How do adaptation measures affect water quality?

In order to adapt ourselves and our environment to the changing climate, we are taking various measures. Many of these adaptation measures have a positive effect on water quality, but some may have a negative effect. The paragraphs below outline the potential positive and negative effects each adaptation measure may have on water quality. The overview can help to enhance positive effects and minimise any negative effects.

More information on the potential effects of adaptation measures on water quality is contained in the interactive Urban Water Quality, Climate and Adaptation knowledge document (pdf, 13 MB). In the section on “climate adaptation measures”, you will find several clusters of adaptation measures. Clicking on a cluster will produce more details. The document also allows you to click through to various specific measures to read more on their potential impact on water quality. Such impact is dependent on various control variables: will these increase or decrease, and is their increase or decrease positive or negative?

Replacing roof covering with greenery

Replacing roof covering with greenery

Effects of adaptation measures on water quality
Adaptation measure

Positive effects

 Potential negative effects
  • Purifies rainwater
  • Reduces sewage water volume
  • Reduces air temperature
  • Adds nutrients (especially intensive green rooftops)

Removing and replacing paved surfaces

Removing and replacing paved surfaces

Effects of adaptation measures on water quality
Adaptation measure Positive effects Potential negative effects
  • Rainwater purification upon infiltration
  • Fewer sewer overflows
  • Decrease in air temperature
  • Greenery can be a source of nutrients

Replacing paved surfaces with permeable pavement

Effects of adaptation measures on water quality
Adaptation measure Positive effects Potential negative effects
  • Fewer sewer overflows
  • Decrease in air temperature

Replacing paved surfaces with infiltration facilities

Effects of adaptation measures on water quality
Adaptation measure Positive effects Potential negative effects

Fewer sewer overflows

Decrease in air temperature

Pathogens may be present (particularly in bioswales)

“Technical” water retention or disconnecting downspouts and subsequent infiltration

"Technical" water retention or disconnecting downspouts and subsequent use or infiltration

Effects of adaptation measures on water quality
Adaptation measure Positive effects Potential negative effects
  • Rainwater purification upon infiltration
  • Fewer sewer overflows
  • Decrease in air temperature
  • Reduced runoff from paved surfaces
  • Reduced permeability of paved surfaces (deep groundwater infiltration)

“Technical” water retention or disconnecting downspouts and subsequent discharge

“Technical” water retention or disconnecting downspouts, followed by discharge onto paved surfaces

Effects of adaptation measures on water quality
Adaptation measure Positive effects Potential negative effects
  • Fewer sewer overflows (water square)
  • Limited decrease in air temperature
  • Pollution runoff from roads
  • More sewer overflows (slanted road)
  • Reduced permeability of paved surfaces (water square)

“Technical” water retention or disconnecting downspouts, followed by discharge onto rooftop

Effects of adaptation measures on water quality
Adaptation measure Positive effects Potential negative effects
  • Fewer sewer overflows
  • Decrease in air temperature
  • Pollution runoff from rooftops

“Technical” water retention or disconnecting downspouts, followed by underground discharge

Effects of adaptation measures on water quality
Adaptation measure Positive effects Potential negative effects
  • Fewer sewer overflows
  • Less pollution runoff into surface water

Creating more surface water

Creating surface water

Effects of adaptation measures on water quality
Adaptation measure Positive effects Potential negative effects

Adding surface water:

Greening urban water:

Fewer sewer overflows

Increased purification by helophytes

Decrease in air temperature

Greater depth (storage pond)

Inflow of bird droppings and dog poo runoff

Increase in oxygen consumption (helophyte filter)

Increase in soil nutrient content

Measures primarily focused on heat reduction

Measures primarily focused on heat reduction: cooling through greenery

Effects of adaptation measures on water quality
Adaptation measure Positive effects Potential negative effects
  • Decrease in water temperature (limited effect)
  • Increased leaf fall
  • Reduced incidence of sunlight
  • Fewer sewer overflows (urban forest)
  • Continuous fertilisation
  • More dog poo runoff

Measures primarily focused on heat reduction: cooling through water

Effects of adaptation measures on water quality
Adaptation measure Positive effects Potential negative effects
  • Decrease in water temperature (limited effect)
  • Oxygen (from fountains)
  • Pathogens (from spray)

Measures primarily focused on heat reduction: cooling through cool, high albedo materials

Effects of adaptation measures on water quality
Adaptation measure Positive effects Potential negative effects
  • Decrease in water temperature (limited effect)
  • More paved surfaces

Measures primarily focused on heat reduction: cooling through shade

Effects of adaptation measures on water quality
Adaptation measure Positive effects Potential negative effects
  • Decrease in water temperature (limited effect)
  • With shade provided by greenery: continuous fertilisation, in some cases more dog poo runoff