Stormwater Management Practices

Study Notes

Heavy rainfall saturates the ground, causing excess water to run across surfaces and into storm sewers and road ditches.
This runoff carries pollutants including debris, chemicals, bacteria, eroded soil, and other pollutants.

Impervious surfaces like pavement and roofs prevent precipitation from absorbing into the ground.
This rapid runoff into storm drains, sewers, and ditches overwhelms natural water systems.
Stormwater infrastructure helps slow down surface runoff, allowing infiltration into the ground.
It captures and reuses stormwater, maintaining or restoring natural water cycles.
The primary goals of stormwater management are to detain stormwater and remove pollutants.

Two distinct eras in stormwater management:
- Pave and Drain Era: focused on rapidly removing stormwater through engineered systems
- Stream Channel and Flood Protection Era: shifted focus to flood control and protecting stream channels

This era prioritized rapid removal of stormwater, often neglecting environmental considerations.
It involved extensive pavement and drainage infrastructure, often at the expense of natural water systems.

This era emphasizes stream channel engineering for flood control, navigation, and drainage improvement.
It may involve straightening, widening, deepening, or relocating existing stream channels.
Negative impacts of stream channeling:
- Increased downstream delivery of pollutants and sediments
- Changes in stream velocities, disrupting natural flow patterns
- Elimination of floodplains and levees that naturally help regulate water flow
- Altering stream base levels, impacting overall stream function
- Increased erosion and sediment load

Pervious Surfaces:
- Porous materials, like pavements and green spaces, that allow rainfall and snowmelt to soak into the soil.
- Functions: recharge groundwater, filter pollutants, reduce contamination, reduce heat island effect, reduce flooding and erosion.
Grey Infrastructure:
- Human-engineered systems like culverts, gutters, storm sewers/drains, and conventional piped drainage.
- Slows stormwater flow to prevent flooding and reduce pollutant entry into waterways.
Green Infrastructure:
- Uses natural elements like soil and plants for stormwater management.
- Examples: vegetated rooftops, roadside plantings, absorbent gardens
- Mimics natural hydrology, capturing, filtering, and reducing stormwater runoff.

Decreased Precipitation: Explore its impact on urban systems
Increased Precipitation: Investigate its impact on urban systems
Higher Temperatures: Analyze its effect on urban systems
Sea Level Rise: Examine its impact on urban systems
For each hazard, identify environmental effects, vulnerable urban systems, and potential consequences.