Your search found 5 records
1 Ceola, S.; Laio, F.; Montanari, A. 2015. Human-impacted waters: new perspectives from global high-resolution monitoring. Water Resources Research, 51(9):7064-7079. [doi: https://doi.org/10.1002/2015WR017482]
Water resources ; Human behavior ; Geographical distribution ; Spatial distribution ; Monitoring ; Satellite observation ; Remote sensing ; Rivers ; Hydrological data ; Models ; Population density ; Environmental effects
(Location: IWMI HQ Call no: e-copy only Record No: H047641)
(3.53 MB)
The human presence close to streams and rivers is known to have consistently increased worldwide, therefore introducing dramatic anthropogenic and environmental changes. However, a spatiotemporal detailed analysis is missing to date. In this paper, we propose a novel method to quantify the temporal evolution and the spatial distribution of the anthropogenic presence along streams and rivers and in their immediate proximity at the global scale and at a high-spatial resolution (i.e., nearly 1 km at the equator). We use satellite images of nocturnal lights, available as yearly snapshots from 1992 to 2013, and identify five distinct distance classes from the river network position. Our results show a temporal enhancement of human presence across the considered distance classes. In particular, we observed a higher human concentration in the vicinity of the river network, even though the frequency distribution of human beings in space has not significantly changed in the last two decades. Our results prove that fine-scale remotely sensed data, as nightlights, may provide new perspectives in water science, improving our understanding of the human impact on water resources and water-related environments.
2 Mittal, N.; Bhave, A. G.; Mishra, A.; Singh, R. 2016. Impact of human intervention and climate change on natural flow regime. Water Resources Management, 30(2):685-699. [doi: https://doi.org/10.1007/s11269-015-1185-6]
River basins ; Stream flow ; Climate change ; Anthropogenic factors ; Human behavior ; Dam construction ; Hydrology ; Models ; Calibration ; Performance evaluation ; Ecosystems ; Monsoon climate / India / Kangsabati River
(Location: IWMI HQ Call no: e-copy only Record No: H047779)
(1.01 MB)
According to the ‘natural flow paradigm’, any departure from the natural flow condition will alter the river ecosystem. River flow regimes have been modified by anthropogenic interventions and climate change is further expected to affect the biotic interactions and the distribution of stream biota by altering streamflow. This study aims to evaluate the hydrologic alteration caused by dam construction and climatic changes in a mesoscale river basin, which is prone to both droughts and monsoonal floods. To analyse the natural flow regime, 15 years of observed streamflow (1950–1965) prior to dam construction is used. Future flow regime is simulated by a calibrated hydrological model Soil and Water Assessment Tool (SWAT), using ensemble of four high resolution (~25 km) Regional Climate Model (RCM) simulations for the near future (2021–2050) based on the SRES A1B scenario. Finally, to quantify the hydrological alterations of different flow characteristics, the Indicators of Hydrological Alteration (IHA) program based on the Range of Variability Approach (RVA) is used. This approach enables the assessment of ecologically sensitive streamflow parameters for the pre- and post-impact periods in the regions where availability of long-term ecological data is a limiting factor. Results indicate that flow variability has been significantly reduced due to dam construction with high flows being absorbed and pre-monsoon low flows being enhanced by the reservoir. Climate change alone may reduce high peak flows while a combination of dam and climate change may significantly reduce variability by affecting both high and low flows, thereby further disrupting the functioning of riverine ecosystems. We find that, in the Kangsabati River basin, influence of dam is greater than that of the climate change, thereby emphasizing the significance of direct human intervention.
3 Lalani, B.; Dorward, P.; Holloway, G.; Wauters, E. 2016. Smallholder farmers' motivations for using conservation agriculture and the roles of yield, labour and soil fertility in decision making. Agricultural Systems, 146:80-90. [doi: https://doi.org/10.1016/j.agsy.2016.04.002]
Farming systems ; Conservation agriculture ; Agricultural practices ; Smallholders ; Farmers attitudes ; Soil fertility ; Yield increases ; Labour ; Decision making ; Psychological factors ; Human behavior ; Adaptation ; Motivation ; Models ; Socioeconomic environment / Africa South of Sahara / Mozambique / Cabo Delgado
(Location: IWMI HQ Call no: e-copy only Record No: H047845)
(0.50 MB)
Conservation Agriculture (CA) has been widely promoted as an agro-ecological approach to sustainable production intensification. Despite numerous initiatives promoting CA across Sub-Saharan Africa there have been low rates of adoption. Furthermore, there has been strong debate concerning the ability of CA to provide benefits to smallholder farmers regarding yield, labour, soil quality and weeding, particularly where farmers are unable to access external inputs such as herbicides. This research finds evidence that CA, using no external inputs, is most attractive among the very poor and that farmers are driven primarily by strong motivational factors in the key areas of current contention, namely yield, labour, soil quality and weeding time benefits. This study is the first to incorporate a quantitative socio-psychological model to understand factors driving adoption of CA. Using the Theory of Planned Behaviour (TPB), it explores farmers' intention to use CA (within the next 12 months) in Cabo Delgado, Mozambique where CA has been promoted for almost a decade. The study site provides a rich population from which to examine farmers' decision making in using CA. Regression estimates show that the TPB provides a valid model of explaining farmers' intention to use CA accounting for 80% of the variation in intention. Farmers' attitude is found to be the strongest predictor of intention. This is mediated through key cognitive drivers present that influence farmers' attitude such as increased yields, reduction in labour, improvement in soil quality and reduction in weeds. Subjective norm (i.e. social pressure from referents) and perceived behavioural control also significantly influenced farmers' intention. Furthermore, path analysis identifies farmers that are members of a Farmer Field School or participants of other organisations (e.g. savings group, seed multiplication group or a specific crop/livestock association) have a significantly stronger positive attitude towards CA with the poorest the most likely users and the cohort that find it the easiest to use. This study provides improved understanding relevant to many developing countries, of smallholder farmers' adoption dynamics related to CA, and of how farmers may approach this and other ‘new’ management systems.
4 Pekel, J.-F.; Cottam, A.; Gorelick, N.; Belward, A. S. 2016. High-resolution mapping of global surface water and its long-term changes. Nature, 540(7633):418-422. [doi: https://doi.org/10.1038/nature20584]
Surface water ; Mapping ; Satellite imagery ; Landsat ; Earth observation satellites ; Water distribution ; Geographical distribution ; Seasonal variation ; Expert systems ; Climate change ; Hydrology ; Models ; Drought ; Evaporation ; Human behavior ; Lakes ; Plateaus / Central Asia / USA / Australia / Aral Sea / Tibetan plateau
(Location: IWMI HQ Call no: e-copy only Record No: H047905)
(8.75 MB)
The location and persistence of surface water (inland and coastal) is both affected by climate and human activity1 and affects climate2,3 , biological diversity4 and human wellbeing5,6 . Global data sets documenting surface water location and seasonality have been produced from inventories and national descriptions7 , statistical extrapolation of regional data8 and satellite imagery9–12, but measuring long-term changes at high resolution remains a challenge. Here, using three million Landsat satellite images13, we quantify changes in global surface water over the past 32 years at 30-metre resolution. We record the months and years when water was present, where occurrence changed and what form changes took in terms of seasonality and persistence. Between 1984 and 2015 permanent surface water has disappeared from an area of almost 90,000 square kilometres, roughly equivalent to that of Lake Superior, though new permanent bodies of surface water covering 184,000 square kilometres have formed elsewhere. All continental regions show a net increase in permanent water, except Oceania, which has a fractional (one per cent) net loss. Much of the increase is from reservoir filling, although climate change14 is also implicated. Loss is more geographically concentrated than gain. Over 70 per cent of global net permanent water loss occurred in the Middle East and Central Asia, linked to drought and human actions including river diversion or damming and unregulated withdrawal15,16. Losses in Australia17 and the USA18 linked to long-term droughts are also evident. This globally consistent, validated data set shows that impacts of climate change and climate oscillations on surface water occurrence can be measured and that evidence can be gathered to show how surface water is altered by human activities. We anticipate that this freely available data will improve the modelling of surface forcing, provide evidence of state and change in wetland ecotones (the transition areas between biomes), and inform water-management decision-making.
5 Manthrithilake, Herath. 2016. Lagoons of Sri Lanka. In Fernando, S. (Ed.); Nadaraja, L. (Photographer). Sri Lanka: a heritage of water. [s.l.]: Author. pp.135-145.
Coastal lagoons ; Ecosystems ; Biodiversity ; Aquatic animals ; Species ; Habitats ; Fishes ; Zooplankton ; Mangroves ; Saltmarshes ; Seagrasses ; Human behavior / Sri Lanka
(Location: IWMI HQ Call no: 333.91 G744 FER Record No: H047922)
(2.28 MB)
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