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Baltic Sea Coastal Processes in Latvia: Research for a Better Future

This research explores the degradation of territories and attempts to reduce it on the Baltic Sea coast in Latvia. It discusses the history, politics, and nature protection efforts related to coastal areas, as well as the impact of coastal erosion and the need for improved coastal management practices.

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Baltic Sea Coastal Processes in Latvia: Research for a Better Future

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  1. LLI – 303, Life in Clean Environment – a Better Future! “Clean Brownfields” Baltic Sea coastal processes in Latvia, research and attempts to reduce the degradation of territories Dr. Jānis Lapinskis University of Latvia Department of Geography and Earth Sciences Jūrkalne, Latvia September 12, 2019

  2. ice dry land Baltic Ice Lake Legend Balticregion 11800 y BP. Baltic Ice Lake during late stages of last glaciation Tartu

  3. N Coastline 10,500 y BP Ancient and modern day dunes 50 km

  4. Coastal settlement density • At the present time in Latvia, within the distance of about 20 km from coastline, there is more than one million inhabitants, (approximately 50% of total state population). • However, in Latvia, unlike in many other European countries, comparatively small number of people live in the direct vicinity of the sea (100-200 m).

  5. offshore nearshore coast, coastal hinterland buildings, Infrastructure dune ridge foredune Flat, sandy (70%) beach breaker zone offshore nearshore coast, coastal hinterland buildings, Infrastructure cliff, bluff Soft cliffs (20%) breaker zone beach Typical coastal morphology and elements in Latvia generaly – 70-500 m generaly – 30-150 m

  6. Why are there so few developed areas directly on the coast? • Innitially – low agricultural value of coastal areas; • 18th century – beginning of 20thcentury – anthropogenically induced „migration of dunes” towards inland; • 1940-1990 – inaccessibility of coastal areas during Soviet occupation; • Nowadays – restrictions related to nature protection.

  7. Last migrating dune of Latvia Plieņciems white dune (protected area)

  8. Coasts, history, politics and nature protection • Paradoxically, but inaccessibilityfor civillian development of many coastal areas during Soviet occupation has „saved” Latvia from various coastal management mistakes specific to Western Europe. • Combination of historical events and circumstaces, provaidedpreservation of natural landscapes and ecosystems. Nowadays, this is ground for establishing of protected natural areas. Total length of such territories along coastline of Latvia is about 255 km.

  9. Coastal layout and features in Latvia Typical low-lying and accreation dominated coastal section of northern part of Latvia Nearshore area (300-800 m wide, depth 5-10 m) Sandy beach (30-40 m wide, 2 m high at the foot of dune) Fore-dune ridge (10-30 m wide, 3-4 m high) Forested coastal hinterland (elevation 3-5 m asl) Old coastal dunes (elevation 5-10 m asl)

  10. Typical retreating (cliffed) coastal section of Latvia Coastal layout and features in Latvia Soft cliff (bluff) (10-15 m high) Sand-gravel beach (15-30 m wide)

  11. 2005. 1 m 2015. 14 m SW Latvia, Nīca municipality. Dune ridge destruction and coastal hinterland retreat due to moderate coastal erosion

  12. Is coastal erosion an issue in Latvia? • Substantial changes in coastal “shape” (coastal hinterland retreat, destruction of dunes, migration of sediments etc.) are occurring only during relatively rare severe storm events. Depending on the exact location, there can be even more than 10 years in between such events. • The total length of the coastal sections, where the coastline was retreating during several last decades is: • 0.1–0.5 m/year ~ 120 km; • 0.6–1.5 m/year ~ 50 km; • 1.6–3.5 m/year ~10 km. Coastline of Latvia – 496 km

  13. Is coastal erosion an issue in Latvia? • Common trends over the last 20-30 years refers to the increase in activity of the coastal processes. There are two main reasons for this: • the coastal system is experiencing growing deficit of sediment supply (mostly due to anthropogenic intervention); • accelerated climate change related stressors in the system. • the average sea level rise; • warmer and shorter winters (less ice); • more frequent and intense westerly storms.

  14. Is coastal erosion an issue in Latvia? Advantages: • Very few heavily developed areas with infrastructure and/or residential buildings in close proximity of coastline; • Coastal sections severely affected by erosion are compiling less than 15% of total coastline; • In most cases erosion is not considered as a treat to recreational resource/value of coastal areas.

  15. Is coastal erosion an issue in Latvia? Disadvantages: • Properties of geomorphology, geological structure and composition of coastal areas in Latvia makes it «sensitive» to changes in climate and sea level increase; • Insufficient understanding about the need for improvement of coastal management practices, for example: • what to do in case of coastal erosion?, • how to decrease future risks?, • which course of action is more cost-efficient?. Liepāja town sewage treatment plant

  16. Preparation of Guidelines took place on the basis of the analysis of data from a monitoring system of coastal geological processes of Latvia, covering time span from 1990 to 2014. Determination and allocation of the five classes of the coastal erosion risk level. Erosion risk class tied recommendations for coastal erosion management. Guidelines for Coastal Erosion Mitigation (2015) 4 2006.07.16. 3,5 2007.08.21. 2008.06.29. 3 2009.06.26. 2011.07.11. 2,5 2013.06.30. Elevation asl. (m) 2 1,5 1 0,5 0 10 20 30 40 50 60 Distance from the ref. point (m) 0

  17. Classes of the coastal erosion risk level Five generalized coastal types (classes), each characterized by a different degree of erosion risk

  18. Defining priorities and searching for sustainability in coastal erosion management and risk mitigation • Taking into account the complexity of issues of coastal erosion and aspects related to environmental protection, as well as the risks associated with problem of high irreducible uncertainty, non-intervention strategy is considered as the best option from all the possible coastal erosion management strategies. Therefore management solution prioritization should be as follows (from best to worst): • No intervention (adaptation); • Non-invasive or minimally invasive anti-erosion measures (dune planting, beach nourishment and other “soft” measures); • "Aggressive" anti-erosion measures (structures) with relatively short service life and short “cowered” length of the coastline; • Highly "aggressive" measures (seawalls, impermeable groins) with long lifetime and high level of coastal alteration.

  19. Coastal retreat forecast for the year 2060.Based on extrapolation of existing historic data;Null-scenario (no intervention). Increase in the total length of coastal sections affected by hinterland retreat by 17.8 % (Σ=331 km). Maximum expected coastal retreat – 150-200 m until the year 2060. Territory of Latvia will be reduced by approx. 9.0 km2. coastal retreat 2060

  20. Forecast (projection) for expected coastal retreat maximum in 2060 (Roja town) Null-scenario (no intervention) Legend 2015. 2060.

  21. Legend Forecast (projection) for expected coastal retreat maximum in 2060 (Liepāja town). Null-scenario (no intervention) 2060.

  22. Summary and resume • The coastal socio-ecological systems are based on interconnected elements of natural, cultural, socio-economic and governance resources. • Goals to achieve for sustainable coastal development in Latvia: • awareness (understanding) improvement in the field of coastal geological processes, • collaboration of coastal municipal stakeholder groups, • understanding of common challenges and opportunities.

  23. Experimental beach nourishment “undertaking” in Kaugurciems Beach nourishment is a priority tool for coastal management applied in the EU countries. Main benefits of this coastal stabilization method are considered as follows: • no contribution to erosion in adjacent coastal sections, • almost full integration into the landscape, • improvement of quality of recreational areas. “Traditional” coastal protection structures at the Liepāja WWTP site. Photography by: VilmārsBogovičs

  24. Measures taken on the beach of Kaugurciems • Nourishment with imported sand. • 3700 cubic meters of sand was refilled along a 500 m long stretch of beach. • Sand was acquired in the Gulf of Riga during dredging of the Lielupe port access channel at the depth of 2.0-4.0 m.

  25. Measures taken on the beach of Kaugurciems “optimal/preferred” crossection of coastal slope after sand nourishment crossection of coastal slope after erosion during severe storm event fore-dune formation after nourishment and “dune planting” measures Height above mean sea level (m) beach face Approximate distance from “first line” buildings (m)

  26. 2019.09.12., Jūrkalne Thank You! Dr. Jānis Lapinskis University of Latvia Department of Geography and Earth Sciences janisl@lu.lv

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