Determination of Appropriate Locations for Proposed Rain Gardens in the City of Isparta Turkey

This study aims to contribute sustainable urban drainage considering ecological, rather than conventional, approaches for urban sustainable stormwater management. The study consists of analysis of appropriate zones for rain gardens (Ayazmana, Bahçelievler, Çünür, Dere, Vatan neighborhoods) through remote sensing, determination of the best locations for rain gardens, and modeling rain gardens as street swales in cross-sectional configuration in densely built urban areas in Isparta, Turkey. With the help of the ArcGIS 10.1 program, thematic maps (including slope, precipitation, and slope-precipitation overlap) were prepared and regions with low slopes were determined. The sample street swales were presented as cross-sectional configuration for various public places (e.g. streets and avenues, parking areas, urban stream beds, refuges, and traffic islands) where surface flow is intense, close to the main road, and within the certain regions (slopes < 10 %; precipitation > 450 mm). For slope-precipitation overlapping analysis; it has been observed that the runoff is less in regions where slopes are more than 10% and the precipitations are less than 450 mm; that the surface runoff is higher in regions where the slopes are less than 10% and the precipitations are more than 450 mm. In the neighborhoods of Ayazmana, Bahçelievler, Çünür, Dere, Modernevler and Vatan, public places (located close to the main road where surface runoff is intense) were selected and assessed among the regions determined (within the range of values appropriate for rain gardens: slopes < 10 %; precipitation > 450 mm). As a green infrastructure system, one of the supporting systems in stormwater management is street swales designed as rain gardens in cities. Findings of this paper will be useful to local governments and policy makers as well as city planners and landscape architects when developing appropriate, efficient, cost-effective, and site-specific green street strategies for cities.