Performance assessment of different dam discharges schemes influencing river water quality

Hydropower energy production policies are usually defined trying to maximize the economical revenue, obeying to environmental restrictions and established downstream water uses requirements. Behind minimum daily averages of river ecological discharges, the hourly nature of the hydropower production schemes presents a pronounced effect on downstream river water quantity and quality. However, the capacity to control the river behaviour can be used to efficiently improve river water quality management practices if we can anticipate the performance of different management strategies. This paper presents a methodology to assess the performance of different turbine discharges schemes related with downstream river water quality. Three different performance indicators are presented and their computation is derived from a hydrodynamic and water quality river model implemented in Sobek. This methodology is applied to a Portuguese river: the river Cávado

Towards a decision support system for flood management in a river basin

A platform for flood forecasting (FEWS-LIMA) in the Portuguese river Lima basin was implemented applying Delft-FEWS software. This platform integrates SOBEK Sacramento hydrological model, SOBEK rivers hydrodynamic models (working together in predicting river hydrodynamics behaviour), and a comprehensive hydrological database. The calibration of these models was achieved using historical river flow data of different rainfall events for two different periods: after the dams construction and before its construction. Models predictions use rainfall time series as input data obtained from Numerical Weather Prediction models. The performance of forecasting platform was verified in real rainfall events, using a backcasting approach for four flood events occurred in the years 2006, 2010, and 2011 in order to demonstrate the accuracy of the modelled processes. In addition, a forecasting event was also considered in order to show the applicability of this methodology in future situations. It was verified, in this case study, that the obtained results have a high correlation to the actually measured typical flood hydraulic parameters

Sacramento model calibration using different methodologies : application to the Itabapoana-MG river basin

Despite the considerable progresses in computational hydraulics the calibration of hydrological models still requires a meticulous and laborious effort. However, the development of model calibration supporting tools has facilitated that work and improved the obtained results. The objective of this paper, developed under a R&D project, is to evaluate the performance achieved by using different calibration techniques for the rainfall-runoff Sacramento model of the Itabapoana-MG river basin. Bom Jesus do Itabapoana, a flood prone city, is located about 35 km downstream of Rosal hydropower plant. The limited capacity of Rosal reservoir implies that it cannot be used to mitigate flooding at downstream cities. However, flood forecasting can be used to avoid potential downstream damages and support decision making to defend and mitigate the undesirable effects. There should be a balance between the models performance and their computational times. It is important consider sufficiently precise results for sound decision-making outcomes, as well as results fast enough to be used in an operational decision support system environment. SOBEK software was chosen for prediction of flood events and Sacramento hydrological model was selected as rainfall- runoff model. SOBEK does not offer a module for automatic calibration of their hydrological models. Thus, for the quantification of Sacramento parameters, it is possible to make use of external algorithms for automatic calibration based on global optimization techniques. This paper assesses the eficiency of using results of automatic calibration using the Rainfall Runoff Library (RRL) within SOBEK hydrological module. In general, the results for RRL were better than the ones reached by SOBEK. Despite differences, the use of RRL as a tool to accelerate the parameters determination process for the Sacramento model has obtained satisfactory results

Hybrid modelling of dike-break induced flow

peer reviewedExperimentelle Modellversuche und numerische Simulationen ergänzen sich gegenseitig in einem hybriden Untersuchungskonzept für deichbruchinduzierte Strömungen. Unter Berücksichtigung der deichbruchspezifischen Randbedingungen werden in Laborversuchen charakteristische Strömungsfeldgrößen mit hochgenauer Messtechnik detailliert aufgezeichnet. Die korrespondierenden numerischen Modellierungen werden auf Basis der zweidimensional tiefengemittelten Flachwassergleichungen sowie der Reynolds-gemittelten Navier-Stokes-Gleichungen durchgeführt

Assessing the effectiveness of a real-time control method for Marina Reservoir management

MODSIM 2011 - 19th International Congress on Modelling and Simulation - Sustaining Our Future: Understanding and Living with Uncertainty4036-404