Vanesa Edo Romero

3D-geological structures with digital elevation models using GPU programming

We present an application that visualises three-dimensional geological structures with digital terrain models. The three-dimensional structures are displayed as their intersections with two-dimensional surfaces that may be defined analytically (e.g., sections) or with grid meshes in the case of irregular surfaces such as the digital terrain models. The process begins with classic techniques of terrain visualisation using hypsometric shading with textures. Then, geometric transformations that are easily conceived and programmed are added, thus representing the three-dimensional structures with their location and orientation. Functions of three variables are used to define the geological structures, and data from digital terrain models are used as one of the variables. This provides a simple source code and results in a short calculation time. Additionally, the process of generating new textures can be performed by a Graphics Processing Unit (GPU), thereby making real-time processing very effective and providing the possibility of displaying the simulation of geological structures in motion. Display Omitted Visualisation of 3D geological structures with DEMs can be done in real-time with GPUs.Models of geological structures can be built using three-dimensional functions.3D functions allow changes in models and help the interpretation of the geology in the real world.3D functions allow the combination of structural domains and overlapping of folding phases.

Sensitivity analysis of main variables present in flash flood processes. Application in two Spanish catchments: Arás and Aguilón

The program Simulation of Hydrological Extreme Events provides a set of functionalities that combined together allows constructing, manipulating, analyzing and comparing the hydrological processes involved in flash flood generation. The program makes use of existing databases of interest in hydrology and available in Spain, such as digital terrain models, coverage of rainfall or curve number. Two pilot watersheds from Spain were selected, Arás and Aguilón, where flash flood episodes have taken place. A sensitivity analysis of the flash flood episodes in response to changes in the main hydrological processes involved has been made, such as spatial and temporal distribution of rainfall, soil moisture status and water flow through channel network. In this work, we found that the antecedent moisture condition is the most influential factor in the magnitude of flash floods produced by the same amount of rain. The temporal distribution of the storm represents the second characteristic in order of relevance. In addition, terrain morphology (specially the slope) is found to be decisive in the results differences obtained.

Developing and programming a watershed traversal algorithm (WTA) in GRID-DEM and adapting it to hydrological processes

A methodology for programming hydrological processes into watersheds using grid-type digital elevation models (DEMs) is investigated. This methodology is based on the basic configuration of the flow directions structure in the DEM, which is stored in files where information about topological relations and other frequently used features are saved. Some basic functions for managing topological data that significantly simplify the source code programming are also presented and described. We develop an algorithm that runs the entire drainage network in a watershed in both directions, upwards and downwards, which is ideal for incorporating structural models of hydrological processes that occur in basins or assessing its characteristics. The main attribute of this method is that information about hydrological processes and properties is transmitted during the routing from one area to another of the basin. The information is used when developing models of these hydrological processes and transmitted throughout the basin. At the end of the article, using this methodology with the SHEE software is illustrated with some examples.

SHEE Program, a Tool for the Display, Analysis and Interpretation of Hydrological Processes in Watersheds

The SHEE (Simulation of Hydrological Extreme Events) software is a tool for the analysis of hydrological processes in catchments. It uses powerful libraries (e.g., OpenGL, GDI, GDAL, Proj4) for the management and display of DEM and datasets. These libraries combine and use information referenced in different geodetic systems. The algorithms pass throughout the drainage network, the models of hydrological processes are incorporated in the algorithm architecture, and the basin features are evaluated. The natural processes which can be simulated are the distributed storm episodes, real or synthetic, the rainfall-runoff transformation and the routing. Three examples are presented below: (1) a real extreme event, (2) a flood episode produced by snowmelt processes, and (3) a variability analysis of flood phenomenon as a response to the variation in the hydrological processes involved.

Models of Parallel Linear Reservoirs (PLR) with Watershed Traversal Algorithm (WTA) in Behaviour Research of Hydrological Processes in Catchments

A methodology for programming hydrological processes in watersheds using grid-type digital elevation models (DEMs) is investigated. We developed a watershed traversal algorithm (WTA) that runs the entire drainage network of a basin in both directions, upwards and downwards, which is ideal for incorporating the models of the hydrological processes of the basins into its structure. The WTA methodology is combined with another one based on models of parallel linear reservoirs (PLR) whose main qualities include: (1) the models are defined by observing the recession curves of real responses of watersheds; (2) the models serve as a way to simulate the routing of water through the watershed and its different reservoirs; and (3) the models allow calculating the water balance with high accuracy, which is essential to the understanding of real events in the watershed and the behaviour of the processes involved. This methodology is applied to research and analysis of real events in a mediterranean catchment.