Long-term variations of annual flows of the Okavango and Zambezi Rivers

Mazvimavi, Dominic; Wolski, Piotr

doi:10.1016/j.pce.2006.08.016

Cited by 65 publications

(46 citation statements)

References 9 publications

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“…Arora and Boer (2001) estimate that the Zambezi River, evaluated at the delta in Mozambique, will experience a total reduction in discharge of about 39 % in 2100. Although, it should be noted that Mazvimavi and Wolski (2006) find recent observed changes in the Zambezi river flows can be explained by a cyclical pattern rather than a trend.…”

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confidence: 80%

An uncertainty approach to assessment of climate change impacts on the Zambezi River Basin

et al. 2015

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Many residents of the Zambezi River Valley are dependent on water-related resources. Greenhouse gas (GHG) emissions may cause a significant change to the climate in the Zambezi Basin in the future, but there is much uncertainty about the future climate state. This situation leaves policy makers at a state of urgency to prepare for these changes as well as reduce the impacts of the changes through GHG mitigation strategies. First and foremost, we must better understand the economic sectors most likely impacted and the magnitude of those impacts, given the inherent uncertainty. In this study, we present a suite of models that assess the effects of climate change on water resources for four countries in the Zambezi basin: Malawi, Mozambique, Zambia, and Zimbabwe. We use information from a large ensemble (6800) of climate scenarios for two GHG emission policies which represent a distribution of impacts on water-related sectors, considering emissions uncertainty, climate sensitivity uncertainty, and regional climate uncertainty. Two GHG mitigation scenarios are used to understand the effect of global emissions reduction on the River Basin system out to 2050. Under both climate polices, the majority of the basin will likely be drier, except for a portion in the north around Malawi and northern Zambia. Three Key Performance Indicators are used-flood occurrence, unmet irrigation demand, and hydropower generation-to understand the impact channels of climate change effects on the four countries. We find that floods are likely to be worse in Mozambique, irrigation demands are likely to be unmet in Mozambique and Zimbabwe, and hydropower generation is likely to be reduced in Zambia. We also find that Climatic Change (2015) 130:35-48 DOI 10.1007/s10584-014-1314 This article is part of a Special Issue on BClimate Change and the Zambezi River Valley^edited by Finn Tarp, James Juana, and Philip Ward. the range of possible impacts is much larger under an unconstrained GHG emissions case than under a strict mitigation strategy, suggesting that GHG mitigation would reduce uncertainties about the future climate state, reducing the risks of extreme changes as compared to the unconstrained emissions case.

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confidence: 80%

An uncertainty approach to assessment of climate change impacts on the Zambezi River Basin

et al. 2015

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“…The Pettitt rank-based approach was used to determine the most probable change-point in the streamflow time-series (Pettitt, 1979). This test is considered robust to changes in distributional form when the location changes, and has shown to possess greater statistical power compared to other tests like the Wilcoxon-Mann-Whitney (Kundzewicz and Robson, 2004;Mazvimavi and Wolski, 2006). Also it is useful to detect a change in the median when the time of change is unknown (Pettitt, 1979;Kundzewicz and Robson, 2004;Mazvimavi and Wolski, 2006).…”

Section: Change-point Analysismentioning

confidence: 99%

“…The most common statistical technique is the non-parametric Mann-Kendall test (Mann, 1945;Kendall, 1975), which is used to identify the existence of monotonic trends in a time-series. The main weakness of the Mann-Kendall statistic is it is designed to detect the monotonic trend, however hydrologic changes can occur both gradually (trend) and abruptly (step-change) (Kundzewicz and Robson, 2004;Mazvimavi and Wolski, 2006). A gradual change is typically slow and constant over time while an abrupt change occurs quickly due to a sudden alteration within a watershed (e.g., reservoir construction, water diversions) (Kundzewicz and Robson, 2000;Smyth et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Drivers of drying on the Yongding River in Beijing

Jiang

Wong

et al. 2014

Journal of Hydrology

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s u m m a r yIn recent decades, the Yongding River in Beijing has ceased to flow due to the impact of climate and anthropogenic factors, which has led to severe environmental degradation. The Beijing government is constructing new freshwater ecosystems on the Yongding River to improve environmental conditions for ecosystem services. Clarification is needed on the influence of precipitation and anthropogenic factors on streamflow decline in Beijing. A hydrological time-series analysis was conducted on recorded streamflow at Guanting Reservoir, Yanchi, and Sanjiadian to estimate the influence of precipitation variability on the drying of the Yongding River in Beijing. From 1980 to 2010, the mean annual rates of streamflow decline were 0.44 m 3 s À1 yr À1 (Guanting), 0.42 m 3 s À1 yr À1 (Yanchi), and 0.03 m 3 s À1 yr À1 (Sanjiadian). The most probable abrupt change-point for annual streamflow was 1999 at Guanting Reservoir and Yanchi, and was 2000 at Sanjiadian. Between the pre-change (1980)(1981)(1982)(1983)(1984)(1985)(1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999) and post-change (2000-2010) periods, mean annual streamflow decreased by 68.56% (Guanting), 66.92% (Yanchi), and 96.78% (Sanjiadian). A multiple regression analysis using annual precipitation and streamflow at Guanting, Yanchi, and Sanjiadian showed an insignificant relationship between local precipitation and streamflow in both periods. Next we assessed the potential impact of upstream human activities on downstream flow using: (1) correlation statistics between upstream flow and downstream flow, (2) water abstracted above Sanjiadian, and (3) upstream socioeconomic data. The results suggest upstream human activities are important drivers on downstream flow decline, which could possibly explain the weak relationship between precipitation and streamflow. Further analysis is needed to clarify the influence of upstream water consumption on Guanting Reservoir to advise management on the new freshwater ecosystems along the Yongding River.

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“…), linear periodic PAR(1) models [Salas et al, 1980] were identified because they are able to provide good forecasts of the inflow processes according to the adopted monthly time step, see the explained variance in Table 2. In particular, the interannual variability characterizing the inflows in the Zambezi system [Rocha and Simmonds, 1997;Mazvimavi and Wolski, 2006] has limited impacts on the considered objectives and it can be captured by autoregressive models.…”

Section: Zambezi River Agent-based Modelmentioning

confidence: 99%

Assessing the value of cooperation and information exchange in large water resources systems by agent‐based optimization

Giuliani

Castelletti

2013

Water Resources Research

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[1] Many large-scale water resources systems, especially in transboundary contexts, are characterized by the presence of several and conflicting interests and managed by multiple, institutionally independent decision makers. These systems are often studied adopting a centralized approach based on the assumption of full cooperation and information exchange among the involved parties. Such a perspective is conceptually interesting to quantify the best achievable performance but might have little practical impact given the real political and institutional setting. In this work, we propose a novel decision-analytic framework based on multiagent systems to model and analyze different levels of cooperation and information exchange among multiple decision makers. The Zambezi River basin is used as a case study. According to the proposed agent-based optimization approach, each agent represents a decision maker, whose decisions are defined by an explicit optimization problem considering only the agent's local interests. The economic value of information exchange is estimated comparing a noncooperative setting, where agents act independently, with the first basic level of cooperation, i.e., coordination, characterized by full information exchange. The economic value of cooperation is also estimated by comparison with the ideal, fully cooperative management of the system. Results show that coordination, obtained with complete information exchange, allows the downstream agents to better adapt to the upstream behaviors. The impact of information exchange depends on the objective considered, and we show coordination to be particularly beneficial to environmental interests.Citation: Giuliani, M., and A. Castelletti (2013), Assessing the value of cooperation and information exchange in large water resources systems by agent-based optimization, Water Resour. Res., 49,[3912][3913][3914][3915][3916][3917][3918][3919][3920][3921][3922][3923][3924][3925][3926]

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Long-term variations of annual flows of the Okavango and Zambezi Rivers

Cited by 65 publications

References 9 publications

An uncertainty approach to assessment of climate change impacts on the Zambezi River Basin

An uncertainty approach to assessment of climate change impacts on the Zambezi River Basin

Drivers of drying on the Yongding River in Beijing

Assessing the value of cooperation and information exchange in large water resources systems by agent‐based optimization

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