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==Nutrients==
==Nutrients==
Plants (including algae) require three macro nutrients to grow: Nitrogen, potassium, and phosphorus. Of these three, phosphorus is the often the "growth-limiting" nutrient. i.e. the local environment may have an abundance of nitrogen and potassium, but algae won't develop unless phosphorus is available too.
Plants (including algae) require three macro nutrients to grow: Nitrogen, potassium, and phosphorus. See [[Nutrients]] page for more information about nutrients. Of these three, phosphorus is the often the "growth-limiting" nutrient. i.e. the local environment may have an abundance of nitrogen and potassium, but algae won't develop unless phosphorus is available too.
[[Phosphorus]]
See [[Phosphorus]] page for more information about phosphorus. See [[Additives]] page for guidance on [[Bioretention: Filter media| filter media]] additives to enhance retention of phosphorus and other types of pollutants in [[Bioretention]], [[Bioswale]], [[Stormwater Planter]] and [[Stormwater Tree Trenches| Stormwater Tree Trench]] facilities.
[[File:TSS_effluent_comparison.PNG|thumb|600px|Under the CCME Water Quality Guidelines for the Protection of Aquatic Life. Freshwater – Long-term Suspended Sediment Concentration: “Maximum increase of 25 mg/L from background levels for any short-term exposure (e.g., 24-h period).” Assumes background level of 5 mg/L and objective of 30 mg/L total (CCME 2002)<ref>Canadian Council of Ministers of the Environment. 2002. Canadian water quality guidelines for the protection of aquatic life: Total
particulate matter. In: Canadian environmental quality guidelines, 1999, Canadian Council of Ministers of the Environment, Winnipeg. https://ccme.ca/en/res/total-particulate-matter-en-canadian-water-quality-guidelines-for-the-protection-of-aquatic-life.pdf</ref>]]
[[File:TP_effluent_comparison.PNG|thumb|600px|Under the Provincial Water Quality Objectives set out by the Ministry of Environment and Energy in 1994, Total phosphorus effluent leaving a SWM facility should be below a concentration level of 30 μg/L. (0.03 mg/L) (MOEE 1994)<ref>Ministry of the Environment and Energy. 1994. WATER
MANAGEMENT POLICIES GUIDELINES - PROVINCIAL WATER QUALITY OBJECTIVES OF THE MINISTRY OF ENVIRONMENT AND ENERGY. July, 1994. Reprinted February 1999. ISBN 0-7778-8473-9 rev. https://dr6j45jk9xcmk.cloudfront.net/documents/3016/moeprovincialwaterqualityobjectivesen.pdf</ref>]]
===STEP stormwater practice effluent quality monitoring results===
The box plot figures to the right show combined stormwater effluent quality monitoring results from STEP monitoring projects conducted over a 25-year time period (between 1997 and 2021) at sites within Greater Toronto Area municipalities.<br>
<br>
Median concentrations of Total Suspended Solids (TSS) in untreated stormwater and [[Oil and Grit Separator]] (OGS) outlet locations were found to exceed the Canadian Water Quality Guideline of 30 mg/L. Median TSS concentrations at stormwater detention pond and chamber system outlet locations were found to be below 30 mg/L, but exceeded the guideline value in 36% of the 231 monitored storm events. Median TSS concentrations at bioretention, permeable pavement and infiltration trench outlet locations were found to be all below 30 mg/L. TSS concentrations in effluent from bioretention was found to exceed 30 mg/L in only 15% of the 301 monitored storm events, and in only 12% of the 296 monitored events for permeable pavements.<br>
<br>
Median concentrations of Total Phosphorus (TP) in untreated stormwater and all stormwater treatment facility type outlet locations were found to exceed the Ontario Provincial Water Quality Objective of 0.03 mg/L. Untreated stormwater was found to exceed 0.03 mg/L in between 96 to 98% of the 545 monitored storm events (Asphalt Reference and SWM Inlet data sets). Stormwater detention pond or chamber system effluent was found to exceed 0.03 mg/L during 91% of the 211 monitored events. Effluent from bioretention outlet locations was found to exceeded 0.03 mg/L during 86% of the 355 monitored events. Effluent from permeable pavement outlet locations exceeded 0.03 mg/L during 62% of the 300 monitored storm events.<br>
<br>
It is notable that green roof and infiltration trench results are from only one site each, and based on a relatively small number of storm events (24 to 25).
Click on the links below for LID BMP-specific treatment performance sections and figures.
*[[Bioretention#Water_Quality| Bioretention Performance section]]
*[[Permeable pavements#Water_Quality| Permeable Pavements Performance section]]
==Heavy metals==
==Heavy metals==
{{:Heavy metals}}
{{:Heavy metals}}
==External Links==
==External Links==
*[https://www.ec.gc.ca/grandslacs-greatlakes/default.asp?lang=En&n=6201FD24-1 Environment Canada on Phosphorus and Excess Algal Growth ]
*[https://www.ec.gc.ca/grandslacs-greatlakes/default.asp?lang=En&n=6201FD24-1 Environment Canada on Phosphorus and Excess Algal Growth ]
*[https://www.ontario.ca/page/lake-simcoe-phosphorus-reduction-strategy Lake Simcoe phosphorus reduction strategy]
*[https://www.ontario.ca/page/lake-simcoe-phosphorus-reduction-strategy Lake Simcoe phosphorus reduction strategy]
*[https://stepapps.shinyapps.io/WQ_Interactive4/ Canadian BMP Water Quality Database]
==References==
==References==