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Ítem The perils of human activity on South American deltas: Lessons from Colombia's experience with soil erosion(INT ASSOC HYDROLOGICAL SCIENCES, 2013-01-01) Restrepo A., Juan D.; Universidad EAFIT. Departamento de Ingeniería; Ciencias del MarThe Andean drainage basins of Colombian deltas exhibit a very delicate variety of ecosystems and environments along its prolonged trajectory, which has made it particularly vulnerable to the onslaught of modernity and human activity. While the increasing intensity of natural disasters in tropical areas is often blamed on global warming, the causes might not be as intractable. Soil erosion and deforestation, both caused by unrestrained human activity, can affect deltas more profoundly. Many anthropogenic influences, including deforestation, an agriculture and pasture increase by 75%, poor soil conservation and mining practices, may have accounted for the overall increasing trends of sediment transport from rivers to Colombian deltas. According to our recent study of human activities in terms of deforestation, 32% of the observed variance in sediment transport from the Magdalena River to its delta could be explained by deforestation. Thus, the amount of sediment transported by the Magdalena to its delta plain, approximately 50 Mt annually, is probably due to deforestation. Also, the Patia River in the Pacific coast has witnessed an increase in sediment transport by 45% during the last decade, an increase mainly accounted for by deforestation. Drawing from Colombia's experience with man-made ecological modifications, this paper offers a preliminary discussion on the implications of human pressure on fluvial ecosystems and their deltas, with the hope that this information will better equip citizens and policymakers across the developing world. Copyright © 2013 IAHS Press.Ítem Expanding level of coastal armouring: Case studies from different countries(COASTAL EDUCATION & RESEARCH FOUNDATION, 2011-01-01) Stancheva, M.; Rangel-Buitrago, N.; Anfuso, G.; Palazov, A.; Stanchev, H.; Correa, I.; Universidad EAFIT. Departamento de Ingeniería; Ciencias del MarConcreting the natural shoreline by use of traditional hard protective structures, as well as by port/harbour developments is commonly known as coastal armouring. Over the recent decades the expanding level of coastline hardening and its adverse impacts on the environment has arisen as one of the most critical problems all over the world. Therefore, our goal in this study was to demonstrate the crucial issue of progressive extent of technogenous coastal occupation by two case studies from different countries in Europe and in South America: Bulgaria and Colombia. To assess direct impact of armouring on the coastline and adjacent areas two case areas were selected for detailed investigation: an 18 km long coastline of the large Varna Bay (Bulgarian Black Sea coast) and 349 km long littoral of the Cartagena municipality (Caribbean coastline of Colombia). An indicative coastal segmentation of the both case sites by geomorphologic and engineering criteria was first implemented in GIS environment. As well as, for quantitative assessment of the influence of all maritime structures (port and coast-protection) on the studied coasts the coefficient of technogenous impact K was explored. A GIS methodology was applied for data processing, mapping the natural landforms/structures and to evaluate the technogenous impact on the both coastlines. The identified high extent of impacts due to built hard defence structures along the selected study areas in Bulgaria and Colombia could be considered as indicative of the large technogenous occupation of the coasts and the increasing level of shoreline armouring as a global issue.Ítem Estuarine Light Attenuation Modelling Towards Improved Management of Coastal Fisheries(SPRINGER, 2019-01-01) Tosic M.; Martins F.; Lonin S.; Izquierdo A.; Restrepo J.D.; Universidad EAFIT. Departamento de Ingeniería; Ciencias del MarThe ecosystem function of local fisheries holds great societal importance in the coastal zone of Cartagena, Colombia, where coastal communities depend on artisanal fishing for their livelihood and health. These fishing resources have declined sharply in recent decades partly due to issues of coastal water pollution. Mitigation strategies to reduce pollution can be better evaluated with the support of numerical hydrodynamic models. To model the hydrodynamics and water quality in Cartagena Bay, significant consideration must be dedicated to the process of light attenuation, given its importance to the bay’s characteristics of strong vertical stratification, turbid surface water plumes, algal blooms and hypoxia. This study uses measurements of total suspended solids (TSS), turbidity, chlorophyll-a (Chla) and Secchi depth monitored in the bay monthly over a 2-year period to calculate and compare the short-wave light extinction coefficient (Kd) according to nine different equations. The MOHID-Water model was used to simulate the bay’s hydrodynamics and to compare the effect of three different Kd values on the model’s ability to reproduce temperature profiles observed in the field. Simulations using Kd values calculated by equations that included TSS as a variable produced better results than those of an equation that included Chla as a variable. Further research will focus on evaluating other Kd calculation methods and comparing these results with simulations of different seasons. This study contributes valuable knowledge for eutrophication modelling which would be beneficial to coastal zone management in Cartagena Bay. © 2019, Springer Nature Switzerland AG.Ítem Observations of bed elevation changes at Cape Canaveral shoals(World Scientific Publishing, 2019-05-01) Paniagua, J.; Universidad EAFIT. Departamento de Ingeniería; Ciencias del MarÍtem Predicción de las magnitudes de retroceso de algunos sectores acantilados de Antioquia en condiciones de ascenso del nivel del mar – Resultados para el sector de Arboletes(Sociedad Colombiana de Ingeniería, 2012-08-08) Paniagua, Juan F.; Correa-Arango, Ivan D.; Universidad EAFIT. Departamento de Ingeniería; Ivan D. Correa-Arango (icorrea@.eafit.edu.co); Juan Felipe Paniagua (jpaniag2@eafit.edu.co); Ciencias del MarSea-level rise related impacts are required for coastal management, especially within littoral fringes with active tectonics and presence of strategic ecosystems likewise Colombian southern Caribbean. “Worst” scenarios predict a sea-level rise for 2100 circa 2 m above level of 1990. Among this context, retreat magnitudes prediction of littoral cliffs of Antioquia, formed along several sectors by soft rocks, is a primary element for medium-large term planning of the region. Considering this, possible shoreline positions along three critical sectors within Antioquia’s coast for 50 years in the future are presented (Arboletes and Turbo towns) and Los Córdobas – Puerto Rey sector (Córdoba department). For the Arboletes sector, considered as the most critical based on population density and present infrastructure, results for 2059 indicate the following: 1) Assuming a constant sea-level rise rate of +2.32 mm/yr (present value), mean shoreline retreat to 2059 would be –64 m. 2) Assuming a sea-level rise rate of +7 mm/yr, mean retreat distances would be about 134 m. 3) Assuming a sea-level rise rate of +22 mm/yr, mean shoreline retreat distances would be 200 m. Mean shoreline retreat distances between 64 and 200 m to 2059 are related to primary magnitude impacts over present infrastructure of Arboletes sector (downtown structures, access roads from Montería and towards Necoclí towns) and also the associated marine inundation of natural drainages, primarily Jobo and Arboletes rivers. Similar results could be shown for the other sectors considered within this study