Blue/green infrastructure solutions are popular in storm water management and lot of different technologies are installed nowadays. In Sweden as in many other countries, bioretention facilities and raingardens are increasing in popularity. Since bioretention technology is relatively new longtime function and accumulation of particles in the filter material is not clarified. A major field study in Ohio aims to evaluate some of the environmental impacts with bioretention facilities and evaluate the risks associated with accumulated pollutants in the filter material. The purpose of the study is to increase the knowledge about risks and requirements with maintenance and waste management.
The field study was carried out at 29 different bioretention sites in the USA in November 2019. The visited sites were mainly located in Ohio around Columbus and Cleveland. A few sites were sampled in Toledo, Lansing and Ann Arbor, Michigan as well as Cincinnati, Kentucky. In field, infiltration tests were made, maintenance needs were documented and a comparison of the actual design in relation to the guidelines was performed. Soil and sediment samples were taken from the forebay and from three different points at three different levels in each filter. In total, 804 samples from 29 sites with a total weight of 1100 kg were collected in two weeks. Half of the samples were brought back to Sweden for analyzes of appearance and concentrations of metals, phosphorus, and 38 different organics.
The samples have been analyzed in spring and summer 2020 and the results are planned to be presented during 2020 and 2021.