direkt zum Inhalt springen

direkt zum Hauptnavigationsmenü

Sie sind hier

Inhalt des Dokuments

High resolution multi-dimensional model for hydrodynamics and water quality in the reservoir

Lupe

Research module 5.4 investigates the current situation in the reservoir and the short term impacts of climate changes on the water quantity and quality, using two- and three-dimensional high resolution hydro-numerical models. Based on the results, critical conditions can be identified and adaption measures will be developed.

We presented preliminary results during stakeholder workshops held in Belo Horizonte and Brasilia in October 2014. Similarly, we presented during the INNOVATE status conference in Recife, also in October 2014. Please find the Poster (including high resolution and tracer injections models) here.

Read/jump to main result, images or publications of SP5-RM4.

Main result and outlook (as of September 2016)

Research project and objectives

Our main task was to analyze hydrodynamics and transport at the local scale, investigating how different inflow scenarios and multiple uses influence water quantity and quality. In the specific, our research focused on Icò-Mandantes bay, located in Itaparica reservoir, where water level variations given to hydropower production (HPP) and evaporation, high concentration of nutrients and low exchange rate facilitate the development of macrophytes (egeria densa) and consequent health risks, if water is used for human consumption. Indeed, the intakes and drainage systems for irrigation agriculture and the eastern axis of the Transposition project are set in the bay, which is used as well for fishery and recreation activities. So far, no aquaculture systems are installed inside the bay, but a few km from it (Fig.1).

Methods applied

In the last years, we set up 2D and 3D models of Icó-Mandantes bay and a 2D model of Itaparica reservoir. Different high resolution (edge lengths ca. 100-500 m) unstructured triangular grids were implemented with the use of Janet (Smile Consult GmbH), an efficient pre-processor tool for mesh generation, to consider different scenarios (Matta et al. 2016a). The TELEMAC modeling system was used to conduct the simulations: a powerful integrated modeling tool for free-surface flows, which solves the two-dimensional shallow water and transport equations with complex algorithms based on the Finite Element Method, computing the water depth, the vertically averaged velocity components and the concentration at each point of the mesh (Hervouet 2007). The results were analyzed with ParaView, an open-source multi-platform data analysis and visualization application (Ayachit  2015).

Summary of main results and management guidelines

Studying various project partners- and stakeholder-oriented scenarios in Icó-Mandantes bay and Itaparica reservoir, we gained a wider knowledge about the systems and their interactions. As mentioned, water is used for different purposes and at the same time is affected by water quality problems, due to e.g. high water level variation (HPP, evaporation), not adequate waste water system. In such bays, water exchange with the main stream of Itaparica hardly occurs and, therefore, we incur in higher risks of withdrawing low quality water or contribute to eutrophication in the bay, if nutrients increase by net cages emissions or by flash floods from the intermittent tributary Riacho dos Mandantes.

                It is extremely important to adapt the management to the climate change scenarios and anthropogenic uses. Indeed, considering a flood event from the small effluent Riacho dos Mandantes due to heavy rain, we saw how it influenced water quantity mainly in the bay itself, in particular in the near field of the river inflow, and how the hypothetical material transported interacts with the different uses. The intakes for irrigation agriculture and Transposition project, which are located in the near field of the tributary (Fig. 1), will be negatively affected by it (on the longer term assuming a wet scenario). Residence times are in fact much higher (> 1 year) in Icó-Mandantes bay, compared to the ones calculated for Itaparica reservoir (ca. 2 months).

Regarding aquaculture, we hypothesized to install a new net cage system producing 130 t y-1 of Tilapia inside the bay and observed the consequent increase of total nitrogen and phosphorus, compared to the current mean values and maximum concentrations allowed (SP1-1; CONAMA 357/05). The results showed that nutrient emissions due to a small production would lead the bay to have an increase of phosphorus concentration of ca. 8 µg L-1 after one week of simulation under drought conditions. Therefore, it should be avoided to install new aquaculture systems in such bays and, otherwise, to ensure enough water column beneath the cages (min. 10 m, SP1-1).

                In our studies, we could also observe that the eastern channel of the Transposition project influenced not relevantly water quantity at the local scale of our models, except for the increase of flow velocities in the near-field of the intake, but water quality control measures need to be applied, because of the critical location of the withdrawal. Nevertheless, the simulations are based on the assumed withdrawals declared by ANA (411/2005), since the axis is not yet operating.

                Finally, we focused in these years on the important role of the wind in our research area, studying wind-induced flow in 2D and 3D, considering various scenarios. Wind is one of the main drivers of hydrodynamics and transport and 3D analyses allow us to observe the consequent circulation patterns along the vertical direction (z) and in this way increase our knowledge of this complex system (Fig. 4). The final simulations of the upcoming year (2016-2017) deal with 3D modeling in regards of stratification in the bay, due to temperature gradients.

References

Ayachit, U. (2015) The ParaView Guide: A Parallel Visualization Application. Kitware, ISBN 978-1930934306

Hervouet, J. M. (2007) Hydrodynamics of free surface flows: modelling with the finite element method. Wiley, New York

Matta, E., Koch, H., Selge, F., Simshäuser, M. N., Rossiter, K., Nogueira da Silva, G. M., Gunkel, G., Hinkelmann, R (2016a) High resolution two-dimensional modeling of flow and transport in Icó-Mandantes bay to support water management. Regional Environmental Change (INNOVATE special issue) subm.

Matta, E., Selge, F., Gunkel, G., Rossiter, K., Jourieh, A., Hinkelmann, R. (2016b) Simulations of nutrient emissions from a net cage aquaculture system in a Brazilian bay. Water Science and Technology 73(10), 2430-2435

Study area and computational domain: Itaparica reservoir (left); computational domain of Icó-Mandantes bay, were multiple uses of water are shown.
Lupe
Velocity field and tracer concentrations, one week after a 3-days-flood-event from the effluent Riacho dos Mandantes, for a dry (left) and a wet scenario (right).
Lupe
Mass-conservative passive tracer set as initial conditions, with an initial concentration equal to 10 [-], after 6 months-simulations for a dry (left) and a wet scenario (right).
Lupe
An example of 3D results, analyzing mean wind and mean flow conditions in the domain, before a wind storm event. Zoom of the flow field on the surface layer in an intermediate part between the bay and the reservoir main stream (left); vertical section of flow velocities (right).
Lupe

PUBLICATIONS

Journal articles:

·         Gunkel, G., Matta, E., Selge, F., Nogueira da Silva, G. M. & Sobral, M. (2015) Carrying capacity limits of net cage aquaculture for Brazilian reservoirs. Revista Brasileira Ciencias Ambientais, in press.

·         Gunkel, G., Selge, F., Keitel, J., Lima, D. M. B., Calado, S., Sobral, M., Rodriguez, M., Matta, E., Hinkelmann, R, Casper P. & Hupfer, M. (2016?) The aquatic ecosystem services of a tropical reservoir (Itaparica, São Francisco, Brazil): impacts, vulnerability, and reservoir management tools. Regional Environmental Change (INNOVATE project special issue) subm.

·         Hattermann, F., Koch, H., Liersch, S., Silva, A.L., Azevedo, R., Selge, F., Silva, G.N.S., Matta, E., Hinkelmann, R., Fischer, P., Venohr, M. (2016?) Climate and land use change impacts on the water-energy-food nexus in the semi-arid northeast of Brazil – scenario analysis and adaptation options. Regional Environmental Change (INNOVATE special issue) subm.

·         Matta E., Koch H., Selge F., Simshäuser M. N., Rossiter K., Nogueira da Silva G. M., Gunkel G., Hinkelmann R (2016?) High resolution two-dimensional modeling of flow and transport in Icó-Mandantes bay to support water management. Regional Environmental Change (INNOVATE project special issue) subm.

·         Matta E., Selge F., Gunkel G., Rossiter K., Jourieh A. & Hinkelmann R. (2016) Simulations of nutrient emissions from a net cage aquaculture system in a Brazilian bay. Water Sci. Technol., Vol. 73, No. 10, pp. 2430-2435.

·         Rossiter, K. W. L., Morais, M., M., Calado, S. C. S., Benachour, M., Matta, E. (2015) Diagnóstico da Qualidade da Água ao longo de um Canal de  concreto: Um estudo de caso do Canal do Sertão Alagoano. Revista Brasileira Ciencias Ambientais, in press.

·         Selge F., Matta E., Hinkelmann R. & Gunkel G. (2016) Nutrient load concept-reservoir vs. bay impacts: a case study from a semi-arid watershed. Water Sci. Technol., Vol. 74, No. 10, DOI: 10.2166/wst.2016.

 

Conference papers:

·         Broecker, T., Özgen, I., Matta, E., Cabral, J., Candeias, A. L. and Hinkelmann, R. (2014) Simulation of Flow and Transport Processes in a Brazilian Reservoir. Lehfeldt, R. & Kopmann, R. (eds): International Conference on Hydroscience & Engineering (ICHE), Hamburg, Germany © 2014 Bundesanstalt für Wasserbau ISBN 97In8-3-939230-32-8.

·         Hattermann, F., Koch, H., Liersch, S., Silva, A.L., Azevedo, J.R., Selge, F., Silva, G.N.S., Matta, E., Hinkelmann, R., Fischer, P., Venohr, M. (2016) Climate and land use change impacts on the water-energy-food nexus in the arid northeast of Brazil – scenario analysis and adaptation options. BMBF Final Conference – Sustainable Land Management: Challenges and Opportunities, March 7-9, 2016, Berlin, Germany.

·         Gunkel, G., Lima, D., Selge, F., Matta, E., Sobral, M. & Calado, S. (2015) Serviços de ecossistemas em reservatórios: Produtos finais, capacidade e processos limitantes – Exemplo de Itaparica, Rio São Francisco. 12°Anais do Simpósio de Hidráulica e Recursos Hídricos dos Países de Expressão Portuguesa, Brasília, 11 pp. APRH, Lisboa. ISBN 978-989-8509-14-7.

·         Gunkel, G., Selge, F., Keitel, J., Lima, D., Calado, S., Sobral, M., Rodriguez, M., Matta, E., Hinkelmann, R., Casper, P., Hupfer, M. (2016) The Itaparica reservoir – Aquatic ecosystem functions: Impact, vulnerability and development of an adapted management. BMBF Final Conference – Sustainable Land Management: Challenges and Opportunities, March 7-9, 2016, Berlin, Germany.

·         Matta, E., Özgen, I., Cabral, J., Candeias, A.L. and Hinkelmann, R. (2014) Simulation of Wind-Induced Flow and Transport in a Brazilian Bay. Lehfeldt, R. & Kopmann, R. (eds): International Conference on Hydroscience & Engineering (ICHE), Hamburg, Germany © 2014 Bundesanstalt für Wasserbau ISBN 978-3-939230-32-8.

·         Matta E., Broecker T., Özgen I., Hinkelmann R., Candeias A.L. (2014) High resolution multi-dimensional modelling of hydrodynamics and water quality in the Luiz Gonzaga reservoir. Round Table 1: Modeling, socioeconomic analysis, and governance for sustainable resource use. INNOVATE Status Conference 2014, III Seminário Internacional Brasil – Alemanha: Uso sustentável de água e do solo de reservatórios em regiões semiáridas. October 14-15, 2014, Recife, Brazil.

·         Matta, E., Selge, F., Gunkel, G., Rossiter, K., Jourieh, A. & Hinkelmann, R. (2015) Quantification of exchange processes between a bay and a river using a two-dimensional high-resolution flow and transport model. Proceedings 17th IWA DIPCON Conference, Berlin, Germany.

·         Matta, E., Simshäuser, M., N., Koch, H., Selge, F., Gunkel, G., Rossiter, K. & Hinkelmann, R. (2015) Modeling the interaction of multiple uses, climate and land-use changes in a bay of Itaparica reservoir, São Francisco river. Proceedings XXI SBRH Conference, Brasilia, Brazil.

·         Matta, E., Moraes N. da Silva, G. , Lorenz, R., Gunkel, G. & Hinkelmann R. (2016) Estimation of water residence time in Icò-Mandantes bay using the TELEMAC-2D modeling system. Proceedings I SBHSF Conference, June 6-9, 2016, Juazeiro, Brazil.

·         Nogueira da Silva, G. M., Matta, E., Gunkel G., Hinkelmann, R., Severi, W., Sobral, M. (2016) Modelling nutrient emissions from a net-cage aquaculture system in Northeastern Brazil. IWA DIPCON Conference, October 23-27, 2016, Dublin, Ireland.

 

INNOVATE Thesis (personal and supervised)

·         Matta, E. (2013) Simulation of wind induced flow in Icò Mandantes bay, Brazil. Master Thesis, Technische Universität Berlin, Germany, and Politecnico di Torino, Italy.

·         Simshäuser, M., N. (2015) Impacts of a tributary on flow and transport in Icó-Mandantes Bay. Bachelor Thesis, Technische Universität Berlin, Germany.

·         Wirth, S. (2015) Auswirkungen eines Wasserüberleitungskanals auf die Strömungs- und Wasserqualitätsverhältnisse in der Icó-Mandantes Bucht. Bachelor Thesis, Technische Universität Berlin, Germany.

 

Other INNOVATE Thesis (or student research work) in our SP-RM

·         Broecker, T. (2014) Simulation of two-dimensional flow and transport processes in a Brazilian reservoir. Master Thesis, Technische Universität Berlin, Germany.

·         Nasser, Said (2013) Numeric Simulation of flow processes in the reservoir of the Luiz Gonzaga Dam in Brasil. Bachelor Thesis, Technische Universität Berlin, Germany.

·         Storck, T. (2013) Elaboration and optimization of a bidimensional grid (mesh) for the Itaparica Reservoir. Student research work, Technische Universität Berlin, Germany.

Zusatzinformationen / Extras

Quick Access:

Schnellnavigation zur Seite über Nummerneingabe

Auxiliary Functions