Stormwater Management Practices Flashcards

What is the goal of stormwater management?

Answer: Reduce pollution and manage flow

The goal of stormwater management is to effectively control the quantity and quality of runoff generated from rainfall. This involves reducing the volume and velocity of stormwater to prevent flooding and erosion, while also treating it to remove pollutants before it enters natural water bodies. Comprehensive management protects infrastructure, human safety, and environmental health.

What is a retention basin used for?

Answer: Store stormwater temporarily

A retention basin is a permanent pond designed to hold stormwater runoff for an extended period, allowing it to slowly infiltrate into the ground or be released at a controlled rate. This temporary storage helps to reduce peak flows during storm events, preventing downstream flooding and erosion, and also allows for some pollutant removal through settling and natural processes.

How does a bioswale function?

Answer: Filters and infiltrates runoff

A bioswale is a vegetated, shallow channel designed to convey stormwater runoff while simultaneously filtering pollutants and promoting infiltration into the ground. The plants and engineered soil media within the bioswale work together to remove sediments, nutrients, and other contaminants from the runoff. This green infrastructure approach helps manage stormwater volume and improve water quality.

Why are permeable pavements beneficial?

Answer: Enable infiltration

Permeable pavements are designed with porous surfaces that allow stormwater to filter through them and infiltrate into the underlying soil, rather than running off the surface. This process helps to reduce stormwater runoff volume, replenish groundwater, and filter out pollutants. By enabling infiltration, permeable pavements mitigate flooding and improve water quality.

What role do vegetated rooftops play?

Answer: Delay runoff and cool buildings

Vegetated rooftops, also known as green roofs, are designed to absorb rainfall, which delays the flow of stormwater runoff into drainage systems. The plants and soil also provide insulation and through evapotranspiration, they help cool the building and its surrounding environment. This reduces the urban heat island effect and lowers energy consumption for air conditioning.

What is the function of storm drains?

Answer: Direct water to treatment or discharge areas

Storm drains are a critical part of urban infrastructure, specifically engineered to collect excess rainwater and surface runoff from impervious surfaces like roads and parking lots. Their primary function is to efficiently convey this water away from developed areas. This directed flow typically leads to a receiving water body, such as a river or lake, or occasionally to a treatment facility, preventing localized flooding.

Why monitor stormwater discharges?

Answer: To assess pollutant levels

Monitoring stormwater discharges is essential for environmental protection because stormwater runoff often picks up pollutants from various surfaces. By assessing pollutant levels, inspectors can identify potential sources of contamination, evaluate the effectiveness of Best Management Practices (BMPs), and ensure compliance with environmental regulations. This data helps protect receiving water bodies from degradation.

What is a dry well?

Answer: Infiltration device for stormwater

A dry well is an underground structure designed as an infiltration device for stormwater. It collects and temporarily stores runoff from impervious surfaces like roofs or driveways. The stored water then slowly infiltrates into the surrounding soil, reducing surface runoff volume and recharging groundwater, rather than flowing into storm drains.

How does stormwater affect receiving waters?

Answer: Degrades water quality

Stormwater runoff often carries pollutants such as sediment, nutrients, chemicals, and bacteria from urban and construction sites. When this polluted runoff enters receiving waters like rivers, lakes, or oceans, it can significantly degrade water quality. This degradation harms aquatic ecosystems, can make water unsafe for human use, and contributes to issues like algal blooms and oxygen depletion.