Sandy beaches can be found all over the world and are on the interface between the sea and the land. Important functions of beaches are the protection of the inland to the forces of the sea and providing local opportunities in recreation. The impact of storm events on the beach is therefore an important topic of research especially with future climate change predicting more extreme events with the influence of Sea Level Rise expected to result in a worldwide decrease in beach area.The famous Copacabana beach, located at the South-Atlantic ocean is one of the most popular tourist attractions in Rio de Janeiro with thousands of visitors per year. The beach is characterized by its parabolic shape with rocky headlands on either sides. In July 2019 a storm event occurred at the beach with a 7-day period of energetic waves. This resulted in significant erosion along the whole beach up to 40 meters leaving not more than 10 meters of beach width in the South part of the beach. The period of erosion was followed up by a period with year-round average wave conditions resulting in rapid natural recovery with the beach returning to its original beach width within a period of 4 weeks. The focus of this research is on the cycle of erosion with subsequent recover which is important in having a long-term sustainable beach cycle.The history of Copacabana beach is marked by one major nourishment in 1970 which resulted in the 55 meter widening of the beach parallel avenue and an average widening of the beach of 35 meters. From 1970 onwards historically available satellite images show a stable beach behavior with the equilibrium profile of the beach showing smaller beach widths in the South compared to the North. A dataset of high resolution Sentinel 2 is analyzed in terms of beach width for a period of 4 years. This clearly shows the short-term variations in beach width of which most are the result of the impact of storm events. This highlights the impact of the July 2019 storm event showing rapid recovery in terms of beach width.Storm events are characterized by a 2 to 7-day period of energetic swell-dominated waves often from in between the South and SSE. The maximum wave height during the July 2019 storm event was of a yearly return period in combination with an erosional impact which was of lower frequency according to locals. What caused the big erosional impact was the long 7-day duration of the storm in combination with an extraordinary wave direction from the SE. Under this wave direction the South part of the beach is most vulnerable due to a convergence of wave energy as a result of bottom refraction. In combination with a lower equilibrium width in this part of the beach due to the lack of sand placement during the 1970 nourishment this part of the beach is most vulnerable to storm impact. The subsequent beach recovery process shows rapid beach width recovery with recovery rates up to 1.4m/day. This is the result of mild wave steepness due to the swell-dominated wave climate in combination with the equilibrium beach state characterized by an attached sandbar. Both these system characteristics are positively related to the recovery rates (Phillips et al., 2017). However, structural erosion is visible in terms of backbeach elevation in the South part of the beach which as of 16 months after the July 2019 erosion event shows no signs of recovery.To further test the beach vulnerability, the July 2019 storm and subsequent recovery period are modelled subsequentially with the XBeach Surfbeat and- stationary mode. With the use of scenario modelling an attempt is made to test the vulnerability related to wave characteristics, erosion/recovery duration and the frequency of storms. Judgement of the model performance resulted in good model applicability and realistic model results for the erosion simulation. The results confirm the highest impact is in the South part of the beach under a SE wave direction. Besides this, the impact of an increased wave height (resulting in a 21% increase in erosional volume with a 10% increase in wave height) is more significant along the whole beach compared to an increased extreme event duration (resulting in a 9% increase in erosional volume with a 20% longer duration). During periods of recovery the swash zone processes become more important. These processes are not well represented in XBeach. To compensate for these effects the Bermslope model can be used forcing the slope in the swash zone to a pre-defined value (Roelvink & Costas, 2017). The model results however still shows a limited interaction between the beachface and the sub-aquatic part of the beach resulting in accretion further offshore than is observed in reality. From this it is concluded that it is not possible to assess the beach vulnerability in relation to recovery rates with XBeach.The third and last part of this research looks into the future changes in beach vulnerability taking into account the effect of climate change. Local long term climate trends are analyzed with the use of multiple data sources. This results in a clear positive trend showing a future increase of mean wave height. For the other climate parameters like the extreme wave height, storm frequency and wave direction a wide range of trends is found. This often shows both a positive and negative trend among the available data. Within the range of future climate trends there is a clear indication of a future increase in beach vulnerability. Both an increase in the mean wave height as a potential increase in extreme wave heights has significant implications on the erosional quantities judging from the model results. Where a 10% increase in extreme event wave heights results in a 22% increase in erosional quantities according to the model results. With a possible eastward change of mean wave direction chances of SE directed storm events increases resulting in increased beach vulnerability in the South under convergence of wave energy. For Sea Level Rise the impact is relatively highest in the South of the beach with beach decay predictions being approximated at a maximum of 8.4 meters as of 2070 with the use of the Bruun rule (Bruun, 1962). From this it is concluded that the vulnerability of the South part of the beach is bound to increase the most in the future with also taking into account the structural backbeach erosion as a consequence of the July 2019 erosion event. Future interventions with the goal decreasing beach vulnerability should focus on either widening or further protecting the South part of the beach.

Growth of world population, sea level rise, land subsidence and climate change gives new challenges for the present and the future. A new innovative approach of engineers is needed to reach socio-economic development with care for the environment. In the Netherlands, an EcoShape consortium is initiated where multiple experts came together from the Dutch private and public sector. In this consortium governmental organisations, knowledge institutes and business companies are involved to search for adaptable and sustainable engineering solutions to exploit and promote the ‘Building with Nature’ program. The main goal is to move from building in nature towards building with nature, using the natural forces present in the system.

Chile has shown interested in the Dutch Building with Nature program and the question raised whether a similar concept could be introduced in the country. Therefore, the organisational structure of the Chilean water sector related to coastal engineering is investigated in this research, as well as several case studies are used to illustrate the potential of Building with Nature in Chilean projects. These projects are the coastal erosion in Pichilemu, a port expansion in San Antonio and coastal erosion in Los Vilos.

The Chilean coast shows in different aspects a very dynamic behavior. For the design of a coastal structure it is important to understand this dynamic behavior and the possible consequences. In addition, the study concluded that Chile is a very privatized country which is important to consider when applying Building with Nature into coastal projects. The privatization has the consequence that a substantial amount of stakeholders need to be involved in the projects also funding can be a challenge.

In general, the conclusion can be drawn that there is lack of information on the coastal characteristics in Chile. More data needs to be conducted to implement trustworthy Building with Nature designs. Additionally, one could state that there is a communication gap between the governmental parties as the Dirección de Obras Portuarias and Ministerio de Obras Públicas and the local parties involved in coastal projects. This is important to solve, as these parties needs to be involved in all coastal projects. Another outcome of the case studies is the absence of an environmental vision for most of the initiated coastal projects investigated and the absence of a long term vision of coastal management.

Meeting with various engineering consultancy firms showed the presence of a strong incentive to enlarge the consciousness on the environmental and societal aspects in Chile, and the ambition for a more co-creative and multidisciplinary design approach. Arcadis Chile has shown interest to establish a platform to introduce the Building with Nature approach in Chile. Together with the Universidad de Valparaíso, Arcadis Chile can be the initiator for the implementation of the philosophy and the increase of awareness among other important actors in the water sector.