Informing regional water-energy-food nexus with system analysis and interactive visualization – A case study in the Great Ruaha River of Tanzania

In sub-Saharan Africa, water resources are scarce and subject to competing uses – especially for agricultural production, energy generation, and ecosystem services. These water intensive activities in the Usangu plains and the Ruaha National Park in southern Tanzania, present a typical case for such water competition at the water-energy-food nexus. To decipher the coupled human-nature interactions in the Great Ruaha River basin and effectively communicate the results to non-technical practitioners, the water-energy-food nexus competition in the system is simulated using an advanced water system modeling approach and findings are visualized via interactive web-based tools (Data-Driven Document, D3) that foster fuller understanding of the findings for both practitioners and stakeholders. Our results indicate that a combination of infrastructural and procedural measures, each acceptable from a social and economic perspective, and understanding that zero flows cannot be totally eliminated during dry years in the Ruaha National Park, are likely to be the best way forward. This study also reveals that the combination of improvements in irrigation efficiency, cutbacks on proposed expansion of irrigated lands, and a low head weir at the wetland outlet, significantly reduces the number of zero flow days (i.e., increasing ecosystem function), resulting in positive effects on agricultural sector from limited (if any) reduction in rice crop yields. These upstream measures are all relatively cost efficient and can combine to free-up resources for other economic activity downstream (i.e. more stable hydropower production).

[1]  David E. Rosenberg,et al.  Blended near‐optimal alternative generation, visualization, and interaction for water resources decision making , 2015 .

[2]  Jeffrey Heer,et al.  SpanningAspectRatioBank Easing FunctionS ArrayIn ColorIn Date Interpolator MatrixInterpola NumObjecPointI Rectang ISchedu Parallel Pause Scheduler Sequen Transition Transitioner Transiti Tween Co DelimGraphMLCon IData JSONCon DataField DataSc Dat DataSource Data DataUtil DirtySprite LineS RectSprite , 2011 .

[3]  Greg Corness,et al.  Human-computer-intuition? Exploring the cognitive basis for intuition in embodied interaction , 2009, Int. J. Arts Technol..

[4]  Brian Davidson,et al.  An integrated hydro-economic modelling framework to evaluate water allocation strategies I: Model development , 2011 .

[5]  Alfred Inselberg,et al.  The plane with parallel coordinates , 1985, The Visual Computer.

[6]  J. Nash,et al.  River flow forecasting through conceptual models part I — A discussion of principles☆ , 1970 .

[7]  A. D. Fisk,et al.  Developing a Framework for Intuitive Human-Computer Interaction , 2008, Proceedings of the Human Factors and Ergonomics Society ... Annual Meeting. Human Factors and Ergonomics Society. Annual Meeting.

[8]  Siza D. Tumbo,et al.  Water competition, variability and river basin governance: a critical analysis of the Great Ruaha River, Tanzania. , 2009 .

[9]  S. Mwakalila,et al.  Climate Change Impacts, Local Knowledge and Coping Strategies in the Great Ruaha River Catchment Area, Tanzania , 2011 .

[10]  P. Reed,et al.  Beyond optimality: Multistakeholder robustness tradeoffs for regional water portfolio planning under deep uncertainty , 2014 .

[11]  N.S.Y. Mdoe,et al.  The economics of irrigated paddy in Usangu Basin in Tanzania: water utilization, productivity, income and livelihood implications , 2004 .

[12]  Patrick A. Ray,et al.  The future nexus of the Brahmaputra River Basin: Climate, water, energy and food trajectories , 2016 .

[13]  Brian Davidson,et al.  An Integrated Hydro-Economic Modelling Framework to Evaluate Water Allocation Strategies II: Scenario Assessment , 2011 .

[14]  Huilin Gao,et al.  Integrating a reservoir regulation scheme into a spatially distributed hydrological model , 2016 .

[15]  Chris North,et al.  Empirical comparison of dynamic query sliders and brushing histograms , 2003, IEEE Symposium on Information Visualization 2003 (IEEE Cat. No.03TH8714).

[16]  Melanie Tory,et al.  Supporting Awareness through Collaborative Brushing and Linking of Tabular Data , 2013, IEEE Transactions on Visualization and Computer Graphics.

[17]  E. Wolanski,et al.  Towards an ecohydrology-based restoration of the Usangu wetlands and the Great Ruaha River, Tanzania , 2006, Wetlands Ecology and Management.

[18]  Myles T. Collins,et al.  Managing the Risk of Uncertain Threshold Responses: Comparison of Robust, Optimum, and Precautionary Approaches , 2007, Risk analysis : an official publication of the Society for Risk Analysis.

[19]  Patrick M. Reed,et al.  An open source framework for many-objective robust decision making , 2015, Environ. Model. Softw..

[20]  Yi-Chen E. Yang,et al.  Calibration approaches for distributed hydrologic models in poorly gaged basins: implication for streamflow projections under climate change , 2015 .

[21]  Sylvie Morardet,et al.  Water for irrigation or hydropower generation?--Complex questions regarding water allocation in Tanzania , 2008 .

[22]  Casey Brown,et al.  Modeling the Agricultural Water–Energy–Food Nexus in the Indus River Basin, Pakistan , 2016 .

[23]  Matthew P. McCartney,et al.  Estimation of environmental flows in the Great Ruaha River Catchment, Tanzania , 2006 .

[24]  Keith Beven,et al.  A manifesto for the equifinality thesis , 2006 .

[25]  P. Reed,et al.  Managing population and drought risks using many‐objective water portfolio planning under uncertainty , 2009 .

[26]  C. Birkett,et al.  The role of vegetation in the water budget of the Usangu wetlands, Tanzania , 2012, Wetlands Ecology and Management.

[27]  Q. J. Wang.  The Genetic Algorithm and Its Application to Calibrating Conceptual Rainfall-Runoff Models , 1991 .

[28]  U. Schneider,et al.  GPCC's new land surface precipitation climatology based on quality-controlled in situ data and its role in quantifying the global water cycle , 2013, Theoretical and Applied Climatology.