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A short class with Sarah and her students. The other ways are under More.
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Today, we're going to discuss resuspension. Can anyone tell me what resuspension means?
Is it when sediment that was settled on the bottom of a body of water gets stirred up again?
Exactly! Resuspension occurs when sediments that have settled in water are disturbed and enter the water column again. This can happen due to turbulent actions in the water.
What causes the turbulence?
Great question! Turbulence often increases with the velocity of water flow, which can happen during heavy rainfall or flooding events.
So, does that mean during a flood, more contaminants can get into the water?
Correct! When sediments are resuspended, contaminants attached to them can also enter the water, potentially affecting water quality.
Remember, T.P.S. - Turbulence, Particles, and Surface Water. This helps us link the components of resuspension!
To summarize, resuspension is influenced by turbulence which is often caused by increased water flow, particularly during flooding.
Now let's dive into how resuspension impacts contaminant transport. Why do you think this is important?
I guess if more sediment gets into the water, more pollutants could too.
Exactly! When sediments resuspend, they carry with them any contaminants that were previously trapped. Can anyone think of an example of where this might be significant?
Maybe in a river after a heavy storm?
Right! Events like storms increase turbulence, leading to higher amounts of suspended solids and contaminants in the water. It's important for monitoring water quality.
Let's use the mnemonic C.W.Q. - Concentration, Water Quality, and Quantity of sediment to remember the importance of monitoring in these scenarios.
In conclusion, the transport of contaminants during resuspension can significantly affect water quality and requires careful management.
Next, let's talk about how particle size affects resuspension. What do you think happens to smaller particles during resuspension?
Do they stay in the water longer because they're lighter?
Exactly! Smaller particles, like colloids, can remain suspended much longer than larger particles due to their size and weight.
So, does that mean the smaller particles hold more contaminants?
Yes, they often have a higher surface area that can adsorb organic compounds, which complicates the resuspension process. Very good observation!
As a mnemonic, think S.A.F.E. - Small particles, Adsorbents, Float Easily. This can remind you how these smaller sizes interact with contaminants.
To summarize, smaller particles can hold more contaminants and stay suspended longer than larger sediment.
The process by which settled sediments are reintroduced into a body of water.
A key factor in sediment resuspension, caused by increased water velocity.
Small particles that remain suspended and can carry contaminants.
An important water quality metric for assessing sediment levels in water.
When the storm does brew, sediments will stew, into water they rise, adding pollutants with surprise.
Imagine a peaceful lake, suddenly disturbed by heavy rainfall. The calm surface turns tumultuous, and sediments rise like ghosts, carrying unseen dangers back into the water—dangerous pollutants swirling into the fish’s habitat.
T.P.S. – Turbulence, Particles, Surface Water helps remember the key aspects of resuspension.
C.W.Q. – Concentration, Water Quality, and Quantity helps us highlight the importance of monitoring.
Term
Resuspension
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Term
Total Suspended Solids (TSS)
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Term
Contaminants
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The process by which sediments previously settled in a body of water are stirred back into the water column.
Irregular, chaotic water flow that increases sediment disturbance and resuspension.
Submicron particles that remain suspended in a liquid, significantly affecting water quality.
A measure of the total amount of suspended particles in water, often used to assess water quality.
Harmful substances that can affect the health of ecosystems and humans typically through water.
This section discusses factors that lead to the resuspension of contaminants from sediments into water, emphasizing the significance of turbulence and other mechanisms.
The section elaborates on the process of resuspension, detailing how sediment can be stirred into the water column due to turbulence, especially in conditions of increased flow. The implications for contaminant transport and the relationship between sediment dynamics and water quality are also covered.
In section 5.2, we explore the various factors influencing the resuspension of sediments, with a focus on the dynamics of water flow and turbulence. Resuspension occurs when low flow conditions are disrupted by events such as rainfall or flooding, leading to increased sediment transport. The interactions between water velocity and sediment characteristics play a crucial role in determining the extent of resuspension. This process is particularly significant as it can enhance the concentration of contaminants in aquatic systems, impacting water quality and the surrounding ecosystem. The complexities of this mechanism, alongside the potential for particles, especially smaller colloidal sizes, to remain suspended, create challenges in predicting environmental impacts and managing sediment contamination effectively.