Drought early warning based on optimal risk forecasts in regulated river systems: Application to the Jucar River Basin (Spain)

Abstract. Drought vulnerability is a complex concept that includes both biophysical and socio-economic drivers of drought impact that determine capacity to cope with drought. In order to develop an efficient drought early warning system and to be prepared to mitigate upcoming drought events it is important to understand the drought vulnerability of the affected regions. We propose a composite Drought Vulnerability Indicator (DVI) that reflects different aspects of drought vulnerability evaluated at Pan-African level in four components: the renewable natural capital, the economic capacity, the human and civic resources, and the infrastructure and technology. The selection of variables and weights reflects the assumption that a society with institutional capacity and coordination, as well as with mechanisms for public participation is less vulnerable to drought; furthermore we consider that agriculture is only one of the many sectors affected by drought. The quality and accuracy of a composite indicator depends on the theoretical framework, on the data collection and quality, and on how the different components are aggregated. This kind of approach can lead to some degree of scepticism; to overcome this problem a sensitivity analysis was done in order to measure the degree of uncertainty associated with the construction of the composite indicator. Although the proposed drought vulnerability indicator relies on a number of theoretical assumptions and some degree of subjectivity, the sensitivity analysis showed that it is a robust indicator and hence able of representing the complex processes that lead to drought vulnerability. According to the DVI computed at country level, the African countries classified with higher relative vulnerability are Somalia, Burundi, Niger, Ethiopia, Mali and Chad. The analysis of the renewable natural capital component at sub-basin level shows that the basins with high to moderate drought vulnerability can be subdivided in three main different geographical regions: the Mediterranean coast of Africa; the Sahel region and the Horn of Africa; the Serengeti and the Eastern Miombo woodlands in eastern Africa. Additionally, the western part of the Zambezi basin, the south-eastern border of the Congo basin and the belt of Fynbos in the Western Cape should also be included in this category. The results of the DVI at the country level were compared with drought disasters information from the EM-DAT disaster database. Even if a cause effect relationship cannot be established between the DVI and the drought disaster database, a good agreement is observed between the drought vulnerability maps and the number of persons affected by droughts. These results are a valuable contribution to the discussion on how to assess drought vulnerability and should contribute to the development of drought early warning systems in Africa.

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Facilitating the Use of Drought Early Warning Information through Interactions with Agricultural Stakeholders

Bulletin of the American Meteorological Society ◽

10.1175/bams-d-14-00219.1 ◽

2015 ◽

Vol 96 (7) ◽

pp. 1073-1078 ◽

Cited By ~ 29

Author(s):

Jason A. Otkin ◽

Mark Shafer ◽

Mark Svoboda ◽

Brian Wardlow ◽

Martha C. Anderson ◽

...

Keyword(s):

Early Warning ◽

Drought Early Warning

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Recognizing the Famine Early Warning Systems Network: Over 30 Years of Drought Early Warning Science Advances and Partnerships Promoting Global Food Security

Bulletin of the American Meteorological Society ◽

10.1175/bams-d-17-0233.1 ◽

2019 ◽

Vol 100 (6) ◽

pp. 1011-1027 ◽

Cited By ~ 29

Author(s):

Chris Funk ◽

Shraddhanand Shukla ◽

Wassila Mamadou Thiaw ◽

James Rowland ◽

Andrew Hoell ◽

...

Keyword(s):

Food Security ◽

Early Warning ◽

Warning System ◽

Climate Extremes ◽

Early Warning Systems ◽

Food Prices ◽

Humanitarian Assistance ◽

Warning Systems ◽

Recent Climate ◽

Drought Early Warning

AbstractOn a planet with a population of more than 7 billion, how do we identify the millions of drought-afflicted people who face a real threat of livelihood disruption or death without humanitarian assistance? Typically, these people are poor and heavily dependent on rainfed agriculture and livestock. Most live in Africa, Central America, or Southwest Asia. When the rains fail, incomes diminish while food prices increase, cutting off the poorest (most often women and children) from access to adequate nutrition. As seen in Ethiopia in 1984 and Somalia in 2011, food shortages can lead to famine. Yet these slow-onset disasters also provide opportunities for effective intervention, as seen in Ethiopia in 2015 and Somalia in 2017. Since 1985, the U.S. Agency for International Development’s Famine Early Warning Systems Network (FEWS NET) has been providing evidence-based guidance for effective humanitarian relief efforts. FEWS NET depends on a Drought Early Warning System (DEWS) to help understand, monitor, model, and predict food insecurity. Here we provide an overview of FEWS NET’s DEWS using examples from recent climate extremes. While drought monitoring and prediction provides just one part of FEWS NET’s monitoring system, it draws from many disciplines—remote sensing, climate prediction, agroclimatic monitoring, and hydrologic modeling. Here we describe FEWS NET’s multiagency multidisciplinary DEWS and Food Security Outlooks. This DEWS uses diagnostic analyses to guide predictions. Midseason droughts are monitored using multiple cutting-edge Earth-observing systems. Crop and hydrologic models can translate these observations into impacts. The resulting information feeds into FEWS NET reports, helping to save lives by motivating and targeting timely humanitarian assistance.

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Thermal extremes in regulated river systems under climate change: an application to the southeastern U.S. rivers

Environmental Research Letters ◽

10.1088/1748-9326/ab8f5f ◽

2020 ◽

Vol 15 (9) ◽

pp. 094012

Author(s):

Yifan Cheng ◽

Nathalie Voisin ◽

John R Yearsley ◽

Bart Nijssen

Keyword(s):

Climate Change ◽

Regulated River ◽

River Systems

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River Water Quality of the Selenga-Baikal Basin: Part II—Metal Partitioning under Different Hydroclimatic Conditions

Water ◽

10.3390/w12092392 ◽

2020 ◽

Vol 12 (9) ◽

pp. 2392

Author(s):

Nikolay Kasimov ◽

Galina Shinkareva ◽

Mikhail Lychagin ◽

Sergey Chalov ◽

Margarita Pashkina ◽

...

Keyword(s):

River Basin ◽

Large River ◽

Metal Partitioning ◽

River Systems ◽

Catchment Scale ◽

Selenga River Basin ◽

Extensive Field ◽

Basin Scale ◽

Wide Range ◽

Dissolved Form

The partitioning of metals and metalloids between their dissolved and suspended forms in river systems largely governs their mobility and bioavailability. However, most of the existing knowledge about catchment-scale metal partitioning in river systems is based on a limited number of observation points, which is not sufficient to characterize the complexity of large river systems. Here we present an extensive field-based dataset, composed of multi-year data from over 100 monitoring locations distributed over the large, transboundary Selenga River basin (of Russia and Mongolia), sampled during different hydrological seasons. The aim is to investigate on the basin scale, the influence of different hydroclimatic conditions on metal partitioning and transport. Our results showed that the investigated metals exhibited a wide range of different behaviors. Some metals were mostly found in the dissolved form (84–96% of Mo, U, B, and Sb on an average), whereas many others predominantly existed in suspension (66–87% of Al, Fe, Mn, Pb, Co, and Bi). Nevertheless, our results also showed a consistently increasing share of metals in dissolved form as the metals were transported to the downstream parts of the basin, closer to the Lake Baikal. Under high discharge conditions (including floods), metal transport by suspended particulate matter was significantly greater (about 2–6 times). However, since high and low water conditions could prevail simultaneously at a given point of time within the large river basin, e.g., as a result of on-going flood propagation, snap-shot observations of metal partitioning demonstrated contrasting patterns with domination of both particulate and dissolved phases in different parts of the basin. Such heterogeneity of metal partitioning is likely to be found in many large river systems. These results point out the importance of looking into different hydroclimatic conditions across space and time, both for management purposes and contaminant modeling efforts at the basin scale.

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Effects of Opened and Closed Spillway Operations of a Large Tropical Hydroelectric Dam on the Water Quality of the Downstream River

Journal of Chemistry ◽

10.1155/2019/6567107 ◽

2019 ◽

Vol 2019 ◽

pp. 1-11 ◽

Cited By ~ 4

Author(s):

Fiona-Annilow Wera ◽

Teck-Yee Ling ◽

Lee Nyanti ◽

Siong-Fong Sim ◽

Jongkar Grinang

Keyword(s):

Water Quality ◽

River Basin ◽

Aquatic Organisms ◽

Quality Parameters ◽

Regulated River ◽

Land Uses ◽

Hydroelectric Dam ◽

Water Ph ◽

The Impact

Water quality downstream of a hydroelectric dam is potentially affected by dam operations and other land uses in the river basin. Previous short-distance studies below the large Bakun Dam indicated poorer water quality during closed spillway. However, the extent of the impact is still unknown. Such knowledge is essential for mitigating the impact of the dam. Thus, the objectives of this study were to determine the water quality up to a distance of 210 km under two spillway operations, namely, closed and opened spillways, and also to determine the changes in water quality from the predam condition. Physicochemical parameters were measured at 15 stations along the Rajang River. Results of this preliminary study indicated that there were significant differences in eight out of nine water quality parameters between opened and closed spillway operations with opened spillway showing better water quality. During closed spillway, as we approached the dam, there was an increasing acidity and a decreasing oxygen content. Furthermore, as the water flows downstream, the unhealthy DO level (<5 mg/L) extended up to 165 km and the linear model showed an increasing DO rate of 0.09 mg/L per km. With opened spillway, DO decreased exponentially from 9.74 mg/L towards the downstream direction to 7.67 mg/L. The increasing turbidity and TSS in the downstream direction indicate contributions from erosion due to other land uses. The river is polluted with organics as indicated by COD of Class IV or V with sources from the dam and the activities in the river basin. Compared to the predam condition, the regulated river is less turbid but warmer and higher in ammonia. Closed spillway led to lower DO and acidic water. However, opened spillway water pH and DO were similar to those in the predam condition. Thus, it is recommended that DO be consistently high enough for the health of sensitive aquatic organisms downstream.

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