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→Forecasting Sediment Accumulation and Cleanouts
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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).<br clear="all" />
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:
*Current storage capacity (from sediment depth measurements or TSS load modelling).
*Minimum efficiency allowed (5% reduction, per MOE 2003).
*The facility’s efficiency–storage relationship, to compare storage loss with the 5% efficiency threshold.
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.
from SWMFs.
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==Gallery==
==Gallery==