| 1. |
- Barron, Jennie
(author)
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Building climate resilience in degraded agricultural landscapes through water management: A case study of Bundelkhand region, Central India
- 2020
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In: Journal of Hydrology. - : Elsevier BV. - 0022-1694 .- 1879-2707. ; 591
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Journal article (peer-reviewed)abstract
- Rainfall variability and water scarcity continue to hamper the food and income security of smallholder farming systems in poverty-affected regions. Innovations in soil and water management, especially in the drylands, are critical for meeting food security and water productivity targets of Agenda 2030. This study analyzes how rainfed agriculture can be intensified with marginal impact on the landscape water balance. The impact of rainwater harvesting structures on landscape hydrology and associated agricultural services was analyzed in the semi-arid Jhansi district of Bundelkhand region in central India. The Parasai-Sindh pilot watershed was subjected to a 5-year (2012-2016) monitoring of rainfed system improvements in water availability and crop intensification due to surface water storage (haveli system), check dams, and field infiltration structures. Hydrological processes were monitored intensively to analyze the landscape's water balance components. Rainwater harvesting (RWH) structures altered the landscape's hydrology, limiting average surface runoff from 250 mm/year to 150 mm/year over the study period. Groundwater levels increased by 2-5 m (m), alleviating water scarcity issues of the communities in recurring dry years. Nearly 20% of fallow lands were brought under cultivation. Crop yields increased by 10-70% and average household income increased from US$ 960/year to US $ 2700/year compared to that in the non-intervention landscape. The combined soil-water-vegetation efforts strengthened water resilience and environmental systems in agricultural landscape.
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| 2. |
- Bishop, Kevin, et al.
(author)
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Effect of DEM-smoothing and -aggregation on topographically-based flow directions and catchment boundaries
- 2021
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In: Journal of Hydrology. - : Elsevier BV. - 0022-1694 .- 1879-2707. ; 602
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Journal article (peer-reviewed)abstract
- It is generally assumed that, in humid climates, the groundwater table is a subdued copy of the surface topography. However, the general groundwater table is unlikely to be affected by the microtopography as seen in high-resolution Digital Elevation Models (DEMs). So far, there has been little guidance on the best resolution DEM to use to determine the shape of the water table or the direction of shallow groundwater flow in headwater catchments. We, therefore, looked at the effects of DEM-smoothing and -aggregation on the calculated flow directions and derived catchment boundaries, and identified areas and landscape features for which the calculated flow directions are particularly sensitive to DEM smoothing or aggregation. For > 40 % of the area of the Krycklan study catchment, the calculated flow directions depend strongly on the degree of smoothing or aggregation of the DEM. The four main landscape features for which DEM smoothing or aggregation strongly affected the calculated flow directions were: local slopes in the opposite direction of the general slope, flat areas, ridges, and incised streambanks. To determine the effects of the changing flow directions on the derived catchment boundaries for the smoothed and aggregated DEMs, we calculated the drainage area for 40 locations, representing the outlets of catchments of varying sizes. The shape and size of the catchments of first-order streams were most affected by the processing of the DEM. These streams were often almost completely smoothed out during the DEM preprocessing steps. These shifts in catchment boundaries and drainage area would have a large effect on the water balance. This study thus highlights the need to carefully consider the effects of DEM smoothing or -aggregation on the calculated flow directions and drainage areas.
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| 3. |
- Casali, Emilien, et al.
(author)
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Macropore flow in relation to the geometry and topology of soil macropore networks: Re-visiting the kinematic wave equation
- 2024
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In: Journal of Hydrology. - 0022-1694 .- 1879-2707. ; 630
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Journal article (peer-reviewed)abstract
- The rapid flow of water through soil macropores significantly affects the partitioning of precipitation between surface runoff and infiltration and also the rate of solute transport in soil, both of which have an impact on the risk of contamination of surface water and groundwater. The kinematic wave equation is often employed as a model of gravity-driven water flow through soil macropores. The exponent in this simple model influences the pore water velocity attained in the macropores at any given input rate and is usually estimated by inverse modelling against measured flow rates or water contents. In theory, the exponent in the kinematic wave equation should depend on the geometry and topology of the conducting macropore networks, although these relationships have not so far been investigated. In this study, we related metrics of soil structure derived from X-ray images to values of the kinematic exponent estimated from drainage experiments on twenty-two columns sampled at three different field sites under two contrasting land uses and at three different depths. We found that smaller values of the exponent in the kinematic wave equation, which would equate to more rapid flow of water through soil macropores, were found in plough pan and subsoil columns of smaller macroporosity, for which biopores comprised a significant fraction. The macroporosity in these columns was more vertically oriented and poorly inter-connected, though still continuous across the sample. In contrast, topsoil columns from both arable land and grassland had better connected, denser and more isotropically-distributed macropore networks and larger values of the kinematic exponent. Our results suggest that for predictive modelling at large scales, it may be feasible to estimate the kinematic exponent using class pedotransfer functions based on pedological information such as land use and horizon type.
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| 4. |
- Chen, Chen, et al.
(author)
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Step-drawdown test for identifying aquifer and well loss parameters in a partially penetrating well with irregular (non-linear increasing) pumping rates
- 2022
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In: Journal of Hydrology. - : Elsevier BV. - 0022-1694 .- 1879-2707. ; 614
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Journal article (peer-reviewed)abstract
- A step-drawdown test with an increasing pumping rate at each step in a fully penetrating well is a typical procedure for estimating aquifer parameters and well losses. However, partially penetrating wells in closed aquifers have also been adopted mainly due to economic constraints with a stepwise increase in the pumping rate. In this study, a new empirical method is proposed based on the stepwise drawdown defined by irregular pumping rates in a partially penetrating well. The method was validated by fitting drawdown data from classical works. The characteristics of the drawdowns and well losses were discussed for varying pumping scenarios. The results indicate that the new empirical method interprets previous works more accurately for a fully penetrating well and also effectively estimates the aquifer and well loss parameters. A new coefficient, the pumping ratevarying index a, was introduced to indicate the pumping rate difference (Delta Q) between the two steps. As such, a negative pumping rate difference would decrease the well-loss and result in a negative a. In addition, the effect of the ratio of the well's screen length to aquifer thickness demonstrates that a longer screen would cause a larger well loss. Finally, the proposed empirical method was applied to a fieldwork conducted in Xiangyang city, central China, to investigate the aquifer and well loss parameters using the particle swarm optimization (PSO) method.
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| 5. |
- Clemenzi, Ilaria, et al.
(author)
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Annual water balance and hydrological trends in the glacierised Tarfala Catchment, Sweden
- 2023
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In: Journal of Hydrology. - 0022-1694 .- 1879-2707. ; 626
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Journal article (peer-reviewed)abstract
- Quantifying components of the hydrological cycle in glacierised catchments is important for the assessment of the temporal distribution, quantity and quality of water resources available to downstream regions, especially under a changing climate. However, this assessment requires long time series of observations, which are typically unavailable for remote catchments, such as those in mountainous areas. In this study, we leverage a unique ∼40 year time series of hydrological data recorded in the subarctic glacierised Tarfala catchment (Sweden) to explore temporal trends in the components of the catchment water balance (precipitation, runoff, change in storage, and evaporation), and to assess if water balance residuals are associated with specific hydro-climatic conditions. No significant temporal trends were found in precipitation and storage changes of the glacierised area, but significant increases were found in evaporation and summer discharge (in part attributed to glacier volume losses). The annual water balance could not be perfectly closed, and water losses were on average 112 mm y−1 larger than the water inputs over the study period. Among the water balance components, discharge contributed most to the total water balance uncertainty, and storage surplus due to antecedent meteorological conditions could explain why water losses in specific years exceeded the uncertainty bounds. It is therefore essential to consider legacy effects from previous years when applying water balance calculations in mountainous and/or glacierised catchments.
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| 6. |
- Döring, Stefan, Dr, et al.
(author)
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Integrating socio-hydrology, and peace and conflict research
- 2024
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In: Journal of Hydrology. - : Elsevier. - 0022-1694 .- 1879-2707. ; 633
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Journal article (peer-reviewed)abstract
- Socio-hydrology strives to incorporate 'the social' into the understanding of hydrological processes, aiming to enrich the analysis of water systems by considering human interactions. While there is a broader interest in integrating socio-political processes into hydrology, our paper specifically emphasizes the significant contributions of peace and conflict research to understanding the complex social dynamics surrounding water. We conduct a brief review of key literature on interstate water sharing, international norms on water, and domestic water disputes, drawing extensively from empirical studies within peace and conflict research—a field with a rich tradition of examining the interplay of water systems and social dynamics. Building on this foundation, we propose ways to weave insights from peace research, especially environmental peacebuilding, into the realm of socio-hydrology. We also highlight the crucial role of power, politics, and social factors in shaping water-related interactions and conflicts. By fostering a dialogue between socio-hydrology and peace and conflict research, we advocate for a more nuanced understanding of water management and governance. This interdisciplinary approach, we argue, is essential for promoting sustainable and equitable water use, and for addressing the challenges posed by water-related conflicts in a rapidly changing global context.
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| 7. |
- Fatolazadeh, Farzam, et al.
(author)
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New spectro-spatial downscaling approach for terrestrial and groundwater storage variations estimated by GRACE models
- 2022
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In: Journal of Hydrology. - : Elsevier. - 0022-1694 .- 1879-2707. ; 615:Part A
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Journal article (peer-reviewed)abstract
- The study proposes a new mathematical method, referred to as spectral combination, to downscale Gravity Recovery And Climate Experiment (GRACE) observations. The goal is to improve the spatial resolution of GRACE from 1̊ to 0.25̊, based upon available hydrological variables. First, a new approach based upon condition adjustment is proposed to estimate uncertainties related to hydrological variables. Second, a spectral-spatial estimator is developed to derive downscaled Total Water Storage Anomalies (TWSA) by optimally combining GRACE models and hydrological variables. Last, groundwater storage anomalies (GWSA) are derived from the downscaled TWSA. The proposed spectral combination approach was tested over the Canadian Prairies by considering GRACE data and required Global Land Data Assimilation System (GLDAS) variables for February 2003 to December 2016. The results reveal greater details in TWSA after spatial downscaling. Quantitatively, retrieved downscaled GWSA were validated using 75 unconfined in situ piezometric wells that were distributed across the Province of Alberta. A correlation of 0.80, with an RMSE of 11 mm, was obtained after downscaling with all wells over the validation area. These results are better than those obtained before downscaling (correlation of 0.42, with an RMSE of 21.4 mm), demonstrating that the proposed approach is successful.
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| 8. |
- Franceschinis, Cristiano, et al.
(author)
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Heterogeneity in flood risk awareness : A longitudinal, latent class model approach
- 2021
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In: Journal of Hydrology. - : Elsevier. - 0022-1694 .- 1879-2707. ; 599
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Journal article (peer-reviewed)abstract
- Insights into the heterogeneity of human behaviours and attitudes toward risk require the understanding of the role played by a plurality of factors, such as risk awareness and trust. However, our knowledge of the interplay of these factors is limited, as is our knowledge of the patterns in risk attitudes and behaviours and their evolution over time. This study explores the interplay between attitudes and behaviours related to flood risk awareness and structural flood protection in two communities in the Eastern Italian Alps, and how they changed over time. To this end, a questionnaire was submitted to a total of 420 residents, in the year 2005 (N = 200) and 2018 (N = 220), and then analysed using Latent Class Analysis. No floods were recorded in the area during this period. The results show that there is a group of residents characterized by low risk awareness and high trust in structural flood protection. Such individuals are likely to live in urban - rather than mountain - communities and are characterized by a lack of or limited experience with floods. They are also prone to believe that such events will not happen in the future. In 2005, this group represented less than half of the sample, but its size substantially increased in 2018. This result has strong implications for local risk managers, because this group of residents is less risk aware than the others and they may deserve special attention and targeted messages in flood risk communication campaigns. This and other results are discussed, including the potential development of generalizable models to provide emergency and risk managers with tools to unveil risk awareness patterns and to tailor risk communication actions to citizens attitudes and behaviours. The paper ends with some considerations about the need not only to better understand but also to address diversity in flood risk awareness.
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| 9. |
- Garcia, Margaret, et al.
(author)
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The interplay between reservoir storage and operating rules under evolving conditions
- 2020
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In: Journal of Hydrology. - : ELSEVIER. - 0022-1694 .- 1879-2707. ; 590
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Journal article (peer-reviewed)abstract
- Reservoir storage helps manage hydrological variability, increasing predictability and productivity of water supply. However, there are inevitable tradeoffs, with control of high frequency variability coming at the expense of robustness to low frequency variability. Tightly controlling variability can reduce incentives to maintain adaptive capacity needed during events that exceed design thresholds. With multiple dimensions of change projected for many water supply systems globally, increased knowledge on the role of design and operational choices in balancing short-term control and long-term adaptability is needed. Here we investigated how the scale of reservoir storage (relative to demands and streamflow variability) and reservoir operating rules interact to mitigate shortage risk under changing supplies and/or demands. To address these questions, we examined three water supply systems that have faced changing conditions: the Colorado River in the Western United States, the Melbourne Water Supply System in Southeastern Australia, and the Western Cape Water Supply System in South Africa. Moreover, we parameterize a sociohydrological model of reservoir dynamics using time series from the three case studies above. We then used the model to explore the impacts of storage and operational rules. We found that larger storage volumes lead to a greater time before the shortage is observed, but that this time is not consistently used for adaptation. Additionally, our modeling results show that operating rules that trigger withdrawal decreases sooner tend to increase the probability of an adaptive response; the findings from this model are bolstered by the three case studies. While there are many factors influencing the response to water stress, our results demonstrate the importance of: i) evaluating design and operational choices in concert, and ii) examining the role of information salience in adapting water supply systems to changing conditions.
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| 10. |
- Hosseini, Seyyed Hasan, et al.
(author)
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Merging dual-polarization X-band radar network intelligence for improved microscale observation of summer rainfall in south Sweden
- 2023
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In: Journal of Hydrology. - : Elsevier BV. - 1879-2707 .- 0022-1694. ; 617:Part C
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Journal article (peer-reviewed)abstract
- Compact dual-polarization doppler X-band weather radars (X-WRs) have recently gained attention in Scandinavia for sub-km and minute scale rainfall observations. This study develops a method for merging data from two X-WRs in Dalby and Helsingborg, southern Sweden (operated at five and one elevation angle levels, respectively) to improve the accuracy of rainfall observations. In total, 87 rainfall events from May-September 2021, observed by 38 tipping bucket gauges in the overlapping coverage of the X-WRs, were used for ground truth. The gauges were classified into four zones. An artificial neural network using doppler and dual-polarization variables (ANN) and a regression-based hybrid of RATEs (single-level rainfall products built-in to the X-WRs) based on the Marshall-Palmer equation (RMP) were calibrated for each zone. The calibrated models at 5-min scale significantly outperformed RATEs for all zones verified by Gilbert skill score (GSS), relative bias (rBIAS), mean absolute error (MAE), and Nash-Sutcliffe efficiency (NSE) not using the calibration data. Quantile-quantile plots confirmed a considerable improvement of the statistical distribution of the merged rainfall estimates for Zone I (closest to Dalby), II (mid-way between Dalby and Helsingborg), and IV (similar range as II for Dalby but farthest to Helsingborg) especially using ANN. Zone III (farthest to Dalby and closest to Helsingborg) was problematic for all RATEs, ANN, and RMP. The lowest-level elevation angle for both X-WRs showed the most erroneous RATEs. Consequently, the problems with Zone III can be solved if multiple levels of Helsingborg X-WR at higher levels are available.
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