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→Forecasting Sediment Accumulation and Cleanouts
Accurate forecasting of sediment accumulation in stormwater facilities helps managers schedule and budget for maintenance. MOE (2003) recommends SWMFs be cleaned when the TSS removal efficiency declines below 5% of its original design criterion<ref name="MOE"></ref>. For example, if a dry pond is designed to remove 60% of TSS, an efficiency reduction to 55% triggers the need for sediment removal. The rate of sediment accumulation differs for each facility, and depends on factors such as the characteristics of drainage area (e.g., land use; level of imperviousness; upstream construction activities and effectiveness of sediment and erosion control practices) and municipal practices (e.g. frequency of road/catchbasin cleaning, sanding/salting practices).
Accurate forecasting of sediment accumulation in stormwater facilities helps managers schedule and budget for maintenance. MOE (2003) recommends SWMFs be cleaned when the TSS removal efficiency declines below 5% of its original design criterion<ref name="MOE"></ref>. For example, if a dry pond is designed to remove 60% of TSS, an efficiency reduction to 55% triggers the need for sediment removal. The rate of sediment accumulation differs for each facility, and depends on factors such as the characteristics of drainage area (e.g., land use; level of imperviousness; upstream construction activities and effectiveness of sediment and erosion control practices) and municipal practices (e.g. frequency of road/catchbasin cleaning, sanding/salting practices).
To assess whether a SWMF needs sediment removal, three factors are required:
To assess whether a SWMF needs sediment removal, three factors are required:
STEP's [https://sustainabletechnologies.ca/app/uploads/2018/04/SWMFG2016_Guide_April-2018.pdf Inspection and Maintenance Guide for Stormwater Management Ponds and Constructed Wetlands] (section 4.5.1: Forecasting Based on Sediment Depth Measurements) describe methods for forecasting the need for sediment removal and provides a sample forecasting exercise.
STEP's [https://sustainabletechnologies.ca/app/uploads/2018/04/SWMFG2016_Guide_April-2018.pdf Inspection and Maintenance Guide for Stormwater Management Ponds and Constructed Wetlands] (section 4.5.1: Forecasting Based on Sediment Depth Measurements) describe methods for forecasting the need for sediment removal and provides a sample forecasting exercise.
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