- Numerical simulation of generation and evolution of geophysical granular flows and their impact in water masses
- Development of an optimal flow control software in channel networks for irrigation systems
- Quantification and modeling of water balance and soil salts and their influence on communities of halophytes in agro-ecosystems of semi-arid Aragon under different climate change scenarios
Numerical simulation of generation and evolution of geophysical granular flows and their impact in water masses
Participants: Universidad de Zaragoza
Duration: 2011-2014
Funding: Ministerio de Economia y Competitividad
Description: The aim of this research project is the development of efficient, accurate and robust numerical tools to simulate granular geophysical flows and their impact in water masses, of omportance for their potential effect in the environment and their high influence in the landscape. It is possible to represent the involved processe by means of numerical simularion. The development of physically based predictive tools allows an enhanced knowledge from different points of view such as the threshold of fluidification preocesses, the bed geometry modification and the transport of materials. It is worth mentioning that the complexity is increased by the transient character of the phenomena. The main objective is the development of reliable numerical methods able to solve the set of equations governing the involved processes. They must enable the prediction of the fate of the material removed during landslides and dambreak processes as well as their effects, by means of an efficient numerical simulation. The hydrodynamics in this kind of problems can be formulated as a set of hyperbolic partial differential equations. They are dreived through a series of hypothesis and the depth average of the original Navier-Stokes conservation laws of mass and momentum for incompressible flow. By means of the depth averaged formularion, the water depth, among other quantities, becomes a variable dependent of space and time. Within the vertical column, thre layers can be defined. A lower layer, of higher density, made of gravel and drebis lying over the movable bed and covered by the lightest later of water. Theproblems of interest are stratified in these layers of different density. The dynamics in each layer can be formulated in a variety of forms and they will be explored. The previous experience in the group within the field of numerical simulation of coupled (non-sequential) unsteady problems has enabled the progress in techniques well adapted to complex cases. These previous results are encouraging to face more difficult cases where density is variable and there is a coupled movement of interacting layers of fluid that exchange mass and momentu,m and where erosion/deposition is present together with geomorphological collapse.
Development of an optimal flow control software in channel networks for irrigation systems
Participants: Universidad de Zaragoza
Duration: 2011-2014
Funding: Ministerio de Economia y Competitividad
Description: In Spain the largest volume of water is used for irrigation. With more than 3,2 million hectares of irrigation fields, the water consumption represents more than 80% of the total demand of water resources. At present, a full conscience of the vital problem that it represents has been reached and important efforts are made to treat water as an element of great value. The new facilities and distribution networks are constructed under this aim and those already existing are adapted within the so called irrigation modernization plan. It seems sensible that any new methodology applied to optimize the water consumptions is fundamental for the great weight on the total of the water resources that this sector demands. In this project, hydroinformatic tools oriented to water volume conservation and control in distribution open channels are going to be developed. They will be based on the innovation by means of dynamic non-linear algorithms. The correct and optimal performance of control structures in channels is an open problem after decades of research and development. A robust and efficient control methodology will be developed being the base of control elements which allow a fast and trustworthy control of the characteristics of the flow. Channel management is more and more based on the implementation of control elements that allow to reduce the workforce necessary for the regulation and to increase their service quality. With the fundamental aim in developing a computational tool that manages the objective-oriented control of gates, the mathematical formulation will be solved with the numerical technologies widely used for open channel flow by the group in the past. Technologies of the upwind finite volume family will be used for the simulation of the flow system of equations as well as for its adjoint system. In both systems of equations, the experience gained in the treatment of the source terms will be used.
Quantification and modeling of water balance and soil salts and their influence on communities of halophytes in agro-ecosystems of semi-arid Aragon under different climate change scenarios
Participants: Universidad de Zaragoza, Estacion Experimental Aula Dei (CSIC), Instituto Pirenaico de Ecologia (CSIC)
Duration: 2012-2013
Funding: La Caixa-Gobierno de Aragón
Description: The overall objective of this project was to study the behavior of halophytes as exporters of salts in semiarid agroecosystems of Aragon and to develop an eco-hydrological model to predict future trends of these systems in drier conditions due to climate change. The results of this study should allow to quantify the amount of salt that can be exported from the system using cattle and ultimately to design strategies for recovery of degraded soil salinity from the extraction and accumulation capacity of soil salts by native halophytes. Our participation included the development and implementation of a mathematical and numerical model for the coupled simulation of surface and subsurface water flow and growth and reproduction of semi-arid vegetation. The capabilities of the model for transforming the rain in a spatial and temporal distribution of water both surface and underground, generating realistic moisture conditions for the establishment and growth of vegetation. The model of growth and reproduction of the vegetation has been coupled to the flow model. This coupling strategy to simulate the growth of vegetation depending on local moisture availability and simulate water consumption by vegetation for their survival and growth. Given the different time scales between water flow and vegetation growth, a nested coupling has benn adopted in which surface flow is solved to a very fine temporal scale, a medium scale subsurface flow, and growth large-scale vegetation. This link allows you to define the depth of the root system of the vegetation , which allows studying the interaction of different types of vegetation on water resources. The coupled model is in the process of validation test cases under controlled conditions (test with analytical solution and experimental cases) showing a good response. It has guaranteed global water conservation, which is the first indicator of quality.
Control and management of lateral storage areas to minimize the environmental impact of river flooding waves. Application to the Pyreenean basin.(GECOZI)
Participants: Universidad de Zaragoza, Confederacion Hidrografica del Ebro, ENIT (Tarbes), UPC (Barcelona), CACG (Francia)
Duration: 2011-2012
Funding: Comunidad de Trabajo de los Pirineos. Gobierno de Aragón
Description: The GECOZI project is a French-Spanish project focusing on the development and implementation of management and control strategies of flood-risk area with the aim to minimize the environmental impacts of the floods. The developed strategies are applied in the Pyrenean massif. GECOZI is sponsored by the Midi-Pyrénées regional council and by the Aragon, Catalonia, and Basque regions.
1D and 2D numerical models coupling for a flood simulation in the Tiber river
Participantes: Universidad de Zaragoza, Universita La Sapienza di Roma
Duración: 2007-2008
Financiación: Acciones Integradas España-Italia, Ministerio de Educación y Ciencia
Flood wave propagation along rivers is significantly influenced by the storage capacity of floodplains and river beds. In order to correctly reproduce the reduction of the peak discharge along the water course, the inundation of floodplains must be carefully simulated. In order to map the flood prone areas, it is common practice to apply 1D mathematical models to simulate the propagation of flood waves in long reaches. This schematization results acceptable if the width of the floodplain is comparable with the main channel width, but if the bottom valley is very wide, a simulation by means of a 2D mathematical model could be more appropriate. However, the application along the water course (30-40 km long) of a fully 2D model could result very burdensome since rarely digital elevation models (DEM) are available with sufficient detail to reproduce river bathymetry. In this case a coupled simulation of both 1D and 2D models seems useful. In this way, the propagation in the main channel will be simulated by means of a 1D model and the inundation of the riverside will be simulated by means of a 2D model. However, the two models cannot be applied in cascade since the water depth in the floodplain influences the water exchanges between main channel and riverside. The aim of this research is to develop and apply to a case study a coupled simulation of both 1D and 2D model in order to simulate in a more correct way the storage capacity of the bottom valley, to compare the results obtained by means of a coupled simulation with those obtained by means of a fully 1D model and to identify the limits of application of 1D models.
