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Implementation of green roofs could help to reduce rapid runoff and help cities to mitigate heat islands. The aim of the study is to assess the water and temperature regimes of four experimental green roof test beds having different growing media and plant coverage during the vegetation season 2018. Experiments were conducted in four test beds (1 × 1 m) established on a flat roof. Two types of growing media were used. The first (A) was a substrate composed of crushed spongolite, crushed expanded clay, and peat. The second (B) was a coarser substrate, composed of crushed expanded clay, crushed bricks, peat, and compost. Two test beds, hereafter designated ACu and BCu, were filled with substrates A and B respectively and planted with a mixture of Sedum spp. cuttings with approximately 10% coverage. The substrate thickness was 6 cm. Two other test beds, designated ACa and BCa, were filled to a depth of 4 cm with A and B growing media, respectively, and planted with a carpet of Sedum spp. with approximate coverage of 100%. The experiment was conducted over one growing season. Continuous monitoring of substrate temperature, water content, and outflow was conducted on each test bed. The lowest runoff coefficient was observed in test bed ACu, while the highest runoff occurred in test bed BCu, with twice the amount of outflow as ACu. The total runoff coefficient of ACa was more than one-third higher than that of ACu. The lowest maximum substrate temperature on the hottest day of the season was observed in bed ACa with a temperature of 40.6 °C, while the highest temperature was seen in bed BCu, 7.9 °C higher. The analysis of the rainfall-runoff relationship calculated for individual rainfall events demonstrated that runoff coefficients depended on initial water content, rainfall intensity, rainfall depth, substrate type, and vegetation cover. Beds planted with sedum carpets and having more extensive vegetation coverage were superior at moderating extremes of temperature.

Isothermal and non-isothermal infiltration experiments with tracer breakthrough were carried out in the laboratory on one intact column (18.9 cm in diameter, 25 cm in height) of sandy loam soil. For the isothermal experiment, the temperature of the infiltrating water was 20°C to the initial temperature of the sample. For the two non-isothermal experiments water temperature was set at 8°C and 6°C, while the initial temperature of the sample was 22°C. The experiments were conducted under the same initial and boundary conditions. Pressure heads and temperatures were monitored in two depths (8.8 and 15.3 cm) inside the soil sample. Two additional temperature sensors monitored the entering and leaving temperatures of the water. Water drained freely through the perforated plate at the bottom of the sample by gravity and outflow was measured using a tipping bucket flowmeter. The permeability of the sample calculated for steady state stages of the experiment showed that the significant difference between water flow rates recorded during the two experiments could not only be justified by temperature induced changes of the water viscosity and density. The observed data points of the breakthrough curve were successfully fitted using the two-region physical non-equilibrium model. The results of the breakthrough curves showed similar asymmetric shapes under isothermal and non-isothermal conditions.

In the published article [1], the authors realized some errors in the affiliation for Martina Sobotkova and Jaromir Dusek, and thus wish to replace the affiliation with the paragraph below [...]

The coastal waters of Hawaii are extremely important for recreation as well as for the health of the marine environment. Non-point source pollution from storm runoff poses a great threat to surface water quality in Hawaii. The State of Hawaii Department of Transportation (HDOT) includes infiltration trenches as a best management practice (BMP) option to reduce pollution caused by stormwater runoff. HDOT guidelines state that the implementation of BMPs is needed to reduce sediment and pollutant loads to streams and the ocean. In this study, the suitability of soils adjacent to highways on Oahu for the siting of infiltration trenches was examined. In addition to field surveys and in-situ tests, laboratory investigations on soil properties, infiltration experiments on undisturbed soil columns, and mathematical modeling of hydraulic functioning of the infiltration trench were conducted. Dissolved metal concentrations in highway stormwater runoff were observed to exceed the groundwater environmental action levels for all heavy metals tested, but the soils had high sorption capacity for these metals. The results of the simulations indicated that all the sampled Oahu soils, with one exception, would require less than two hours to drain a filled hypothetical trench. Therefore, these soils are suitable for construction of infiltration trenches as a possible BMP, even when clogging of soil is considered in the simulation.