Rain Garden

Abstract:  The most widely used approach for evaluating the performance of stormwater best management practices (BMPs) such as rain gardens is monitoring, but this approach can involve a long time period to observe a sufficient number and variety of storm events, a high level of effort, and unavoidable uncertainty. In this paper, we describe the development and evaluation of three approaches for performance assessment of rain gardens: visual inspection, infiltration rate testing, and synthetic drawdown testing. Twelve rain gardens in Minnesota underwent visual inspection, with four determined to be nonfunctional based on one or more of the following criteria: (1) presence of ponded water, (2) presence of hydric soils, (3) presence of emergent (wetland) vegetation, and (4) failing vegetation. It is believed that these rain gardens failed due to a lack of maintenance. For the remaining eight rain gardens, an infiltrometer was used to determine the saturated hydraulic conductivity (Ksat) of the soil surface at several locations throughout each basin in what is termed infiltration rate testing. The median Ksat values for the rain gardens ranged from 3 to 72 cm/h. Synthetic drawdown testing was performed on three rain gardens by filling the basins with water to capacity where possible and recording water level over time. The observed drain times for two of those rain gardens were in good agreement with predictions based on the median of the infiltrometer measurements. The observed drain time for the third rain garden was much greater than predicted due to the presence of a restrictive soil layer beneath the topsoil. The assessment approaches developed in this research should prove useful for determining whether the construction of the rain garden was performed properly, a rain garden is functioning properly, and for developing maintenance tasks and schedules.

A major problem of increased urbanization is the rise in pollution caused by runoff. A solution to this problem can be found through the use of Sustainable Urban Drainage Systems (SUDS) such as rain gardens. Previous research has focused primarily on hydrologic design including the degree to which groundwater is replenished by these systems and models have been developed to quantify the extent of that recharge. However these models do not simulate the transport or fate of pollutants. In this paper, a preliminary heavy metal retention computer model is proposed that consists of two parts: a water flow module and pollutant retention module. To describe flow behaviour a dualpermeability approach is implemented which facilitates the prediction of both matrix and macropore flow. This subroutine is then combined with the retention module, which utilizes and couples the linear, Langmuir and Freundlich isotherms with the advection-diffusion equation. Both submodels are validated using exist...

Homeowners spend hundreds of dollars watering their yard, but there is an easy way to save money and resources—rain gardening. But what is it? As simple as collecting rain to reuse in front and backyards.

Creating Rain Gardens is a comprehensive book for the DIY-er, covering everything from rain barrels to simple living roofs, permeable patios, and other low-tech affordable ways to save water in the garden.

Water conservation experts Cleo Woelfle-Erskine and Apryl Uncapher walk homeowners through the process, with step-by-step instructions for designing and building swales, French drains, rain gardens, and ephemeral ponds—the building blocks of rain-catching gardens. From soil preparation, planting, troubleshooting, and maintenance, to selecting palettes of water-loving plants that provide four-season interest and a habitat for wildlife, Creating Rain Gardens covers everything a gardener needs to create a beautiful rain garden at home.