How does imperviousness develop and affect runoff generation in an urbanizing watershed?

Gerald Krebs, Ulla-Maija Rimpiläinen, Outi Salminen

Research output: Contribution to journalArticlepeer-review


Imperviousness associated with urbanization remains one of the biggest challenges in sustainable urban design. The replacement of forests, marshlands, buffers, and wetlands with impervious surfaces, strongly influences hydrological processes in urbanizing areas. This study analyzes the contribution of four constructed surfaces types – roofs, yards, roads, and an international airport – to surface runoff within a 21 km2 watershed, and presents the development over five decades (1977−2030). The land-cover model, used to assess watershed imperviousness in 2030, utilizes coefficients between impervious areas generating surface runoff and the floor area, developed during the study. The conducted imperviousness analysis allows the evaluation of land-use development impacts on the stream network, and the identification of hydrologically active areas for urban planning and stormwater management. Research reveals the importance of yard imperviousness related to suburban residential housing for stormwater runoff generation, and the impacts of transport-related imperviousness on stormwater runoff.
Original languageEnglish
Number of pages17
JournalFennia -International Journal of Geography
Issue number2
Publication statusPublished - 2013
Externally publishedYes


  • urban planning
  • land-use
  • imperviousness
  • stormwater runoff
  • imperviousness-components

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