Hydrologic performance of bioretention systems is significantly influenced by the media composition and underdrain configuration. This research measured hydrologic performance of column-scale bioretention systems duri...Hydrologic performance of bioretention systems is significantly influenced by the media composition and underdrain configuration. This research measured hydrologic performance of column-scale bioretention systems during a synthetic design storm of 25.9 mm, assuming a system area：catchment area ratio of 5%. The laboratory experiments involved two different engineered media and two different drainage configurations. Results show that the two engineered mediawith different sand aggregates were able to retain about 36% of the inflow volume with tree drainage conlaguratlon. However, the medium with marine sand is better at delaying the occurrence of drainage than the one with pumice sand, denoting the better detention ability of the former. For both engineered media, an underdrain configuration with internal water storage （IWS） zone lowered drainage volume and peak drainage rate as well as delayed the occurrence of drainage and peak drainage rate, as compared to a free drainage configuration. The USEPA SWMM v5.1.11 model was applied for the tree drainage configuration case, and there is a reasonable fit between observed and modeled drainag.e-rates when media-specific characteristics are available. For the IWS drainage configuration case, air entrapment was observed to occur in the engineered medium with manne sand. F^lhng ot an IWS zone is most likely to be influenced by many factors, such as the structure of the bioretention system, medium physical and hydraulic properties, and inflow characteristics. More research is needed on the analysis and modeling of hydrologic process in bioretention with IWS drainage configuration.展开更多
文摘Hydrologic performance of bioretention systems is significantly influenced by the media composition and underdrain configuration. This research measured hydrologic performance of column-scale bioretention systems during a synthetic design storm of 25.9 mm, assuming a system area：catchment area ratio of 5%. The laboratory experiments involved two different engineered media and two different drainage configurations. Results show that the two engineered mediawith different sand aggregates were able to retain about 36% of the inflow volume with tree drainage conlaguratlon. However, the medium with marine sand is better at delaying the occurrence of drainage than the one with pumice sand, denoting the better detention ability of the former. For both engineered media, an underdrain configuration with internal water storage （IWS） zone lowered drainage volume and peak drainage rate as well as delayed the occurrence of drainage and peak drainage rate, as compared to a free drainage configuration. The USEPA SWMM v5.1.11 model was applied for the tree drainage configuration case, and there is a reasonable fit between observed and modeled drainag.e-rates when media-specific characteristics are available. For the IWS drainage configuration case, air entrapment was observed to occur in the engineered medium with manne sand. F^lhng ot an IWS zone is most likely to be influenced by many factors, such as the structure of the bioretention system, medium physical and hydraulic properties, and inflow characteristics. More research is needed on the analysis and modeling of hydrologic process in bioretention with IWS drainage configuration.
