Rainwater management
Rainwater management
Rainwater management is about reducing runoff and water pollution by treating urban areas as a living system—trying to keep water in balance with natural processes. It includes collecting rain for reuse, preventing floods, and keeping waterways clean.
Why it matters
- Rainwater is a valuable water source that can supplement drinking water and everyday uses.
- Collecting rainwater saves energy, lowers greenhouse gas emissions, and helps prevent floods and water shortages.
- Good rainwater management supports sanitation and the environment and can reduce damage from heavy rainfall.
Key ideas (Components)
- Rainwater harvesting and use
- Urban flood management
- Gray-green infrastructure
- Constructed wetlands
- Separate sewer systems
- Land use
- Low-impact development (LID)
- Rainwater management in agriculture
- Tools and planning methods
- Terminologies (explained simply)
Rainwater harvesting and use
- Harvesting means collecting rain from roofs or other surfaces and storing it for later use.
- Common uses: watering gardens, livestock, irrigation, washing, and sometimes drinking after proper treatment.
- Benefits: saves water and energy, reduces costs, and helps with local water supply.
Urban flood management
- Focuses on reducing the impact of heavy rains on cities.
- Urban flooding can disrupt transport and supply chains.
- Gray-green approach mixes traditional drainage (gray) with nature-based solutions (green) to drain water and absorb or filter it.
Gray-green infrastructure
- Gray parts: conventional drainage networks and large pipes.
- Green parts: ponds, parks, and plants that store or soak up water.
- The goal is to prevent floods and reduce pollution, often as part of the “sponge city” concept.
Constructed wetlands
- Artificial wetlands treat wastewater and rainwater.
- They act as natural cleaners and can store water during heavy rain.
- Treated water can be reused after passing through aeration and soil filters.
Separate sewer systems
- Replacing old combined sewers that carry both rain and wastewater with separate systems.
- Benefits: better flood drainage and reduced pollution of water bodies because rainwater is not mixed with sewage.
Land use
- The amount of pervious (water- soaking) vs. impervious (water-runoff) surfaces matters for floods.
- Increasing green spaces and vegetation increases pervious areas.
- New developments should reduce impervious surfaces like asphalt and concrete where possible.
Low-impact development (LID)
- LID uses natural processes to handle rain, improving infiltration and evapotranspiration.
- Common practices: porous pavement, bioretention areas, green roofs, and rainwater harvesting.
- LID helps protect water quality, supports habitats, and keeps water moving more naturally through a watershed.
Rainwater management in agriculture
- Farmers can collect surface runoff in ponds and use ridges to capture water on slopes.
- This boosts irrigation in dry periods and can improve crop yields when combined with soil fertility management.
Tools and planning
- Modern design treats rainwater as an integrated part of a project from early stages.
- Software tools (like Rainwater+) help designers plan systems, improve communication, and reduce construction conflicts.
- Integrated approaches bring together engineering, ecology, and finance to create practical, scalable solutions.
Terminologies (in plain terms)
- Low-impact development (LID): small-scale, nature-based methods to manage rain and protect water quality.
- Water sensitive urban design (WSUD): a way to design cities that respects water needs and uses water wisely.
- Integrated urban water management (IUWM): coordinating all parts of the water cycle in a city.
- Sustainable urban drainage systems (SUDS): a set of techniques that mimic natural drainage to manage rainwater.
Bottom line
Rainwater management turns rain from a potential problem into a resource. By harvesting rain, redesigning urban spaces, and using a mix of gray and green solutions, cities can reduce floods, save water, and protect the environment. This approach works at all scales—from individual buildings to whole neighborhoods—and even supports farming in dry areas.
This page was last edited on 27 January 2026, at 21:17 (CET).