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Restore affected estuaries: Reduce sediment pollution

Adaptation Strategies and Actions

Restore affected estuaries: Reduce sediment pollution

Adaptation type: 
Coastal management and restoration


Inform communities about the harmful effects of sediment pollution by providing research and resources for communities to share and use.

Coastal systems face widespread environmental changes due to climate change (sea-level rise, increased water temperatures, etc.) and direct anthropogenic (human caused) activities. Pollution, especially sediment pollution, can threaten an estuary’s productivity?, function, and stability.


What is Sediment Pollution?
According to the Environmental Protection Agency (EPA), sediment is the most common water pollutant. Sediment pollution refers to an abundance of sediment that wind and water transport and detrimentally deposit into new areas. Sediment pollution occurs from digging during land development, stormwater runoff from farmland and residential communities, and from hard coastal protection structures (such as seawalls) that redirect sand movement.1

Effects of Sediment Pollution:
Sediment pollution has widespread effects such as impairing infrastructure, disrupting ecological events, and creating environments that are harmful to our health and economy.

  • Sediment Pollution Affects the Efficiency and Integrity of Infrastructure
    Sediment pollution can occur quickly or gradually. During storm events, sediment is easily carried by whipping winds and flowing water. Consequently, storm drains are clogged by sediment, resulting in  backflows and flooded streets. Additionally, hard shoreline structures can redirect sediment transport into water channels. This gradual sediment accumulation reduces shipping efficiency and towns are forced to consistently dredge commercial and recreational channels.
  • Sediment Pollution Impacts the Next Generation of Benthic Organisms
    Humans are not the only ones impacted by sediment pollution - fish and other aquatic organisms are impacted too. Suspended sediment clouds the water (increased turbidity)  and can make predator and prey detection difficult, which can affect normal food web interactions. Sediment can also bury and smother fish eggs, thus cutting off their oxygen supply and reducing their chance of survival.
  • Sediment Pollution Creates Hypoxic (Low Oxygen) Conditions
    Water quality is degraded by sediment pollution because the increased turbidity reduces light for benthic aquatic plants and algae. A reduction in photosynthesis can lead to hypoxic (low oxygen) conditions which can cause expansive plant and animal die-off events.
  • Sediment Pollution Carries and Sequesters (Stores) Toxic Metals and Substances (Mercury, Lead, and PCBs)
    Toxic substances are commonly transported, deposited and sequestered by sediments. Some toxic substances like mercury, lead, and polychlorinated biphenyls (PCBs) come from current and historical industrial waste that infiltrate into water through runoff events and dumping. Long term financial woes and health issues for communities arise when sediment buries and sequesters (stores) these substances. For instance, from the 1940’s until the banning of PCB production in the 1970’s, the 18,000 acre harbor of New Bedford, Massachusetts was a dumping site for industrial waste that contained high amounts of PCBs. New Bedford Harbor was listed as a superfund site (an area contaminated by PCBs) in 1982 and remediation efforts were in effect in 1998; however, the harbor still needs extensive dredging, contaminated sediment removal, and management to this day.2 Furthermore, almost all consumption of locally caught fish and shellfish from this area is prohibited because of PCB contamination.3

Industrial and Residential Actions to Reduce Sediment Pollution:
Green spaces, pervious (permeable) hard surfaces, and subsurface infiltrative wastewater systems not only mitigate nutrient pollution, they also help reduce sediment pollution.4,5,6 For specific actions related to effectively treating stormwater with green spaces, permeable hard surfaces, and subsurface infiltration systems (SIS), refer to Restore affected estuaries: Reduce nutrient pollution.

The following are additional resources that can also reduce sediment pollution.

Settling tank/clarifier design. Created by Monroe Environmental. Permission given by Monroe Environmental
Settling tank/clarifier design. Created by Monroe Environmental. Permission given by Monroe Environmental
  • Sedimentation Basins (“Settling Tanks” or “Clarifiers”)
    These are large tanks where water flows very slowly so suspended sediment is able to sink.  Sedimentation basins are massive in size and common at water treatment facilities.7
  • Establish A Total Maximum Daily Load (TMDL)
    In other states, such as Maryland, estuaries have been put on an “environmental diet” where total maximum daily load limits of nutrients and sediment have been established. In the Chesapeake Bay, the amount of sediment and nutrients that are being influxed into the estuary are being measured and monitored so water quality standards are met. The Chesapeake Bay TMDL for nutrients calls for a 20% reduction in sediment loading.8
  • Mulch and Garden Boxes/Raised Beds
    Mulch and raised beds protect garden soil from erosion.
  • Straw Erosion Control for Tilling
    Using straw as a border for tilled area can prevent and reduce erosion.

Sediment pollution is primarily driven by anthropogenic (human-caused) activities and weakens the estuaries that protect coastal communities. More frequent and extreme storms are projected under future climate change, which is expected to increase erosion and sediment pollution. While there are technologies than can mitigate sediment pollution, it has been proven that green spaces are one of the most effective management practices to combat sediment pollution as well as nutrient pollution. If communities do not implement sediment pollution management and mitigation efforts as changes in climate develop, their infrastructure, environment, and economy may become more vulnerable to additional stressors.


1. Environmental Protection Agency (EPA). Contaminated Sediment Remediation Guidance for Hazardous Waste Sites. US EPA Office of Solid Waste and Emergency Response, EPA-540-R-05-012, December 2005.

2. Environmental Protection Agency (EPA). New Bedford Harbor: Harbor Cleanup.(EPA, Updated April 7, 2016. Accessed September 12, 2016).

3. Environmental Protection Agency (EPA). Fish Consumption Regulations and Recommendations: Massachusetts Regulation/ U.S. EPA Recommendations for Eating Fish, Shellfish and Lobster Caught in Three Fish Closure Areas Around the New Bedford Harbor. (EPA, Updated September 2015, Accessed September 12, 2016).

4. Tornes L (2005) Effects of rain gardens on the quality of water in the Minneapolis-St. Paul metropolitan area of Minnesota, 2002-04. Report #2005-5189, US Geological Survey, Mounds View, MN.

5. Pan J, Fei H, Song S, Yuan F, Yu L. (2015) Effects of intermittent aeration on pollutants removal in subsurface wastewater infiltration system. Bioresour Technol. 2015 Sep;191:327-31. doi: 10.1016/j.biortech.2015.05.023. Epub 2015 May 16.

6. Alyaseri, I. and Zhou, J. (2015) Comparative Evaluation of Different Types of Permeable Pavement for Stormwater Reduction—St. Louis Green Alley Pilot Study. International Low Impact Development Conference 2015: pp. 274-284. doi: 10.1061/9780784479025.028

7. Encyclopædia Britannica Online (2016). S. v. "sedimentation tank”.  Accessed September 12, 2016.

8. National Research Council (NRS) (2011) Achieving Nutrient and Sediment Reduction Goals in the Chesapeake Bay: An Evaluation of Program Strategies and Implementation. (Accessed September 2016).

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