1,721,105 research outputs found
Hydrological forecasting uncertainty assessment: Incoherence of the GLUE methodology
No full textIn corso di pubblicazion
ODESSEI: Open architecture DEcision Support System for Environmental Impact – Assessment, planing and management
No full textThe ODESSEI system, created under the Eureka EU487 project, is a decision-making geographic information system for the planning and management of water resources and environmental impact assessment. This system is designed for agencies responsible for the planning, management and control of a given region thanks both to the computing resources with which it is equipped and to a structure offering different levels of use. The system consists of a sophisticated group of mathematical models, a database, a geographic information system and an expert system, integrated by a user-friendly interface developed on advanced software. The multi-level access structure allows the system to be used according to the particular degree of specialisation and professional discipline of the user accessing it. The system has been organised on a modular basis to allow the integration of new modelling components, or their replacement with more recent ones. Lastly, by the addition of special modules, simple interface is provided with the most common data filing standards and with similar types of system
Assessing the TOPKAPI non-linear reservoir cascade approximation by means of a characteristic lines solution
No full textTOPKAPI is a physically based distributed rainfall-runoff model derived upon the assumption that the horizontal flow at a point in the soil, over the slopes and in the channel network can be approximated by means of a kinematic wave model. The TOPKAPI model combines this kinematic approach with a digital elevation model (DEM)-based description of a basin. Similarly to what is done in the finite element approach, the basic model equations are derived by integrating in space the point process equations up to a finite dimension, the pixel, thus converting the original kinematic partial differential equations into a cascade of finite dimension non-linear reservoir ordinary differential equations. These new equations are 'structurally similar' for all the processes (flow in the soil, over the slopes and in the channel network) and are shown to be representative of the original equations at the new finite pixel scale. With a view to assessing the quality of the approximation, the paper presents a comparison study in which a quasi-analytical approach based upon the characteristic kinematic wave solution of the original equations is compared to the solution provided by the non-linear reservoir finite scale approximation. The test is first applied to a simplified theoretical case in order to show the quality of the approximation at small scales. Successively it is applied to two real-word cases: the Upper Reno catchment based on 400 x 400 m(2) pixels and the Sieve River catchment using 1 x 1 km(2) pixels. All the results show that the cascade of non-linear reservoirs is a good finite dimension approximation of the subsurface flow in the soil, the flow over the slopes and the flow in the channel network, which allows us to properly retain the physical properties of the original equations at finite scales that range from a few metres up to I k
BAP: Uno schema di calcolo per la simulazione di perturbazioni propagantesi contro corrente in canali a pelo libero
No full textThe paper describes a new scheme to simulate discharge propagation phenomena against the flow in open channels and canals. The scheme is based on the application of the integral solution of the parabolic model, linearized around a steady flow profile at every DELTA t, and it is unconditionally stable as consequence of its integral form. The method is generally applicable to mild slope canals (for example irrigation canals) and can also be used in the case of rapidly varying discharge if we accept a small error in advance in the initial phase of the phenomena, that is when the inertial terms are not negligible
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