Pärnu Bay study area Are Kont Valdeko Palginõmm Hannes Tõnisson Ülo Suursaar Agnes Anderson Acknowledgements: BONUS BaltCoast project has received funding from BONUS (Art 185), funded jointly by the EU and [national funding institution acknowledgements, as appropriate].

Design Step Pärnu Bay study area including City of Pärnu and Valgeranna summer resort

Vulnerability of Pärnu to 2.1 m storm surge

Define the administrative boundaries for the Virtual System Pärnu County: City of Pärnu Rural municipalities: Varbla Tõstamaa Audru Tahkuranna Häädemeeste Kihnu

Define the linkages between the ESE components Environmentally sensitive area under growing human pressure Shallow bay and low-lying coast Sea-level fluctuations caused by windstorms associated with occasional ice attacks Extensive floods, erosion of sandy beaches and shoreline changes

Define the linkages between the ESE components Valuable natural resources providing a number of ecosystem services and being a driving force for economic growth Public beaches and warm seawater in summer associated with relevant infrastructure The Pärnu Bay has a considerable importance in fisheries. Over 80% of the coastal fishing in Estonia is connected with this region The bay is an important spawning ground and an area of development of juvenile fish for many species

Define the linkages between the ESE components Marine spatial planning of the Pärnu Bay is under developing The marine spatial planning should be harmonized with the existing coastal plannings

What external hazards are there? Occasional, extreme storm events in autumn or early winter Such storms may cause storm surges of 2-3 m height in the practically tideless Pärnu Bay

What external hazards are there? Concurrent impacts are: inundation of low-lying urban and coastal areas damage of critical infrastructure coastal erosion siltation of navigation channels secondary pollution from re-suspended bottom sediments and storm debris

What external hazards are there? The impacts of extreme storms are usually track- dependent: travelling from west to northeast, the cyclone must retain a great deal of its strength the track must pass Estonia about 100-500 km north, which yields local SW-W winds with sustained speeds up to 20-30 m/s pre-elevated (by up to 50-70 cm) mean Baltic Sea level as a result of preceded stormy period or a series of successive cyclones

Describe the state of the system and knowledge gaps Large-scale topographic, geological, soil, vegetation, etc. maps Profiles, reports and results of different kind of natural studies Hydrodynamics of Pärnu Bay has been measured and modelled and the results are related to the records of meteorological stations and tide gauges

Describe the state of the system and knowledge gaps Initiated by the Ministry of the Environment, a preliminary risk assessment in case of storm surges and floods has been done and the areas at risk have been mapped. After the last extreme storm in January 2005, a lot of measures have been taken: improve the rescue service system inform the people in advance about possible hazards change the regulations considering constructing in the areas at risk

Describe the state of the system and knowledge gaps We do not have any socio-economic models for the study area We do not know quantitatively the reactions to extreme events in the economic and social spheres

Pärnu Bay study area conceptual model Compensation by insurance companies City of Pärnu Valgeranna Natural hazard – storm surge Inundation of city center Erosion of sandy beach Damaged dwellings, infrastructure, tourist facilities Problems with sewage system, water quality Disturbances in transport and communication Loss of sunning and swimming area Lost profit from tourist service Inundation of Audru polder Responses and adaptations Raising of awareness, warning of people Health and rescue services Regulations of constructing in areas at risk Changes in coastal and marine spatial planning Conservation of breeding ground for waterfowl Facilitation of natural tourism and playing golf Siltation of navigation channel

Most important impacts are: 1 Most important impacts are: 1. Inundation of the City – affected people, infrastructure and real estate 2. Rapid sediment re-distribution - Erosion (damage and loss of infrastructure) and accumulation (again damage to infrastructure – siltation of harbour channels)

Inundation of the City (what happened, current situation): Maximum event (2005 storm Gudrun) 8 km2 of the City Under the water (over 25%); Sea level up to 275 cm (Critical level is only 160 cm) Damaging events are expected at least once in 20-30 years (without climate change); 775 houses were affected 300 people were evacuated 1 casuality

Inundation of the City (What is the future): Inundation level up to 400 cm (in perfect storm scenario) by year 2100 (sea-level rise according to RCP 8.5 + stronger storm), which is over 1 m over the current max; 1/10 year inundation is expected to cover 4.85 km2 (15% of the City, 600 people affected); 1/100 year inundation is expected to cover 7.1 km2 (21% of the City, 3800 people affected); 1/1000 year inundation is expected to cover 9.44 km2 (31% of the City, 8500 people affected - 21% of the City population) ;

Inundation of the City (Actions taken): Estonian Water Act, Chapter 51 on the assessment and management of flood risks. Based on this, the document “The preliminary assessment of flood risks” has been compiled and approved by the Ministry of the Environment in 2012; only densely populated areas are regarded as risk areas, in Pärnu region these are the city of Pärnu and densely populated areas in Audru Municipality, in the village of Papsaare; for these areas, maps with a different likelihood have been compiled (from 1 time per 10 years up to 1 time per 1,000 years) which are available at the respective map application of the Land Board. emeregncy act re-newed (For the whole Estonia);

Inundation of the City (Actions taken): Emergency commission established (Pärnu county) and action procedure and diferent actions for diferent flood levels; First response (sandbags for smaller events to protect lower buildings); Preliminary closure of streets that will be affected (no additional problems with extreme-event-adventure tourists); Affected infrastructure, dwellings and tourist attractions is calculated for diferent events – 37 km of steerts will be Under the water; Insurance companies have ordered their own inundation maps, more detailed than public ones and not only for densely populated areas

275 cm above mean sea-level

Inundation of the City (Gaps and solutions): Informing inhabitants is not up the task yet (there is storm warning and prediction of flood level but information is not translated to „normal people language“) – Solution?; it is known what buildings and infrastructure are affected in case of different flood levels, however, for most of them, there is no plan how to protect these and how to compensate the costs, number of public buildings (over 20% of 1/10 year inundated buildings are public buildings) will be also affected – Solution?! no clear future plans for increasing sea-level and resulting increase in flood levels – Solution?; Clear and throughout information (also for less densely inhabited areas) on flood levels belongs to insurance companies only – how to inform public? Urgent need for delivering such an information to public

Rapid sediment re-distribution (Current state) Rapid erosion in neighbouring municipalities; Loss of high-valued recreational sandy beaches; Damage to tourism infrastructure (no sandy beaches, destruction of trees and adventure track, damage to the tourism facilities (Lottemaa, etc.); Siltation of the harbour channel from Port of Pärnu (most important harbour in the region, 4th biggest cargo harbour in Estonia 1 800 000 t/year);

Rapid sediment re-distribution (Actions taken) Small-scale projects to build dunes (increaisng natural protection, reducing sediment flow to harbour channel) Local coastal protection measures (often hard protection), however, often dangerous and causing undesirable effect; No general action plan, lack of co-ordination, lack of general thinking.

Rapid sediment re-distribution (Future) Increasing erosion from neighbouring municipalities; Increasing damage to buildings and infrastructure; Loss of sandy beaches; Lost profit from recreation service Increased pressure to Pärnu beaches; Increasing costs of harbour channel maintenance (dredging).

Rapid sediment re-distribution (Gaps and solutions) No general plan for coastal protection - land and sea actions are planned separately in Estonia Nourishement of the beaches with material from harbour channel dredging (problems with sand quality? Legislation restriction? Cost?) More extensive dune building, who is paying? Loss of sea- view?; No more local hard defence measures, what happens with the existing ones?;

Small scale questions Drinking water – mostly groundwater, away from inundation area, well protected from floods – may affect land subsidence? Problems with some smaller wells near to the coast with increasing sea-level; Sewage treatment system – out of order during inundations = affecting bathing water quality ->impact to tourism – solution? Water is anyway with poorest quality along the Estonian coast, however, good for fish (rich in nutrients), etc.; Impact on public transport (during inundation and impact of erosion) - 6 buslines will be affected. Future access to low-lying harbour region and storing areas?

Data and Methods What strategy did you choose for the simulation modeling? Numerical modeling in the Pärnu Bay area has mainly been and is still used in hydrodynamical research This research has been closely related to the records of meteorological observation A multidisciplinary approach has been developed in order to combine the effects of climatic forcing on hydrodynamics and geomorphic shore processes

Data and Methods What strategy did you choose for the simulation modeling? In the current project, many different kind of large-scale maps (topographic, geological, hydrological, soil, vegetation, land cover, areas at risk, etc.) from different times can be used together with the reports of specific investigations and the results of numerical modeling

Data and Methods Which models were chosen? 2D hydrodynamic model (Gulf of Riga – Väinameri area; incl. Pärnu Bay). With this model, a number of sea level and flow hindcast studies as well as sensitivity experiments of extreme conditions have been carried out Modeling system composed of WRF atmosphere model (fed by MIROC5 reanalysis and local weather data) and FVCOM ocean model will be used to hindcast historic extreme surge events in the Pärnu Bay as well as the meteorological and hydrological parameters of similar storms under future climate conditions GIS has been used in monitoring, mapping and spatial planning, and can be used also in the current project

Problem scaling No