Vicente Negro

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.

Offshore Wind Foundation Design: Some Key Issues

Despite the growth of the offshore wind industry, there are currently doubts relating to the design of wind facilities in the sea. This paper expounds current, already identified structural uncertainties: problems for soil characterization and transition piece (TP) design. This document also introduces new doubts or issues to be researched in the near future in this field (wave theory, scour process, wave load actions, scale difficulty, etc.), not as yet identified due to the scarce experience in the offshore wind industry. With this in mind, technical offshore wind standards related to foundation design have been reviewed.

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.

Dimensionless wave height parameter for preliminary design of scour protection in offshore wind farms

ABSTRACT Matutano, C., Negro, V., López-Gutiérrez, J.S., Esteban, M.D. and del Campo, J.M, 2013. Dimensionless wave height parameter for preliminary design of scour protection in offshore wind farms The scour phenomenon jeopardizes the operating capacity of offshore structures since it compromises their stability. The study of this phenomenon in the field of offshore wind farms began few years ago. Considering that these structures are subjected to waves, currents and tides. This article describes the results of an investigation aimed at the analysis methods used in the design of the protections against scour phenomenon on offshore wind farms in transitional waters, using medium and large diameter monopile type deep foundations. In order to do this, a thorough review of those premises was performed, from one of the first experiences in 1991 (Denmark), to the recently implemented and proposed in the UK, defining its main characteristics (acting maritime climate, the correlation between wave height and period associated with a given recurrence) and the type of protection used (weight average, nominal diameter in the case of breakwater type protection, width and behavior). Taking into consideration the experience with offshore wind farms in current operation, the design data analysis, the basis of climate and the soil-structure interaction, the dimensionless wave height parameter (H0), the erosion extension (Lext), and the quantification of maximum scour depth (Smax) have been calibrated for a preliminary design of protections around a large diameter pile, obtaining initial values for H0 in the vicinity of 6 and 15, and values for the extension of protection design between L/4 and L/2.

Review of coastal Land Reclamation situation in the World

ABSTRACT Martín-Antón, M.; Negro, V.; del Campo, J.M., López-Gutiérrez, J.S., and Esteban M.D., 2016. Review of coastal Land Reclamation situation in the World. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 667–671. Coconut Creek (Florida), ISSN 0749-0208. Land reclamation from the sea has been occurring since ancient times, especially in harbors. The vast majority of the worlds docks now occupy spaces that were once water and this heavily influences the coastal landscape. Japan has been one of the countrys most needing to expand into the sea due to its topography and land requirements for agriculture, urbanization and, especially, industries and port facilities. Ninety per cent of Tokyo Bays coastline is reclaimed land, which is almost 250 km2 of new land. In the 21st century, this disproportionate conquest of the sea has shifted to other countries. In the Persian Gulf, the coast has been indiscriminately occupied with artificial island projects for residential purposes. Some of them are finding some difficulties, such as “The Palms” and “The World” in Dubai, with a loss of sand, which is effect of currents and waves. In China, due to economic expansion and export needs, industrial areas are spreading on the coast. Caofeidian (Bohai Bay) is the largest landfill island in the world with 150 km2, more than twice the sum of Dubai islands area. This disproportion of public works in Asia contrasts with the rest of the world. For example, the Bay of Algeciras (Spain-UK) is the largest container traffic Port in the Mediterranean with 2.5 km2 of reclaimed land, 100 times less than Tokyo Bay. A further problem associated with this practice is liquefaction, caused mainly by earthquakes, leading to ground subsidence in buildings, such as in Niigata (1964) or in San Francisco (1989), all on reclaimed land. This research paper aims to study land reclamation in the World with current statistics, geotechnical problems, the impact on the coastal landscape and future developments.

The effect of scour protections in offshore wind farms

ABSTRACT Matutano, C., Negro, V., López-Gutiérrez, J. S., Esteban, M.D., Hernández, A,. 2014. The effect of scour protections in offshore wind farms. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 012–017 ISSN 0749-0208. The installation of offshore scour protection systems in offshore wind farms allows avoid the effect of scour phenomenon around these structures. Up to date, numerous research projects have been carried out to justify the necessity of the scour protection systems and also to optimize their design. Protection systems based on riprap is frequently used due to its low cost and easy availability compared to other solutions such as geotextile bags or prefabricated concrete blocks. The sizing of these structures can be performed according to a series of recommendations that can optimize the costs associated with them, but there have been only few studies with real data up to now which have allowed identify the need for such protections. This investigation aims to assess the functionality of the scour protections adopted through the available data about their characteristics and the scour depth developed around the foundations. In this sense, this paper presents the results of a study that analyzes the functionality of scour protections in different European offshore wind farms.

Hydrodynamic Regimes in Offshore Wind Farms

ABSTRACT Matutano, C.; Negro, V.; López-Gutiérrez, J.S., and Esteban, M.D., 2016. Hydrodynamic regimes in offshore wind farms. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 892–896. Coconut Creek (Florida), ISSN 0749-0208. Offshore wind power has sharply increased its presence in the last few decades. This expansion has derived in much bigger structures to be placed on the seabed; however, no revision about hydrodynamic regimes that should be taken into account during the design of these facilities has been carried out. The equations developed by Morison et al. in 1950 to estimate the wave loads are commonly assumed as valid within professional and scientific activity, and no revision of their investigation has been carried out since then. The formulation developed 65 years ago may not be reliable enough to accurately predict the phenomena, since they were established for smaller bodies. This paper analyses the available data from several European offshore wind farms in order to determine their hydrodynamic domain and nature of forces that structures bear. The analysis has been performed with the aim of establishing the relationship between inertia and drag forces acting on piles under wave loading conditions. Different criteria from main standards within the sphere of maritime works have been followed for the analysis. Results clearly show how inertia dominates in most cases and, consequently, the acceleration of fluid particle motion is a critical variable for predicting coastal phenomena. In this sense, this research remarks the importance of that mathematical expressions incorporate this fact, both for structural calculation and coastal process prediction and they should be reviewed in future research studies.

An analysis of recent changes in Spanish Coastal Law

ABSTRACT Negro, V., López-Gutiérrez, J.S., Esteban, M.D., Matutano, C., 2014. An analysis of recent changes in Spanish Coastal Law. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 448–453, ISSN 0749-0208. Spanish coastal legislation has changed in response to changing circumstances. The objective of the 1969 Spanish Coastal Law was to assign responsibilities in the Public Domain to the authorities. The 1980 Spanish Coastal Law addressed infractions and sanctions issues. The 1988 Spanish Coastal Law completed the responsibilities and sanctions aspects and included others related to the delimitation of the Public Domain, the private properties close to the Public Domain, and limitations on landuse in this area. The 1988 Spanish Coastal Law has been controversial since its publication. The “European Parliament Report on the impact of extensive urbanization in Spain on individual rights of European citizen, on the environment and on the application of EU law, based upon petitions received”, published in 2009 recommended that the Spanish Authorities make an urgent revision of the Coastal Law with the main objective of protecting property owners whose buildings do not have negative effects on the coastal environment. The revision recommended has been carried out, in the new Spanish Coastal Law “Ley 2/2013, de 29 de mayo, de protección y uso sostenible del litoral y de modificación de la Ley 22/1988, de 28 de Julio, de Costas”, published in May of 2013. This is the first major change in the 25 years since the previous 1988 Spanish Coastal Law. This paper compares the 1988 and 2013 Spanish Coastal Law documents, highlighting the most important issues like the Public Domain description, limitations in private properties close to the Public Domain limit, climate change influence, authorizations length, etc. The paper includes proposals for further improvements.

Runup variability due to time dependence and stochasticity in the beach profiles: two extreme cases of the Spanish coast

ABSTRACT Díaz-Sánchez, R., López-Gutiérrez, J.S., Lechuga, A., Negro, V., 2013. Runup variability due to time dependency and stochasticity in beach profiles. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings of the 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 001-006, ISSN 0749-0208. Equations for extreme runup worked out from several experimental studies are compared. Infragraviatory oscillations dominate the swash in a dissipative state but not in intermediate reflective states. Therefore two kinds of equation depending on either significant wave height, H0, or the Iribarren number, ξ0, should be used. Through a sand bed physical model with a uniform sand bed slope, equations are proposed for both beach states, and results are compared with precedent field and physical model experiments. Once the equations are chosen, the time-longshore variability in a medium long term time scale of the foreshore slope is evaluated in two extreme cases relating to the Spanish coast. The Salinas beach on the North coast (Bay of Biscay) displayed a permanent dissipative beach state with small variations in the beach foreshore slope both along the shore and in time, so foreshore slope deviations in a medium-long term period were irrelevant and extreme runup is predicted with the wave height worked out from the design return period. Peñíscola beach on the East coast (Mediterranean sea) displayed an intermediate state. If only time variations are analysed, variations in determining extreme runup are irrelevant. In contrast, significant differences were found when the longshore variations were studied in this Mediterranean beach.

Use of a scrapped ship as a floating breakwater for shore protection

ABSTRACT Fernández Lázaro, A., Gutiérrez Serret R.M., Negro, V. and López-Gutiérrez, J.S., 2012. Use of a scrapped ship as a floating breakwater for shore protection. The purpose of this research is to assess the effectiveness of a ship used as a detached floating breakwater for coastal protection and forming salients of sand or tombolos. Floating breakwaters have been extensively used as port or coastal protection structures and display advantages in terms of construction and ecology, amongst others. However, the greatest problem these structures present is the limited range of wave heights and periods for which they are really effective. Furthermore, ships may be considered as floating structures which, used as breakwaters, would keep the advantages of floating breakwaters and would increase their range of applicability. The possibility of using ships at the conclusion of their useful life for this purpose would also involve greater economic and environmental advantages. Tests were carried out to assess the ships effectiveness as a detached floating breakwater using a scaled down physical model to determine the vessels transmission coefficient (Kt) as to regular waves with significant periods of 5 sec to 12 sec and significant wave heights of 1.5 m to 4 m at depths from 20 m to 35 m. The ship proves effective for waves up to 4 m significant height and significant periods up to 9 sec. Hanson and Kraus and Pilarzyks analytical models, which take transmission coefficients into account, were used to analyse the shores response to the breakwater protection. The results obtained show that salients form for waves with periods between 6 sec and 9 sec. It is also concluded that the depths tested are far different from the more usual shallow water involved in constructing detached breakwaters and the shores response is therefore scarce.