Changes

{{TOClimit|2}}

{{TOClimit|2}}

==Overview==

==Overview==

Improvements in the quality of stormwater runoff is one of the primary benefits of low impact development strategies. Although some chemical changes occur inside the practices, much of the pollution reduction of low impact development strategies comes from runoff reduction. i.e. diverting excess water through [[infiltration]] or [[evapotranspiration]].   

Improvements in the quality of stormwater runoff is one of the primary benefits of low impact development strategies. Although some chemical changes occur inside the practices, much of the pollution reduction of low impact development strategies comes from runoff reduction. i.e. diverting excess water through [[infiltration]] or [[evapotranspiration]].   

==Nutrients==

==Nutrients==

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.

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).

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.

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: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

[[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>]]

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===

===STEP stormwater practice effluent quality monitoring results===

The box plot figures to the right show 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>

The box plot figures to the right show 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>