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Hard surfaces

Increases in hard surfaces such as pavement, roads and housing development have an impact on the process of run-off, infiltration and erosion. When trees and natural vegetation cover is replaced with hard surfaces the water runs off more quickly and soaks in less.

Hard surfaces may cause:

  • an increase in flooding due to less water being retained in the soils, wetlands etc.
  • a decrease in water quality due to a reduction in sediment trapping
  • an increase in erosion due to increased run-off and concentration of flow into one area, i.e. when it comes out of a drain or gutter.

Flow speed increases over hard surfaces  Photo by Cathy Ellis

Quick facts

When 10%
of a catchment is covered in impervious surfaces, many types of pollution sensitive aquatic insects decline by as much as one third, compared to streams in undeveloped forested watersheds. Studies have shown that there is no ‘safe zone’, meaning that even minimal development can negatively affect aquatic life in urban streams.[1]

 

Examples of innovations to address issues associated with hard surfaces include:

    • porous pavement replacing hard surfaces used for roads, footpaths and carparks
    • flood retention areas
    • grass verges and swales instead of hard gutters
    • sediment traps
    • artificial wetlands
    • rooftop and hanging gardens
    • industrial water cleansing.

References

  1. ^ Aquatic Life Declines at Early Stages of Urban Development 6/3/2010, U.S. Department of the Interior, U.S. Geological Survey, viewed 2013, <http://www.usgs.gov/newsroom/article.asp?ID=2475>.

Last updated: 22 March 2013

This page should be cited as:

Hard surfaces, WetlandInfo, Department of Environment and Heritage Protection, Queensland, viewed 13 April 2017, <https://wetlandinfo.ehp.qld.gov.au/wetlands/management/pressures/lacustrine-palustrine-threats/hydrology/impervious-surfaces.html>.

Queensland Government
WetlandInfo   —   Department of Environment and Heritage Protection