New design parameters for biparabolic beach profiles (SW Cadiz, Spain)

165 profiles of seventy-one beaches along the Gulf of Cadiz (SW, Spain) were studied to improve the formulation of the beach profile in tidal seas. Maritime climate, degree of energy exposure and size of the sand grains were taken into account to study the two sections of the biparabolic profile. The objective of the study was the determination of more accurate formulations of the design parameters for the equilibrium profile that involves tidal seas. These formulations were modelled and validated based on existing profiles to quantify the error existing between the real profile and the modelling. This comparative analysis was extended by considering the formulations proposed by other authors. The best results were obtained with the proposal presented herein

A Design Parameter for Reef Beach Profiles—A Methodology Applied to Cadiz, Spain

The southwestern coast of Spain is in a tidal zone (mesotidal) which causes the equilibrium profile to be developed in two different sections: the breakage section and the swash section. These two sections give rise to the typical bi-parabolic profile existing in tidal seas. The existence of areas with reefs/rocks which interrupt the normal development of the typical bi-parabolic profile causes different types of beach profiles. The objective of this article is designing an easy methodology for determining new formulations for the design parameters of the equilibrium profile of beaches with reefs in tidal seas. These formulations are applied on 16 profiles to quantify the error between the real profile data and the modelling results. A comparative analysis is extended to the formulations proposed by other authors, from which it is found that better results are obtained with the new formulations

Virtual resources for the improvement of teaching in the course of Port and Coastal Engineering (dregree in Civil Engineering)

Port and Coastal Engineering is a subject included in the third year of the degree in Civil Engineering (Civil Constructions and Hydrology specialty) taught at the Polytechnic School of Algeciras. As this is a subject with a very specific syllabus, there is no textbook (or even appropriate references) that contemplates all the related topics of the whole course. Moreover, there are many students who, for different reasons (repeaters, Erasmus, labour obligations, ...), cannot attend the regular classes. This lack of attendance has been leading to another problem: this kind of students have been leaving the subject for several years. In addition, understanding of the basic concepts becomes even more complicated for Erasmus students enrolled in the subject because of the language barrier. In order to solve this problem, a project of teaching innovation has been launched which consists of the creation of a set of evaluable tasks for the different topics addressed to be performed by the students. In this way, the students are motivated to keep up-to-date the course contents. A comparison of the last year results with those of the preceding five years is provided. Finally, an analysis of the significance of the improvement is also presented

Increase in the Erosion Rate Due to the Impact of Climate Change on Sea Level Rise: Victoria Beach, a Case Study

This article provides a general methodology for calculating the retreat of the coastline and the volume of sand necessary to renourish a beach due to sea level rise (SLR) in the medium-long term. An example is presented, Victoria Beach, and a projection is made for the years 2030, 2040, 2050, and 2100. The results obtained take into account global sea level rise (GSLR), which is worldwide, and local sea level rise (LSLR), which considers climate variability and vertical land movements. Regarding GSLR, data were provided by the projections from IPCC (Intergovernmental Panel on Climate Change) scenarios and empirical models, such as Rahmstorf and Pfeffer. The LSLR data came from the tide gauge station located in Cadiz. Finally, the results obtained showed that global warming impacts erosive effects and the subsequent volume of sand required to renourish beaches. The total sea level rise (TSLR) projections indicated for Victoria Beach are relatively higher than the GSLR projections. Even in the best IPCC scenario (RCP 2.6), Victoria Beach presents a significant erosion of 52 m, requiring a volume of sand of 1.0 Mm3 to supply renourishment.14 página

Use of the ANKI Software in Coastal Engineering Courses: Methodology and Results

Many people believe that engineering subjects require only mathematical and physical abilities as well as space perception. However, some aspects of the syllabus, must be memorized to achieve optimal academic results. The pandemic situation has meant a reduction in face-to-face classes, which has made it difficult to highlight (through repetition by teachers) those concepts that must be learnt by heart due to their importance. As is well known, the Notecard Question and Answer Technique (NQAT, based on Leitner’s system) helps students to learn those important ideas that must be kept in the long term memory to remember when needed. Therefore, an educational project is presented here that contemplates the creation of a database of question-answer cards to facilitate the memorization of concepts, formulas and key values of different parameters essential for understanding coastal engineering problems. The methodology was experimented in different courses, related to Coastal and Port Engineering. These courses are included in the third year of the Marine Sciences and Civil Engineering Bachelor degrees as well as in the MSc degree in the University of Cadiz. The program chosen was the ANKI, of broad application, easy to use and free to access. As a collateral advantage, students became familiar with this software and were able to use it in other subjects. Through a selective distribution of the different topics, all the students participated in the task of preparing the cards. Their use was encouraged by a series of online tests and a “supplementary bonus” to the final examination. The results obtained between the current course (with flash cards) and the previous one (without flash cards) did not show any substantial change in the number of students who pass the subject. However, students reported that it took less time to memorize formulations and key concepts

Increase in the erosion rate due to the impact of climate change on sea level rise: Victoria Beach, a case study

This article provides a general methodology for calculating the retreat of the coastline and the volume of sand necessary to renourish a beach due to sea level rise (SLR) in the medium-long term. An example is presented, Victoria Beach, and a projection is made for the years 2030, 2040, 2050, and 2100. The results obtained take into account global sea level rise (GSLR), which is worldwide, and local sea level rise (LSLR), which considers climate variability and vertical land movements. Regarding GSLR, data were provided by the projections from IPCC (Intergovernmental Panel on Climate Change) scenarios and empirical models, such as Rahmstorf and Pfeffer. The LSLR data came from the tide gauge station located in Cadiz. Finally, the results obtained showed that global warming impacts erosive effects and the subsequent volume of sand required to renourish beaches. The total sea level rise (TSLR) projections indicated for Victoria Beach are relatively higher than the GSLR projections. Even in the best IPCC scenario (RCP 2.6), Victoria Beach presents a significant erosion of 52 m, requiring a volume of sand of 1.0 Mm3 to supply renourishmentPostprint (published version

Influence of Di erent Sieving Methods on Estimation of Sand Size Parameters

Sieving is one of the most used operational methods to determine sand size parameters which are essential to analyze coastal dynamics. However, the influence of hand versus mechanical shaking methods has not yet been studied. Herein, samples were taken from inside the hopper of a trailing suction dredger and sieved by hand with sieves of 10 and 20 cm diameters on board the dredger. Afterwards, these same samples were sieved with a mechanical shaker in the laboratory on land. The results showed di erences for the main size parameters D50, standard deviation, skewness, and kurtosis. Amongst the main results, it should be noted that the highest values for D50 and kurtosis were given by the small sieves method. On the other hand, the lowest values were given by the mechanical shaker method in the laboratory. Furthermore, standard deviation and skewness did not seem to be a ected by the sieving method which means that all the grainsize distribution was shifted but the shape remained unchanged. The few samples that do not follow these patterns have a higher percentage of shells. Finally and definitely, the small sieves should be rejected as a sieving method aboard

Learning from hydrological and hydrogeological problems in civil engineering. Study of reservoirs in Andalusia, Spain

This study presents a novel review of seven case histories of Andalusian reservoirs (Southern Spain) affected by different hydrological and hydrogeological problems that have led to severe malfunctions. The failures reported are related to (i) water quality degradation due to salinization and acid mine drainage, (ii) leakage in karstified terrains, (iii) environmental and hydrogeological impacts associated with an inadequate water planning and (iv) large evaporative losses from the reservoir. Detailed information on the geological context, hydrological/hydrogeological origin of the problem, repercussions on infrastructure functioning and remedial measures applied or proposed has been gathered for each case. Results of on-site research carried out by the authors in some of the locations studied and a comparative analysis of similar case histories at international level are also included. The purpose of this work is to emphasize the need of learning from past mistakes and provide guidance for future dam construction works, especially in the Mediterranean region. It also highlights the role of geological and hydrogeological research in dam sitting and the consequences of inadequate terrain characterisation, biased hydrological planning and data misinterpretation or undervaluation. This review evidences the need of conducting comprehensive studies that do not only focus on the infrastructure itself, but also on non-constructive aspects (monitoring of geological features and hydrological variables) and relevant processes (e.g. leakage, salinization and contamination) that might compromise the efficient functioning of the infrastructur

¿Cambia mucho el tamaño de grano obtenido mediante tamizado manual frente al mecánico?

Los procesos erosivos en el litoral, junto con la importancia económica del turismo (Houston, 2008), hacen que las realimentaciones periódicas de nuestras playas sean sumamente frecuentes. Y el tamaño de la arena es uno de los más importantes parámetros a la hora proyectar este tipo de obras. La media o la desviación típica del tamaño de grano son imprescindibles para comprobar si la arena de préstamo (terrestre o sumergida) es adecuada para sustituir a la transportada previamente por el mar (Pranzini et al., 2018). Además, el conocimiento de la distribución granulométrica del sedimento hace posible prever la reacción del perfil transversal ante una tormenta (Larson y Kraus, 1991), o calcular la cantidad necesaria de arena para abordar una regeneración (USACE, 2002). Por otra parte, a la hora de tomar decisiones sobre la zona de vertido de una cántara llena de arena, el gestor precisa conocer los parámetros antes mencionados de manera casi inmediata. Eso significa que los análisis del sedimento deben efectuarse a bordo de la draga, mientras se desplaza de la zona de préstamo hacia la costa a regenerar. Sin embargo, debido a la habitual escasez de espacio, a la ausencia de un laboratorio adecuado y al no siempre fiable suministro eléctrico, los tamizados deben hacerse a mano. Ya se ha estudiado la influencia del tiempo de tamizado a la hora de analizar la distribución granulométrica de una arena de playa o de duna (Roman-Sierra et al., 2013). Sin embargo, hasta este momento no se ha analizado la posible diferencia en la media y la desviación típica de una arena tamizada de manera manual a bordo de una draga frente a una tamizadora mecánica en un laboratorio en tierra. Asímismo, para ahorrar espacio y esfuerzo físico, a bordo de la draga suelen usarse tamices de 10 cm de diámetro frente a los más habituales de 20 cm en laboratorio. Para dar respuesta a estas preguntas, se aprovechó una regeneración efectuada en Cádiz en el año 2017 para efectuar una serie de pruebas a bordo de la draga Njord. Los extrapolables y más que útiles resultados, así como la influencia y consecuencias que tienen las diferencias observadas en la dirección de obras de regeneración de playas, se expondrán durante la presentación oral

Audiovisual Resources in Laboratory Practices for Hydraulic Engineering

During the laboratory practices of a subject, students write all the data, methodology, development and final results for later study at home. When a certain period of time passes since the essay was carried out, there are details that many of the students forget. They do not relate the methodology and development with the laboratory equipment used. The use of audiovisual resources can help students to better study the practical part of the subject. The new teaching resources will be applied in a block of the Hydraulics subject, which is included in the second year of the degree in Civil Engineering, at the Algeciras School of Engineering and Technology. The subject has a theoretical-practical part and another of laboratory practices. The course is divided into three blocks: Hydrostatics, Hydrokinematics and Hydrodynamics. The article will focus on the improvement of the teaching resources of the part of the laboratory practices, of the hydrostatics block. Audio-visual resources will consist of explanatory videos with the development of laboratory practices. The videos show for each of the tests the initial data, the methodology to be applied and the development of the practice. These videos help students to reinforce the knowledge acquired in the laboratory. In addition, the use of these resources helps Erasmus students (for language reasons) to understand the practices. Additionally, the generated material can be used as a resource in the case of non-face-toface practices (as in previous courses due to the Covid-19 pandemic). For the implementation of this initiative, a teaching innovation project has been developed. Eventually, the students show a great interest in the virtualization of the laboratory practices and a high degree of satisfaction with the available videos. Moreover, their academic results improved slightly with this new methodology