Sediment Fencing: A Comprehensive Guide to Erosion Control

Introduction

Sediment fencing is a vital erosion control technique that prevents soil from washing away during construction and other land-disturbing activities. It is a temporary barrier made of fabric or other materials that traps sediment carried by runoff.

According to the Environmental Protection Agency (EPA), sediment fencing reduces sediment runoff by up to 90%.

Types of Sediment Fences

There are various types of sediment fences available, each with its unique characteristics:

1. Silt Fence:
- Made of woven or non-woven geotextile fabric
- Designed to retain fine particles and prevent soil erosion

2. Straw Bale Filter:
- Constructed from stacked bales of straw
- Effective in trapping sediment and filtering runoff

3. Brush Filter:
- Consists of bundled branches or brush
- Used to stabilize slopes and reduce sediment discharge

4. Compost Filter Berm:
- Made from composted organic material
- Highly absorbent and effective in removing pollutants

5. Log Filter:
- Formed by placing logs perpendicular to the flow of water
- Creates a natural barrier to trap sediment

Choosing the Right Sediment Fence

The choice of sediment fence depends on several factors:

• Soil type: Different soils have varying erosion potential.
• Slope: Steeper slopes require more robust fencing.
• Rainfall intensity: Areas with heavy rainfall necessitate stronger fences.
• Cost: Budgeting constraints may influence the type of fence selected.

Benefits of Sediment Fencing

Sediment fencing offers numerous environmental and economic benefits:

• Reduces sediment runoff: Protects water quality by preventing soil erosion.
• Controls flooding: Traps sediment, reducing the risk of flooding.
• Protects infrastructure: Prevents sediment from clogging drainage systems and damaging roads.
• Improves land stability: Stabilizes slopes and prevents erosion.
• Cost-effective: Reduces the costs associated with sediment-related repairs and maintenance.

Installation of Sediment Fences

Proper installation is crucial for the effectiveness of sediment fences. Steps involved:

1. Site Preparation:
- Clear the installation area of debris and vegetation.
- Grade the ground to create a level surface.

2. Installing Fence:
- Set fence posts at 5-12 feet intervals.
- Stretch and secure the fabric or filter material to the posts.
- Bury the bottom of the fence in a trench to prevent underflow.

3. Stakes and Anchoring:
- Drive stakes into the ground beside the posts.
- Tie the fabric to the stakes to stabilize the fence.

4. Toe-in:
- Extend the bottom of the fence into a trench to prevent water from flowing under it.

5. Turnover:
- Fold the top portion of the fence over and secure it in place to prevent erosion.

Maintenance of Sediment Fences

Regular maintenance is essential to ensure the effectiveness of sediment fences:

• Inspection: Inspect fences regularly for tears, gaps, or sagging.
• Repair: Repair or replace damaged sections immediately.
• Cleaning: Clean fences as needed to remove accumulated sediment.
• Removal: Remove sediment fences once the site is stabilized and no longer at risk of erosion.

Table 1: Performance of Different Sediment Fences

Table 2: Installation Costs of Sediment Fences

Table 3: Maintenance Frequency of Sediment Fences

Tips and Tricks

• Use higher quality fabric or filter material for increased durability.
• Install fences perpendicular to the direction of water flow.
• Consider using sediment basins or traps to supplement fencing.
• Inspect fences more frequently during periods of heavy rainfall.
• Educate contractors and workers on the importance of maintaining sediment fences.

Step-by-Step Approach

1. Planning:
- Determine the type of fence needed and the installation location.
- Obtain necessary permits and consult with local authorities.

2. Site Preparation:
- Clear the installation area and grade the ground.
- Mark the fence line and set fence posts.

3. Installing Fence:
- Stretch and secure the fabric or filter material to the posts.
- Bury the bottom of the fence in a trench.

4. Stakes and Anchoring:
- Drive stakes beside the posts and tie the fence to them.

5. Toe-in:
- Extend the bottom of the fence into a trench to prevent underflow.

6. Turnover:
- Fold the top portion of the fence over and secure it.

7. Maintenance:
- Inspect, repair, and clean fences regularly.

FAQs

1. How often should sediment fences be inspected?
- Sediment fences should be inspected monthly or more frequently during heavy rainfall.

2. What is the lifespan of a sediment fence?
- Sediment fences typically last for 6-12 months, depending on the material and environmental conditions.

3. Can sediment fences be reused?
- Silt fences can be reused if they are properly maintained and not damaged.

4. What are the environmental impacts of sediment fencing?
- Sediment fencing has minimal environmental impacts, as it does not release harmful chemicals or alter the natural landscape.

5. Is sediment fencing required by law?
- Many government agencies require the use of sediment fencing on construction sites and other erosion-prone areas.

6. Who is responsible for maintaining sediment fences?
- The contractor or landowner is responsible for maintaining sediment fences on their property.