Professional Courses
Industry-relevant training in Business, Technology, and Design to help professionals and graduates upskill for real-world careers.
Categories
Interactive Games
Fun, engaging games to boost memory, math fluency, typing speed, and English skills—perfect for learners of all ages.
Typing
Memory
Math
English Adventures
Knowledge
Enroll to start learning
You’ve not yet enrolled in this course. Please enroll for free to listen to audio lessons, classroom podcasts and take practice test.
Interactive Audio Lesson
Listen to a student-teacher conversation explaining the topic in a relatable way.
Understanding Resuspension
Unlock Audio Lesson
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.
Mechanisms of Contaminant Transport
Unlock Audio Lesson
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.
Particle Size and Resuspension Dynamics
Unlock Audio Lesson
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.
Introduction & Overview
Read a summary of the section's main ideas. Choose from Basic, Medium, or Detailed.
Quick Overview
Standard
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.
Detailed
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.
Audio Book
Dive deep into the subject with an immersive audiobook experience.
Introduction to Resuspension
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
Resuspension is when this surface sediment gets taken away, it gets because of the turbulent action of the water, there is enough energy for it to dislodge this mud from the water and it now becomes a cloud here. The suspended solids, the total suspended solids in water increases and it goes downstream and downstream it can deposit again.
Detailed Explanation
Resuspension occurs when sediment particles that are normally settled at the bottom of a body of water are stirred up and become suspended within the water column. This happens due to the turbulence created by flowing water, such as during rain, floods, or even wave action. When the energy from the flowing water exceeds the forces holding the sediment in place, these particles are dislodged and mixed into the water, leading to an increase in total suspended solids (TSS). As a result, the water can appear cloudy and may carry contaminants downstream.
Examples & Analogies
Think of a jar of muddy water. When you leave it undisturbed, the dirt settles at the bottom, and the water looks clear. But if you shake the jar, the sediment disturbs, creating a cloud of mud in the water. Similarly, when rivers flow rapidly—especially during heavy rains—they stir up the sediment on the riverbed, making the water look murky.
Conditions Triggering Resuspension
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
Resuspension will occur when you increase turbulence. When does turbulence increase? When the velocity of water is increasing. Flow increases during the time of very heavy rainfall, flooding, lot of sediment gets carried, this is what we call as silting.
Detailed Explanation
Resuspension is strongly influenced by turbulence in the water. Turbulence increases when the flow velocity of the water rises, which often occurs during heavy rains or flooding. During these events, large amounts of sediment can be disturbed due to the high energy of the flowing water, leading to silting where fine sediments are carried away from their original locations.
Examples & Analogies
Think of a busy river during a storm, with rainwater pouring in. The increased water flow acts like a vigorous blender, stirring up everything in its path, including sediments on the riverbed. As the blender mixes the mud with water, it creates a frothy mixture, just like how a river carries suspended sediments when it floods.
Impact on Water Quality
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
Now, all of this gets into water, okay. So you get TSS total suspended concentration is 𝑤𝑎 in the water. This is not in sediment anymore, it is water. Suppose you get 2000 milligrams per liter of suspended solids concentrations.
Detailed Explanation
When sediments are resuspended into the water, they transform the water quality by increasing the total suspended solids (TSS) concentration. For instance, if the concentration of these suspended solids is 2000 milligrams per liter, this signifies that a significant amount of sediment is in the water column, which can affect aquatic life and water clarity. The high concentration could potentially lead to harmful effects, such as blocking sunlight and disturbing the habitats of aquatic organisms.
Examples & Analogies
Imagine a swimming pool filled with clear water. If a bunch of dirt and sand is tossed into the pool, the water becomes cloudy and uninviting, making it hard to see through. Similarly, when sediments are resuspended into a river, the water quality deteriorates, and aquatic life may struggle to thrive in such murky conditions.
Colloids and Contaminant Retention
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
When the sediment gets re-suspended, you also have to realize that the adsorption of organic chemical on the solid is in the organic carbon. The size of the organic carbon is colloidal, the submicron. Submicron particles do not settle down fast, so the contamination remains in the water for a long period of time.
Detailed Explanation
Resuspended particulate matter often contains colloidal particles, which are very small (less than one micron). These submicron particles are less likely to settle quickly because of their size and the water's dynamic forces. This means that contaminants attached to these colloidal particles can persist in the water for longer periods, enhancing the risk of exposure to aquatic life and humans.
Examples & Analogies
Think of tiny specks of dust in the air. If you blow on them gently, they can float around for a long time without settling. Similarly, when sediment is disturbed and its particles become colloidal, they can remain suspended in water for extended periods, carrying any attached contaminants with them.
Influence of Particle Size Distribution
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
What I mean is this, let us say there is a distribution of particles this dp versus percentage, this is particle size distribution in the sediment. The entire thing goes up into water. So, this is the particle size distribution in the suspended water.
Detailed Explanation
When sediment particles are resuspended into the water, their size distribution changes. Most of the contaminants are associated with smaller particles, such as fine organic sediments and colloids that are more prone to remain in suspension. This non-uniform distribution means that different sizes of particles play different roles in contaminant transport in water, with smaller particles often retaining more contaminants than larger ones.
Examples & Analogies
Imagine mixing flour and sugar in a bowl. If they get stirred up, larger granules may settle quickly, while fine sugar can linger in the air for a longer time, making it harder to catch. Similarly, in water, smaller resuspended particles remain longer, carrying contaminants while larger particles settle out faster.
Contaminant Spread and Ecological Impact
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
This is a mechanism of spreading contamination where the contamination was now secluded in say 100 meters square of sediment. Now, it has gone and spread over several kilometers.
Detailed Explanation
Resuspension can lead to the widespread distribution of contaminants initially localized in sediment. This dispersion can extend contamination from a small area to a much larger one, potentially affecting vast ecosystems and increasing the ecological and chemical risks associated with those contaminants as they are brought into contact with more water and aquatic life.
Examples & Analogies
Think of a small puddle of spilled paint on a sidewalk. If it's left undisturbed, it stays contained. But if someone steps in it and splashes it around, that small puddle can spread across a wide area, making it much harder to address. The same principle applies to contaminants: when sediments are disturbed, they can move from a small area to a large body of water, impacting everything in between.
Definitions & Key Concepts
Learn essential terms and foundational ideas that form the basis of the topic.
Key Concepts
-
Resuspension: The process by which settled sediments are reintroduced into a body of water.
-
Turbulence: A key factor in sediment resuspension, caused by increased water velocity.
-
Colloidal particles: Small particles that remain suspended and can carry contaminants.
-
Total Suspended Solids (TSS): An important water quality metric for assessing sediment levels in water.
Examples & Real-Life Applications
See how the concepts apply in real-world scenarios to understand their practical implications.
Examples
-
During a heavy storm, river currents increase, causing sediment to resuspend and pollutants to mix with floodwaters.
-
In a lake after dredging, fine sediments can remain suspended, affecting water clarity and quality.
Memory Aids
Use mnemonics, acronyms, or visual cues to help remember key information more easily.
🎵 Rhymes Time
-
When the storm does brew, sediments will stew, into water they rise, adding pollutants with surprise.
📖 Fascinating Stories
-
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.
🧠 Other Memory Gems
-
T.P.S. – Turbulence, Particles, Surface Water helps remember the key aspects of resuspension.
🎯 Super Acronyms
C.W.Q. – Concentration, Water Quality, and Quantity helps us highlight the importance of monitoring.
Flash Cards
Review key concepts with flashcards.
Glossary of Terms
Review the Definitions for terms.
-
Term: Resuspension
Definition:
The process by which sediments previously settled in a body of water are stirred back into the water column.
-
Term: Turbulence
Definition:
Irregular, chaotic water flow that increases sediment disturbance and resuspension.
-
Term: Colloidal particles
Definition:
Submicron particles that remain suspended in a liquid, significantly affecting water quality.
-
Term: Total Suspended Solids (TSS)
Definition:
A measure of the total amount of suspended particles in water, often used to assess water quality.
-
Term: Contaminants
Definition:
Harmful substances that can affect the health of ecosystems and humans typically through water.