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[[File:Selbig graph.png|400px|thumb|alt=graph of P removal with street sweeping|<font size=3>Research conducted by Bill Selbig (USGS) shows that streets, when cleaned of leaf litter prior to a storm, can significantly decrease phosphorus loads in stormwater runoff ([https://www.usgs.gov/centers/umid-water/science/using-leaf-collection-and-street-cleaning-reduce-nutrients-urban?qt-science_center_objects=0#qt-science_center_objects Link to study])</font size>]] | [[File:Selbig graph.png|400px|thumb|alt=graph of P removal with street sweeping|<font size=3>Research conducted by Bill Selbig (USGS) shows that streets, when cleaned of leaf litter prior to a storm, can significantly decrease phosphorus loads in stormwater runoff ([https://www.usgs.gov/centers/umid-water/science/using-leaf-collection-and-street-cleaning-reduce-nutrients-urban?qt-science_center_objects=0#qt-science_center_objects Link to study])</font size>]] | ||
− | At this time, the MPCA has not developed guidance for how to credit reductions in phosphorus or total suspended solid loading associated with enhanced street sweeping. We anticipate developing this guidance in 2022. In developing this guidance, consider the following | + | At this time, the MPCA has not developed guidance for how to credit reductions in phosphorus or total suspended solid loading associated with enhanced street sweeping. We anticipate developing this guidance in 2022. In developing this guidance, consider the following. |
*Baseline: Credits toward permit compliance, such as compliance with <span title="The amount of a pollutant from both point and nonpoint sources that a waterbody can receive and still meet water quality standards"> [https://stormwater.pca.state.mn.us/index.php?title=Total_Maximum_Daily_Loads_(TMDLs) '''total maximum daily loads''']</span>, can only be applied toward enhanced street sweeping. This is sweeping that results in pollutant reductions above pollutant reductions associated with sweeping that occurred at the <span title="The year from which stormwater practices can be credited toward meeting a total maximum daily load (TMDL) wasteload allocation (WLA)"> '''[https://stormwater.pca.state.mn.us/index.php?title=Baseline_year baseline year]'''</span>. | *Baseline: Credits toward permit compliance, such as compliance with <span title="The amount of a pollutant from both point and nonpoint sources that a waterbody can receive and still meet water quality standards"> [https://stormwater.pca.state.mn.us/index.php?title=Total_Maximum_Daily_Loads_(TMDLs) '''total maximum daily loads''']</span>, can only be applied toward enhanced street sweeping. This is sweeping that results in pollutant reductions above pollutant reductions associated with sweeping that occurred at the <span title="The year from which stormwater practices can be credited toward meeting a total maximum daily load (TMDL) wasteload allocation (WLA)"> '''[https://stormwater.pca.state.mn.us/index.php?title=Baseline_year baseline year]'''</span>. | ||
*Accounting for seasonality: The image on the right illustrates the seasonal nature of phosphorus loading in areas where leaves and other organic sources are a source of phosphorus. Most models and other methods of estimating annual loads do not consider this seasonality and most likely significantly underestimates annual phosphorus loading. Accurate representation of impacts from enhanced street sweeping will require adjusting initial (baseline) calculations of loading. The MPCA is discussing appropriate methods for accounting for this seasonality. | *Accounting for seasonality: The image on the right illustrates the seasonal nature of phosphorus loading in areas where leaves and other organic sources are a source of phosphorus. Most models and other methods of estimating annual loads do not consider this seasonality and most likely significantly underestimates annual phosphorus loading. Accurate representation of impacts from enhanced street sweeping will require adjusting initial (baseline) calculations of loading. The MPCA is discussing appropriate methods for accounting for this seasonality. |
Reporting phosphorus and TSS reduction credits from street sweeping
At this time, the MPCA has not developed guidance for how to credit reductions in phosphorus or total suspended solid loading associated with enhanced street sweeping. We anticipate developing this guidance in 2022. In developing this guidance, consider the following.