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Infiltration-based stormwater best management practices (BMPs) are progressively being utilized to mitigate issues such as increased runoff and poor water quality associated with urbanization. However, they are often difficult to accurately model due to the extensive design variables involved, particularly in high water table regions where groundwater mounding can cause primary infiltration to shift from vertical to horizontal. This study assessed an infiltration-based stormwater management system for a commercial property in Southwest Florida using integrated ArcMap 10.8.2 -ICPR4 software. A unique modeling technique captured the shift from vertical to horizontal infiltration in high water table conditions, employing ICPR4's "percolation ring" and "percolation link". The integration of GIS with the ICPR model enabled detailed modeling, assessment, and visualization of runoff in high water table areas. Three site-specific design storms were employed to analyze the pre- and post-developed conditions of the study area and assess whether existing BMPs met Environmental Resource Permit (ERP) requirements. While the system complies with ERP standards, it was found to be oversized based on storage basin stages and stormwater discharges from the simulated 100-year/24-h storm event. This is because 45–68% of the total volume entering the stormwater management basins infiltrated during the analysis period. The infiltration rate in the models was initially heavily dependent on vertical infiltration. However, horizontal groundwater flow substantially increased with the increasing water stage in the detention ponds after vadose zone saturation. These findings highlight the significance of modeling techniques in accurately capturing the performance of infiltration-based stormwater management systems in high water table conditions. [ABSTRACT FROM AUTHOR]

A closer look at the built environment shows that opportunities lie in transforming buildings with nature-based solutions for fostering climate resilience. To understand the potential of buildings in contributing to transforming cities, we conducted a systematic literature review to synthesize the evidence of the provided benefits of nature-based solutions implemented on their roofs and facades. Our goal is to highlight findings about the co-benefits of nature-based solutions on buildings in real-life case studies. After systematic screening and selection, the 222 reviewed research papers support that there is confidence in the climate resilience performance and benefits green walls, green roofs, and living walls provide, contributing to heat resilience and indirectly to social-ecological justice, especially when they are installed in old buildings. Our findings show that other recorded benefits include the provision of vegetation, habitat and biodiversity enhancement, and strong evidence of water retention and purification. We also report on design characteristics of nature-based solutions which are recommended when they are implemented on buildings. Green roofs were especially well-documented and it underlines the need of more studies about diverse NBS. From the synthesis of the state of the art, we propose that further research about the design of nature-based solutions on buildings is required to extend their co-benefits to noise reduction, air pollution entrapment and filtering, and carbon sequestration. In our paper, we found that the most important knowledge gap for future research is holistic perspectives on designing NBS on buildings.

Long-term retention performance is a common performance indicator for low-impact development practices, such as rain barrels, rain gardens, and green roofs. This paper introduces a numerical approach for the estimation of annual retention ratios of stormwater by bioretention. The annual retention ratio is taken as the ratio of the annual accumulated volume of stormwater retained by bioretention over the total volume of runoff draining into the system. The hydrologic model Storm Water Management Model (SWMM) is used to simulate the relevant flows of a bioretention system with parametric variations of the watershed area ratio and hydraulic conductivity of the soil media. Under these two dominant performance-governing parameters, retention ratios are calculated using the 10-year (2004-2013) rainfall record in Hong Kong at 1-min intervals. This indicator can be readily applied to estimate the long-term retention performance of a bioretention using particular values of watershed area ratio and hydraulic conductivity of soil media under the climate of Hong Kong. The study also analyzes the influence of variation of annual precipitation on the estimated retention performance. Flow data monitored on a pilot-scale physical model of bioretention during a number of rainfall events are used to validate the numerical simulation. [ABSTRACT FROM AUTHOR]