Water quality

Overview

Improvements in the quality of stormwater runoff is one of the primary benefits of low impact development strategies.

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Nutrients

Phosphorous

Plants (including algae) require three macro nutrients to grow: Nitrogen, potassium, and phosphorous. Of these three, phosphorous 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 phosphorous is available too.

Major sources of man-made phosphorous in the environment include agricultural fertilizers...

Compost is a commonly used source of organic material in the engineered soils used in many LID. The phosphorous content of composted materials varies hugely depending upon the material used and the method of production.

Leaf screens can help separate out a significant source of additional nutrient entering a stormwater treatment facility. Leaf screens should be cleared and the accumulated leaves and debris be disposed of off site.

Many rapidly growing species of vegetation can assimilate significant quantities of phosphorous and nitrogen from the water stream. To prevent the season release of these sequestered nutrients, the dead vegetation should be harvested in the fall, and also disposed of off site.

Phragmites australis, Carex praegracilis, and Carex microptera uptake significantly more total phosphorus (TP) and total nitrogen (TN) mass into harvestable tissue than Typha latifolia, Scirpus validus, and Scirpus acutus. .

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  Algae on Rocks in Mississauga, ON Ryan Hodnett

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See Also

• Winter

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External Links

• Environment Canada on Phosphorus and Excess Algal Growth
• Lake Simcoe phosphorus reduction strategy

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References

1. REDIRECT Special:ArticleFeedbackv5

The portion of water precipitated onto a catchment area, which then flows as surface discharge from the catchment area past a specified point.

Water from rain, snow melt, or irrigation that flows over the land surface.

A stormwater management strategy that seeks to mitigate the impacts of increased urban runoff and stormwater pollution by managing it as close to its source as possible. It comprises a set of site design approaches and small scale stormwater management practices that promote the use of natural systems for infiltration and evapotranspiration, and rainwater harvesting.

Refers to the conditions in which an organism lives and survives or the conditions in which an organism resides. These conditions can be described as aspects of a “physical”, “social” or an “economic” environment, depending on the perspective perceived by the observer.

Decayed organic material used as a plant fertilizer. Compost helps to support healthy plant growth through the slow release of nutrients and the retention of moisture in the soil.

Low Impact Development. A stormwater management strategy that seeks to mitigate the impacts of increased urban runoff and stormwater pollution by managing it as close to its source as possible. It comprises a set of site design approaches and small scale stormwater management practices that promote the use of natural systems for infiltration and evapotranspiration, and rainwater harvesting.

Total phosphorus

Total nitrogen

A shallow excavated surface depression containing prepared filter media, mulch, and planted with selected vegetation.