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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

^ U.S. Department of the Interior, U.S. Geological Survey, (6 March 2010). Aquatic Life Declines at Early Stages of Urban Development. [online] Available at: http://www.usgs.gov/newsroom/article.asp?ID=2475 [Accessed 1 January 2013].

Last updated: 22 March 2013

This page should be cited as:

Department of Environment, Science and Innovation, Queensland (2013) Hard surfaces, WetlandInfo website, accessed 20 December 2024. Available at: https://wetlandinfo.des.qld.gov.au/wetlands/management/pressures/lacustrine-palustrine-threats/hydrology/impervious-surfaces.html