RIBAGUA-Revista Iberoamericana del Agua最新文献

Valdevaqueros dune, in the south of Spain, exhibits high migration rates associated with strong easterly winds in the Strait of Gibraltar. The system is located in an area of high human pressure and its dynamic has collided with land use causing a significant impact from scientific and technical points of view but also from a media and social perspective. This paper focuses on the historical evolution of the dune system since the beginning of the 20th century by studying the available cartographic and photographic material, analyzing the different phases, the mechanisms and natural agents governing the dune behaviour and the implications arising from the activities in the area. The intervention on the dune corridor started in the early 1940s and has conditioned the evolution of all the processes in the physiographic region. The current dune morphodynamics is explained by the sediment budget. The system receives sand from the submerged zone, which is transported by westerly wind waves. This material accumulates and widens the dry beach. The easterly winds erode the sediment in the dry beach and transports it to the dune. In the last fifty years, the dry beach (fetch) has grown, on average, over 150 m and the system stores enough sand to sustain these transport mechanisms for decades. From these results, we discuss different alternatives for the integrated management of the area.

On February 2nd 2014 a severe storm destroyed part of the La Zurriola Beach groin in San Sebastián. This groin had been recently studied at the Centre for Harbours and Coastal Studies of CEDEX due to the damage that the structure suffered since 2007 in some locations. The study was composed of three physical model tests of the groin behaviour under extreme waves, at the scale 1/40. These tests included the current situation (until 2014), the armour layer reinforcement and finally the study of the probable behaviour without that reinforcement. The model reproduced quite well the location and typology of the observed damage, along with the destruction that came only a few months later. As well, the reinforcement was formerly proposed during the reparation works carried out in the summer 2014.

One of the main threats to coastal systems and low-lying areas around the world is increasing flooding due to the effects of climate change, mainly due to sea-level rise. A regional-scale —O (100 km)— methodology to analyze the impact of coastal flooding is herein presented. The procedure combines high-resolution historical databases and projections of marine dynamics. Exposure is well represented over a high-resolution digital terrain model deeply improved including coastal defences. An empirical parameterization of the run-up that results from wave breaking is calibrated with field data, and further improved to evaluate flooding in ports. Such run-up feeds an efficient two-dimensional hydrodynamic model that allows the characterization of the inundation inland. Using scenarios that combine regional projections of sea-level rise with extreme events, the proposed methodology has been applied to the coast of Asturias (North of Spain).

This paper goes through the main three stages, planning, design and construction, of a singular port infrastructure: the new western breakwater of Almería port. The main issues of each of these phases are outlined along this document, aiming to present the complete cycle of this protection infrastructure, from its conception and design to its materialization.

The article is mainly focused on the design stage, since this case is special for having been developed by means of level I and level III Methods. Level III methods are a relatively novelty both in the national and international scenario, since they use probabilistic methods for the design. This article could be considered as a guide for the design of future breakwaters, as it includes the standard methodology for level I methods as well as the procedure for verifications by means of level III methods.

Brine discharges are flows driven by the density difference between the environmental fluid, the seawater, and the discharge. They are generated by the rejected water of desalination plants, hence they are common in nature nowadays, and have a great impact on protected ecosystems. Two well-distinguished regions can be differentiated in the study of the behaviour of these discharges: the near field region, located in the vicinity of the discharge point and characterised by high dilution rates due to the turbulence effects; and the far field region, where the brine turns into a gravity current that flows down the seabed with low dilution rates. The behaviour of these gravity currents is dependent on the brine discharge characteristics, the bathymetry and the hydrodynamic conditions of the receiving water.

This work shows the experimental characterization of the far field region of brine discharges through advanced non-intrusive laser optical techniques PIV (Particle Image Velocimetry) and PLIF (Planar Laser Induced Fluorescence), under controlled laboratory conditions. By means of synchronized PIV-PLIF techniques, high-quality accurate instantaneous measurements of velocity and concentration are obtained. The aim of these experiments is to study the quasi-steady flow properties of gravity currents generated by a constant flux release mimicking the far field of brine discharges. Different experimental set-upswith different initial conditions (flow rate, thickness, slope, salt concentration) were carried out in a 3 × 3 × 1 m tank. Through PIV-PLIF analysis, conclusions about the influence of these variables on the mixing at the interface between fluids have been obtained. As an example, keeping constant the rest of variables, steeper slopes and higher flow rates favour dilution, reaching stable entrainment values close to 5·10-2 against base case (with slope near zero and lower flow rate) values close to 2·10-2.

In addition, a high resolution and quality experimental database has been generated, which will allow to calibrate/validate both simplified tools, based on systems of integrated equations, and advanced hydrodynamic modelling tools.

This article describes the innovative aspects in design and construction of the western breakwater of the outer port at Punta Langosteira (A Coruña, Spain). The secondary breakwater is formed by the south breakwater (1.^st phase) and the western breakwater (2.^nd phase), currently under construction, and it is intended to complete the shelter provided by the main breakwater of the outer port of A Coruña and to ensure high operability of the new port facilities, as well as to contain the movement of the beaches to the west of the port. The bidding process, which permitted variations to the preliminary design, favors innovation, allowing for a variety of solutions based on the use of different armor units, and cubipods were finally selected for the main armor layer. The 1.35 km long secondary breakwater is protected by a single-layer 25 t and 30 t cubipod armor in the trunk, and a double-layer 45 t cubipod armor in the roundhead. The alternative cubipod solution allows for a breakwater which withstands wave climates higher than the defined limit state (H_s=8.75 m in the trunk) and significantly reduces the economic cost and the concrete consumption. In order to optimize and validate the alternative solution, 3D hydraulic stability and overtopping test were performed with 1/51 scale, similar to those made to justify the preliminary design by the port authority. 1,360 cubipod units (15- and 25-tonne) from the southern and northern breakwaters, which are now sheltered by the new breakwater, have been re-used at the western breakwater. A transition single- to double-layer armor has been constructed, with opposite fitting, increasing progressively the thickness of the filter layer to maintain a homogeneous exterior surface of the armor when modifying the armor thickness.

Llanos de Moxos are vast plains in the Bolivian Amazonia that are continually flooded by the Mamore river. The flood lasts for several days affecting important cities like Trinidad, drowning people, drowning cattle and swamping arable land. Because of the cloudy skies, remote sensing observations are limited to some areas and few days. Thus, there is huge uncertainty about characteristics of flood events and possible consequences. Two-dimensional (2D) numerical simulation proved to be an important tool for understanding flood events. The HEC-RAS model is one of the most popular hydraulic models. In 2014 a new version of HEC-RAS (HEC-RAS-v5) was released including 2D capabilities. The present study applied the new HEC-RAS-v5 to simulate the February 2014 flood event in the Bolivian Amazonia. The flood simulated shows good performance when compared with satellite image of the flood event. In addition, the simulation provides information like water depth, flow velocity and a temporal variation of the flood. Specific locations where water begins to overflow were identified. Over most of the flooded area the water velocity is lower than 0.25 m s⁻¹. During first ten days of the flood the flood extent increases rapidly. The flood depth allows identifying areas exposed to different hazard levels. The west plain of the Mamore river is the most exposed to the flood; it shows bigger flood extent, longer flood duration and deeper water depth. The flood that threatens the city of Trinidad originates in two locations; one located 32 km at the north and other located 10 km at the south west. The flood from the north gets close to Trinidad twelve days after it begins to overflow, while the flood from the south gets close to Trinidad seven days after it begins to overflow. Although the flood from the north is deeper than the flood from the south, the flood from the south begins flooded before the north. Thus, water borne and vector borne diseases may originate at the south earlier than the north. The city of San Javier gets covered by flood five days after the water begins to overflow. The study shows the applicability and the value of the 2D capabilities of the new HEC-RAS for flood studies.

In this study runoff coefficients for different return periods from statistical analysis of rainfall and runoff and from the curve number method were obtained. For this purpose about 100 basins in different places of Mexico with more than 20 years of record in the hydrometric station were analyzed besides having few alterations by the construction of waterworks, without significant storage upstream of the hydrometric station, with an estimated time of concentration, less than 12 hours and with a ratio between the average of the annual maximum daily runoff and the average of the instantaneous maximum annual runoff lower than 0.5. It was found that runoff coefficients increase with increasing rainfall in the basin, but asymptotically tend to a limit value; the slope of the basin is a very important parameter which largely determines the runoff coefficients and the Curve number method overestimates the effective rainfall runoff and, therefore, the runoff coefficient. The overestimation tends to be higher as the rainfall in the basin increases.