Examples of BMP selection options for various construction site risk conditions
| Functional activity | BMPs for lower risks | BMPs for moderate risks | BMPs for higher risks |
|---|---|---|---|
| Planning | One-step clearing, grading, and stabilization | Two-phase clearing and grading, and stabilization | Multiple phases for clearing, grading, road and utility installation, building construction, etc. |
| No mark-offs for critical areas needed | Infiltrative soils (i.e., for septic drainfields, rain gardens) marked off limits to traffic | Infiltrative soils, tree preservation area(s), stream buffers marked off | |
| One stabilized site exit, comprised of rock pad | Length and width of rock pad extended to deal with exit traffic and mud conditions | Shaker rack or wheel washer used to ensure minimization of trackout | |
| No crossings needed, or use of existing stabilized bridge or channel crossing | Installation of temporary culvert or other stabilized stream crossing | Installation of permanent stream crossing, e.g., moving up installation of planned bridge, etc. | |
| Drainage management | No upland flows to divert from active construction area | Diversion ditch or berm installed upslope to keep run-on off the site | Upslope run-on diversions installed; installation of stabilized channel to carry upland flows through site |
| Sheet flow only; no concentrated flows | Small, flat ditches double-seeded and lined with straw erosion control blanket | Larger, steeper ditches triple-seeded and lined with turf reinforcement mat | |
| No sediment trap or pond needed; sediment barrier suffices | One or more sediment traps needed to remove soil from site runoff flows | Multiple sediment traps and sediment ponds needed; use of flocculants to help remove very small particles | |
| Soil stabilization | No need for interim soil stabilization with one-step clearing / grading approach | All site areas are seeded after grading except for building pad and immediate area used for materials | Phased stabilization as project progresses; soil binders / blown straw used on bare areas idle > 14 days |
| Grass seed and blown straw mulch or hydroseeding used to stabilize site | Erosion control blanket installed over grass seed, with heavier seeding rate on slopes | Same as previous, with native mix and turf reinforcement mat or sod installed on steepest slopes | |
| Sediment traps | Fiber rolls / logs or Type C silt fence used for downslope perimeter control | Type B or Type C silt fence used for downslope perimeter control | Heavy duty silt fence used at multiple intervals on long slopes |
| Rock bags or other simple dike used for storm drain inlets | Filter fabric insert used for storm drain inlet protection | Catch basin insert used for maximum removal of sediment and other pollutants | |
| Dust control not necessary due to short duration of project | Dust control addressed via water truck as needed | Polymers or other soil binders applied on construction roads as needed for dust control |