Modeling Green Roof Potential to Mitigate Urban Flooding in a Chinese City
The Middle and Lower Reaches of the Yangtze River (MLRYR) region, which has humid subtropical climate conditions and unique plum rain season, is characterized by a simultaneous high-frequency urban flooding and reduction in groundwater levels. Retrofitting the existing buildings into green roofs is...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-07-01
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| Series: | Water |
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| Online Access: | https://www.mdpi.com/2073-4441/12/8/2082 |
| _version_ | 1797561685476638720 |
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| author | Li Liu Liwei Sun Jie Niu William J. Riley |
| author_facet | Li Liu Liwei Sun Jie Niu William J. Riley |
| author_sort | Li Liu |
| collection | DOAJ |
| description | The Middle and Lower Reaches of the Yangtze River (MLRYR) region, which has humid subtropical climate conditions and unique plum rain season, is characterized by a simultaneous high-frequency urban flooding and reduction in groundwater levels. Retrofitting the existing buildings into green roofs is a promising approach to combat urban flooding, especially for a densely developed city. Here, the application potential of the Green Roof System (GRS) and the Improved Green Roof System (IGRS) designed to divert overflowing water from green roofs to recharge groundwater were analyzed in a densely developed city, Nanchang, China. For the first time, the influence of GRS on the hydraulic condition of Combined Sewage System/Storm Water System (CSS/SWS) is analyzed, which is a direct reflection of the effect of GRS on alleviating urban flooding. The simulation results show that GRS can retain about 41–75% of precipitation in a 2-hour timescale and the flooding volumes in the GRS/IGRS region are 82% and 28% less than those of the Traditional Roof System (TRS) in 10- and 100-yr precipitation events, respectively. In the continuous simulations, GRS also enhances Evapotranspiration (ET), which accounts for 39% of annual precipitation, so that reduces the cumulative surface runoff. Considering the IGRS can provide more hydrological benefits than the GRS under the same climate conditions, we may conclude that the widespread implementation of both the GRS and the IGRS in Nanchang and other densely developed cities in the MLRYR region could significantly reduce surface and peak runoff rates. |
| first_indexed | 2024-03-10T18:18:25Z |
| format | Article |
| id | doaj.art-f40670e813274c6db33cdb4597f6d1aa |
| institution | Directory Open Access Journal |
| issn | 2073-4441 |
| language | English |
| last_indexed | 2024-03-10T18:18:25Z |
| publishDate | 2020-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Water |
| spelling | doaj.art-f40670e813274c6db33cdb4597f6d1aa2023-11-20T07:35:30ZengMDPI AGWater2073-44412020-07-01128208210.3390/w12082082Modeling Green Roof Potential to Mitigate Urban Flooding in a Chinese CityLi Liu0Liwei Sun1Jie Niu2William J. Riley3College of Construction, Jiangxi Normal University, Nanchang 330022, ChinaSouthern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, ChinaInstitute of Groundwater and Earth Science, Jinan University, Guangzhou 510632, ChinaEarth Science Division, Lawrence Berkeley National Lab, Berkeley, CA 94720, USAThe Middle and Lower Reaches of the Yangtze River (MLRYR) region, which has humid subtropical climate conditions and unique plum rain season, is characterized by a simultaneous high-frequency urban flooding and reduction in groundwater levels. Retrofitting the existing buildings into green roofs is a promising approach to combat urban flooding, especially for a densely developed city. Here, the application potential of the Green Roof System (GRS) and the Improved Green Roof System (IGRS) designed to divert overflowing water from green roofs to recharge groundwater were analyzed in a densely developed city, Nanchang, China. For the first time, the influence of GRS on the hydraulic condition of Combined Sewage System/Storm Water System (CSS/SWS) is analyzed, which is a direct reflection of the effect of GRS on alleviating urban flooding. The simulation results show that GRS can retain about 41–75% of precipitation in a 2-hour timescale and the flooding volumes in the GRS/IGRS region are 82% and 28% less than those of the Traditional Roof System (TRS) in 10- and 100-yr precipitation events, respectively. In the continuous simulations, GRS also enhances Evapotranspiration (ET), which accounts for 39% of annual precipitation, so that reduces the cumulative surface runoff. Considering the IGRS can provide more hydrological benefits than the GRS under the same climate conditions, we may conclude that the widespread implementation of both the GRS and the IGRS in Nanchang and other densely developed cities in the MLRYR region could significantly reduce surface and peak runoff rates.https://www.mdpi.com/2073-4441/12/8/2082Green roofurban floodinggroundwater rechargehydrological benefitrainwater retention |
| spellingShingle | Li Liu Liwei Sun Jie Niu William J. Riley Modeling Green Roof Potential to Mitigate Urban Flooding in a Chinese City Water Green roof urban flooding groundwater recharge hydrological benefit rainwater retention |
| title | Modeling Green Roof Potential to Mitigate Urban Flooding in a Chinese City |
| title_full | Modeling Green Roof Potential to Mitigate Urban Flooding in a Chinese City |
| title_fullStr | Modeling Green Roof Potential to Mitigate Urban Flooding in a Chinese City |
| title_full_unstemmed | Modeling Green Roof Potential to Mitigate Urban Flooding in a Chinese City |
| title_short | Modeling Green Roof Potential to Mitigate Urban Flooding in a Chinese City |
| title_sort | modeling green roof potential to mitigate urban flooding in a chinese city |
| topic | Green roof urban flooding groundwater recharge hydrological benefit rainwater retention |
| url | https://www.mdpi.com/2073-4441/12/8/2082 |
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