Kaarel Orviku

Coastal Damages on Saaremaa Island, Estonia, Caused by the Extreme Storm and Flooding on January 9, 2005

Abstract A cyclone known as Gudrun in the Nordic countries developed above the North Atlantic and traveled over the British Isles, Scandinavia, and Finland on January 7–9, 2005. As a result of high initial levels of the Baltic Sea, the fast-traveling cyclone with a favorable trajectory and strong SW–W winds created a record high storm surge (275 cm) in Pärnu, as well as in many other locations along the west Estonian coast. The January storm induced clearly visible changes in the development of shores and the dynamics of beach sediments over almost all of Estonia. The precondition for the profound changes observed from this storm—which has been observed in connection with some previous major storms—was a combination of the absence of protecting ice cover in the sea, relatively high sea level for a long period before the storm, and a very intensive storm surge taking place over the background of the already elevated sea level. Strong storm waves combined with the high sea level caused substantial changes in the coastal geomorphology of depositional shores on Saaremaa Island, Estonia. The most exceptional changes occurred in the areas that were well exposed to the storm winds and wave activity—for instance, in Kelba, where the high rate of erosion (<3000 m3) resulted in the elongation of a spit by 75 m. Our conclusion is that the January 2005 storm caused significantly larger changes to the depositional shores in west Estonia than the cumulative effects of ordinary storms over the preceding 10–15-year period.

Past and current climate change

This section describes long-term observed climatic changes in atmospheric parameters. The focus is on surface climate conditions, but changes in atmospheric circulation are discussed as they often are behind climatic variability seen on regional and local scales. For a summary introduction on mean atmospheric states and conditions in the Baltic Sea Basin see Annex 1.2 with sections on the general atmospheric circulation (A.1.2.1), surface air temperature (A.1.2.2), precipitation (A.1.2.3), clouds (A.1.2.4), and global radiation (A.1.2.5).

Observation and analysis of coastal changes in the West Estonian Archipelago caused by storm Ulli (Emil) in January 2012

ABSTRACT Tõnisson, H., Suursaar, Ü., Rivis, R., Kont, A. and Orviku, K., 2013. Observation and analysis of coastal changes in the West Estonian Archipelago caused by storm Ulli (Emil) in January 2012. The study analyzes the meteorological parameters, hydrodynamic conditions and coastal changes at three practically tideless locations on Saaremaa Island caused by storm Ulli (sustained wind speed 20 m/s, gusts 28 m/s) which struck the Estonian coast on 4 January 2012. It was the last and the most influential storm of a series of storms which began on November 2011. Wind and sea-level data from nearby meteorological and hydrological stations were used to provide the forcing data for hydrodynamic study. Wave hindcast was performed using a semi-empirical SMB-type wave model. Shorelines, scarp positions and beach profiles were measured in August 2011, and again during each of storm Berit (in November) and storm Ulli (in January). Local storm surge height reached 1 m, significant wave height (Hs) was up to 2.8 m, the combined sea level and Hs reached 3.65 m, and local wave run-up reached 3.2 m during Ulli. At Cape Kiipsaare, recession of the sandy scarp reached 9 m (at the rate of nearly 1m per hour). The loss of sand was approximately 4–5 m3 per 1 m of shoreline. Erosion occurred on the shores exposed to the prevailing wind direction while accumulation was recorded on the leeward side of the spit. Erosion mostly occurred at the elevations between 1–3 m. Although the winter 2011/12 included a series of influential storms, nearly two-thirds of coastal erosion during the winter 2011/2012 was caused by storm Ulli, which featured the highest sea levels.

Natural Development and Human Activities on Saaremaa Island (Estonia) in the Context of Climate Change and Integrated Coastal Zone Management

The coastal zone is a crucial environment that is experiencing pressure from a wide variety of different agents and interests. Many sandy beaches high in recreation value are suffering from increasing erosion, and the shoreline is receding in these areas despite of tectonic land uplift. Sediment deficit is evident in many places. One key problem in recent decades has been a rapid increase in the number of holiday houses built as close as possible to the seashore. Unlike in the Nordic countries, where major coastal settlement expansion took place after WWII, almost the entire coast of Estonia was, until 1991, proclaimed a Soviet border zone in which activities were strongly restricted. A revival in coastal land use and a rapid increase in coastal settlement have occurred over the last 15–20 years. This paper focuses on Climate Change impacts, natural and artificial changes on the coast of Saaremaa Island associated with increasing pressure and conflicting interests. We also examine the advantages and disadvantages of existing legislation regulating land use within the Estonian coastal zone in the context of integrated coastal zone management. The paper ends with an outlook.

Changes on coasts of western Estonia and Russian Gulf of Finland, caused by extreme storm Berit in November 2011

The study is analyzing the meteorological parameters, hydrodynamic conditions and coastal changes caused by extreme storm known as Berit, which travelled across the Baltic Sea from 27th to 29th of November in 2011. Wind speed on West Estonian islands reached to 19,7 m/s (gusts 29 m/s), 20,4 m/s on the northern coast (gusts 27 m/s) and 15 m/s (gusts 20 m/s) on the Russian Gulf of Finland coast. Sea level at Pärnu reached to 110 cm, 142 cm at Narva-Jõesuu and +190 cm near St Petersburg (outside from the Flood Protection Facility). Shorelines, scarp positions and beach profiles were measured at the end of summer in several sites along Estonian coast and Russian Gulf of Finland coast. Two researchers spent the whole duration of the storm in Harilaid Peninsula and recorded changes in shoreline, scarp positions and beach profiles. Wave run-up and sea-levels were also recorded. All the measurements were carried out using DGPS with the accuracy of 1 cm in vertical and horizontal scale. Russian study site was measured a few days after the storm. In order to assess variations in forcing conditions during the storm a wave hindcast was performed using a SMB-type wave model. Calibrated against the field measurements, the model is forced by wind data, and it calculates significant wave parameters for a chosen location. Significant wave height 1.5 km off the Kelba study site was 2.8 m and maximum waves reached to 4.4 m. The first results indicate that 1.5 m high sandy scarp in Cape Kiipsaare receded up to 4 m. The loss of sand was ca 6 m3 per 1 m of shoreline. The speed of recession was around 0.6 m/h during the peak of the storm. The length of gravel-pebble spit at Kelba increased and new gravel ridges in the proximal part reached to 2.8 m. In the Russian part of the eastern Gulf of Finland as a result of storm and flood the scarp up to 2 m high was formed along 15 km of dunes of the northern coast (Komarovo, Repino). It was the first strong erosion event observed after extreme dunes damage during autumn 2006-winter 2007.

Regional Environmental Sensitivity Index (RESI) Classification of Estonian Shoreline (Baltic Sea)

ABSTRACT Aps, R.; Tõnisson, H.; Suursaar, Ü., and Orviku, K, 2016. Regional Environmental Sensitivity Index (RESI) Classification of Estonian Shoreline (Baltic Sea). In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 972 - 976. Coconut Creek (Florida), ISSN 0749-0208. Despite improving navigation safety measures, there is a growing risk of accidental oil spills and associated oil pollution on the Baltic Sea, an area which has been designated as a Particularly Sensitive Sea Area by the International Maritime Organization. Environmental Sensitivity Index (ESI) maps have been an integral component of oil-spill contingency planning and response in the United States since 1979, serving as a quick reference for oil spill responders. The ESI ranks shoreline into 10 classes in relation to sensitivity, natural persistence of oil, and ease of clean-up. Some countries outside the US have adopted the ESI approach to classify their own shorelines for similar oil spill contingency planning, the resulting maps being referred to as Regional Environmental Sensitivity Index (RESI) maps. However, problems arise when applying the classification system. This article highlights the difficulties of applying the standard ESI classification to the Estonian shoreline and suggests a potential RESI classification scheme for Estonia that would divide cliff shores among sensitivity classes 1 and 5, with most of them into class 5, the designation for those that are the most difficult to clean up (mixed sediments on the beach and no access from the land). An Estonian RESI map layers are integrated into the SmartResponse Web - an analytical tool for emergency response and recovery that is used to combine the information related to the accident, development of an oil spill and information on environmental sensitivity of the Baltic Sea shoreline. The SmartResponse Web enables the identification and dynamic assessment of environmental risks as a continuous process for purposes of determining best practices for reducing or even eliminating the risks, and it is used by the Estonian oil spill response authorities for contingency planning, training and in emergency situation.

Retreat rate of cliffs and scarps with different geological properties in various locations along the Estonian coast

ABSTRACT Orviku, K., Tõnisson, H., Kont, A., Suuroja, S. and Anderson, A., 2013. Retreat rate of cliffs and scarps with different geological properties in various locations along the Estonian coast. Recently reported increased water depths and greater wave heights, perhaps associated with increased storminess, are likely to lead to more active changes, such as increased beach erosion, faster shoreline migration and sediment redistribution. A coastal environment particularly sensitive to the impact of sea-level rise is that of highly erodible cliffs and scarps. As structures are often built close to such formations, it is important to determine the retreat rate of cliffs and scarps. Among other things, knowing the retreat rate can help regulators plan coastal protection measures and can help property owners decide where to place their structures to avoid damage. The principal objective of the current study is to find and analyze the retreat rate of cliffs and scarps in several locations along the Estonian coast. Variable geological conditions, exposure to the sea and human influence are considered. The study was carried out in five different locations along the Estonian coast representing different geological properties, variable human influence and hydrodynamic conditions. Aerial photographs, orthophotos, RTK-GPS, leveling survey and archive data was used to measure the changes on the edges of the scarps and cliffs. It was found that the fastest rate of retreat appears on the location where the softest sediments are exposed to the roughest wave conditions – in Cape Kiipsaare. Here the yearly scarp-line retreat reached over 7 m/y (17 m3/y per meter of shoreline) which is faster than the fastest retreat rate of soft cliffs recorded anywhere else, but still two times lower in terms of the eroded volume of sediments.

Incorporating dynamic factors to the Environmental Sensitivity Index (ESI) shoreline classification - Estonian and Spanish examples

ABSTRACT Aps, R., Tõnisson, H, Anfuso, G., Perales, J.A., Orviku, K., Suursaar, Ü. 2014. Incorporating dynamic factors to the Environmental Sensitivity Index (ESI) shoreline classification - Estonian and Spanish examples. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 235–240, ISSN 0749-0208. Oil transportation is growing in the Baltic Sea area and especially in the Gulf of Finland where it will reach approximately 180–200 million tons a year by 2020. Growing oil transportation is considerably contributing to the risk of accidental spill-related shoreline oiling. This paper focuses on amending the Environmental Sensitivity Index (ESI) related shoreline classification to local conditions by dynamically changing the categorization of the shoreline in terms of its susceptibility to spilled oil caused by extreme meteorological events. This takes into consideration a number of natural physical factors. The paper presents the results of two European case studies: the Estonian shoreline of the Gulf of Finland (Baltic Sea), and the Spanish coast of the Gibraltar Strait. Susceptibility to spilled oil of some categories of the Estonian shoreline (sandy shores, till shores and gravel shores) occasionally changes over time from low to high sensitivity and back; especially conditioned to the influence of heavy storms. The studies carried out in Spain revealed a well recognizable indirect proportionality between foreshore slope and the tidal range. At many locations, the dynamic morphological characteristics of the beach appeared to be largely determined by contouring and specific conditions that are modifying the initial ESI related categorization of the sandy beaches concerned. The novelty of this work is in attempt to move from the standard ESI related, and locally adapted, static shoreline classification towards more dynamic shoreline monitoring based on characterization of the elements sensitive to oil pollution on shorelines.

Field experiments with different fractions of painted sediments to study material transport in three coastal sites in Estonia

ABSTRACT Tõnisson, H., Suursaar, Ü., Kont, A., Orviku, K., Rivis, R., Szava-Kovats, R. Vilumaa, K., Aarna, T., Eelsalu, M., Pindsoo, K., Palginõmm, V., Ratas, U. 2014. Field experiments with different fractions of painted sediments for studying material transport in three coastal study sites in Estonia. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 229–234, ISSN 0749-0208. Our current understanding of the morphodynamics in swash and surf zones is limited due to their turbulent and irregular nature. The importance of this zone to sediment transport led us to perform a sophisticated field experiment using painted sediments. Sediments collected locally from beach ridges were sorted into the following diameters: 1–2 5 cm, 2.5–5 cm and 5–10 cm. The sediments were painted, amassed in piles and placed at 0.5–10 m depths in three sites near the Estonian coast. The locations were recorded with GPS devices and photographed. The sediment piles placed in the sea were monitored at least once after an intense storm or once before and after the storm season. Some sediments were placed on the shoreline and monitored daily for a shorter period. Hydrodynamic parameters were also measured or hindcasted during the experiment. We found that wave breaking during storms can take place even at 6 m depth, but mostly between 2–4 m depth. Sediment fractions between 1–10 cm diameters can be transported over 20 m towards the shore. Even sediment piles at 10 m depth were moved 2–4 m, but towards the open sea. Sediments accumulated on the shoreline moved up to 3 m/hour along the shore and approximately 350 m during three months. We also found that calm periods can be more influential in places where regular vessel-generated waves wash the shores. As vessel-generated waves often approach from a different angle than natural waves, they can cause notable erosion during the periods when natural waves are weak or absent.

The impact of a port to the surrounding shores based on the 10 years monitoring results: Port of Sillamäe case study (Gulf of Finland, Baltic Sea)

The current study was focusing on the shore processes and the coastal sea fronting Sillamäe town. The shores near the Sillamäe starting west from the Voka settlement and ending at the top of Cape Kannuka were described as one litho dynamic system with a good natural balance in the recent past. The main aim of the paper was to analyse the impact of a port establishment to the changes in the coastal evolution and sediment budget in the vicinity of Sillamäe town based on the regular monitoring results (9 different shore profiles - by using RTK-GPS or Leica level, repeated photographs in several locations, shoreline mapping - by using RTK-GPS or handheld GPS, scarp measurements - by using orthophotos and RTK-GPS). The results suggest that either a stable geomorphic state or a slow accumulation prevailed along major part of the studied coast. After stronger storms, occasional erosion events were registered in several sections of the study site. However, these changes were mostly temporary and a stable state was usually restored soon after the erosion event. Finally, we can conclude that the monitoring of shore processes from 2004-2013 has not registered any changes on the shores directly influenced from the new harbour. Major changes on the shores are caused by natural extreme events. The changes in shore processes resulted from these events are comparable to the ones registered in the other naturally developing sites in Estonia.