Changes

The mean performance value recorded at the outlet for Permeable Pavement practices' ability to remove Total [[Phosphorus]] (TP) was calculated based on 300 separate recordings between 2005-2007, and 2010-2017 amongst the three sites previously mentioned.

The mean performance value recorded at the outlet for Permeable Pavement practices' ability to remove Total [[Phosphorus]] (TP) was calculated based on 300 separate recordings between 2005-2007, and 2010-2017 amongst the three sites previously mentioned.

As can be seen in the corresponding boxplot, the mean performance removal efficiency of the bioretention practices monitored are not meeting the acceptable upper extent range of nutrients as of 0.03 mg/L (30 µg/L) (Environment Canada, 2004<ref name="example1">Environment Canada. (2004). Canadian guidance framework for the management of phosphorus in freshwater systems. Ecosystem Health: Science‐based solutions report no. 1–8. Cat. No. En1–34/8–2004E. </ref>; OMOEE, 1994<ref>Ontario Ministry of Environment and Energy (OMOEE), 1994. Policies, Guidelines and Provincial Water Quality Objectives of the Ministry of Environment and Energy. Queen’s Printer for Ontario. Toronto, ON.</ref>).

As can be seen in the corresponding boxplot, the mean performance removal efficiency of the permeable pavement practices monitored are not meeting the acceptable upper extent range of nutrients as of 0.03 mg/L (30 µg/L) (Environment Canada, 2004<ref name="example1">Environment Canada. (2004). Canadian guidance framework for the management of phosphorus in freshwater systems. Ecosystem Health: Science‐based solutions report no. 1–8. Cat. No. En1–34/8–2004E. </ref>; OMOEE, 1994<ref>Ontario Ministry of Environment and Energy (OMOEE), 1994. Policies, Guidelines and Provincial Water Quality Objectives of the Ministry of Environment and Energy. Queen’s Printer for Ontario. Toronto, ON.</ref>).

The median value of the 355 samples taken was '''0.04 mg/L''' whereas the mean was '''0.08 mg/L''', with a '''62%''' guideline exceedance. Given the age of most of these practices, more inspection, maintenance and necessary rehabilitation will be needed to ensure they are able to meet the federal and provincial governments' guideline requirement for stormwater quality.

The median value of the 355 samples taken was '''0.04 mg/L''' whereas the mean was '''0.08 mg/L''', with a '''62%''' guideline exceedance. Given the age of most of these practices, more inspection, maintenance and necessary rehabilitation will be needed to ensure they are able to meet the federal and provincial governments' guideline requirement for stormwater quality.

==Recent Performance Research==

==Recent Performance Research==

*[https://www.waterrf.org/system/files/resource/2020-11/DRPT-4968_0.pdf (Clary et al., 2020) - International Stormwater BMP Database: 2020 Summary Statistics.]

*[https://www.waterrf.org/system/files/resource/2020-11/DRPT-4968_0.pdf International Stormwater BMP Database: 2020 Summary Statistics (Clary et al. 2020)]

**The International Stormwater Best Management Practices (BMP) Database is a publicly accessible repository for BMP performance monitoring study, design, and cost information.  As of December 2019, the BMP Database contains data sets collected over four decades from over 700 BMP studies through the U.S., Canada, Sweden, New Zealand, Australia, China, etc. that are accessible on the project website ([www.bmpdatabase.org]). The performance data for both TSS and TP are as follows within the report:

**The International Stormwater Best Management Practices (BMP) Database is a publicly accessible repository for BMP performance monitoring study, design, and cost information.  As of December 2019, the BMP Database contains data sets collected over four decades from over 700 BMP studies through the U.S., Canada, Sweden, New Zealand, Australia, China, etc. that are accessible on the project website ([www.bmpdatabase.org]). The performance data for both TSS and TP are as follows within the report:

***Median TSS value of outflow/effluent of stormwater from P.P is 22 mg/L in comparison to 77 mg/L influent levels. These levels are computed using the BCa bootstrap method described by Efron and Tibishirani (1993). This value is below the required CWQG levels for TSS in stormwater.

***Median TSS value of outflow/effluent of stormwater from P.P is 22 mg/L in comparison to 77 mg/L influent levels. These levels are computed using the BCa bootstrap method described by Efron and Tibishirani (1993). This value is below the required CWQG levels for TSS in stormwater.

***Median Total phosphorus (TP) value of outflow/effluent of stormwater from P.P is 0.10 mg/L in comparison to 0.17 mg/L influent levels. These levels are computed using the BCa bootstrap method described by Efron and Tibishirani (1993). This value is below the required federal (Environment Canada, 2004) and provincial (OMOEE, 1994) levels for TP in stormwater ((Clary et al., 2020<ref>Clary, J., Jones, J., Leisenring, M., Hobson, P. and Strecker, E. 2020. International stormwater BMP database 2020 summary statistics. Water Environment & Reuse Foundation.</ref>).

***Median Total phosphorus (TP) value of outflow/effluent of stormwater from P.P is 0.10 mg/L in comparison to 0.17 mg/L influent levels. These levels are computed using the BCa bootstrap method described by Efron and Tibishirani (1993). This value is below the required federal (Environment Canada, 2004) and provincial (OMOEE, 1994) levels for TP in stormwater ((Clary et al., 2020<ref>Clary, J., Jones, J., Leisenring, M., Hobson, P. and Strecker, E. 2020. International stormwater BMP database 2020 summary statistics. Water Environment & Reuse Foundation.</ref>).

*[https://www.sciencedirect.com/science/article/abs/pii/S0959652618335376 (Xie, et al. 2019) - Permeable concrete pavements: A review of environmental benefits and durability.]

*[https://www.sciencedirect.com/science/article/abs/pii/S0959652618335376 (Xie, et al. 2019) - Permeable concrete pavements: A review of environmental benefits and durability.]

 

*[https://www.sciencedirect.com/science/article/abs/pii/S0043135419308450 (Ostrom and Davis, 2019) - Evaluation of an enhanced treatment media and permeable pavement base to remove stormwater nitrogen, phosphorus, and metals under simulated rainfall.]

*[https://pubmed.ncbi.nlm.nih.gov/24845330/ (Lee, et al. 2014) - Performance evaluation and a sizing method for hydrodynamic separators treating urban stormwater runoff.]

**This article by Ostrom and Davis, 2019, out of the University of Maryland discusses a new treatment media that can be developed to improve dissolved pollutant removal and retention in permeable pavement practices. This structural media is called "High Permeability Media Mixture (HPMM)", and was designed as a base material for P.P practices that can retain phosphorus in stormwater that enters the practice. The results of this study showed that effluent total dissolved phosphorus (TDP) levels was lower than influent for all samples (12 storms). Removal efficiency was between 48 - 98% effective with a median effluent level of 0.045 - 0.05 mg/L (dependent upon the 3 configurations used) in comparison to TDP event mean concentrations of 0.22 mg/L (Ostrom and Davis, 2019<ref>Ostrom, T.K. and Davis, A.P. 2019. Evaluation of an enhanced treatment media and permeable pavement base to remove stormwater nitrogen, phosphorus, and metals under simulated rainfall. Water research, 166, p.115071.)</ref>.

**This study conducted performance monitoring over a 6-year period (137 separate storm events) of four different hydrodynamic separators in Korean urban catchments between 2006 - 2012. Removal rates were relatively low at all four sites (1. Roadway site: Avg. Inflow = 239.32 mg/L vs Avg. Outflow = 122.2- mg/L /  2. Residential site:  Avg. Inflow = 59.74 mg/L vs Avg. Outflow = 50.35 mg/L / 3. Roadway Site: Avg. Inflow = 62.50 mg/L vs. Avg. Outflow = 33.76 mg/L / 4. Residential(63.5%) & Roadway (36.5%) CDA site: Avg. Inflow = 236.24 mg/L vs. Avg. Outflow = 160.54 mg/L). The low removal rates were due to high rates of extreme overflow events occurring with most suspended sediment being quite small/fine in nature (<75μm)(Lee, et al. 2014<ref>Lee, D.H., Min, K.S. and Kang, J.H., 2014. Performance evaluation and a sizing method for hydrodynamic separators treating urban stormwater runoff. Water science and technology, 69(10), pp.2122-2131)</ref>.

==References==

==References==