- Title
- Assessment of the impact of cyclones on the annual sediment budget in a pacific island catchment using a hydro-sedimentological model
- Creator
- Jorquera, E.; Rodríguez, J. F.; Saco, P. M.; Timmermans, H.
- Relation
- 23rd International Congress on Modelling and Simulation (MODSIM2019). Proceedings of the 23rd International Congress on Modelling and Simulation (MODSIM2019) (Canberra, A.C.T. 01-06 December, 2019) p. 972-978
- Publisher Link
- http://dx.doi.org/10.36334/modsim.2019.K6.jorquera
- Publisher
- Modelling and Simulation Society of Australia and New Zealand (MSSANZ)
- Resource Type
- conference paper
- Date
- 2019
- Description
- Pacific Islands are one of the world hotspots for climate change, with sea level rise (SLR) and increases in tropical cyclones (TC) activity posing a serious threat to coastal areas and ecosystems. Precipitation and extreme sea level events associated with TC generate floods that cause damage to agriculture, home and businesses and also produce considerable amounts of sediment that end up in the adjacent coastal areas. Our study focuses on coastal wetlands that receive sediments from the Dreketi River catchment on the northern coast of Vanua Levu, Fiji which are likely to be heavily affected by climate change. Recent studies have identified this area of the coast as a storm tide high-risk zone, and also that the Dreketi River catchment contributes most of the sediment to the adjacent Great Sea Reef (GSR) or Cakaulevu. The purpose of this work is to identify the impact of TC on the annual sediment yield through a physically-based hydro-sedimentological model. To address this, the period from 1970 to 2017 was simulated daily with SWAT, obtaining flow and sediment discharges at the outlet of Dreketi River catchment. For the same period, the cyclones within a radius of 600 Km of the barycentre of the catchment were analysed using the Southwest Pacific Enhanced Archive of Tropical Cyclones (SPEArTC). Two types of analysis were performed. The first one focused on the meteorological data, and the aim was to relate the maximum rainfall in the catchment with TC. The second one was based on the results of the hydro-sedimentological model assessing two aspects; i) which percentage of the annual sediment budget can be explained by TC, and ii) in how many cases the maximum annual sediment yield is due to a TC. Regarding the meteorological data, three meteorological stations were analysed with focus on the maximum daily rainfall. It was found that a TC caused the extreme values in each station in 10, 13 and 15 out of 45 years, respectively. However, the modelling results showed that on average 14% of the total annual sediment yield is related to TC and that TC caused the maximum annual sediment discharge in 19 out of 45 years (42%). These results indicate that even though TCs could not always generate the highest daily value during a year, due to the duration of the event and its intensity they have a significant impact on the annual sediment budget.
- Subject
- hydro-sedimentological modelling; Pacific Island Nations; tropical cyclones; SWAT
- Identifier
- http://hdl.handle.net/1959.13/1448791
- Identifier
- uon:43486
- Identifier
- ISBN:9780975840092
- Language
- eng
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