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Total Suspended Solids (TSS) Reduction Presenter: Keith Noble, Saginaw Bay District Office
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A compliance assistance document is available on the MS4 website Reduce suspended solid discharges
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Total Suspended Solids Reduction Permits require reduction of TSS Permits require reduction of TSS Jurisdictional Permit - Maximum Extent Practicable with a Goal of 25% reduction Watershed Permit – Maximum Extent Practicable (?% reduction) Watershed Permit – Maximum Extent Practicable (?% reduction) Total reduction from the whole system Total reduction from the whole system
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Reduction from paved surfaces to surface waters as compared to annual loading from runoff with no suspended controls. Includes: Includes: Streets, roads and highways Streets, roads and highways Parking lots Parking lots Other impervious surfaces Other impervious surfaces
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Permits also require: Reduction in dust and suspended solids from unpaved surfaces Reduction in dust and suspended solids from unpaved surfaces Reduce the discharge of other pollutants from impervious surfaces Reduce the discharge of other pollutants from impervious surfaces Salt and Sand for improved traction Salt and Sand for improved traction Petroleum products Petroleum products
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TSS Reduction can be achieved by a combination of the following: Pollution Prevention - Improved Material Handling
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Pollution Prevention- Street Sweeping
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Cleaning Catch Basins
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Catch Basin Inserts
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Pollution Prevention - Treatment Settling (Wet Detention Pond)
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Treatment Filtration Vegetated Buffer Filter Berm Filter Berm at stream crossing
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Treatment Infiltration Bioswales Retention Ponds
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Removal efficiencies of BMPs assumes that: Installed according to product specifications Installed according to product specifications Built according to design criteria Built according to design criteria Are adequately maintained Are adequately maintained
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TSS Reduction Reduction of sediment from activities already regulated shall not be counted toward the TSS reduction. Reduction of sediment from activities already regulated shall not be counted toward the TSS reduction. Regulated activities include: Regulated activities include: Construction sites regulated under the Part 91 Soil Erosion and Sedimentation Control ProgramConstruction sites regulated under the Part 91 Soil Erosion and Sedimentation Control Program Facilities regulated by the industrial storm water programFacilities regulated by the industrial storm water program
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First Progress Report First Progress Report Describe current level of control Describe current level of control Estimate load reduction from existing controls (Perform TSS calculations) Estimate load reduction from existing controls (Perform TSS calculations) TSS reduction to be reported
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Second Progress Report Second Progress Report Evaluate effectiveness of current practices (TSS calculations) Evaluate effectiveness of current practices (TSS calculations) Identify methods for improving effectiveness or to achieve 25% goal Identify methods for improving effectiveness or to achieve 25% goal To be implemented in 2013 To be implemented in 2013 TSS reduction to be reported
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Mean TSS Runoff values for several land uses TSS Concentration TSS Concentration Land Use Category (Paved surfaces) Mean mg/l Mean lbs/ft 3 High Density Residential 970.0061 Commercial (Parking Lots, Sidewalks) 770.0048 Industrial (Fleet Maintenance, Storage Yards) 1490.0093 Highway (Roads, Streets, etc.) 1410.0088 Adapted from Rouge River Wet Weather demonstration Project, Selection of Storm Water Pollutant Loading Factors RPO-MOD- TM34.00, October 1994, Table 3-13 (To convert mg/l to lbs/ft 3, multiply by 6.243 X 10 -5) Calculating TSS Reduction
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Step 1- Determine the uncontrolled load for each facility. TSS lbs/ft 3 is taken from the table on TSS runoff values for land uses. Step 1- Determine the uncontrolled load for each facility. TSS lbs/ft 3 is taken from the table on TSS runoff values for land uses. TSS in lbs X Precipitation in feet X area of pavement in ft2 = TSS pounds ft3 year year ft3 year year TSS load for 20 miles of road Precipitation = 32 inches = 2.7 ft (0.0088 lbs/ft3)(2.7 ft/year)[(20 miles)(25 ft)(5280 ft/mile)] = 62,726 lbs/year
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Step 2 - Add up the uncontrolled load for each paved surface that discharges to the MS4. Step 2 - Add up the uncontrolled load for each paved surface that discharges to the MS4. Load from: Load from: 20 miles of residential roads = 62,726 lbs 1 acre municipal parking lots = 565 lbs 10,000 ft 2 paved surfaces at parks = 165 lbs 20,000 ft 2 paved surfaces at DPW = 502 lbs Total for all paved surfaces = 63,958 lbs Calculating TSS Reduction
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Step 3 – Select the BMPs for each site and calculate the TSS removed, after implementation, for each site based on the chosen BMPs Step 3 – Select the BMPs for each site and calculate the TSS removed, after implementation, for each site based on the chosen BMPs Use BMPs already in place or under consideration Use BMPs already in place or under consideration Removal efficiencies can be found on data bases Removal efficiencies can be found on data bases Use appropriate efficiency numbers that are defensible Use appropriate efficiency numbers that are defensible Uncontrolled TSS load X BMP efficiency for type of paved area = TSS reduction for type of paved area Calculating TSS Reduction
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[CA1] Ralph to add BMPs.[CA1] Calculating TSS Reduction
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TSS Removal Efficiency of Select BMPs Treatment Method Median Suspended Solids Removal Efficiency (%) Dry Detention 49 49 Wet Detention 80 80
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TSS Removal Efficiency Use Actual Amount Removed for: Use Actual Amount Removed for: Street Sweeping Street Sweeping Catch Basin Cleanout Catch Basin Cleanout Sediment Removed from catch basin inserts Sediment Removed from catch basin inserts Efficiency Dependent upon: Efficiency Dependent upon: Loadings Loadings Equipment Equipment Frequency Frequency
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Example 1 Example 1 10 miles of roads with open channels (vegetated ditches next to roads without curbs) 31,363 lbs (.68 for open channels BMP) = 21,327 lbs removed 21,327 lbs removed Example 2 Example 2 Sediment picked up from 10 miles of street sweeping on curbed streets that were swept twice during the year (To determine the number of cubic yards of sediment from street sweeping, multiply the number of yd 3 by lbs/yd 3 (actual sediment removed from streets)) = 10,000 lbs removed 10,000 lbs removed BMP Removal Efficiency
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Example 3 Example 3 Vegetative filters at parks (lawns) 165 lbs (.86 for Vegetative Buffers) =142 lbs removed Example 4 Example 4 Sediment removed from catch basin inserts at DPW (actual sediment taken from catch basin inserts) = 450 lbs removed Example 5 Example 5 Dry detention basin at Municipal parking lot 565 lbs (.49 for Dry Detention Basin) = 277 lbs removed BMP Removal Efficiency
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Step 4 - Add up the calculated load removal for each site that discharges in the MS4 area and the actual amounts removed from catch basin cleanout, street sweeping and catch basin inserts. This is the TSS removed from the system after BMP implementation. Step 4 - Add up the calculated load removal for each site that discharges in the MS4 area and the actual amounts removed from catch basin cleanout, street sweeping and catch basin inserts. This is the TSS removed from the system after BMP implementation. Roads with open channels BMP = 21,327 lbs removed Sediment from street sweeping = 10,000 lbs removed Parks with vegetative buffers= 142 lbs removed Sediment from catch basin inserts = 450 lbs removed Parking lot with dry detention basin = 277 lbs removed Total TSS removed = 32,196 lbs 32,196 pounds of sediment are not discharged to the receiving waters
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Step 5 – Divide the sum of the TSS removed from the system, after BMPs are applied, by the sum of the loading from the system, before BMPs are applied. Step 5 – Divide the sum of the TSS removed from the system, after BMPs are applied, by the sum of the loading from the system, before BMPs are applied. Sum of TSS removed with BMPs = 32,196 lbs Sum of TSS removed with BMPs = 32,196 lbs Sum of TSS load without BMPs 63,958 lbs Sum of TSS load without BMPs 63,958 lbs 63,958 lbs – 32,196 lbs = 31,762 lbs TSS load w/out BMPs TSS removed w/ BMPs - = Treated TSS load 31,762 lbs of sediment is deposited into the receiving waters
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Step 6 – The result, times 100, is the percentage reduction Step 6 – The result, times 100, is the percentage reduction (Sum of TSS load with BMPs ) X 100 = % TSS Reduction Sum of TSS load without BMPs (Sum of TSS load with BMPs ) X 100 = % TSS Reduction Sum of TSS load without BMPs 32,196 lbs x 100 = 50.3% TSS reduced 32,196 lbs x 100 = 50.3% TSS reduced 63,958 lbs 63,958 lbs Percent TSS reduction is 50.3 %
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Existing practices (BMPs) already in place within the MS4 may achieve the 25% reduction goal. Existing practices (BMPs) already in place within the MS4 may achieve the 25% reduction goal. Do existing practices meet the Maximum Extent Practicable standard? Do existing practices meet the Maximum Extent Practicable standard?
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Questions?
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