This dataset contains the total annual releases of radionuclides released directly to the environment through direct discharge (i.e. releases to water) from the closed mine sites near Elliot Lake, Ontario, Canada.Note that there is no stack emissions for the Elliot Lake.

Get data about the water quality for Ontario's inland lakes. The data is collected through volunteer monitoring efforts – citizen science. The [Lake Partner environment map](https://www.ontario.ca/page/map-lake-partner) The Lake Partner Program (LPP) measures water quality in inland lakes across Ontario. This dataset provides water quality and water clarity data, as well as data on the concentrations of: * total phosphorus * calcium * chloride * sulphate Spatial information for lake monitoring locations across Ontario are also available. Keywords: Lake, Water, Citizen Science, Community Science, Volunteer, Phosphorus, Calcium, Chloride, Water Clarity

This dataset contains Lake Ontario prey fish abundance and distribution statistics, collected every year during spring and fall bottom trawl surveys. The New York State Department of Environmental Conservation and the U.S. Geological Survey have conducted annual, spring and fall bottom trawl surveys in U.S. waters of Lake Ontario since 1978. In 2015, the Ministry of Natural Resources and Forestry started contributing to this program to include survey coverage in Ontario waters. The ministry also intermittently conducts mid-water trawling during the summer months on a limited geographic area largely confined to the Eastern Basin. The survey has varied sample distribution across lake depths and jurisdictions. The south shore of Lake Ontario has well-distributed coverage of depths between 8 and 200 metres. Coverage along the north shore is less uniform due to a lack of suitable trawl sites at shallower depths.

Designed to represent true ground and bathymetric elevation, this digital elevation model (DEM) covers two sections of the Greater Toronto Area (GTA) along the western shoreline of Lake Ontario: * Hamilton in the west to Niagara-on-the-Lake in the east * Scarborough in the west to Port Hope in the east

PURPOSE:Chlorophyll a is a photosynthetic pigment common to aquatic algae, and its measurement can provide an estimate of free-floating algae abundance in an aquatic system. For more than 40 years, the Fisheries and Oceans Canada - Great Lakes Laboratory for Fisheries and Aquatic Sciences (DFO-GLLFAS) office in Sault Ste. Marie Ontario has collected water samples for chlorophyll a spectrophotometric analysis, producing data in the form of mg/m3. The collection of chlorophyll a data was generally conducted to assist in characterizing the aquatic systems level of primary productivity, since that can influence fish abundance. This was a supplementary measure of the quality of fish habitat in these systems for a variety of fish-related projects of relevance to DFO’s mandate. Consistency of data collection was dependent on the duration of each project and funding available. DESCRIPTION:The initial study collected chlorophyll a data from the five lakes in the Turkey Lakes Watershed (TLW – Upper and Lower Batchawana Lakes, Wishart Lake, Little Turkey Lake and Turkey Lake) as well as Quinn Lake which is located outside of the TLW (see Smokorowski et al. 2006) in partnership with Environment and Climate Change Canada (ECCC) and Natural Resources Canada (NRCAN), as part of Canada’s Acid Rain Initiative. The TLW study was established in 1979 to evaluate the impacts of acid rain on terrestrial and aquatic ecosystems. This dataset encompasses chlorophyll a data collected from five lakes in the TLW and Quinn Lake (data also collected by the Canadian Wildlife Service and Environment and Climate Change Canada) from 1983 - 2010 with some gaps of varying duration (Webster et al., 2021). Note that an experimental habitat removal took place in some TLW lakes and Quinn Lake in 1999 and 2000. Specifically, in autumn of 1999, 50% of the coarse woody material was removed from the shorelines of Little Turkey Lake and Quinn Lake, and in autumn of 2000, 50% of the course woody material was removed from Wishart Lake shoreline (details available in Smokorowski et al., 2006). Methods Summary: Sampling was only conducted during the open water season and the frequency and extent of sampling frequency in each waterbody varied and was project- and funding-dependent. There are no chlorophyll a data for the years 1986, 1989 – 1990, 1996 – 1997, 2006-2007 and 2009.Sampling was accomplished by rinsing on site an appropriately-cleaned 1 L, brown-opaque polyethylene bottles at least three times. For hand draw samples, the bottle was immersed sub-surface (less than 0.5 meters) to collect the sample. Composite tube samples were collected using an integrated water sampling tube that collected epilimnion water from the entire water column to a depth of 5 meters. Up to five - 1 L (1000 mL) samples were collected per station and returned to the lab on ice. Each 1 L sample was filtered using glass fiber filters (Whatman GF/C, 42.5 mm) within one day of sampling, and then frozen prior to standard chlorophyll a analysis (American Public Health Association [APHA] 1985). From 1983-1998, Chlorophyll a concentrations (mg/L) was calculated based on APHA 1985; from 1998 to present the calculation was based on APHA (1998). The sample dataset information includes the georeferenced sampling locations, the raw data for chlorophyll a calculations, and the calculated chlorophyll a concentrations using both the APHA (1985) and APHA (1998) methods. This dataset was published in partnership with the Canadian Institute of Ecology and Evolution - Living Data Project, which was funded by a CREATE grant from the Natural Science and Engineering Research Council of Canada. We would like to recognize Caroline Dallstream for her effort in publishing this dataset. SAMPLING METHODS:Methods Summary: Sampling was only conducted during the open water season and the frequency and extent of sampling frequency in each waterbody varied and was project- and funding-dependent. There are no chlorophyll a data for the years 1986, 1989 – 1990, 1996 – 1997, 2006-2007 and 2009. See Sampling was accomplished by rinsing on site an appropriately-cleaned 1 L, brown-opaque polyethylene bottles at least three times. For hand draw samples, the bottle was immersed sub-surface (less than 0.5 meters) to collect the sample. Composite tube samples were collected using an integrated water sampling tube that collected epilimnion water from the entire water column to a depth of 5 meters. Up to five - 1 L (1000 mL) samples were collected per station and returned to the lab on ice. Each 1 L sample was filtered using glass fiber filters (Whatman GF/C, 42.5 mm) within one day of sampling, and then frozen prior to standard chlorophyll a analysis (American Public Health Association [APHA] 1985). From 1983-1998, Chlorophyll a concentrations (mg/L) was calculated based on APHA 1985; from 1998 to present the calculation was based on APHA (1998). The sample dataset information includes the georeferenced sampling locations, the raw data for chlorophyll a calculations, and the calculated chlorophyll a concentrations using both the APHA (1985) and APHA (1998) methods.USE LIMITATION:To ensure scientific integrity and appropriate use of the data, we would encourage you to contact the data custodian.

This is a magnitude 5.0 earthquake scenario under Lake Ontario, very close to Toronto. This fault is not known to be active but demonstrates a plausible earthquake scenario for Toronto region.

The attribute table included in the dataset provides some limited metadata information that is specific to each lake. This includes the: * survey year * survey method * original map scale This dataset should be used for discovery of Bathymetry data. It provides no bathymetric information, but allows users to discover where bathymetry data exists and in what format. Related datasets: * [Ontario waterbody location identifer](https://data.ontario.ca/dataset/ontario-waterbody-location-identifier)

This program summarizes long term water chemistry and chlorophyll a monitoring in north central Ontario lakes developed under Canada’s Long Range Transport of Air Pollutants (LRTAP) initiative to understand and track lake acidification caused by atmospheric deposition. Centered on the intensively studied Turkey Lakes Watershed since 1979 and complemented by broader headwater and mesoscale lake networks around Sault Ste. Marie, Ontario, as well as a few locations near Parry Sound, Ontario, the monitoring integrates catchment scale approaches to link atmospheric inputs, watershed processes, and aquatic responses. Water chemistry measurements quantify acid–base status, major ions, nutrients, and trace metals to diagnose sensitivity to acidification, episodic stress during events such as spring snowmelt, and long term chemical recovery following emission controls. Chlorophyll a is used alongside chemistry to indicate phytoplankton biomass, lake productivity, and overall water quality, providing biological context for fish habitat and ecosystem condition. Together, these coordinated datasets support both detailed process studies and regional assessments of lake sensitivity, productivity, and ecological recovery across a heterogeneous landscape.

This dataset contains measurements of water (chemistry and algal pigments) and sediment (chemistry and size fraction) quality in nearshore areas of Lake Huron surrounding cage aquaculture operations including North Channel, Manitoulin Island and Georgian Bay. Seasonal ice-free monitoring and sampling occurred in Ontario nearshore areas between 1998-2016. The dataset also contains the limits of detection and quantification for the parameters measured, GPS coordinates and depths (sample, Secchi, composite and maximum) for the lake sampling locations.

A feature is a representation of a real world object, such as a lake, stream, dam or rapid. There are three hydrographic feature classes:  points, lines and polys. All may impede or be hazardous to waterflow and/or navigation on a watercourse or waterbody. This data shows natural and manmade point features. Examples include: * waterfalls * rapids * rocks * Sea Lamprey barriers * shipwrecks This product requires the use of geographic information system (GIS) software. [Technical Bulletin: Data migrated to new Ontario Hydro Network (OHN) - Hydrographic Feature Data Classes (PDF)](https://geohub.lio.gov.on.ca/datasets/mnrf::ontario-hydro-network-ohn-hydrographic-point/)