Your search found 6 records
1 Cuthbert, M. O.; Taylor, R. G.; Favreau, G.; Todd, M. C.; Shamsudduha, M.; Villholth, Karen G.; MacDonald, A. M.; Scanlon, B. R.; Kotchoni, D. O. V.; Vouillamoz, J.-M.; Lawson, F. M. A.; Adjomayi, P. A.; Kashaigili, J.; Seddon, D.; Sorensen, J. P. R.; Ebrahim, Girma Yimer; Owor, M.; Nyenje, P. M.; Nazoumou, Y.; Goni, I.; Ousmane, B. I.; Sibanda, T.; Ascott, M. J.; Macdonald, D. M. J.; Agyekum, W.; Koussoube, Y.; Wanke, H.; Kim, H.; Wada, Y.; Lo, M.-H.; Oki, T.; Kukuric, N. 2019. Observed controls on resilience of groundwater to climate variability in sub-Saharan Africa. Nature, 572(7768):230-234. [doi: https://doi.org/10.1038/s41586-019-1441-7]
Groundwater recharge ; Climate change ; Resilience ; Groundwater table ; Observation ; Precipitation ; Hydrology ; Hydrography ; Models ; Arid zones ; Rain / Africa South of Sahara / Benin / Uganda / United Republic of Tanzania / Zimbabwe / South Africa / Namibia / Niger / Ghana / Burkina Faso
(Location: IWMI HQ Call no: e-copy only Record No: H049316)
https://www.nature.com/articles/s41586-019-1441-7.epdf?author_access_token=UgizrPwmrGzlbL33bjbvQdRgN0jAjWel9jnR3ZoTv0M3C122Ih9FQbr0PbeOlDAX9EZlbSwXsaUcJ-Vq-8EelgPfWJQTdVE-2_3g7yypNR4C-qTOMe7Ux1weufjBdaT9SyaKgJjfKYgJ2fqsjIRLng%3D%3D
https://vlibrary.iwmi.org/pdf/H049316.pdf
https://vlibrary.iwmi.org/pdf/H049316.pdf
(7.21 MB)
Groundwater in sub-Saharan Africa supports livelihoods and poverty alleviation1,2 , maintains vital ecosystems, and strongly influences terrestrial water and energy budgets3 . Yet the hydrological processes that govern groundwater recharge and sustainability—and their sensitivity to climatic variability—are poorly constrained4,5 . Given the absence of firm observational constraints, it remains to be seen whether model-based projections of decreased water resources in dry parts of the region4 are justified. Here we show, through analysis of multidecadal groundwater hydrographs across sub-Saharan Africa, that levels of aridity dictate the predominant recharge processes, whereas local hydrogeology influences the type and sensitivity of precipitation–recharge relationships. Recharge in some humid locations varies by as little as five per cent (by coefficient of variation) across a wide range of annual precipitation values. Other regions, by contrast, show roughly linear precipitation–recharge relationships, with precipitation thresholds (of roughly ten millimetres or less per day) governing the initiation of recharge. These thresholds tend to rise as aridity increases, and recharge in drylands is more episodic and increasingly dominated by focused recharge through losses from ephemeral overland flows. Extreme annual recharge is commonly associated with intense rainfall and flooding events, themselves often driven by large-scale climate controls. Intense precipitation, even during years of lower overall precipitation, produces some of the largest years of recharge in some dry subtropical locations. Our results therefore challenge the ‘high certainty’ consensus regarding decreasing water resources4 in such regions of sub-Saharan Africa. The potential resilience of groundwater to climate variability in many areas that is revealed by these precipitation–recharge relationships is essential for informing reliable predictions of climate-change impacts and adaptation strategies.
2 Bayu, T.; Kim, H.; Oki, T. 2020. Water governance contribution to water and sanitation access equality in developing countries. Water Resources Research, 56(4):e2019WR025330. [doi: https://doi.org/10.1029/2019WR025330]
Water governance ; Water availability ; Sanitation ; Hygiene ; Sustainable Development Goals ; Human rights ; Developing countries ; Indicators ; Performance evaluation ; Political aspects ; Economic situation
(Location: IWMI HQ Call no: e-copy only Record No: H049634)
https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2019WR025330
https://vlibrary.iwmi.org/pdf/H049634.pdf
https://vlibrary.iwmi.org/pdf/H049634.pdf
(3.07 MB) (3.07 MB)
Access to basic water service and basic sanitation service has been acknowledged as fundamental human rights. It also has been mentioned in UN Sustainable Development Goals 6 to ensure that all people will have equal access to both water and sanitation service, as well as embedded in Goal 10 that aims to reduce inequality and promoting inclusiveness. However, the WHO/UNICEF Joint Monitoring Programme 2017 reported that 844 million people are still living without basic access to water, and 2.3 billion are still excluded from basic sanitation service. In this study, we present quantitative global-scale analysis of inequality of accessing the water and sanitation services from different wealth groups in 82 developing countries. We found that access inequality is rampant among developing countries particularly in terms of accessing basic sanitation service which the poor populations tend to be excluded in accessing the basic service. Based on combined multiple global data sets, we further identify which components of water governance are the key contributors to access inequality in water and sanitation services. We conclude that social and political dimension of water governance, such as government effectiveness, are influencing the occurrence of inequality of access to sanitation service in developing countries, while the inequality of access to basic water service was strongly influenced by the economic aspect of water governance, such as absorption of aid funds.
3 Kim, H.; Wigneron, J.-P.; Kumar, S.; Dong, J.; Wagner, W.; Cosh, M. H.; Bosch, D. D.; Collins, C. H.; Starks, P. J.; Seyfried, M.; Lakshmi, V. 2020. Global scale error assessments of soil moisture estimates from microwave-based active and passive satellites and land surface models over forest and mixed irrigated/dryland agriculture regions. Remote Sensing of Environment, 251:112052. [doi: https://doi.org/10.1016/j.rse.2020.112052]
Soil moisture ; Estimation ; Irrigated farming ; Dry farming ; Satellite observation ; Vegetation ; Forests ; Evapotranspiration ; Precipitation ; Salinity ; Models
(Location: IWMI HQ Call no: e-copy only Record No: H050079)
(13.10 MB)
Over the past four decades, satellite systems and land surface models have been used to estimate global-scale surface soil moisture (SSM). However, in areas such as densely vegetated and irrigated regions, obtaining accurate SSM remains challenging. Before using satellite and model-based SSM estimates over these areas, we should understand the accuracy and error characteristics of various SSM products. Thus, this study aimed to compare the error characteristics of global-scale SSM over vegetated and irrigated areas as obtained from active and passive satellites and model-based data: Advanced Scatterometer (ASCAT), Soil Moisture and Ocean Salinity (SMOS), Advanced Microwave Scanning Radiometer 2 (AMSR2), Soil Moisture Active Passive (SMAP), European Centre for Medium-Range Weather Forecasts Reanalysis 5 (ERA5), and Global Land Data Assimilation System (GLDAS). We employed triple collocation analysis (TCA) and caluclated conventional error metrics from in-situ SSM measurements. We also considered all possible triplets from 6 different products and showed the viability of considering the standard deviation of TCA-based numbers in producing robust results.
Over forested areas, it was expected that model-based SSM data might provide more accurate SSM estimates than satellites due to the intrinsic limitations of microwave-based systems. Alternately, over irrigated regions, observation-based SSM data were expected to be more accurate than model-based products because land surface models (LSMs) cannot capture irrigation signals caused by human activities. Contrary to these expectations, satellite-based SSM estimates from ASCAT, SMAP, and SMOS showed fewer errors than ERA5 and GLDAS SSM products over vegetated conditions. Furthermore, over irrigated areas, ASCAT, SMOS, and SMAP outperformed other SSM products; however, model-based data from ERA5 and GLDAS outperformed AMSR2. Our results emphasize that, over irrgated areas, considering satellite-based SSM data as alternatives to model-based SSM data sometimes produces misleading results; and considering model-based data as alternatives to satellite-based SSM data in forested areas can also sometimes be misleading. In addition, we discovered that no products showed much degradation in TCA-based errors under different vegetated conditions, while different irrigation conditions impacted both satellite and model-based SSM data sets.
The present research demonstrates that limitations in satellite and modeled SSM data can be overcome in many areas through the synergistic use of satellite and model-based SSM products, excluding areas where satellite-based data are masked out. In fact, when four satellite and model data sets are used selectively, the probability of obtaining SSM with stronger signal than noise can be close to 100%.
Over forested areas, it was expected that model-based SSM data might provide more accurate SSM estimates than satellites due to the intrinsic limitations of microwave-based systems. Alternately, over irrigated regions, observation-based SSM data were expected to be more accurate than model-based products because land surface models (LSMs) cannot capture irrigation signals caused by human activities. Contrary to these expectations, satellite-based SSM estimates from ASCAT, SMAP, and SMOS showed fewer errors than ERA5 and GLDAS SSM products over vegetated conditions. Furthermore, over irrigated areas, ASCAT, SMOS, and SMAP outperformed other SSM products; however, model-based data from ERA5 and GLDAS outperformed AMSR2. Our results emphasize that, over irrgated areas, considering satellite-based SSM data as alternatives to model-based SSM data sometimes produces misleading results; and considering model-based data as alternatives to satellite-based SSM data in forested areas can also sometimes be misleading. In addition, we discovered that no products showed much degradation in TCA-based errors under different vegetated conditions, while different irrigation conditions impacted both satellite and model-based SSM data sets.
The present research demonstrates that limitations in satellite and modeled SSM data can be overcome in many areas through the synergistic use of satellite and model-based SSM products, excluding areas where satellite-based data are masked out. In fact, when four satellite and model data sets are used selectively, the probability of obtaining SSM with stronger signal than noise can be close to 100%.
4 Zhang, P.; Jeong, J.-H.; Yoon, J.-H.; Kim, H.; Wang, S.-Y. S.; Linderholm, H. W.; Fang, K.; Wu, X.; Chen, D. 2020. Abrupt shift to hotter and drier climate over inner East Asia beyond the tipping point. Science, 370(6520):1095-1099. [doi: https://doi.org/10.1126/science.abb3368]
Climate change ; Arid climate ; Warm season ; Soil moisture ; Droughts ; Air temperature ; Trends ; Observation / East Asia / Mongolia
(Location: IWMI HQ Call no: e-copy only Record No: H050100)
(4.03 MB)
Unprecedented heatwave-drought concurrences in the past two decades have been reported over inner East Asia. Tree-ring–based reconstructions of heatwaves and soil moisture for the past 260 years reveal an abrupt shift to hotter and drier climate over this region. Enhanced land-atmosphere coupling, associated with persistent soil moisture deficit, appears to intensify surface warming and anticyclonic circulation anomalies, fueling heatwaves that exacerbate soil drying. Our analysis demonstrates that the magnitude of the warm and dry anomalies compounding in the recent two decades is unprecedented over the quarter of a millennium, and this trend clearly exceeds the natural variability range. The “hockey stick”–like change warns that the warming and drying concurrence is potentially irreversible beyond a tipping point in the East Asian climate system.
5 Chen, C.-Y.; Wang, S.-W.; Kim, H.; Pan, S.-Y.; Fan, C.; Lin, Y. J. 2021. Non-conventional water reuse in agriculture: a circular water economy. Water Research, 199:117193. [doi: https://doi.org/10.1016/j.watres.2021.117193]
Water reuse ; Agriculture ; Irrigation water ; Wastewater treatment plants ; Technology ; Economic aspects ; Water use ; Water quality ; Sewage ; Public health ; Nutrients ; Hydraulic fracturing ; Stormwater runoff ; Cooling water ; Decentralization
(Location: IWMI HQ Call no: e-copy only Record No: H050454)
(2.41 MB)
Due to the growing and diverse demands on water supply, exploitation of non-conventional sources of water has received much attention. Since water consumption for irrigation is the major contributor to total water withdrawal, the utilization of non-conventional sources of water for the purpose of irrigation is critical to assuring the sustainability of water resources. Although numerous studies have been conducted to evaluate and manage non-conventional water sources, little research has reviewed the suitability of available water technologies for improving water quality, so that water reclaimed from non-conventional supplies could be an alternative water resource for irrigation. This article provides a systematic overview of all aspects of regulation, technology and management to enable the innovative technology, thereby promoting and facilitating the reuse of non-conventional water. The study first reviews the requirements for water quantity and quality (i.e., physical, chemical, and biological parameters) for agricultural irrigation. Five candidate sources of non-conventional water were evaluated in terms of quantity and quality, namely rainfall/stormwater runoff, industrial cooling water, hydraulic fracturing wastewater, process wastewater, and domestic sewage. Water quality issues, such as suspended solids, biochemical/chemical oxygen demand, total dissolved solids, total nitrogen, bacteria, and emerging contaminates, were assessed. Available technologies for improving the quality of non-conventional water were comprehensively investigated. The potential risks to plants, human health, and the environment posed by non-conventional water reuse for irrigation are also discussed. Lastly, three priority research directions, including efficient collection of non-conventional water, design of fit-for-purpose treatment, and deployment of energy-efficient processes, were proposed to provide guidance on the potential for future research.
6 Cullmann, J.; Dilley, M. (Ed.); Egerton, P.; Grasso, V. F. (Ed.); Honore, C.; Lucio, F.; Luterbacher, J.; Nullis, C.; Power, M.; Rea, A.; Repnik, M.; Stander, J.; Idle, T. (Ed.); Msemo, N. (Ed.); Baubion, N.; Roudier, P.; Woillez, M.- N.; Gomes, A. M.; Dobardzic, S.; Pina, C. L.; Naran, B.; Richmond, M.; Harding, J.; Macasil, M. L. K.; Chaponniere, E.; Hoyer, B.; Losenno, C.; Vaananen, E.; Baugh, C.; Prudhomme, C.; Brovko, E.; Giusti, S.; Hoogeveen, J.; Maher, S.; Neretin, L.; Pek, E.; Gutierrez, A.; Ramage, S.; Venturini, S.; Intsiful, J.; Barnwal, A.; Iqbal, F.; Aich, V.; Debevec, L.; Grey, S.; Sumner, T.; Marsden, K.; Katsanakis, R.; Sengupta, R.; Bensada, A.; Olhoff, A.; Ivanova, O.; Kappelle, M.; Nield, M.; Wang, Y.; Bertule, M.; Glennie, P.; Lloyd, G. J.; Benchwick, G.; Creitaru, L.; Larroquette, B.; Stephens, E.; Properzi, F.; Schade, M.; Bogdanova, A.- M.; Kull, D.; de France, J.; Aich, V.; Alexieva, A.; Bastani, H.; Berit, A.; Berod, D.; Bode, G.; Boscolo, R.; Chernov, I.; de Coning, E.; Eggleston, S.; Ehlert, K.; Delju, A.; Douris, J.; Gallo, I.; Kim, H.; Migraine, J.- B.; Msemo, N.; Polcher, J.; Sparrow, M.; Stefanski, R.; Tripathi, R.; Vara, R. L. S.; Woolnough, S.; Zuniga, J. A.; Christiana, P.; Luo, T.; Saccoccia, L. 2021. 2021 state of climate services: water. Geneva, Switzerland: WMO. 46p. (WMO No.1278)
Water resources ; Climate change ; Information services ; Early warning systems ; Socioeconomic aspects ; Communities ; Flooding ; Water stress ; Drought ; Forecasting ; Governance ; Water supply ; Gender ; Decision making ; Disasters ; Economic losses ; Hurricanes ; Resilience ; Policies ; Hydroelectric power generation ; Meteorological stations ; Disaster risk management ; Disaster risk reduction ; Natural disasters ; Case studies / Asia / Thailand / Africa / Gambia / Europe / Slovakia / North America / Central America / Hondura / Caribbean / South America
(Location: IWMI HQ Call no: e-copy only Record No: H050659)
(4.62 MB) (4.62 MB)
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