Assessment of Natural Hazards Exposure - Castle of Ambras (Innsbruck)
Veronika Lechner, Fabian Nagl, Bernhard Kohl and Gerhard Markart Department of Natural Hazards (BFW)
CHEERS – Workshop
BFW - Innsbruck 13-11-2019 Ambras castle Damage events – Ambras castle 1985 - The wall surrounding the castle was overturned by the high water discharge of the Lanser brook (which was additionally endowed with water from the Sistrans brook).
Sistranser Bach
Foto:Lanser Lageder Bach Damage events - Ambras castle Wall has been rebuilt – with culverts
Retention Basin at Amras
Foto: Lageder Road to Ambras Castle flooded - July 2016 Traffic chaos in Ambras
Monsoon-like storms over Tyrol
Street near Ambras Castle
This event was triggered by an outbreak of the Sistrans brook above Aldrans surface runoff caused landslides above Ambras Castle flooded the road at Ambras Castle – access road acted as a dam Damage events - Ambras castle
Foto: Lageder Planned 1st attempt Further development of an approach developed for the region Pichl-Schladming- Haus in the Ennstal valley - derivation of flood potential not covered by WLV hazard zone maps Runoff coefficient map
Runoff Deduction of catchments areas without connection to torrents Routing the runoff from pixel to pixel – runoff potential in the catchments Calculation of surface runoff velocity Flooding potential map Runoff coefficient map for “catchment” Schintertalbach – to Ambras castle Flooding of access road and parking lots extremely unlikely in future after the 2016 event extensive measures were taken to protect the access road to Ambras Castle from water accumulation
Installation of culverts in the wall to ensure rapid drainage In torrential rain runoff from the inner courtyard of Ambras Castle repeatedly flooded adjacent rooms. Securing of valuable goods by the personnel during rain events is necessary. Access by staff during thunderstorms possible - due to the construction measures taken
Source photo: https://www.schlossambras-innsbruck.at/entdecken/das-schloss/innenhof/ Hence concentration of future work on an acute problem:
Rock (Innsbruck Quartz Phyllite) in the east of Ambras Castle is strongly loosened / weathered - Erosion by the Lanser brook, this undercuts the rock - sooner or later technical security Lanser Bach measures necessary to ensure stability of the castle in this area Ambras Castle Bank protection only partially functioning - “hanging in the air”
Loose sediment easy to mobilize
Forest ranger will be informed Side erosion rock partly heavily weathered rock break-offs
bank protection unstable Next steps BFW:
• Comparison of older and actual aerial photos - attempt to document changes in the last decades • Comparison with terrestrial photographs - Carrying out a flight with UAV not allowed (approach zone airport Innsbruck - no-fly zone for UAVs) • Short report for Stakeholders (e.g. Hofburg administration) Development of the channel section and the slopes should be observed at least
Taking Measures not within the competence of the WLV But: Hofburg administration / City of Innsbruck Thanks to DI Leopold Stepanek (Austrian Service for Torrent and Avalanche Control - WLV) for providing information and assistance in the field