J. Javier Diez

Geometric Detached Breakwater Indicators on the Spanish Northeast Coastline

Abstract Many beaches have been eroded and the obvious environmental and landscape degradation of many coastal stretches are problems that coastal engineers are spending time solving. With this in mind, different protection methods have been used over time, most on the basis of the artificial nourishment of beaches and the building structures such as groynes and detached breakwaters. Detached breakwaters are artificial structures, generally parallel to the coastline, inspired by the working of natural formations, protecting a certain stretch from wave action and being able to create accretion areas. This is why these structures have been in general use, with different results, since the 1970s in countries such as Japan, the United States, Israel, Spain, Italy, and Australia. The study undertaken for this research focuses precisely on this type of structure, with the purpose of providing an overall view of the state of the art in this field. In addition, the effects of a detached breakwater on the shoreline for a series of real cases on the Spanish coastline were analysed to check whether the empirical relations given by different researchers for classifying the shorelines type of response were fulfilled for them all or not. This study only takes formulas on the basis of the geometrical characteristics of breakwaters into consideration as being the most used by design engineers for predesigning a construction. All the formulas studied are based on the nondimensional B/X monomial, which is a ratio between the two most important geometric breakwater parameters (the length of the detached breakwater, B, and its distance to the initial coastline, X), so the result of this work led us to propose the following geometric model for the case of the Catalonian coastline: tombolo formation if B/X ≥ 1.3; salient formation if 1.3 > B/X > 0.5; limited shore response if 0.5 ≥ B/X.

Cancun-Nizuc Coastal Barrier

Abstract This paper is the result of the analysis of several studies made by the Autonomous National University of Mexico (UNAM) (during 1989–1991) and by the Federal Commission of Electricity (CFE) (during 2000–2001 and 2003) since hurricane Gilbert hit the Yucatan Peninsula (1988). The analysis was finished at the end of 2004 with the development of a hydrodynamic and morphodynamic model of the littoral system. These studies were looking for a solution to the erosion suffered by the Cancun littoral barrier (“island”) and to obtain a good understanding of the littoral dynamic processes in the barrier of Cancun-Nizuc. Although the erosion of this barrier only became obvious after Gilbert occurred, there is evidence to conclude that the hurricane effects are not the origin of the erosion. The hurricane only worsened a process that existed for a long time, probably due to the inadequate and excessive occupation of the beach front that reduced the capacity of recovery (“resilience”) of the beach profile. Different measures were taken to protect the zone, but they soon failed; the erosion continued and hurricanes Ivan and Wilma worsened the conditions of the whole barrier. Finally, the recovery of the barrier was tackled by means of sand nourishment. This nourishment has been completed in June 2006 in parallel with the drafting of this paper.

Further Studies for Stabilizing the Entry Channel to Foz Fishing Port, Lugo

Abstract This article discusses a case study made on research carried out on a currently decaying inner harbor in a Cantabrian estuary (ría) (northern Spain), of which natural shelter conditions had led to the development of an old fishing vessel refuge against extraordinary winds and storms and the subsequent construction of a port. Previous research work has been on-going since 1978, seeking shore protection through simple beach restoration based solely on field observations with purely morphodynamic comprehension aims. The object of this investigation work is to now analyze possible definitive solutions for stabilizing the ports entry channel and maintaining its depth by using not only accumulated field experience but new measurements and numerical models.

Meteocean Influence on Inland and Coastal Floods in the East of Spain

ABSTRACT Diez, J.J.; Esteban, M.D.; López-Gutiérrez, J.S., and Negro, V., 2013. Meteocean influence on inland and coastal floods in the east of Spain. The Santa Irene flood, at the end of October 1982, is one of the most dramatically and widely reported flood events in Spain. Its renown is mainly attributable to the collapse of the Tous dam, but its main message is to be the paradigm of the incidence of the maritime/littoral weather and its temporal sea-level rise on the coastal plains inland floods. The Santa Irene flood was attributable to a meteorological phenomenon known as gota fría (cold drop), a relatively frequent and intense rainy phenomenon on the Iberian Peninsula, particularly on the Spanish E to SE inlands and coasts. There are some circumstances that can easily come together to unleash the cold drop there: cold and dry polar air masses coming onto the whole Iberian Peninsula and the north of Africa, high sea-water temperatures, and low atmospheric pressure (cyclone) areas in the western Mediterranean basin; these circumstances are quite common during the autumn and, as it happens, in other places around the world (E/SE Africa). Their occurrence, however, shows a great space-temporal variability (in a similar way to hurricanes on Caribbean and western North Atlantic areas or also in a similar way to typhoons). In fact, all of these are equivalent, although different, phenomena, able to have a different magnitude each time. This paper describes the results of a detailed analysis and reflection about this cold drop phenomenon as a whole, on the generation of its rains, and on the different natures and consequences of its flood. This paper also explains the ways in which the nearby maritime weather and the consequential sea level govern floods on different zones of any hydrographical basin. The Santa Irene case can be considered as a paradigm to explain the influence of nearby maritime climatic conditions on flooding phenomena not only in coastal but also in upward inland areas.

Functional and Environmental Design of Detached, Low Crest Level Breakwaters

Abstract In this article we research the design of detached breakwaters, a type of coastal defence work designed to combat erosion on beaches in a stable, sustainable fashion. Our aim is to formulate a functional and environmental (nonstructural) method of design that defines the fundamental characteristics of a detached breakwater as a function of the desired effect on the coast whilst meeting social demands and preserving or improving the quality of the littoral environment. We aim to make this method generally applicable by considering relations between variables of different natures (climatic, geomorphologic, and geometric) influencing the changes experienced on the coast after the detached breakwater has been built. We carried out the study of the relations between the different variables on the data from 19 actual, existing detached breakwaters on the Spanish Mediterranean coastline, and we followed a methodology based on the implementation of nondimensional monomials and on a search for relations of dependency between them. Finally, we discussed the results obtained and came up with a proposal for a design method that uses some of the graphic relations found between the variables studied and that achieves the main objective. For example, a case of a detached breakwaters geometric presizing is solved as a practical demonstration of how the method is applied.

Reason and Being of Engineering Geology

This paper demonstrates the importance of a holistic comprehension of the Earth like a planet that is alive, not only in its Biosphere, looking at the atmosphere-ocean-crust-mantle interactions as its different sectorial expressions (climate, fluid-dynamics, morpho-dynamics, tectonics…) following the solar radiation and nuclear geothermal sources of energy. It considers the environmental incidence of different engineering activities to realize their underfeeding as the raison, and leads to that holistic formation as the being of the engineering geology.

Coastal Floods and Climate Change

The Earth has been undergoing a global warming trend since the Little Ice Age being mostly assumed to be progressively increasing along the last and a half centuries. But this secular warming and the previous Little Ice Age cold wave had precedents linked with sea level and other climatic actions. Populations have been driven by climatic conditions, and processes of founding and expanding cities in coastal areas, on the other hand, have undergone great changes over time, under increasing conditions of vulnerability and even hazard. Therefore, the risk of flooding can be attenuated, but never eliminated. And question goes further due to concomitant phenomena, as subsidence and isostasy, which are exacerbated by the transformation of terrain and by settlements. This paper pretends a syncretistic discussion to face the problem in its most realistic way. It reflects on the “cold drop” phenomenon as a whole, on the generation of its rains and on the different natures and consequences of its floods, and compare with other cyclone events. And it approaches the ways in which the maritime weather and the consequent sea level govern floods on the lowest hydrographical basin.

Human Factor in Resilience Systems

This paper shows the importance of a holistic comprehension of the Earth as a living planet, where man inhabits and is exposed to environmental incidences of different nature. The aim of the paper here summarized is a reflection on all these concepts and scientific considerations related to the important role of men in the handling of natural hazards. Our Planet is an unstable and dynamical system highly sensitive to initial conditions, as proposed by Chaos theory (Gonzalez-Miranda 2004); it is a complex organic whole, which responds to minimal variations which can affect several natural phenomena such as plate tectonics, solar flares, fluid turbulences, landscape formation, forest fires, growth and migration of populations and biological evolution…. This is known as the “butterfly effect” (Lorenz 1972), which means that a small change of the system causes a chain of events leading to large-scale unpredictable consequences. The aim of this work is dwelling on the importance of the knowledge of these natural and catastrophic geological, biological and human systems so much sensible to equilibrium conditions, to prevent, avoid and mend their effects, and to face them in a resilient way.

Coastal Impacts Around Guadiaro River Mouth (Spain)

The “Port of Sotogrande” Beach (San Roque, Cadiz, Spain) has suffered significant erosion and changes since the construction of the marina and port of Sotogrande (San Roque, Cadiz, Spain). This paper reviews the dynamical processes on Guadiaro front and establishes relationship between them. It sets from a comparative evolution of the Alboran Sea Coast outlets and bays since the Little Ice Age, which shows that the Guadiaro estuary has remained functional while all other Alboran fluvial estuaries silted to soon become deltas, to analyse the most detailed recent changes on the beach. The study shows the evidences of the coastal impacts around the mouth, even further than mouth littoral barriers, of the port infrastructures; and it provides new elements to understand the dynamical processes on the mouth and surroundings as well. That should be fundamental for shore protection along the whole coastal stretch.