Towards Coupling of 1D and 2D Models for Flood Simulation—A Case Study of <i>Nilwala</i> River Basin, Sri Lanka
The <i>Nilwala</i> river basin is prone to frequent flooding during the southwest monsoon and second intermonsoon periods. Several studies have recommended coupling 1D and 2D models for flood modelling as they provide sufficient descriptive information of floodplains with greater computa...
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| Format: | Article |
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MDPI AG
2022-01-01
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| Series: | Hydrology |
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| Online Access: | https://www.mdpi.com/2306-5338/9/2/17 |
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| author | Lanthika Dhanapala M. H. J. P. Gunarathna M. K. N. Kumari Manjula Ranagalage Kazuhito Sakai T. J. Meegastenna |
| author_facet | Lanthika Dhanapala M. H. J. P. Gunarathna M. K. N. Kumari Manjula Ranagalage Kazuhito Sakai T. J. Meegastenna |
| author_sort | Lanthika Dhanapala |
| collection | DOAJ |
| description | The <i>Nilwala</i> river basin is prone to frequent flooding during the southwest monsoon and second intermonsoon periods. Several studies have recommended coupling 1D and 2D models for flood modelling as they provide sufficient descriptive information of floodplains with greater computational efficiency. This study aims to couple a 1D hydrological model (HEC-HMS) with a 2D hydraulic model (iRIC) to simulate flooding in the <i>Nilwala</i> river basin. Hourly rainfall and streamflow data of three flood events were used for calibration and validation of HEC-HMS. The model performed exceptionally well considering the Nash–Sutcliffe coefficient, percent bias, and root mean square error. The flood event of May 2017 was simulated on iRIC using the streamflow hydrographs modelled by HEC-HMS. An overall accuracy of 81.5% was attained when the simulated extent was compared with the surveyed flood extent. The accuracy of the simulated flood depth was assessed using the observed water level at <i>Tudawa</i> gauging station, which yielded an NSE of 0.94, PBIAS of −4.28, RMSE of 0.18 and R<sup>2</sup> of 0.95. Thus, the coupled model provided an accurate estimate of the flood extent and depth and can be further developed for hydrological flood forecasting on a regional scale. |
| first_indexed | 2024-03-09T21:47:08Z |
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| id | doaj.art-412e5ead5eff4c0ead3ead794c7fa3e4 |
| institution | Directory Open Access Journal |
| issn | 2306-5338 |
| language | English |
| last_indexed | 2024-03-09T21:47:08Z |
| publishDate | 2022-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Hydrology |
| spelling | doaj.art-412e5ead5eff4c0ead3ead794c7fa3e42023-11-23T20:13:32ZengMDPI AGHydrology2306-53382022-01-01921710.3390/hydrology9020017Towards Coupling of 1D and 2D Models for Flood Simulation—A Case Study of <i>Nilwala</i> River Basin, Sri LankaLanthika Dhanapala0M. H. J. P. Gunarathna1M. K. N. Kumari2Manjula Ranagalage3Kazuhito Sakai4T. J. Meegastenna5Department of Agricultural Engineering and Soil Science, Faculty of Agriculture, Rajarata University of Sri Lanka, Anuradhapura 50000, Sri LankaDepartment of Agricultural Engineering and Soil Science, Faculty of Agriculture, Rajarata University of Sri Lanka, Anuradhapura 50000, Sri LankaDepartment of Agricultural Engineering and Soil Science, Faculty of Agriculture, Rajarata University of Sri Lanka, Anuradhapura 50000, Sri LankaDepartment of Environmental Management, Faculty of Social Sciences and Humanities, Rajarata University of Sri Lanka, Mihintale 50300, Sri LankaFaculty of Agriculture, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, JapanIrrigation Department, Colombo 00700, Sri LankaThe <i>Nilwala</i> river basin is prone to frequent flooding during the southwest monsoon and second intermonsoon periods. Several studies have recommended coupling 1D and 2D models for flood modelling as they provide sufficient descriptive information of floodplains with greater computational efficiency. This study aims to couple a 1D hydrological model (HEC-HMS) with a 2D hydraulic model (iRIC) to simulate flooding in the <i>Nilwala</i> river basin. Hourly rainfall and streamflow data of three flood events were used for calibration and validation of HEC-HMS. The model performed exceptionally well considering the Nash–Sutcliffe coefficient, percent bias, and root mean square error. The flood event of May 2017 was simulated on iRIC using the streamflow hydrographs modelled by HEC-HMS. An overall accuracy of 81.5% was attained when the simulated extent was compared with the surveyed flood extent. The accuracy of the simulated flood depth was assessed using the observed water level at <i>Tudawa</i> gauging station, which yielded an NSE of 0.94, PBIAS of −4.28, RMSE of 0.18 and R<sup>2</sup> of 0.95. Thus, the coupled model provided an accurate estimate of the flood extent and depth and can be further developed for hydrological flood forecasting on a regional scale.https://www.mdpi.com/2306-5338/9/2/17<i>Nilwala</i> river basincoupled flood modellingHEC-HMSiRIC |
| spellingShingle | Lanthika Dhanapala M. H. J. P. Gunarathna M. K. N. Kumari Manjula Ranagalage Kazuhito Sakai T. J. Meegastenna Towards Coupling of 1D and 2D Models for Flood Simulation—A Case Study of <i>Nilwala</i> River Basin, Sri Lanka Hydrology <i>Nilwala</i> river basin coupled flood modelling HEC-HMS iRIC |
| title | Towards Coupling of 1D and 2D Models for Flood Simulation—A Case Study of <i>Nilwala</i> River Basin, Sri Lanka |
| title_full | Towards Coupling of 1D and 2D Models for Flood Simulation—A Case Study of <i>Nilwala</i> River Basin, Sri Lanka |
| title_fullStr | Towards Coupling of 1D and 2D Models for Flood Simulation—A Case Study of <i>Nilwala</i> River Basin, Sri Lanka |
| title_full_unstemmed | Towards Coupling of 1D and 2D Models for Flood Simulation—A Case Study of <i>Nilwala</i> River Basin, Sri Lanka |
| title_short | Towards Coupling of 1D and 2D Models for Flood Simulation—A Case Study of <i>Nilwala</i> River Basin, Sri Lanka |
| title_sort | towards coupling of 1d and 2d models for flood simulation a case study of i nilwala i river basin sri lanka |
| topic | <i>Nilwala</i> river basin coupled flood modelling HEC-HMS iRIC |
| url | https://www.mdpi.com/2306-5338/9/2/17 |
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