Combined UMN-MPCA 2014-2017 lake data on Secchi depth, CDOM, Chlorophyll and total suspended solids

This file contains approximately 1460 records on four water quality variables measured on near-surface water samples of lakes in Minnesota (primarily) and also in Wisconsin and Michigan collected by our research group from 2014 to 2017 and similar data collected by the Minnesota Pollution Control Agency in its annual lake water quality assessment program from 2015 to 2017. The variables are Secchi depth (SD), colored dissolved organic matter (CDOM) measured as the Napierian light absorption coefficient at 440 nm, chlorophyll-a, and total suspended solids concentrations. The database was used for a published paper to analyze the effects of CDOM on SD and show that high CDOM levels limit light penetration and thus SD in colored lakes.