Coastal erosion study at Fredheim
Top image: Evangeline Sessford (left) and Ole Patrick Larsen on fieldwork at Fredheim, drilling into the active layer to collect macrofossils (i.e. plant material) for radiocarbon dating of uplifted marine terraces. Photo: Anne Hormes/UNIS.
MSc student Evangeline Sessford has studied coastal erosion in Spitsbergen, and one of the study sites was Fredheim in Tempelfjorden. Various mitigation techniques for the cultural heritage at Fredheim have been reviewed resulting in suggestions to protect the coast rather than move the buildings or let nature run its course. Sessford will defend her master thesis at UNIS on 15 May 2013.
13 May 2013
Press release from UNIS
Evangeline Sessford’s thesis has explored Holocene coastal development and used it alongside present day erosion and aggradational rates, and geomorphological processes as an analogue for possible future predictions concerning coastal evolution. The implementation of geomorphological maps has proved to be of significant value in understanding these processes. Furthermore, one can utilize data for mitigation strategies concerning cultural heritage threatened by coastal erosion.
Four study sites in Central Spitsbergen, Svalbard have been used to assess modern processes and erosion rates on unconsolidated sediment coasts. The overall trend finds that erosion is active while the mechanisms behind erosion are complex and vary spatially even on extremely small regional scales in the order of 100s of metres. The average erosion rates for the four study sites range between 0 and 2 m/yr, with most segments eroding at rates between 0.3 and 0.4 m/yr. Spatial variation in coastal geomorphology, i.e. cliff morphology, cryology, and lithology, between these sites is one of the major factors influencing variations in erosion rate. However temporal variations i.e. storminess, sea ice, wind regime and temperatures largely impact future changes.
Present day coastal processes are used as a key to past shoreline development and when the past processes are seen from the context of the present, it is possible to outline possible future changes. Therefore, insight into the Holocene development of beaches through uplifted marine terraces has contributed to better understanding of these small scale variations. One of the field sites, Fredheim has been more thoroughly examined to delve into this topic.
The following general conclusions concerning Svalbard coasts have been drawn:
- Svalbard has a number of coastlines made up of unconsolidated sediments which are currently undergoing erosion. The magnitude of erosion varies spatially and temporally, even on very small regional scales
- Thermal erosion is not a major threat to Svalbard coasts as there is a lack in ground ice. However increase in snow accumulation at the coasts assists in pro-nival fluvial erosion and thawing of permafrost.
- Future development of Arctic coastlines are mainly reliant on temporal changes
- Beach aggradation and erosion are dependent upon sediment availability, accommodation space, wind direction, frequency of storm events, and interactions between snow, ice foot, sea ice and permafrost.
- The effect of sea ice on coastal erosion is still a topic widely unexplored. The magnitude in which sea ice protects, constructs and erodes coastlines needs further analysis
- The need for more Quaternary mapping along Svalbard coasts is imminent
Having conducted spatial and temporal analysis of Holocene coastal development and combining it with modern erosion rates, research broadened to applied science in the field of coastal engineering to illustrate the benefits of collaboration between research disciplines. In so doing, various mitigation techniques for the cultural heritage at Fredheim have been reviewed resulting in suggestions to protect the coast rather than move the buildings or let nature run its course.
It is recommended that mitigation strategies concerning cultural heritage need to combine knowledge of past processes in varying climatic settings to understand the probability of future events occurring. The total risk of the cultural heritage relates to the probability, frequency and magnitude of coastal erosion, taking into consideration the expected loss of cultural value.
Evangeline Sessford will defend her master thesis, “Spatial and temporal analysis of Holocene coastal development: applications to erosion assessment and cultural heritage mitigation in Svalbard”, at UNIS on Wednesday 15 May at 09:15 in auditorium “Lassegrotta”.