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Erosion, Sediment, and Turbidity Control

Turbidity & Chemical Treatment

Resources on reducing turbidity through flocculants, polymer treatment, dewatering, and other approaches for managing fine suspended sediment in construction runoff.

List of Approved PAM/Flocculants

See NC DWR’s current list of approved PAMs and flocculants.

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Extension Publications

Using Polyacrylamide (PAM) to Reduce Erosion on Construction Sites

Two men adding granular PAM to a hydroseeder tank.

This factsheet covers the use of polyacrylamides as a means of erosion control on construction sites. PAM characteristics and considerations are discussed as well as basic directions for use.

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Chemical Turbidity Control in Pumped Construction Site Water

A small stilling basin with both rock and coir baffles plus gravel outlet protection. Water passes over blocks of flocculant, which helps sediment settle. A rock splash pad is at the pipe outlet to prevent scour and resuspension.

This publication describes methods to reduce turbidity and suspended solids in water being pumped into stilling basins or sediment bags, usually on construction sites where dewatering is needed.

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Chemical Treatment to Control Turbidity on Construction Sites

A check dam system using a length of corrugated pipe to protect a PAM log from heavy sediment (check dams); the pipe also provides a mixing zone and prevents the log from being exposed to drying conditions.

Construction sites of more than one acre are required to install systems to retain sediment produced onsite. This factsheet describes several chemical treatment options, including polyacrylamides (PAM), gypsum and alum, for reducing turbidity in impounded water.

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Technical Guides & Tools

Research Publications

  • Polyacrylamide and chitosan biopolymer for flocculation and turbidity reduction in soil suspensions
    Kang, J., & McLaughlin, R. A. Journal of Polymers and the Environment, 2020.
    Compared polyacrylamide and chitosan for flocculating suspended soil particles and reducing turbidity.
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  • Acute toxicity of polyacrylamide flocculants to early life stages of freshwater mussels
    Buczek, S. B., Cope, W. G., McLaughlin, R. A., & Kwak, T. J. Environmental Toxicology and Chemistry, 2017.
    Evaluated the acute toxicity of different polyacrylamide flocculants to sensitive early life stages of freshwater mussels.
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  • Simple systems for treating pumped, turbid water with flocculants and a geotextile dewatering bag
    Kang, J., & McLaughlin, R. A. Journal of Environmental Management, 2016.
    Evaluated practical flocculant-assisted systems for treating pumped turbid water using geotextile dewatering bags.
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  • Transport of dissolved polyacrylamide through a clay loam soil
    Kang, J., McLaughlin, R. A., Amoozegar, A., Heitman, J. L., & Duckworth, O. W. Geoderma, 2015.
    Investigated the movement and retention of dissolved polyacrylamide through clay loam soil.
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  • Erosion, sediment, and turbidity control and monitoring research to meet water quality goals
    McLaughlin, R. A., & Cope, W. G. North Carolina Department of Transportation, 2014.
    Synthesized NCDOT-supported research addressing erosion, sediment, turbidity control, monitoring, and water quality protection during highway construction..
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  • Turbidimetric determination of anionic polyacrylamide in low carbon soil extracts
    Kang, J., Sowers, T. D., Duckworth, O. W., Amoozegar, A., Heitman, J. L., & McLaughlin, R. A. Journal of Environmental Quality, 2013.
    Developed a turbidimetric method for measuring anionic polyacrylamide in low-carbon soil extracts.
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  • Soil factors influencing suspended sediment flocculation by polyacrylamide
    McLaughlin, R. A., & Bartholomew, N. Soil Science Society of America Journal, 2007.
    Examined how soil properties influence the effectiveness of polyacrylamide for flocculating suspended sediment.
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