Tables: Stormwater Pollutant Removal Criteria¶
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1. Table 4-1: TSS Removal Rates for BMPs¶
| Best Management Practice (BMP) | Adopted TSS Removal Rate (%) |
|---|---|
| Bioretention System | 90 |
| Constructed Stormwater Wetland | 90 |
| Dry Well | Volume Reduction Only^{1} |
| Extended Detention Basin | 40 to 60^{2} |
| Infiltration Structure | 80 |
| Manufactured Treatment Device | See N.J.A.C. 7:8-5.7(d)^{3} |
| Pervious Paving System | Volume Reduction Or 80^{4} |
| Sand Filter | 80 |
| Vegetative Filter | 60-80 |
| Wet Pond | 50-90^{5} |
Source context and notes
# TSS Removal Rates for Individual BMPs As noted above, the Stormwater Management Rules require an 80 percent TSS reduction in the post-construction runoff from a land development site that increases impervious surface by 0.25 acres or more. This reduction is to be achieved by conveying the site's runoff through one or more onsite BMPs that have the ability to remove a portion of the TSS load. To demonstrate compliance with this requirement, the NJDEP has adopted official TSS removal rates for each of the BMPs described in detail in Chapter 9. These BMPs and their adopted TSS removal rates are presented below in Table 4-1. Different removal rates and BMPs may be utilized if supporting information is provided and accepted by the applicable review agencies. It is important to note that the TSS removal rates shown in Table 4-1 have been based upon several sources of BMP research and monitoring data as well as consultation with numerous stormwater management experts. As demonstrated by that research, actual TSS removals at specific BMPs during specific storm events will depend upon a number of site factors and can be highly variable. As such, the TSS removal rates presented in Table 4-1 are considered representative values that are based upon a recognition of this variability and the state's need to develop and implement a statewide stormwater management program. Furthermore, the TSS removal rates are also considered to accurately represent the relative TSS removal efficiencies of the various BMPs listed in the table. Table 4-1: TSS Removal Rates for BMPs | Best Management Practice (BMP) | Adopted TSS Removal Rate (%) | | --- | --- | | Bioretention System | 90 | | Constructed Stormwater Wetland | 90 | | Dry Well | Volume Reduction Only^{1} | | Extended Detention Basin | 40 to 60^{2} | | Infiltration Structure | 80 | | Manufactured Treatment Device | See N.J.A.C. 7:8-5.7(d)^{3} | | Pervious Paving System | Volume ReductionOr
80^{4} | | Sand Filter | 80 | | Vegetative Filter | 60-80 | | Wet Pond | 50-90^{5} | 1 See text below. 2 Final rate based upon detention time. See Chapter 9. 3 To be determined through testing on a case-by-case basis. See text below. 4 If system includes a runoff storage bed that functions as an infiltration basin. See Chapter 9. 5 Final rate based upon pool volume and detention time. See Chapter 9.
2. Table 4.2 – Typical Phosphorous and Nitrogen Removal Rates for BMPs¶
| Best Management Practice (BMP) | Total Phosphorous Removal Rate (%) | Total Nitrogen Removal Rate (%) |
|---|---|---|
| Bioretention Basin | 60 | 30 |
| Constructed Stormwater Wetland | 50 | 30 |
| Extended Detention Basin | 20 | 20 |
| Infiltration Basin | 60 | 50 |
| Manufactured Treatment Devices | See N.J.A.C. 7:8-5.7(d) | See N.J.A.C. 7:8-5.7(d) |
| Pervious Paving² | 60 | 50 |
| Sand Filter | 50 | 35 |
| Vegetative Filter | 30 | 30 |
| Wet Pond | 50 | 30 |