrow pygam hvplot holoviews panel