BMP Library¶
The BMP Library contains engineering knowledge pages for all 25 Best Management Practices defined in the NJ Stormwater BMP Manual (Chapters 9-11).
Chapter 9 - Small-Scale Green Infrastructure¶
Small-scale GI practices are typically applied at the lot or parcel level.
| BMP | Description |
|---|---|
| Bioretention | Vegetated depression with engineered media |
| Cistern | Rainwater harvesting tank with pre-storm void |
| Dry Well | Subsurface infiltration structure for rooftop drainage |
| Grass Swale | Vegetated conveyance channel with partial infiltration |
| Green Roof | Vegetated roof system for ET-based volume reduction |
| Infiltration Basin | Open basin designed for infiltration into native soils |
| Pervious Pavement | Porous paving surface with stone reservoir base |
| Rain Garden | Small-scale bioretention for residential use |
| Small-Scale Sand Filter | Below-grade sand chamber for urban lot water quality |
| Subsurface Gravel Wetland | Gravel-filled subsurface treatment system with liner |
| Tree Trench | Subsurface infiltration beneath structural cells and tree canopy |
| Vegetated Filter Strip | Dense vegetated area receiving level-spread sheet flow |
Chapter 10 - Large-Scale Green Infrastructure¶
Large-scale GI practices are typically applied at the site or regional scale.
| BMP | Description |
|---|---|
| Constructed Stormwater Wetland | Shallow marsh system for water quality and peak attenuation |
| Extended Detention Basin | GI-qualifying dry basin with slow release and partial VRC |
| Infiltration Trench | Subsurface linear stone trench for deep infiltration |
| Sand Filter | Surface or underground filter using sand media |
| Wet Pond | Permanent water body designed for stormwater treatment |
Chapter 11 - Non-GI Stormwater Systems¶
Non-GI practices include conventional and manufactured treatment approaches.
| BMP | Description |
|---|---|
| Blue Roof | Rooftop detention via controlled-flow drain insert |
| Dry Detention Basin | Quantity-only basin; separate WQ BMP required |
| Extended Detention Basin | Non-GI detention over liner or low-permeability soils |
| Hydrodynamic Separator | NJDEP-certified swirl separator for pretreatment |
| MF/UF Membrane System | Membrane filtration for high-standard water quality |
| Manufactured Treatment Device | Proprietary NJDEP-certified treatment unit |
| Oil/Grit Separator | Gravity separator for petroleum and grit removal |
| Underground Detention | Modular subsurface chambers for peak flow attenuation |
BMP Page Template¶
All BMP pages follow the structure defined in Agents/03_component_templates.md.
Source Alignment (Auto-Synced Draft)¶
Auto-synced from Outs/Phase2B_SmallScaleGI_Content.md -> "1.2 BMP Types in Chapter 9" on 2026-03-05. Manual review required before release.
The 2026 Chapter 9 includes the following GI BMP types, each addressed in a dedicated sub-section:
| BMP Type | Primary Volume Reduction Mechanism | GI Status (2026) |
|---|---|---|
| Cisterns (9.1) | Beneficial reuse (rainwater harvesting) | GI — with demonstrated reuse demand |
| Dry Wells (9.2) | Infiltration into native soil | GI |
| Grass Swales (9.3) | Infiltration + conveyance | GI — when meeting Chapter 12 criteria |
| Green Roofs (9.4) | Evapotranspiration + detention | GI — ET credit method (Ch. 14) |
| Pervious Paving Systems (9.6) | Infiltration through pavement surface | GI — when meeting Chapter 12 criteria |
| Small-Scale Bioretention (9.7) | Infiltration + ET | GI — without impermeable liner |
| Small-Scale Infiltration Basins (9.8) | Infiltration | GI |
| Vegetative Filter Strips (9.10) | Sheet flow filtration + infiltration | GI — limited WQV credit |
| Small-Scale Sand Filters (9.9) | Filtration (no native infiltration) | Non-GI in 2026 if lined |
| Manufactured Treatment Devices (9.5) | Hydrodynamic separation / media filtration | Non-GI (moved to Ch. 11 in 2026) |
Auto-synced from Outs/Phase2C_LargeScaleGI_Content.md -> "1.2 BMP Types in Chapter 10 (2026)" on 2026-03-05. Manual review required before release.
| BMP Type | Chapter | Primary Mechanism | GI Status (2026) |
|---|---|---|---|
| Large-Scale Bioretention | 10.1 | Infiltration + ET | GI — without impermeable liner |
| Infiltration Basins | 10.2 | Infiltration | GI |
| Sand Filters (GI) | 10.3 | Filtration + partial infiltration | GI — specific configuration |
| Standard Constructed Wetlands | 10.4 | Extended detention + biological treatment | Context-dependent — see §1.3 |
| Wet Ponds | 10.5 | Extended detention + settling | Non-GI in most configurations |
Auto-synced from Outs/Phase2D_NonGI_MTD_Content.md -> "1.1 Role of Non-GI Practices in Stormwater Management" on 2026-03-05. Manual review required before release.
Non-GI stormwater BMPs serve a defined and necessary role in the New Jersey regulatory framework even though they cannot satisfy the volumetric reduction component of the GI Requirement. Their functions include:
Water Quality Treatment (the TSS Standard): N.J.A.C. 7:8 requires that major development achieve ≥80% TSS removal by mass from the water quality storm (WQV event). Non-GI systems are capable of meeting this standard and may be used to satisfy TSS removal obligations where GI is infeasible.
Stormwater Quantity Control (the Peak Rate Standard): N.J.A.C. 7:8 requires that post-development peak discharge rates not exceed pre-development rates for specified storm frequencies (2-year and 100-year storms in most cases). Dry detention basins, extended detention basins, and blue roofs provide the storage volume required for peak attenuation independent of infiltration.
Partial GI Compliance: On sites where only a portion of the WQV can be addressed through GI BMPs (due to site constraints), Non-GI practices address the remaining water quality and quantity obligations for the portion of runoff that cannot be infiltrated, evapotranspirated, or harvested.