From 2018 to 2023, ministry staff collected water quality samples year-round from seven rivers that flow into Lake Ontario in the Greater Toronto Area. They did this to understand the amount of pollutants and other materials that these rivers carry into the lake. **Parameters measured** The dataset contains information on the water quality of these rivers, including: - Nutrients - Major ions - Suspended solids - Heavy metals - Microbial indicators **Sample types** The dataset has two types of water samples: 1. Discrete samples collected at a specific time 2. Composite samples collected over periods of time

Water quality and ecosystem health data are collected in the nearshore zone of the Great Lakes to address the problem of nuisance benthic algae. Monitoring data include physical and chemical water quality data as well as biological data, primarily from Cladophora and dreissenid mussels on the lakebed. Monitoring is conducted (i) to improve understanding of the factors impacting nearshore water quality, algae growth, and ecosystem health; (ii) to develop ecosystem health indicators for the nearshore; (iii) to provide validation and calibration data for modelling; (iv) to support the development of a binational nearshore assessment and management framework; and, (v) to measure the success of ongoing and future phosphorus reduction targets to support a healthy ecosystem.

This data set includes information on sampling locations, water chemistry and chlorophyll collected at 18 locations in the Great Lakes-St. Lawrence River and 4 locations in Lake Simcoe.

Blooms of nuisance and toxic cyanobacteria, referred to as cyanobacteria harmful algal blooms (cHABs), occur seasonally in Saginaw Bay, Lake Huron, and pose a threat to human health, affect the quality of life, and significantly degrade the ecosystem. NOAA Great Lakes Environmental Research Laboratory and the Cooperative Institute for Great Lakes Research (CIGLR), University of Michigan, started regular water quality monitoring of Saginaw Bay, Lake Huron in 2012. Since that time the monitoring effort has expanded to incorporate additional parameters and sample locations. Physical, chemical, and biological water quality data were collected during repeated sampling trips to a set of stations before, during, and after HAB events (from May - October). Data for these discrete sampling events include: Secchi disk depth, Conductivity, Temperature and Depth (CTD), CTD specific conductivity, CTD beam attenuation, CTD beam transmission, CTD dissolved oxygen, CTD photosynthetically active radiation, turbidity, particulate microcystin, dissolved microcystin, extracted phycocyanin, extracted chlorophyll-a, total phosphorus, total dissolved phosphorus, soluble reactive phosphorus, ammonia, nitrate + nitrite, urea, particulate organic carbon, particulate organic nitrogen, dissolved organic carbon, chromophoric dissolved organic material absorbance at 400 nm, total suspended solids, and volatile suspended solids. The bulk water quality parameters were analyzed via established techniques and procedures for routine water quality monitoring and analysis (APHA 1992, 1998, 2017). This research was funded by the Great Lakes Restoration Initiative (GLRI) to support the projects “Decision Support Tools to Link Predictions to HABs and Source Water Protection”, Synthesis Observation and Response (SOAR), and Real-time Environmental Coastal Observation Network (ReCON).

Data is collected each year, according to the lake-by-lake cycle. Information includes: * water chemistry * approximately 80 index and reference stations throughout the Great Lakes basin

This U.S. Geological Survey (USGS) Data Release provides high-resolution, nearshore, spatial water-quality data collected from Seneca Lake, New York, on July 9-10 and October 9-10, 2019. All data are reported as raw measured values and are not rounded to USGS significant figures. Continuous water-quality monitors were mounted to a boat at approximately 0.5-meters below the water surface and used to measure water nitrate, chlorophyll fluorescence (fChl), fluorescent dissolved organic matter (fDOM), dissolved oxygen, specific conductance, phycocyanin fluorescence (fPC), turbidity, pH, and temperature.