Construction projects can create big stormwater runoff problems. The water floods across bare land, picking up soils, chemicals, trash and other pollutants. This contamination then harms downstream waterways when it leaves the site.
So how can builders prevent stormwater pollution?
The answer is BMPs. BMP stands for Best Management Practices.
BMPs are special techniques, actions and controls that keep construction site pollutants from washing away in runoff during rains. They are the best methods to manage and treat stormwater.
This guide explains the most effective BMPs for:
- Controlling site erosion
- Managing water flows
- Stopping spills and leaks
- Capturing loose sediment
Understanding BMP options and how to combine them is key for builders to lessen their environmental impact. Let’s explore the proven solutions.
The 2 BMP Categories
1. Erosion Control
These BMPs focus on keeping soil planted in place so rains can’t loosen and move sediments:
- Mulch blanketing exposed ground
- Permanent and temporary seeding
- Laying erosion-resisting mats and blankets
- Preserving or planting native vegetation buffers
2. Sediment Control
These BMPs capture loose soil that storms start washing along:
- Silt fences filtering out eroded sediments
- Drain inlet protections trapping sediment
- Special ponds and traps to contain sediment so it settles out
Many options exist in each category. Builders determine the ideal mix of combined controls that minimize erosion and capture unavoidable soil disturbances based on region and project size.
Let’s look closer at some of the most vital BMPs for handling soils and sediments on active construction sites. Their benefits underscore why best management practices are indeed best practices.
The Top 12 Construction BMPs
1. Save Existing Plants
Keeping living trees, grasses, and soils intact prevents erosion. Fence off areas around waterways and drainage routes to protect vegetation.
2. Quickly Seed and Mulch
Immediately put seed and mulch on any land stripped bare. This temporary cover blocks erosion. Use extra erosion blankets on steep hills.
3. Install Silt Fences
Place silt fences along slopes to filter sediment out of runoff. Trench in fences firmly so water doesn’t sneak under and make them fall over.
4. Protect Storm Drains
Block drains with gravel bags, rolls, or fabric to keep sediment from entering. Clean any drains that get clogged.
5. Stabilize Site Exits
Minimize off-site mud tracking. Use stone exit pads to shake and wash vehicle tires.
6. Divert Flows Away from Bare Soils
Use berms and swales to redirect runoff away from disturbed ground towards protected slopes or holding ponds.
7. Install Check Dams
Place temporary dams in drainage ditches and channels. This slows water flow so sediment settles out instead of washing away.
8. Build Sediment Traps/Basins
Create pits and ponds at drainage low points. This contains eroded soil on-site for particle settlement. Size basins suitable for expected water volumes.
9. Reinforce Channels
Line channel walls with turf mats or rocks to prevent stormwater flows from eroding banks.
10. Protect Slopes
Cover bare inclined areas with erosion control blankets or hydroseeding mix. Divert any uphill runoff safely around slopes if possible.
11. Stage Land Clearing
Only clear sections actively under current construction. This leaves other areas vegeated to naturally control erosion. Don’t strip everything at once.
12. Cover Soil Piles
Temporarily seed piles or wrap with silt fencing. Place piles away from drainages and roads to limit sediment pickup.
Pro Tip: For best results, pair erosion protections like seeding together with sediment controls like drain covers. Defenses working together handle more risks.
Making BMPs Work
Getting started right facilitates positive cascades:
- Install key perimeter controls (silt fences, drain covers) before extensive earth-moving operations commence. This first line of defense localizes initial water flow threats.
Regular Review
- Inspect all BMPs weekly and after storm events. Catch any developing issues early before major failures. Identify additional areas needing enhanced protections.
Proactive Upkeep
- Remove trapped sediments routinely before capacity thresholds are exceeded. This maintains intended function.
- Repair or replace damaged barriers, traps and controls ASAP to preserve integrity. Eliminate any gaps.
Adaptive Enhancements
- Expand BMPs based on updated risk assessments from consistent inspection learnings. For example, adding a swale to divert flows away from a expanding disturbed zone.
Conscientious Documentation
- Log all BMP administration activities thoroughly – installation notes, inspection checklists, fix details, expansion locations. Photographically document pre/post conditions.
Staying proactive with BMPs through methodical mitigation practices keeps contractors successful and sites sustainable – come inspection time or storm season. It takes diligent follow-through, but outcomes manifest steadily when teams work towards common runoff prevention goals. Let’s build wisely together.
Reference:
TxDOT: Stormwater Pollution Prevention Plan (SWP3) guidance document
TxDOT: Storm Water Field Inspector’s Guide
EPA: Developing Your Stormwater Pollution Prevention Plan
