Details

Autor(en) / Beteiligte

• Zhong, Yihua
• Ballesteros–Cánovas, Juan Antonio
• Favillier, Adrien
• Corona, Christophe
• Zenhäusern, Gregor
• Manchado, Alberto Munoz Torrero
• Guillet, Sebastien
• Giacona, Florie
• Eckert, Nicolas
• Qie, Jiazhi
• Tscherrig, Georges
• Stoffel, Markus

Titel

Historical flood reconstruction in a torrential alpine catchment and its implication for flood hazard assessments

Ist Teil von

• Journal of hydrology (Amsterdam), 2024-02, Vol.629, p.130547, Article 130547

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2024

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• •We present a 700-year flood history for an Alpine catchment using documentary and systematic data.•The comprehensive flood dataset aligns well with the long-term flood variability from the Swiss Alps.•We model discharge for 32 historical floods using archival records, topographic maps, and engineering plans.•Past mitigation works effectively helped to protect the city of Brig-Glis from major flood damage.•The inclusion of historical data improves flood discharge estimates for longer return periods. Flood marks and descriptions of past floods in archival records are valuable sources of information to complement the often short – and sometimes lacunary – systematic records provided by gauge stations, especially in mountain and smaller catchments for which the network of recording stations is still fragmentary. Yet, historical accounts of floods are only rarely used to calculate discharge during past floods and to complement estimates of flood frequency and magnitude. This is because the definition of flood types and the reconstruction of past topography of the now urbanized riverscapes is often challenging. Here, we employ an approach by which we combine (i) archival (1331–1965) and continuous gauge (1966–2020) records of past floods, (ii) information on past topography and mitigation measures found on topographic maps and contemporary documents specifying the dimensions of contemporary engineering plans and (iii) a hydraulic model to derive a c. 700-year history of flood activity and related discharges for the Saltina River, Brig-Glis (Valais, Swiss Alps). Periods of increased flood activity match with flood-rich episodes in the Rhone River and high lake levels at Lago Maggiore (Ticino), and the time series passes stationarity tests since at least 1828 CE. For a total of 32 floods occurring prior to the installation of the gauge station in 1966, we provide discharges following a descriptive classification, and demonstrate that major floods occurred in 1755 (∼140 m3s−1), 1828 (∼160 m3s−1), and 1921 (∼120 m3s−1). We also evidence that the construction of mitigation measures has contributed to a reduction in flood frequency, but that the occurrence of extraordinary floods has again been on the rise since the early 21st century.