Title: Alternative/Innovative Technologies for Erosion, Sediment, and Turbidity Control
1Alternative/Innovative Technologies for Erosion,
Sediment, and Turbidity Control
- Rich McLaughlin
- Soil Science Department
- rich_mclaughlin_at_ncsu.edu
- North Carolina State University
2New and Improved Devices/Systems
- Erosion Control
- Surface Outlets
- Baffles
- Turbidity Reduction
- Other Innovations
3Ground Covers
- Vegetation establishment is the goal
- Ground cover protects soil before grass emergence
- Types
- Straw mulch
- Hydraulically applied mulch
- Erosion Control Blankets
4Straw Mulch
5Straw Mulch High Failure Rate
Patching w/ Blanket
6Hydraulically Applied Mulch
- Wood fiber
- 1500 lbs/acre
- with or without PAM
- Bonded Fiber Matrix (crimped wood fiber PAM)
- 2500-3500 lbs/acre
- 21 slopes?
7Usually Need Up and Down Application
8Erosion Control Blankets
- Straw
- Jute
- Excelsior (wood shavings)
- Coir (coconut)
- Nettings
- Biodegradable
- Photodegradable
- Permanent
9Erosion Control Ground Cover Demonstrations
Hydroseed
Compost
Straw
10Field and Laboratory Testing
11Ground Covers with/without PAM (20 lb/acre)
12One Failure Begets Another
13Surface Outlet (Skimmer)
14Skimmer Diagram
15Flashboard Riser Outlet
- Adjustable standing pool
- Can empty for sediment removal
16Example of a Flashboard Riser Installation
Isolated View
Cross-sectional View
Flashboard Riser
Gravel Fill for Riser Access
Water Level
Solid Earthen Dam
Removable Stop Logs
17Baffles
Porous
Silt Fence/Weir
18Porous Baffle
Fence Design
Support Posts, 12 into Bottom or Side
Support Rope or Wire to Prevent Sagging
Stake to Support Wire
Sawhorse Design
Porous fabric attached with zip ties and stapled
to bottom in front.
2 x 4 Wood
Rebar into basin bottom.
Flow
19PAM for Turbidity Control
20PAM (polyacrylamide) Facts
- Long-chain polymer with a net-negative charge
(anionic). - Very low acute toxicity.
- Used for water treatment (drinking/wastewater,
industrial) and food processing. - Comes in powder, solid block, solution, or
emulsion formulations. - Binds suspended solids together in flocs which
can settle out of the water.
21(No Transcript)
22Ditch Checks and Floc Log in Pipe
23More PAM Spots
24In-Stream Treatment
25PAM Sediment Bag
26Injected PAM Corrugated Pipe
1226
27Pump Into Pipe w/ Solid PAM
28DOT Experimental Basin Design
29Maximum Sediment Control
30Two Stage Treatment
Sediment
Turbidity
31Keys to Making PAM Logs/Powder Work for You
- Match PAM to your soil or suspended sediment and
water chemistry. - Reduce sediment load prior to PAM treatment.
- Keep the PAM moist.
- Create high flow onto PAM.
- Create high mixing (turbulence) after PAM.
- Allow for settling post-treatment.
32Questions?
33Alternatives to Rock Check Dams
34Ditch Checks and Lining to Reduce Erosion
35Baffle Testing