Coastal erosion and sand encroachment in the Blanda Storage Reservoir
Monitoring and research on sand encroachment has been conducted in the Blanda Storage Reservoir since 1993. Research has focused on monitoring erosion on the banks of the reservoir, sand encroachment from the reservoir site and monitoring fertiliser distribution, within sand encroachment areas, to support vegetation. Estimates suggest that the area affected by sand encroachment, since 1998, is approx. 52 hectares.
Meteorological conditions in the northwest of Iceland in 2012 were dry and warm whereas the conditions in 2013 were cold and wet. The main results from monitoring and research on erosion and sand encroachment by the Blanda Storage Reservoir can be seen below:
- Wave erosion levels were low on the banks of the Blanda Storage Reservoir between 2011 and 2012 or 0.08 m on average. Wave erosion levels were 0.12 m between 2012 and 2013. Wave erosion levels within this area have been low for four consecutive years. The average erosion rate between 2004 and 2012 was 0.42 m. Erosion levels rise during windy conditions and when the reservoir water level is high.
- Signs of sand encroachment were identified within new areas after the summer of 2012 and again in 2013. This could be due to unusually low water levels in the reservoir during this period.
- Fertiliser distribution in the sand encroachment area by the reservoir began in 2010 as a mitigation measure implemented to support vegetation in the area. Lyme grass sowing was one of the more successful measures implemented in the area. An assessment of the area in 2013 showed that fertilisation measures were taking effect and grass vegetation had increased. However, sheep and geese grazing in the area had an effect on the outcome.