Many studies in the literature have assessed the blue–green infrastructure (BGI) characteristics that influence its cooling potential for sustainable urban development. Common assessment methods include satellite remote sensing, numerical simulations, and field measurements, each defining different cooling efficiency indicators. This methodological diversity creates uncertainties in optimizing BGI management. To address this, a literature review was conducted using Google Scholar, Web of Science, and Scopus, examining how the BGI cools urban space, which spatial data and methods are most effective, which methodological differences may affect the results, and what the current research gaps and innovative future directions are. The results suggest that remote sensing is ideal for large-scale BGI comparisons, numerical simulations for local development scenarios, and field measurements for assessing conditions closest to residents. Maximum BGI cooling intensity averages show 4 °C from remote sensing, 3 °C from field measurements, and 2 °C from numerical simulations. Differences in conclusions may arise from differences in the data resolution, model scale, BGI delineation method, and cooling range calculation. The key BGI characteristics include object size, vegetation fraction, foliage density, and spatial connectivity. Future research should prioritize the integration of the different methods, BGI shape complexity effectiveness assessment, and effects of urban morphology on evaluating BGI characteristics’ effectiveness, and explore digital twin technology for BGI management optimization. This study integrates key information on BGI’s cooling capabilities, serving as a useful resource for both practitioners and researchers to support resilient city development.

Within the scope of the conducted experiment the authors analysed the efficiency of runoff reduction by the system of extensive type green roofs. The observations were based on storm events in the area of Lower Silesia at the Agro and Hydrometeorology Station Wrocław-Swojec. The authors analysed the thickness of plant substrate, and also estimated the quality of runoff waters under the conditions of periodic atmospheric deposition. Also considered were such indicators as electrolytic conductivity, N, NO₃⁻, NO₂⁻, NH₄⁺, P, PO₄³⁻. The experiment included roof substrates designed in two variants, with known hydraulic and physical properties of the soil material. The analysis was performed for models with vegetation layer based on pumice and zelolite, covered with five plant species from the sedum family. The modelling of the hydraulic properties was conducted with variably saturated medium, using the Hydrus 1D software. The performance of systems with primary layer thickness of 11 cm and 9, 8, 7, 6 and 5 cm was estimated. The designed models reduced the average peak flows to 89%, and in addition they caused a delay in the initiation of the runoff which was dependent on the intensity and distribution of rainfalls in time, and on the initial moisture of the profiles. Simulations, performed for variable substrate thickness, permit the conclusion that in the case of thin-layer profiles (5 cm), the relative retention index was decidedly lower and amounted to 35.9% for the substrate with zeolite (originally 60.6%) and 41% for the substrate with pumice (originally 65.7%). In the case of total nitrogen and phosphates, statistical analysis revealed significant differences (p < 0.05) in relation to specific concentrations in the rainwater and in the control surface. The total nitrogen in the runoff from the green roof was nearly twice as high as that in the rainwater and amounted to, on average, 8.3 mg L⁻¹.

Green roofs have received much attention in recent years due to their ability to retain rainwater, increase urban diversity, and mitigate climate change in cities. This interdisciplinary study was carried out on three historical green roofs covering bunkers in Wrocław, located in southwestern Poland. It presents the results of a three-year investigation of the water storage of these roofs. The study also presents soil conditions and spontaneous vegetation after their functioning for over 100 years. The soils covering the bunkers are made of sandy, sandy-loam, and loamy-sand deposits. This historical construction ensures good drainage and runoff of rainwater, and is able to absorb torrential rainfall ranging from 100 to 150 mm. It provides suitable conditions for vegetation growth, and forest communities with layers formed there. In their synanthropic flora, species of European deciduous forests dominate, which are characteristic of fresh or moist and eutrophic soils with a neutral reaction. Some invasive species, such as Robinia pseudoacacia, Padus serotina, and Impatiens parviflora, also occur with high abundance. Nowadays, historical green roofs on fortifications, although they have lost their primary military role, are of historical and natural value. These roofs can promote the nonmilitary functions of historical fortifications in order to strengthen the ties between nature and heritage. Protecting and monitoring historical green roofs should be included in the elements of the process of sustainable development and the conservation of these structures in order to mitigate climate change in the outskirts of the city. For this, it is necessary to ensure proper conservational protection, which, in addition to maintaining the original structure, profiles, and layout of the building, should include protection of their natural value.

Many studies aim to assess the characteristics of blue-green infrastructure (BGI) that influence its cooling potential. Commonly used methods include satellite remote sensing, numerical simulations, and field measurements, each defining different cooling efficiency indicators. However, the methodological diversity creates uncertainties in optimizing BGI planning and management. This gap was addressed through a literature review, examining how BGI cools urban space, which spatial data and methods are most effective, which methodological differences may affect the results, and what are current research gaps and innovative future directions. Results suggest that differences in conclusions may arise from geographic and seasonal variations, as well as the spatial resolution of data, model scale, BGI delineation method, cooling range calculation approach, and urban morphology differences. The most influencing BGI characteristics include object size, vegetation fraction, density, height and multi-layering, foliage density, and spatial connectivity. The role of shape complexity remains uncertain across methodological approaches. Future research should prioritize the effects of urban morphology on BGI characteristics effectiveness and explore innovative approaches like Digital Twin technology for BGI management optimization. This paper comprehensively integrates key information related to BGI's cooling capabilities, serving as a useful resource for both practitioners and researchers to support resilient cities development.

Green architecture, including green roofs, can limit the effects of urbanization. Green roofs soften the thermal effect in urban conditions, especially considering the significant increase in the European and global population and that a significant share of the age group, mainly the elderly is exposed to diseases caused by high temperatures. We studied runoff and the quality of water from green roof systems in Lower Silesia, within the area of the Agro and Hydrometeorology Station Wrocław-Swojec, in the years 2012–2016. In the study, two systems with a vegetation layer based on light expanded clay aggregate and perlite were analyzed. The studies were based on the assessment of peak flow reduction, rainwater volume preservation and peak wave reduction. The calculated maximum retention performance indicator, relative to rainfall, for perlite surfaces was up to 65%, and in relation to the control surface up to 49%. In addition, the quality of water from runoff was estimated in the conditions of annual atmospheric deposition, taking into account such indicators as electrolytic conductivity; the content of N, NO₃, NO₂, NH₄, P, PO₄; and the content of metals, Cu, Zn, Pb and Cd. The load of total nitrogen exceeded the values of concentration in rainwater and amounted to 7.17 and 13.01 mg∙L⁻¹ for leca and perlite, respectively. In the case of the metal content, significantly higher concentrations of copper and zinc from green surfaces were observed in relation to precipitation. For surfaces with perlite, these were 320 mg∙L⁻¹ and 241 mg∙L⁻¹, respectively, with rainwater concentrations of 50 and 31 mg∙L⁻¹.