Question

which of the following is designed to prevent both excess nutrients and sediments from entering the waterways?

waste water treatment plants
silt fences
retention ponds
sewage treatment facilities

Explanation:

Analyze the question requirements

The question asks to identify which management practice is designed to prevent both excess nutrients and sediments from entering waterways.

Evaluate the options

• Waste water treatment plants and Sewage treatment facilities: These primarily treat point-source municipal wastewater to remove pathogens, organic matter, and nutrients, but they are not designed as runoff management practices to capture land-surface sediment and nutrient runoff before entering waterways.
• Silt fences: These are temporary barriers used on construction sites. They are highly effective at trapping sediment, but they do not significantly filter out dissolved excess nutrients.
• Retention ponds: These are designed to capture stormwater runoff. By holding the water, they allow suspended sediments to settle to the bottom. Additionally, biological processes (such as uptake by aquatic plants and algae in the pond) help remove dissolved nutrients before the water is slowly released into local waterways. Thus, they manage both pollutants.

Connect to known concepts

Using the Water Pollution and Pollution Management knowledge points, we can determine that retention ponds serve as a dual-purpose structural control for nonpoint source pollution by addressing both physical sedimentation and biological nutrient uptake.

Answer:

• Waste water treatment plants
• Silt fences
• Retention ponds (Correct answer)
• Sewage treatment facilities