Discovering Dependencies, Trade‐Offs, and Robustness in Joint Dam Design and Operation: An Ex‐Post Assessment of the Kariba Dam

Abstract

Globally, many countries are actively seeking to maximize the hydropower potential of major river basins, yielding proposals for constructing approximately 3,700 major dams in the near future. At present, economic cost-benefit analyses are the dominant approach for evaluating candidate dam designs. Yet they typically fail to explore the interdependence of dam design and operation by (i) monetizing and aggregating potentially conflicting and heterogeneous objectives into a single metric and (ii) using predefined operating rules aimed at maximizing specific performance objectives for the dams to be designed. Careful consideration of alternative reservoir operating schemes can help to avoid biases in how optimal dam sizes are identified while also clarifying their capacity to adapt to changing hydroclimatic conditions and human demands. This paper presents an integrated framework to solve coupled dam sizing and operation design problems. The framework combines Multiobjective Robust Decision Making and Evolutionary Multiobjective Direct Policy Search into a novel approach to dam sizing, which internalizes the operation design problem and explicitly considers uncertainty in external drivers. We demonstrate the potential of this integrated dam design framework through an ex-post design analysis of the Kariba dam in the Zambezi river basin. Our results show that careful exploration of the coupled planning/operation search space yields designs that significantly outperform the existing Kariba system. Moreover, we demonstrate that our framework leads to a significant reduction in capital costs (i.e., smaller reservoir sizes) while simultaneously improving system robustness with respect to changing hydroclimatology and human irrigation demands.

Inventory of dams in Germany

“…The construction of dams can lead to negative socioeconomic and environmental consequences (Best, 2019;Zarfl et al, 2019). The relocation of people and conflicts regarding water use at different catchment locations can have a long-term effect on communities.…”

Inventory of dams in Germany

“…Many countries aim to expand the hydropower potential in the near future (Bertoni et al, 2019;Timpe and Kaplan, 2017;Zarfl et al, 2014), especially due to its advantage to produce energy only when the electrical system demands it (Zarfl et al, 2019).…”

“…Information and data about dams are crucial for dam operators, scientists and policy makers (Hecht et al, 2019;Tullos et al, 2009), for instance, for the assessment of hydropower plants construction (Bertoni et al, 2019;Gernaat et al, 2017;Moran et al, 2018;Winemiller et al, 2016), estimation of the hydrological footprint (Bakken et al, 2013(Bakken et al, , 2014Popescu et al, 2020;Postel, 2000), seasonal forecasting of water availability and water levels in rivers for navigation (Zhang et al, 2019), flood and drought risk assessment and management (Di Baldassarre et al, 2017;Ehsani et al, 2017;Elmer et al, 2012;Metin https://doi.org/10.5194/essd-2020-266 Open Access Earth System Science Data Discussions Preprint. Discussion started: 31 October 2020 c Author(s) 2020.…”

“…Dam operations are normally complex and influenced by environmental and anthropogenic factors (Gutenson et al, 2020). Many studies have explored the effects of dam operation rules, however, operation rules are not easily available, especially for private hydropower plants (Bertoni et al, 2019;Giuliani et al, 2016;Mediero et al, 2007;Pan et al, 2014;Quinn et al, 2019).…”

Participatory integrated assessment of water resource projects in Thailand

“…The environmental and social impact of dam projects has raised considerable academic interest, both in terms of ex-post assessments (e.g. Kirchherr et al, 2016;Sivongxay et al, 2017;Bertoni et al, 2019) and ex-ante studies attempting to find ways to reduce negative impacts (e.g. Kirchherr et al, 2018;Lanzanova et al, 2019;Yigzaw et al, 2019).…”