Monitoring water balance of a rain garden by installation of flow monitoring devices on a residential property

Abstract

Rain gardens are infiltration best management practices that are installed in existing and new construction for the purposes of water quality in receiving waters and stormwater volume reduction. Nationally, rain gardens are transitioning from landscaping features with beneficial environmental effects to facultative engineered systems for meeting water quality standards or providing peak flow attenuation in combined sewersheds. The objectives of this study were to site, design, install, and monitor the hydraulic characteristics of a typical rain garden installation on a private residential property. Infiltration tests by infiltrometer and full-inundation methods were conducted yielding results that indicate infiltration rates in current rain garden design guidance may be too conservative. Guidance for the design and installation of rain gardens are provided that may improve their large-scale implementation as part of a watershed management plan.