SURFACE WATER

Author: TAGUAS RUIZ ENCARNACIÓN V..
Year: 2003.
University: CÓRDOBA [www.uco.es].
Place of defense: ETSIAM.
Place of preparation: ETSIAM.

Summary: The mechanisms generating runoff and soil loss has been widely studied in arid areas such as Andalusia, but most efforts at modeling as Field measurements have been concentrated in scale plot, despite its limitations in predicting hydrological . There are a number of studies dealing with the loss of soil in olive groves, all built on plots of up to 200 m2 which examines the impact of the use of olive groves and / or soil management. The results of these studies are diverse, and in some cases contradictory, mainly because of the different environmental conditions in which they have done. Therefore, it seems appropriate to expand the scale of study not isolated geomorphological units where the number of natural phenomena involved in the movement of water and sediment is larger and more complex than in the hillside plots and where results are more responsive to the conditions real in which they occur. This article deals with the study of erosion in two micro approximately 6 hectares, subject to minimum tillage and no tillage with covers. The first part is devoted to the analysis of their inherent variability watershed from the point of view of the topography and soil along with the considerations arising from the management. They were located lso points where processes of erosion and deposition are obvious to analyze the most influential variable in these phenomena, so as to facilitate the interpretation of the values of runoff and erosion. The second part is dedicated to the acquisition and analysis of data to provide information of water balance and loss of soil micro scale with the management. To that end, it has designed and installed a small hydrological station in each of the basins study of which have been obtained data of precipitation, runoff and sediment concentration in a cycle of more than a year (2005-2006). Finally, the last parts, has been selected a simulation model of hydrological processes and erosion, AnnAGNPS (Annualized Agricultural Non-Point Source), for calibration and validation as episodes recorded to try resutlados model and its extrapolating to other scenarios.

Author: Vericat Querol Damián.
Year: 2004.
University: LLEIDA [www.udl.es].
Place of defense: Departament de Medi Ambient i Ciències del Sòl.
Place of preparation: Universitat de Lleida.

Summary: This thesis examines the transport of sediment and associated processes river in the lower river Ebro hydrologically for two years means (2002-2004). The transport of sediment, which includes both the burden of substance and suspended sediment has been sampled upstream and down the complex reservoirs Mequinenza-Riba-roja-Flix. The morphological changes and granulometric have been analyzed downstream from the dam Flix. The average annual sediment load upstream of the dams is 1,640,000 tons, of which 99% are in suspension. The average annual transport downstream from the reservoirs is 450,000 tons (60% in suspension and 40% load fund). The reservoirs hold about 95% of the load suspended. The average annual transport downstream from the dam Flix represents 3% of what the river was carrying at the beginning of the twentieth century in the absence of reservoirs. Most of the sediment that the river carries now comes, therefore, his own channel, which causes an incision annual average of 30 mm. A very important part of the cargo is transported annually during avenues high magnitude. For example, transportation upstream of the dam during the floods of February and March 2003 was 1700000 tons of sediment. The average concentration of suspended sediment during these episodes was 0.5 g / l and the average load fund 100 g / ms. The sediment transported as cargo fund represented a 1.5% of the total sediment transported. Downstream of the dam from the river Flix transported 175,000 tons of sediment during the same floods, half as load fund. The average concentration of suspended sediment was 0.05 g / l and the average load fund was 150 g / ms. Both modes of transport have great temporal and spatial variability. The distribution of material grading the bed is directly controlled by the flow of competition and the availability of sediment. The flood of high magnitude of 2002-2003 mobilized the armor surface, increasing the availability of sediment (material subperficial) and causing a noticeable incision of the river channel. In contrast, during the 2003-2004 flow was not sufficiently competent to mobilize more coarse fractions, and thus the dominant process was to re-acorazamiento the riverbed. Both years show a complete cycle of incisión-acorazamiento. Changes in the morphology river downstream from the dam Fix during the second half of the twentieth century show loss of sedimentary areas active (sediment availability) due to the colonization by riparian vegetation, and the decrease in the width of the channel ( 20%), reducing, as a consequence, section active. Lack of sediment and the reduction of flood control changes in the morphology fluvia medium and long term. Keywords: sediment transport, river morphology, river regulated distribution grading, Ebro river.

Author: CROZZOLI GARRIDO LAURA.
Year: 2004.
University: LLEIDA [www.udl.es].
Place of defense: E.T.S. Enginyeria Agronoma..
Place of preparation: E.T.S.DE ENGINYERS AGRONOMS.

Summary: This thesis explores the hydrological response of the high basin of the river Ter (1,400 km2), from modelización-lluvia runoff and analysis of historical floods. The findings apply to the development of the mapping of flooded areas of a municipality in the watershed. The detailed study of precipitation and the response of sistéma river during flood extraordinary has been the axis methodology followed for the analysis of hydrological functioning end of the basin. That analysis has been used to estimate the parameters used in hydrologic modeling and its subsequent calibration. We have studied 10 episodes extraordinary from 1617 to 2004, of which it has been determined their periods return, and all except the 1617, the duration and homogeneity of rain in the basin, and its response time. It has also analyzed how the incrusión the flow of flood 1932 (registered but disconnected from the series), and 1940 (unregistered), the number of flow registrádos (1945-2004), improving the estimation of the probability occurrence of crecidadas, especially episodes with periods of return in excess of 500 years. Specifically, the flow of the avenue of 1940 was estimated by modeling water from peak levels reached (limnimarcas). Statistical analysis of the full range of flow rates was performed using the method Maximum Verosimilitud. The functions that are better adapted to the estimated time of return of the informacón censored were Generalized Extreme Value and Log- Normal III. The flow of rising 500 years of Ter Roda has been estimated at 7,200 m3 / s (5.1 m3/s.km2). Finally, it has developed a catrografía of flood areas Roda Ter from their vulnerability coniderando topographical features and hydrological history of each municipality.

Author: MAO LUCA.
Year: 2004.
University: POLITÉCNICA DE MADRID [www.upm.es].
Place of defense: UNIVERSIDAD POLITECNICA DE MADRID.
Place of preparation: UNIVERSIDAD DE PADUA - UNIVERSIDAD POLITECNICA DE MADRID.

Summary: This Doctoral Thesis seeks diagnose the phenomenon geo-torrencial in different areas, with its essential elements and their side effects, which require uniformity with the principles of hydraulics and torrential plurality interpretive aspects that allow water and sediment. In short, make a radiography of the state of affairs from a wide geographical framework, which covers the largest number of aspects that the problem holds, in response to the nature of experimental science, but without losing sight of the potential that any practical purpose research in this area of knowledge raises. This study has focused on two small basins tracks. The first in the Italian Alps (5.07 km2), represents the typical high mountain basin, outstanding high both in their main course and in their hillside slopes, provides in section Out of a measuring station conveniently equipped, for your information may be addressing scientific paradigms of the phenomenon geo-torrencial: How quantifies the nascent movement of the materials of the bed; What physical demarcation can be attributed to the parameters laid down geomorphological to define the problem geo-torrencial; The extent to which the equations that quantify transport solid respond with measurements made on the ground, for pointing out some of the strongest arguments and raised more frequently. Briefly, an investigation focused on deepening the understanding of processes, based on the quantification of their effects. The second largest (307.67 km2) is the OS of Spain and is affected by a serious nature geo-torrencial, since the issuance of sediments by the main course of the watershed has a direct impact on sedimentation of a site of high ecological value, declared by UNESCO World Heritage. The investigation in this case was directed to lay some sound science, for the restoration of hydraulics course in question and the resulting solution or at least mitigate the current problem. The report undertakes both situations, highlight the similarities and analyzes different, and as inference of independent research, clarifies the effectiveness of the scientific and technical means available in the present state of knowledge geo-torrencial.

Author: BENITEZ REYNOSO ALBERTO.
Year: 2004.
University: SEVILLA [www.us.es].
Place of defense: DEPARTAMENTO DE GOEGRAFÍA FÍSICA Y ANÁLISIS GEOGRÁFICO REGIONAL.
Place of preparation: UNIVERSIDAD DE SEVILLA.

Summary: The dissertation consists of six chapters and appendices. In Chapter I provides the theoretical design of the thesis, namely the description of the problem and the approach, which justifies the development of relations in terms of mathematical models, raised the objectives, assumptions and describes the variables used in relations (rainfall, flow or runoff, evapotranspriación or shortfall and area of the basin). In chapter II is characterized both the Great River Plate Basin as each of the basins components thereof (Bolivian part) as follows: Bermejo River Basin, Pilcomayo River Basin and Paraguay River basin. In addition, it presents, in summary seasonal variation of the flow in each of them. The theoretical framework on which is based the study is presented in Chapter III, which basically refer to the "systemic approach" and the "multivariate analysis." In chapter IV summarizes the methodology used to: A-Part Experimental. B-Estimated processes independently (rainfall, runoff and evapotranspiration). C-Integration of the processes through the development of the relations between them or mathematical models. Chapter V is dedicated to the presentation of the results obtained. Here are all the models developed and the best models for the prediction of flow or runoff from other variables (precipitation, evapotranspiration and area of the basin). The findings, implications and limitations to which they have arrived as a result of the study as a doctoral thesis are presented in chapter VI. Finally, listed references bibiliográficas and presents the annexes.

Author: BOTERO HERNÁNDEZ BLANCA ADRIANA.
Year: 2005.
University: POLITÉCNICA DE VALENCIA [www.upv.es].
Place of defense: ESCUELA DE CAMINOS CANALES Y PUERTOS.
Place of preparation: UNIVERSIDAD POLITÉCNICA DE VALENCIA.

Summary: An analysis of frequency of the floods has been a topic of great interest in Hydrology for many years. Depending on the specific needs paralas which perform analysis rising interest can be in the middle, low or high frequency curve. The estimate of the floods which stood at the top, namely those with small probability of occurrence or periods of high return is needed in projects where the risk in the design should be zero. Such projects such as large dams, large-scale hydraulic works, nuclear power plants and others, are characterized because in the event of failure, the loss of life, economic and environmental impacts would be incalculable. The main problem is that, paradoxically, the estimation of extreme floods or high return is associated period of great uncertainty. This is mainly due to the extrapolations made since the row length of available flow is much shorter period that the return of the flood of interest. Moreover functions traditionally used for the analysis of frequency of floods, can obtain flow growing while higher the return period, without considering that there must be a physical limit paralas floods that may occur in a watershed area and climatic characteristics hydrological and determined conditions for maximum production runoff. In this thesis is posed by the use of information Not Systematic and distribution functions with the estimated upper limit for high flood period of return and the FSL. It has designed a methodology for the analysis of frequency of floods which introduces a scheme Maximum Versimilitud, which allows to include any type of data to make both part dela information Systematics and the No. Systematic, and the use of distribution functions with ceiling EV4 (distribution function value end of four parameters), LN4 (Lognormal four parameters) and TDF (distribution function transformed). Three alternatives have been implemented to estimate the upper limit for such functions, one of which is the Generic Equation (EG), which had not been used before in Hydrology. This methodology was applied in 6 cases of study rivers located in the Mediterranean region Spanish with satisfactory results. We performed by MonteCarlo simulations, an analysis of error in the estimates for the period quantiles high return and the upper limit and an analysis of robustness. This enabled the scope of the proposed models and recommendations for use.