Modification of the "green" roof using technical solutions to reduce the negative impact of stormwater in urban conditions

Abstract

The effectiveness and shortcomings of the "green" roof in the management of rainwater in the urban environment are analyzed. The scheme of the construction of a typical "green" roof and its classification in terms of types are shown. The proposal to increase the efficiency of stormwater management with the help of "green" roofs, through their integration with other systems, that is, the creation and implementation of "hybrid green roofs" (Hybrid Green Roofs), is substantiated. The possibility of a "blue" roof as a rainwater management technology without vegetation, which allows for effective retention of rainwater, is analyzed. The design scheme and principle of operation of the "green-blue" roof are given, and a comparative analysis of its effectiveness in stormwater management with traditional and "green" roofs is made. The results of research are presented, which showed that the measured runoff of rainwater from a "blue" roof is about 0.45 dm3/s compared to a regular roof with a runoff volume of 1.55 dm3/s. On the other hand, the runoff from the "green-blue" roof is about 0.1 dm3/s, compared to the control roof (0.3 dm3/s). It is substantiated that a "green-blue" roof is more effective in retaining rain runoff during long-term precipitation than a "blue" roof. However, both options can be applied to urban buildings as effective methods of managing stormwater runoff in urban areas. The scheme of construction and the principle of operation of the "purple" roof is given - as a type of roof that includes a spongy layer of hydrophilic mineral wool, a dense layer of polyester fabric, and can include an additional cellular layer to increase the amount of rainwater that can be retained, thereby reducing peak flow up to 95%. The results of the study are presented, which confirm the technical feasibility of the "purple" roof technology in terms of slowing down the flow and reducing the volume of storm water during rainfall of various intensities. A "Purple" roof, based on the concept of "storage", is conceptually and technically different from a "green" roof and can effectively delay peak rainfall, thereby reducing the pressure on the local stormwater management system. Unlike a "green-blue" roof, a "purple" roof is passive in nature - water flows off without any mechanical drainage points to divert the water. A diagram characterizing the degree of retention of rainwater, depending on the intensity of precipitation, by different types of roofs is presented. The authors proposed a comparative analysis of rainwater runoff management using traditional roofs, "green" roofs, and roofs modified with other "green" roof systems.