Print Email Facebook Twitter Coastal Erosion Mitigation at RN90 Title Coastal Erosion Mitigation at RN90: Integral approach to Erosion Mitigation along the Caribbean Coast of Colombia Author Voorend, S.J.M. Contributor Stive, M.J.F. (mentor) Reniers, A.J.H.M. (mentor) van Overeem, J. (mentor) Huisman, B.J.A. (mentor) Faculty Civil Engineering and Geosciences Department Hydraulic Engineering Programme Civil engineering Date 2017-06-15 Abstract As a result of increased economic development in Colombia, the pressure on the natural system has increased. The export of natural resources through international ports at both the Pacific Ocean and Caribbean Sea causes conflicts between infrastructure and the dynamic behaviour of the coastal system. This Master Thesis focusses on the bay between Barranquilla and Santa Marta, along the Caribbean Sea. The case study combines structural erosion with an internationally recognized ecological zone and a vulnerable coastal highway (RN90) which connects the port of Barranquilla to the hinterland. The complex problem requires an integral approach, which aims at providing a most promising, long term solution to mitigate the adverse effects of coastal erosion. Relevant stakeholders were identified by means of a stakeholder analysis. No stakeholder was found who is responsible for coastal zone management in Colombia. The lack of ownership of the problem led to a late identification of the problem and resulted in the necessity to construct an emergency revetment along the RN90 at KM19. The processes driving the coastal erosion are: The natural relocation of the Rio Magdalena, the decreased supply of sediment from the Rio Magdalena and the strong gradient in alongshore sediment transport along the bay. The coastline development was predicted using different methods for several time scales. For short time scales (<5 years) historic coastline positions were analysed using satellite images. On intermediate time scales (5 -50 years) the process-based coastline model UNIBEST was used. The equilibrium bay position was estimated using MEPBAY, which is based on the Parabolic Bay Shape Method. Continuous, structural (long-term) erosion should be anticipated in the middle sections of the bay, since a timescale in the order of a thousand years is estimated before the bay reaches an equilibrium position. Using the predicted coastline development, two critical locations along the RN90 were identified; at KM19 immediate action is required and at KM28 action should be taken within the next 15 years. Six alternatives were defined to mitigate the adverse effects of erosion at the critical locations. The measures were implemented in UNIBEST to predict the coastline development. The impact of the alternatives was evaluated using a Multi Criteria Analysis (MCA), with the criteria defined as the stakeholder requirements resulting from the stakeholder analysis. Hard coastal protection works, such as the “Revetment”, “Breakwater” and “Groin Field”, can provide local protection for critical locations by shifting the erosion away from the critical locations to the downstream area. However they are expected to become very costly over time as the static constructions require extensive maintenance and scour protection in the highly dynamic coast zone. The alternative “Nourishment” was best appreciated in the qualitative scoring, however the benefits of a nourishment are not appreciated enough to account for the relatively high costs. The most promising alternative is identified as the alternative “Relocate Road”. On the basis of the predicted coastline development a new road is built more landward at the critical locations. The solution requires limited intervention in the coastal zone and can be combined with the already planned highway expansion. An addition study is required to select the most suitable highway alignment taking into account the local soil characteristics. In general it is advised to assign coastal management to an existing or new governmental body, to ensure coastal protection is organized on a nation level. This will not only concentrate coastal knowledge, but will allow for monitoring and pre-emptive actions as well to avoid the necessity for short-term emergency solutions. Subject ColombiaCaribbean CoastRio Magdalena‘Ruta Nacional 90’RN90Coastal erosionAlongshore transportErosion mitigationMulti-criteria analysisDelft3D-WAVEUNIBESTMEPBAY To reference this document use: http://resolver.tudelft.nl/uuid:b32ba95f-421e-4793-828d-b6cb4051c213 Coordinates 11.00000, -74.50000 Part of collection Student theses Document type master thesis Rights (c) 2017 Voorend, S.J.M. Files PDF MSc Thesis S.J.M. VOOREND.pdf 8.84 MB Close viewer /islandora/object/uuid:b32ba95f-421e-4793-828d-b6cb4051c213/datastream/OBJ/view