Quantitative assessment of rain gardens: A case study in Istanbul University Faculty of forestry

Abstract

Deterioration of natural water cycle caused by urbanization brings necessities to use proper water management tools in cities. Rain gardens are one of the most essential tools in cities which can be defined as a new concept in Turkey. Those systems can be interpreted as green areas which can mitigate urban runoff. In this study rain gardens were evaluated through experimental methods. Three identical Rain Garden Modules (RGM) were constructed which represents a typical rain garden system were located on the site. Three plant species (Anemone nemorosa, Viola odorata, Iris germenica) that were determined as ecologically suitable for environmental conditions of the study area and rain garden system were evaluated in terms of plant growth and survival during study. In addition, soil moisture levels, infiltration and water retention abilities of the rain gardens were evaluated along with the environmental conditions. It was concluded that Viola odorata and Iris germenica are good candidates for rain gardens in Istanbul climate. However Anemone nemorosa was negatively influenced by dry periods. Findings of this study confirms that rain gardens are sustainable systems in Istanbul environment. Therefore by using proper application techniques integration of those systems into city infrastructure will bring positive effects to urban water management.