A national flood awareness system for ungauged catchments in complex topography: The case of development, communication and evaluation in New Zealand
Abstract Effectively forecasting and communicating flood hazards at national or continental scales is critical to reducing impacts of flooding. Yet, it remains a challenge due to the predominance of ungauged catchments in often complex and steep terrain. We present the development, communication, an...
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| Format: | Article |
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Wiley
2025-03-01
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| Series: | Journal of Flood Risk Management |
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| Online Access: | https://doi.org/10.1111/jfr3.12864 |
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| author | Céline Cattoën Jono Conway Nava Fedaeff Daniel Lagrava Paula Blackett Kelsey Montgomery Ude Shankar Trevor Carey‐Smith Stuart Moore Andrea Mari Tilmann Steinmetz Sam Dean |
| author_facet | Céline Cattoën Jono Conway Nava Fedaeff Daniel Lagrava Paula Blackett Kelsey Montgomery Ude Shankar Trevor Carey‐Smith Stuart Moore Andrea Mari Tilmann Steinmetz Sam Dean |
| author_sort | Céline Cattoën |
| collection | DOAJ |
| description | Abstract Effectively forecasting and communicating flood hazards at national or continental scales is critical to reducing impacts of flooding. Yet, it remains a challenge due to the predominance of ungauged catchments in often complex and steep terrain. We present the development, communication, and evaluation of a national flood awareness system, the Aotearoa (New Zealand) Flood Awareness System, AFAS. Forecasts are produced with an uncalibrated, semi‐distributed hydrological model, driven by a high‐resolution convective‐scale atmospheric model with statistical perturbations in rainfall, soil moisture and baseflow to generate a 50‐member ensemble. We implement a relative flow and flood exceedance threshold framework to evaluate hourly forecasts across six categories from below normal to extremely high. Forecast performance is categorically assessed against observations, for a 2.5‐year reforecast, at 272 sites nationwide, up to 48 h ahead. Overall, AFAS produces skilful streamflow forecasts in catchments with complex topography, even with operational delays ingesting observations. We explore a novel approach to river forecast communication using daily videos. We suggest rethinking large‐scale streamflow forecast communication by balancing a depth with breadth approach (pointwise absolute flows versus distributed relative flows), to raise collective awareness before and during natural disasters. AFAS appears to be the first system producing public‐friendly videos to communicate streamflow forecasts in their topographical context. Future development of AFAS will benefit from a federated approach across national and regional agencies, including sharing of real‐time weather observations, forecasting tools and expertise. |
| format | Article |
| id | doaj-art-e29feb3512ed43548e97334f4d52a760 |
| institution | OA Journals |
| issn | 1753-318X |
| language | English |
| publishDate | 2025-03-01 |
| publisher | Wiley |
| record_format | Article |
| series | Journal of Flood Risk Management |
| spelling | doaj-art-e29feb3512ed43548e97334f4d52a7602025-08-20T01:49:58ZengWileyJournal of Flood Risk Management1753-318X2025-03-01181n/an/a10.1111/jfr3.12864A national flood awareness system for ungauged catchments in complex topography: The case of development, communication and evaluation in New ZealandCéline Cattoën0Jono Conway1Nava Fedaeff2Daniel Lagrava3Paula Blackett4Kelsey Montgomery5Ude Shankar6Trevor Carey‐Smith7Stuart Moore8Andrea Mari9Tilmann Steinmetz10Sam Dean11National Institute of Water and Atmospheric Research (NIWA) Christchurch New ZealandNational Institute of Water and Atmospheric Research (NIWA) Lauder New ZealandNational Institute of Water and Atmospheric Research (NIWA) Auckland New ZealandNational Institute of Water and Atmospheric Research (NIWA) Christchurch New ZealandNational Institute of Water and Atmospheric Research (NIWA) Hamilton New ZealandNational Institute of Water and Atmospheric Research (NIWA) Christchurch New ZealandNational Institute of Water and Atmospheric Research (NIWA) Christchurch New ZealandNational Institute of Water and Atmospheric Research (NIWA) Wellington New ZealandNational Institute of Water and Atmospheric Research (NIWA) Wellington New ZealandNational Institute of Water and Atmospheric Research (NIWA) Wellington New ZealandNational Institute of Water and Atmospheric Research (NIWA) Wellington New ZealandNational Institute of Water and Atmospheric Research (NIWA) Wellington New ZealandAbstract Effectively forecasting and communicating flood hazards at national or continental scales is critical to reducing impacts of flooding. Yet, it remains a challenge due to the predominance of ungauged catchments in often complex and steep terrain. We present the development, communication, and evaluation of a national flood awareness system, the Aotearoa (New Zealand) Flood Awareness System, AFAS. Forecasts are produced with an uncalibrated, semi‐distributed hydrological model, driven by a high‐resolution convective‐scale atmospheric model with statistical perturbations in rainfall, soil moisture and baseflow to generate a 50‐member ensemble. We implement a relative flow and flood exceedance threshold framework to evaluate hourly forecasts across six categories from below normal to extremely high. Forecast performance is categorically assessed against observations, for a 2.5‐year reforecast, at 272 sites nationwide, up to 48 h ahead. Overall, AFAS produces skilful streamflow forecasts in catchments with complex topography, even with operational delays ingesting observations. We explore a novel approach to river forecast communication using daily videos. We suggest rethinking large‐scale streamflow forecast communication by balancing a depth with breadth approach (pointwise absolute flows versus distributed relative flows), to raise collective awareness before and during natural disasters. AFAS appears to be the first system producing public‐friendly videos to communicate streamflow forecasts in their topographical context. Future development of AFAS will benefit from a federated approach across national and regional agencies, including sharing of real‐time weather observations, forecasting tools and expertise.https://doi.org/10.1111/jfr3.12864ensemble flood forecastingextreme eventsflood early warning systemhydrological modellinghydrometeorology |
| spellingShingle | Céline Cattoën Jono Conway Nava Fedaeff Daniel Lagrava Paula Blackett Kelsey Montgomery Ude Shankar Trevor Carey‐Smith Stuart Moore Andrea Mari Tilmann Steinmetz Sam Dean A national flood awareness system for ungauged catchments in complex topography: The case of development, communication and evaluation in New Zealand Journal of Flood Risk Management ensemble flood forecasting extreme events flood early warning system hydrological modelling hydrometeorology |
| title | A national flood awareness system for ungauged catchments in complex topography: The case of development, communication and evaluation in New Zealand |
| title_full | A national flood awareness system for ungauged catchments in complex topography: The case of development, communication and evaluation in New Zealand |
| title_fullStr | A national flood awareness system for ungauged catchments in complex topography: The case of development, communication and evaluation in New Zealand |
| title_full_unstemmed | A national flood awareness system for ungauged catchments in complex topography: The case of development, communication and evaluation in New Zealand |
| title_short | A national flood awareness system for ungauged catchments in complex topography: The case of development, communication and evaluation in New Zealand |
| title_sort | national flood awareness system for ungauged catchments in complex topography the case of development communication and evaluation in new zealand |
| topic | ensemble flood forecasting extreme events flood early warning system hydrological modelling hydrometeorology |
| url | https://doi.org/10.1111/jfr3.12864 |
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