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Loading and lake circulation structures recurrent patterns of water quality on the Toronto – Mississauga waterfront of Lake Ontario
- Source :
- Journal of Great Lakes Research. 47:323-342
- Publication Year :
- 2021
- Publisher :
- Elsevier BV, 2021.
-
Abstract
- Urban centers line western Lake Ontario where urban rivers, wastewater treatment plants and stormwater load nutrients, major ions and suspended solids to the nearshore. In 2018, nearshore water quality and associated physical conditions bordering the cities of Toronto and Mississauga were assessed as a benchmark for future effects of urban growth and municipal infrastructure projects to improve water quality. Conductivity and UV-fluorescence were used as water quality surrogates and mapped over blocks of shoreline stratified by distance offshore. Patterns in UV-fluorescence aligned with loading points, and generally higher levels near the shoreline, were correlated with concentrations of nutrients, major ions and suspended solids. Water quality was more land-impacted over the shoreline from the Credit River to Humber Bay contrasting with the more lake-like conditions from Toronto Eastern Beaches to the Rouge River. Within Toronto Harbour, cross-harbour gradients in water quality varied with weather-related changes in river and storm water loading. Mixing areas at wastewater treatment plant outfalls and tributary mouths, frequently shaped by alongshore lake circulation, resulted in a mosaic of water quality over the shoreline. Area-wide elevation of chloride and conductivity, and poorer water quality in late spring, was linked to heightened river discharge. Thermal stratification affected how discharges were distributed in the water column, but measurements at the lake surface reflected the strongest overall land-effects on water quality. The patterns of temporal-spatial variability identified within geographically-defined areas of shoreline can be used as past footprints in future monitoring to detect change.
- Subjects :
- 0106 biological sciences
Hydrology
Shore
geography
Suspended solids
geography.geographical_feature_category
Ecology
Discharge
010604 marine biology & hydrobiology
Stormwater
Outfall
010501 environmental sciences
Aquatic Science
01 natural sciences
Water column
Tributary
Environmental science
Water quality
Ecology, Evolution, Behavior and Systematics
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 03801330
- Volume :
- 47
- Database :
- OpenAIRE
- Journal :
- Journal of Great Lakes Research
- Accession number :
- edsair.doi...........69847a5300863a961bb95fd642ffd7ee