ALBERT

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 24〈/p〉 〈p〉Author(s): Johnson U. Kitheka〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉This study was undertaken in the Athi-Sabaki river basin in Kenya in East Africa.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The study focused on the determination of the influence of streamflow variability on salt fluxes. This involved monitoring of river discharge and river salinity in the period between 2012 and 2018.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights〈/h6〉 〈p〉: This study demonstrates that Athi-Sabaki river discharges significant quantity of salt to the sea. There are significant seasonal and inter-annual variations in salt fluxes that are due to variations in river discharge and rainfall in the basin. The relationship between streamflow variations and variations of salinity in the river was inverse with highest salinity concentrations and fluxes occurring during low flow conditions. The river salinity and TDS concentrations decreased with an increase in river discharge due to dilution effect and flushing of salt from the river. The highly polluted sub-basins draining through the City of Nairobi exhibited relatively higher salinity and salt fluxes as compared to non-polluted ones draining rural areas. The total salt flux in the basin ranged between 29 × 10〈sup〉3〈/sup〉 and 261 × 10〈sup〉3〈/sup〉 tons year〈sup〉−1〈/sup〉. The relatively high salinity and salt fluxes were attributed to the discharge of wastewaters, seepage of groundwater and irrigation return flows. The study calls for water pollution control, sustainable irrigation and landuse practices in the basin.〈/p〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 24〈/p〉 〈p〉Author(s): Dagnachew Daniel Molla, Tenalem Ayenew Tegaye, Christopher G. Fletcher〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉The volcano-tectonic lakes basin of Abaya-Chamo is part of the Main Ethiopian Rift system and exhibits large variations in geomorphology, physiography and climate between the rift floor and the plateau.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Despite the importance of streamflow for water resources management and planning in the basin, many of the rivers there are ungauged. To make quantitative estimates of streamflow for spatially resolved water availability in such a highly heterogeneous environment, therefore, requires numerical modeling. This study is the first to quantify the surface and shallow groundwater resources in Abaya-Chamo, and to validate the physically fully distributed hydrologic model WetSpass under highly data-limited conditions, in a complex two-lake environment.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights〈/h6〉 〈p〉Simulated total river flow and estimated baseflow were verified at 15 gauging stations, with a good agreement. The WetSpass model is shown to be suitable for such a complex setting with a correlation coefficient of 0.95 and 0.97 for total flow and baseflow respectively at a statistically significant level (p-value 〈 0.05). The simulated annual water budget reveals that 74.6% of the 22.1 billion lit/yr in total precipitation in the basin is lost through evapotranspiration, 15.7% through surface runoff, and only 9.7% recharges the groundwater system. The simulations also revealed the surface runoff and groundwater recharge are the most sensitive to soil textural class, while evapotranspiration depends more strongly on land use.〈/p〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S2214581818302623-ga1.jpg" width="159" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 24〈/p〉 〈p〉Author(s): Zeinab Mohammadi Raigani, Kazem Nosrati, Adrian L. Collins〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉The Kamish River catchment (308 km〈sup〉2〈/sup〉); a mountainous agricultural catchment under dry-land and rangeland farming located in Kermanshah province, in western Iran.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The main objective of this study was to apportion sub-basin spatial source relative contributions to target channel bed sediment samples using a composite fingerprinting procedure including a Bayesian un-mixing model. In total, thirty-four geochemical tracers, eleven elemental ratios and different weathering indices were measured or estimated for 43 tributary sediment samples collected to characterise three sub-basin spatial sediment sources and eleven target bed sediment samples collected at the outlet of the main basin. Statistical analysis was used to select three different composite signatures.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Using a composite signature based on KW-H and DFA, the respective relative contributions (with uncertainty ranges) from tributary sub-basins 1, 2 and 3 were estimated as 54.3% (47.8–62.0), 11.4% (4.2–18.7) and 34.3% (27.6–39.9), compared to 72.0% (61.6–82.7), 13.6% (9.0–18.5) and 14.2% (3.1–25.4) using a combination of KW-H and data mining, and 50.8% (42.8–59.9), 28.7% (20.2–37.3) and 20.3% (12.7–27.2) using a fingerprint selected by KW-H and PCCA. The root mean square difference between these source estimates highlighted sensitivity to the composite signatures. Evaluation of the un-mixing model predictions using virtual mixture tests confirmed agreement between modelled and known source proportions.〈/p〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S2214581819301247-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 25〈/p〉 〈p〉Author(s): Thushara De Silva M., George M. Hornberger〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉The Mahaweli multipurpose water resources system of Sri Lanka, spread across 25,500 km〈sup〉2〈/sup〉, incorporates the Mahaweli, Kala Oya, Malwatu Oya, Kantale Oya and Maduru Oya river basins.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉We developed a model that can be used to assess water resources management alternatives of reservoir cascade operation to fulfill diverse and often conflicting water demands. The Mahaweli project is mainly operated for hydropower generation and irrigated agriculture. This study quantifies performances of water management alternatives considering trade-offs between hydropower and agricultural yield. Reliability, resilience, and vulnerability are other considerations that we explore.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉In the Mahaweli reservoir system, water is used primarily for paddy irrigation and hydropower generation. Increasing water diversions for paddy irrigation leads to decreases in hydropower so in times of limited water availability, decisions about trade-offs are required. In addition to diversions, decisions about how much arable land to cultivate during times of water shortage affect measures of risk related to paddy yield. Our results show that existing infrastructure places a constraint on how much water diverted for irrigation can be used productively and also leads to spatial variability in improvements in risk measures at the expense of reductions in expected yield across the basin.〈/p〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 25〈/p〉 〈p〉Author(s): Luis Angel Espinosa, Maria Manuela Portela, Rui Rodrigues〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Madeira Island, Portugal (a small island of the North Atlantic Ocean).〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Droughts from January 1937 to December 2016, were studied using monthly rainfall at 41 rain gauges covering most of the island. The gaps of the original rainfall data were filled by Multiple Imputation by Chained Equations (MICE). The drought conditions were assessed by means of the Standardized Precipitation Index (SPI), specifically the SPI6. To study the drought variability, some clustering techniques and principal components analysis (PCA) were applied to the SPI field.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Three homogeneous regions (northern slope, southern slope, and central region), each of them with different temporal climatic variability may be identified. Furthermore, for each region, the droughts were characterized in terms of magnitude and duration, and based on a kernel occurrence rate estimator (KORE) as well as on frequency of the drought periods. Finally, two climatic drivers, namely the El Niño-Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO) were teleconnected to the drought variability at the identified homogeneous regions for the period under study. It was not possible to establish a clear relationship between ENSO/NAO and drought occurrence. Nevertheless, the results showed that the spatio-temporal drought variability in Madeira Island has been subjected to noticeable changes in recent years (2001–2016) with a considerable higher number of periods under drought conditions than in the past.〈/p〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 25〈/p〉 〈p〉Author(s): Xiao-feng Zhang, Hao-chen Yan, Yao Yue, Quan-xi Xu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉The middle and lower reaches of the Jinsha River Basin (MLJRB).〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The main objective is to evaluate the impact of climate change and anthropogenic activities to the water and sediment resources of the studied region in 1960—2015. The variation of runoff and suspended sediment load is first analyzed with regard to their trends and abrupt change. Different factors attributable to the variation are then quantitatively separated.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉The annual runoff and sediment load across the MLJRB both decreased abruptly and coincidently in the recent two decades, with the transitional years detected to be 2006 and 2002, respectively. Comparing the post-transition period to the pre-transition period, runoff decreased 14.7% and sediment load decreased 63%. Climate change is the major contribution for the decrease in runoff, which explains 56.3% of the reduction, and impoundment of large reservoirs and water consumption contributed 18.6% and 2.7% respectively. The other 22.5% was ascribed to water-soil conservation and other factors. In contrast to water resources, human activities were dominant in sediment reduction, including 44.9% caused by large reservoirs, 1% from increased water consumption and 35% by conservation measures and other potential factors. Remarkably, almost 90% of the sediment load can be trapped as the direct consequence of the construction and operation of two huge dams, Xiluodu and Xiangjiaba, since 2013.〈/p〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S2214581819300102-ga1.jpg" width="378" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 25〈/p〉 〈p〉Author(s): Achamyeleh G. Mengistu, Leon D. van Rensburg, Yali E. Woyessa〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉This study was conducted in Soutloop River Catchment, Northern Cape, South Africa.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Although hydrologic models play a critical role in the management of natural resources in arid areas, their application is challenged by the scarcity of data for calibration and validation. Therefore, this study aimed at to configure, calibrate and validate SWAT model in a data-scarce catchment by using the regionalization with physical similarity approach. This approach uses dual calibration and validation procedure, 〈em〉i.e.〈/em〉, one in the donor catchment (by using SWAT-CUP (SWAT Calibration and Uncertainty Programs) and the other on the study catchment (by manual calibration and verification).〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Based on the sensitivity analysis, sixteen parameters were calibrated by SWAT-CUP. The result from the uncertainty analysis indicated acceptable values of both the R-factor (0.8〈sup〉**〈/sup〉) and P-factor (0.7**). The model performance evaluation also showed acceptable ranges of values (〈em〉e.g.〈/em〉, NS was 0.76** and R〈sup〉2〈/sup〉 was 0.78**). However, the main calibration and validation process was conducted outside the target catchment, though it was assumed that the donor and target catchments have similar hydrological responses. Therefore, the study suggested further inspection methods to minimize the model uncertainty in the study catchment. This study enables researchers to exploit the river eco-regional classifications of South Africa to apply hydrologic models to estimate the components of water balance in arid/semi-arid catchments.〈/p〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 25〈/p〉 〈p〉Author(s): Mohammad Zendehbad, Peter Cepuder, Willibald Loiskandl, Christine Stumpp〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Urban aquifer of Mashhad city, northeastern Iran.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Measuring the ratios of the stable nitrate isotopes and hydrogeochemistry of major components in order to specify the origin of nitrate contamination and potential transformation processes in the aquifer.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉This study represents the first isotopic characterization of groundwater nitrate to identify the sources of excessive nitrate in the urban aquifer and provides a reference for the potential implementation of executive programs on groundwater quality and protection. Nitrate concentration exceeded the limits for nitrate in drinking water in most of the wells (110 out of 261). Isotopic composition of the oxygen and nitrogen of NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 in groundwater indicated sewage as the primary source of nitrate contamination. Denitrification was identified as a non-significant process in the aquifer. Concentrations of anions (Cl〈sup〉−〈/sup〉, SO〈sub〉4〈/sub〉〈sup〉2−〈/sup〉 and PO〈sub〉4〈/sub〉〈sup〉3−〈/sup〉) and NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 showed strong correlations confirming potential wastewater influence. Most of the groundwater was weakly acidic, and the chemistry of the groundwater was rather affected by urbanization and land-use than by aquifer rock interactions. The absence of a reliable sewer collecting system, particularly in the central and southern parts of the study area, directly resulted in the poor water quality. Considering the lack of natural attenuation processes in the groundwater, management options need to be considered for reducing nitrogen input into groundwater.〈/p〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S221458181930062X-ga1.jpg" width="499" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 23〈/p〉 〈p〉Author(s): D.A. Hughes〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Sub-Saharan Africa.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Water resources availability assessments are highly uncertain due to inadequate observation networks, and this is expected to get worse into the future. This uncertainty is expected to increase in the future due to climate, environmental, population and other socio-economic development changes.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for this region〈/h6〉 〈p〉This paper argues for a coordinated effort to provide improved water resources information by water scientists both within the region and from outside. It further proposes a unified approach based on hydrological modelling that incorporates realistic measures of uncertainty and that can be applied to the region as a whole using a common methodology. The concept is designed to make the best use of all available data sets, including local observations as well as emerging global data. The suggested approach has scientific credibility (based on previous studies), is technically feasible and offers a range of long-term benefits. The overall conclusion is that without a project of this type, water resources planning and management decisions in the region will continue to be based on inadequate information and unquantified uncertainties.〈/p〉 〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 27〈/p〉 〈p〉Author(s): GZ Ndhlovu, YE Woyessa〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study Region〈/h6〉 〈p〉The Kabompo River Basin (KRB) in Zambia is one of the 13 basins found in the Zambezi River Basin in Southern African region.〈/p〉 〈/div〉 〈div〉 〈h6〉Study Focus〈/h6〉 〈p〉Global Climate Model (GCMs) projections have spatial resolution of up to several hundred kilometres, which may not be adequate for capturing local details mostly needed for impact assessment at local and regional scale. Downscaling techniques developed to improve the detail include; regional climate modelling and statistical techniques linking climate information at GCM resolution with that at local scale. This paper deals with evaluation and assessment of the impact of climate change on water balance for the KRB. In order to evaluate climate change impact, six bias–corrected and downscaled GCM outputs were acquired and used as inputs for hydrological modelling with the SWAT model to determine the impact under two future climate scenarios.〈/p〉 〈/div〉 〈div〉 〈h6〉New Hydrological Insights for the Region〈/h6〉 〈p〉The results indicate that the future catchment water balance for KRB under RCP4.5 will have insignificant variation from the current catchment water balance as annual statistics show that rainfall will reduce by 1 % while water yield and runoff will increase by 5 % and 6 % respectively. Meanwhile under RCP8.5, annual statistics show that rainfall will increase by 19 % while water yield and runoff will increase by 40 % and 65 % respectively and resulting in a significant increase in catchment water balance.〈/p〉 〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 27〈/p〉 〈p〉Author(s): Eniola Damilola Ashaolu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Osun Drainage Basin, Nigeria.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Estimating spatial and temporal patterns of recharge is important for sustainable groundwater resources management. This is especially true for data poor regions, such as the Basement Complex in Nigeria, which has shallow aquifers, a proliferation of wells and no efficient groundwater monitoring network. This study evaluates the performance of a spatially distributed monthly water balance model (WetSpass-M) in estimating groundwater recharge. The WetSpass-M model has moderate data demands, which allows for comprehensive assessment of recharge.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉27 % of the rainfall in Osun drainage basin becomes recharge, while the remaining is lost through evapotranspiration (43 %), surface runoff (21 %) and interception (9 %). September is the month with highest recharge, ranging between 0 and 73 mm in the north and 129 up to 213 mm in the south and northeast of the basin. The study revealed the significance of the applied water balance model in understanding the spatial and temporal status of recharge. Therefore, the spatial and temporal patterns of recharge should be taken into consideration in preparing a sustainable groundwater resources management plan for the Osun drainage basin. Artificial recharge might be adopted to store storm water runoff during wet periods to improve the groundwater supply in dry months. Also, monthly groundwater withdrawals should be regulated in relation to spatial and temporal recharge patterns.〈/p〉 〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 27〈/p〉 〈p〉Author(s): Enoch Bessah, Abdulganiy O. Raji, Olalekan J. Taiwo, Sampson K. Agodzo, Olusola O. Ololade, Alexandre Strapasson〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study Region〈/h6〉 〈p〉Pra River Basin, Ghana.〈/p〉 〈/div〉 〈div〉 〈h6〉Study Focus〈/h6〉 〈p〉The study modelled the changes in water yield using regional, sub-regional and local climate conditions from modelling outputs at spatial resolutions of 44 km, 12 km and 0.002 km respectively to drive the Integrated Valuation of Ecosystem Services and Trade-offs model at three time periods of land use land cover (LULC). Changes in historical water yield (simulated for 1986, 2002 & 2018 LULC using the mean climatic parameters from 1981-2010) and future scenario (simulated for 2018 LULC using the mean climatic parameters from 2020-2049) for annual, seasonal and monthly periods were assessed.〈/p〉 〈/div〉 〈div〉 〈h6〉New Hydrological Insights for the Region〈/h6〉 〈p〉The results show that future annual water yield could change by -46%, -48%, +44% and -35% under the regional, sub-regional, local and ensemble mean of the climate scenarios respectively. Seasonal water yield from the ensemble mean of the future climate scenario was projected to decrease between 2-16 mm, with a mean decrease of 33.39% during the December–February season. There was no directional effect of spatial resolution on water yield. The future period could be impacted by both drought and flood. We recommend that re/afforestation should be encouraged to improve infiltration and reduce deforestation which was 2.27% per annum in the assessed period to prevent flood causing runoffs, while irrigation technology will help to improve resilience to drought.〈/p〉 〈/div〉

Description: 〈p〉Publication date: April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 22〈/p〉 〈p〉Author(s): Sitotaw Haile Erena, Hailu Worku〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉This study was conducted in Dire Dawa city, Ethiopia.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉This study aims to explore the hydrological impacts of land use land cover changes using rational method. As to perform land use analysis, four decade based satellite imagery were analyzed using ERDAS imagine. The hydrological effect of land cover change and respective surface runoff was calculated using rational method.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉The trend of land use land cover analysis shows that the city has been experiencing significant decrease in forest land with continuous concomitant increases in bare land and settlements through the study period. In response of land use changes, the trend of surface runoff showed continuous increasing trend. The result of focus group discussion confirms that land use change has significantly affected the trend of surface runoff generation. The study also found out that the amount of surface runoff was positively sensitive to forest land and negatively to bare land and settlement classes. To demonstrate the future effect of surface runoff, the study developed worst and best case scenarios. The worst case showed that if the current land use continuous in the coming years, the watershed could receive more surface runoff that threaten the existence of the city. The best case scenario suggested rehabilitation of bare land cover and rooftop rainwater harvesting as promising condition to drop the amount of surface runoff. The output of the study provides environmental friendly surface runoff mitigation strategies that can be adopted at household and community levels.〈/p〉 〈/div〉

Description: 〈p〉Publication date: April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 22〈/p〉 〈p〉Author(s): Olga V.O. Gomes, Eduardo D. Marques, Vinicius T. Kütter, José R. Aires, Yves Travi, Emmanoel V. Silva-Filho〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study Region〈/h6〉 〈p〉Porous aquifer system of Northeastern Guanabara Bay, Rio de Janeiro, Brazil.〈/p〉 〈/div〉 〈div〉 〈h6〉Study Focus〈/h6〉 〈p〉The present work aimed to comprehend the geochemical processes responsible for the considerable range of salinity (48 to 5651 μS. cm〈sup〉−1〈/sup〉) through chemical composition of groundwater (hydrogeochemical modeling through PHREEQC) allied to chemical ratios (Cl/Br ratio) and stable isotopes data (δ〈sup〉18〈/sup〉O and δ〈sup〉2〈/sup〉H).〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉The PHREEQC modeling showed that high pH and low pe values conditioning the main processes controlling the hydrogeochemical evolution of groundwater in that region. The salinity origins should be explained by 4 hypotheses: 1) a group related to recharge zones, close to the basin headboard or connected to the fractured aquifers from the basement rocks (low Cl/Br ratio and predominance of light δ〈sup〉18〈/sup〉O and δ〈sup〉2〈/sup〉H isotopes; 2) a group formed by groundwater with high Cl/Br ratio and predominance of heavy δ〈sup〉18〈/sup〉O and δ〈sup〉2〈/sup〉H isotopes, associated to dissolution processes of Tertiary brackish water environment sediments; 3) a group formed by groundwater with low Cl/Br ratio, high Cl〈sup〉−〈/sup〉 concentrations and low δ〈sup〉18〈/sup〉O and δ〈sup〉2〈/sup〉H, related to groundwater under influence of Caceribu River (high content of domestic effluents); and 4) a group composed by groundwater with high salinity, high Cl〈sup〉−〈/sup〉 concentrations and enrichment of δ〈sup〉18〈/sup〉O and δ〈sup〉2〈/sup〉H, located at a mangrove area, where the influence of seawater intrusion in the aquifer is recognized.〈/p〉 〈/div〉

Description: 〈p〉Publication date: April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 22〈/p〉 〈p〉Author(s): Johannes Christoph Haas, Steffen Birk〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Austria.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Using publicly available data for the main components of the hydrological cycle we use standardization to calculate countrywide and regional averages of groundwater levels, stream stages and precipitation. These averages get analyzed for the occurrence of trends, compared with each other and the Austrian water use over time.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉It is shown that groundwater levels trend downwards until the 1980s, from whereon they recover. Precipitation follows this track, but the downward trend is much less severe. River stages lack data for the downward trending period, but follow the upward trend too. The trend in groundwater is a reverse of the trends observed in water use and we hypothesize that the discrepancy between average precipitation and average groundwater pre 1980s could be caused by the increasing water use in this period, especially since Austrias water demands are mostly sourced from groundwater.〈/p〉 〈/div〉

Description: 〈p〉Publication date: April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 22〈/p〉 〈p〉Author(s): Anna Malagó, Fayçal Bouraoui, Bruna Grizzetti, Ad De Roo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Mediterranean River Basins.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Human activities and consequent pollution have put the freshwater and marine ecosystems of the Mediterranean region under pressure, with high risk of eutrophication phenomena. In this study, an extended version of the Geospatial Regression Equation for European Nutrient losses model (GREEN), originally developed for estimating nutrient loads from diffuse and point sources in Europe, was extended to include additional nutrient sources using a grid cell discretization. The spatial resolution is 5 arc minute and the model inputs consist of the latest and best available global data.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉The results of this study show that during 2003–2007 (baseline), 1.87 Tg/y of total nitrogen (TN), 1.22 Tg/y of nitrates (N-NO〈sub〉3〈/sub〉), 0.11 Tg/y of total phosphorus (TP) and 0.03 Tg/y of orthophosphate (P-PO〈sub〉4〈/sub〉) were discharged in the Mediterranean Sea. The source apportionment analysis showed that the main contributor to total nitrogen and nitrate loads is agriculture followed by natural background, while for orthophosphate dominant sources include wastewater and scattered dwellings. Two scenarios were investigated to assess sustainable water and nutrient management options, showing that the reduction of 50% of nitrogen surplus leads to a significant reduction of nitrogen emission in regions characterized by high intensity agriculture, while the upgrading of wastewater treatment plants to tertiary level was more efficient for TP reduction.〈/p〉 〈/div〉

Description: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 23〈/p〉 〈p〉Author(s): Le Thi Thanh Thuy, Seiki Kawagoe, Ranjan Sarukkalige〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉In this study, three provinces in Northeast Vietnam including Bac Kan, Thai Nguyen, and Tuyen Quang are examined to determine the precipitation variation characteristics.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The average yearly temperature during the last two decades in Northeast Vietnam has increased by 0.72 °C when compared to the period 1962–1990. The Clausius Clapeyron (CC) relation indicates that a warmer atmosphere can result in higher moisture-holding capacity; hence, there is the possibility of increased extreme rainfall with respect to the rise in temperature. We evaluate the relationship between the average 24-hour temperature and rainfall extremes using the binning method. The estimation of the 24-hour probable maximum precipitation (PMP) is then implemented based on the moisture maximization and Hershfield statistical methods.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉The 99.9〈sup〉th〈/sup〉 percentiles of 24-hour precipitation are close to the super CC scaling up to peak points of 22.6–25.6 °C and decrease at higher temperatures. The Hershfield method produces 24-hour PMP results ranging from 232 mm to 895 mm. PMP outputs using the moisture maximization method based on the 100-year dew point are higher than those results generated from the statistical method except for Chiem Hoa station. Considering possible changes in future relative humidity under a warming climate from GCMs and RCM projections for two RCP scenarios, RCP 8.5 indicates the possible rise in probable extreme precipitation.〈/p〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 24〈/p〉 〈p〉Author(s): Marianna Túri, Mihály Molnár, Tatiana Orehova, Aglaida Toteva, Vladimir Hristov, Aleksey Benderev, Anikó Horváth, László Palcsu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Lom depression, Bulgaria.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉A multi-tracer investigation was applied to identify the recharge conditions and isotope hydrological character of four aquifers in the Lom depression (Northwest Bulgaria) using environmental isotopes (δ〈sup〉18〈/sup〉O, δ〈sup〉2〈/sup〉H, δ〈sup〉13〈/sup〉C, 〈sup〉3〈/sup〉H, 〈sup〉14〈/sup〉C) and noble gases. The radiocarbon age model of Ingerson and Pearson was used to estimate the mean residence time of groundwater samples from four aquifers (Dacian, Pontian, Meotian, Sarmatian). Our study focuses on the study of recharge conditions and provides an additional information to hydrodynamic understanding of the four aquifers.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉The mean residence time of groundwater samples represent the last twelve thousand years. In addition to a recently recharged groundwater sample, some samples represent the early Holocene and samples closely correspond to the late Pleistocene or the transition time between the early Holocene – late Pleistocene. The lower noble-gas recharge temperature values may indicate that the recharge occurred during the Late Glacial–Holocene climatic transition. These data can also be used to verify the existence of paleowater from the Pontian and Sarmatian aquifers on a trend of the mean residence time of older water heading north away from the study area. Besides the paleoclimatological investigation, it was determined that the Pontian aquifer has no hydraulic connection with the Danube River. The sandy layers and lenses forming the Dacian aquifer are apparently hydraulically isolated and therefore have high degree of heterogeneity.〈/p〉 〈/div〉

Description: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 23〈/p〉 〈p〉Author(s): Meredith Goebel, Rosemary Knight, Max Halkjær〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study Region〈/h6〉 〈p〉The northern coast of the Monterey Bay, California, USA, extending from the coastline to 3.5 km offshore.〈/p〉 〈/div〉 〈div〉 〈h6〉Study Focus〈/h6〉 〈p〉Three-hundred and twenty line-kilometers of airborne electromagnetic (AEM) data were acquired offshore. These data spanned 20 km of coastline, extending up to 3.5 km offshore in water up to 18 m in depth. Inversion of these data resulted in resistivity models extending to depths between 50 and 200 m below sea level. The data were interpreted in conjunction with onshore monitoring well data, hydrologic and geologic reports, and electrical resistivity tomography (ERT) data to locate the freshwater/saltwater interfaces throughout the region. A resistivity-to-water-quality transform was established using well-based water quality and resistivity logging measurements. For resistivity values that could not be converted to water quality with this transform, local auxiliary information was used on a case-by-case basis to interpret the observed features. Some low resistivity anomalies were identified near the shore at depth, which were interpreted to be artifacts of the 1D assumption in the inversion scheme used for these AEM data.〈/p〉 〈/div〉 〈div〉 〈h6〉New Hydrogeological Insights for this Region〈/h6〉 〈p〉We found that the acquisition of AEM data provided valuable information about water quality in the offshore extents of the aquifers, a region inaccessible to traditional monitoring methods, but one that plays an important role in the modeling, prediction, and management of saltwater intrusion.〈/p〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 24〈/p〉 〈p〉Author(s): Tenzin Tsering, Mahmoud S.M. Abdel Wahed, Sidra Iftekhar, Mika Sillanpää〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study Region〈/h6〉 〈p〉Teesta River of Eastern Himalayas, India.〈/p〉 〈/div〉 〈div〉 〈h6〉Study Focus〈/h6〉 〈p〉This article addresses the mechanisms of weathering in the Teesta River, for the first time based on the original data of major ions. Water samples were collected along the Teesta River in Sikkim Himalaya, India. The evaluation of the major ion and trace elements against the standard guideline values and the average chemical composition of world rivers were discussed.〈/p〉 〈/div〉 〈div〉 〈h6〉New Hydrological Insights〈/h6〉 〈p〉The predominance of Ca, Mg and HCO〈sub〉3〈/sub〉 in all waters reflects the influence of carbonate weathering on the Teesta River. However, an increase in the Na/Ca ratio was linked to the increase of Si downstream, indicating that silicate weathering was predominant in the lowlands of Teesta drainage. The rate of silicate weathering is dependent on an overall balance of key factors including gradient, contact time, temperature and vegetation. The higher concentration of cations was balanced by the SO〈sub〉4〈/sub〉 originating from the action of H〈sub〉2〈/sub〉SO〈sub〉4〈/sub〉 and H〈sub〉2〈/sub〉CO〈sub〉3〈/sub〉 on carbonates and silicates. Rock weathering (carbonate-silicate weathering) is the key mechanism that controls the major ion chemistry of the Teesta River followed by evaporite dissolution.〈/p〉 〈/div〉

Description: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 23〈/p〉 〈p〉Author(s): Hung Van Pham, Frans C. Van Geer, Vuong Bui Tran, Wim Dubelaar, Gualbert H.P. Oude Essink〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Mekong Delta, Vietnam (MKD).〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Present-day distribution of fresh-saline groundwater is highly heterogeneous in the MKD. Close to the coastline, fresh groundwater is found in aquifers up to 500 m below ground surface. To gain better insight into the fresh-saline groundwater evolution since the late Pleistocene, we simulated long-term groundwater flow and salt transport in a two-dimensional NW-SW cross-section over the MKD. To fully consider the regression and transgression phases of sea-level changes over the past 60 ka, variable-density groundwater flow and salt transport was simulated with SEAWAT to reproduce characteristics of the present-day distribution of fresh-saline groundwater and its age. We simulated nine scenarios to evaluate the most important factors controlling freshening and salinization processes of the MKD groundwater system. We compared the final model stage with present day observations of groundwater salinity and age.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉The sedimentation and erosion processes, related to sea-level changes over the last 60 ka, were important drivers of the fresh-saline distribution in the present MKD. The two-dimensional model indicates that most fresh groundwater in the MKD was recharged 60–12 ka before present, when the sea-level was at its lowest and the top sedimentary layers had a relatively high permeability. Due to deposition of a clayey top layer during the Holocene, at present, groundwater recharge of the deeper MKD groundwater system is very limited.〈/p〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S2214581818301010-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 23〈/p〉 〈p〉Author(s): Kathleen Rugel, Stephen W. Golladay, C. Rhett Jackson, Robin J. McDowell, John F. Dowd, Todd C. Rasmussen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉The Lower Flint River Basin (LFRB): a karst catchment in southwestern Georgia, USA.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Using the U.S. EPA Reach File 3 data set, we generated stream reach azimuths for all tributaries of the Lower Flint River Basin (LFRB) in southwestern Georgia, USA, then compared these results to regional bedrock jointing orientations and stream chemistry (indicating incoming groundwater discharge) in one tributary of the LFRB, Ichawaynochaway Creek. Our objective was to determine if stream bearing might be a useful predictor of increased groundwater discharge in streams of the LFRB where groundwater development has significantly impacted baseflows.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉We identified a dominant N-S trend in 44% of reaches in tributaries of the LFRB with lesser E-W, NNW, NW and NE trends. Bedrock joints and stream reaches in Ichawaynochaway Creek (a tributary of the Flint River) shared similar azimuth trends. When we compared stream reach orientation with known locations of enhanced groundwater inputs (previously detected by Rugel and others) we found that 55% of the time reaches in Ichawaynochaway Creek with increased groundwater discharge followed NW or NNW bearings (mean N49W). Further investigation to replicate these results in other tributaries of the LFRB is warranted and may help inform management strategies which could protect both ecological and economic interests in this region.〈/p〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 24〈/p〉 〈p〉Author(s): Hailemariam Meaza, Amaury Frankl, Biadgilgn Demissie, Jean Poesen, Amanuel Zenebe, Girmay Gebresamuel, Tesfaalem Ghebreyohannes Asfaha, Sofie Annys, Veerle Van Eetvelde, Miro Jacob, Jozef Deckers, Dirk Raes, Jan Nyssen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Region〈/h6〉 〈p〉Ethiopia’s Rift Valley.〈/p〉 〈/div〉 〈div〉 〈h6〉Focus〈/h6〉 〈p〉matching agricultural water demand and supply is a growing policy challenge in drylands. We investigated the water balance components in Raya (3507 km〈sup〉2〈/sup〉) and Ashenge (80.5 km〈sup〉2〈/sup〉) grabens. The rainfall depth, river discharge, abstraction, climate and soil data (2015–2017) were used to address the research question.〈/p〉 〈p〉New hydrological insights: the average annual rainfall of the graben’s escarpment and its bottom was 806 ± 162 and 508 ± 110 mm, respectively. Heavy rains produce floods up to 732 m³ s〈sup〉−1〈/sup〉 in the rivers that flow into the Raya graben. Moreover, greater runoff and river discharges volumes were recorded at the graben escarpments than at the graben bottom outlets (p 〈 0.001) due to the greater contributing area (p 〈 0.001, R〈sup〉2〈/sup〉 = 0.98) and headwater elevation (p 〈 0.001, R〈sup〉2〈/sup〉 = 0.98). About 24% of the water entering both graben bottoms comes from the runoff from the adjacent slopes, and about 40% of the runoff reaching the Raya graben bottom flowed out at the outlet. About 76% and 77.5% of the annual rainfall was lost through evapotranspiration from the Raya and Ashenge grabens, respectively. So about 16% and 33% of the average annual inflows infiltrated into the sediments in the Raya and Ashenge grabens, respectively. These insights provided by this study into the water balance in grabens along the Rift Valley can be used to help achieve sustainable agricultural development.〈/p〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S2214581818302258-ga1.jpg" width="363" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 24〈/p〉 〈p〉Author(s): Sylvain Biancamaria, Moussa Mballo, Patrick Le Moigne, José Miguel Sánchez Pérez, Grégory Espitalier-Noël, Youen Grusson, Roxelane Cakir, Vincent Häfliger, Florian Barathieu, Marhiu Trasmonte, Aaron Boone, Eric Martin, Sabine Sauvage〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study Region〈/h6〉 〈p〉Garonne Basin, France.〈/p〉 〈/div〉 〈div〉 〈h6〉Study Focus〈/h6〉 〈p〉This study analyses water mass variations for the whole Garonne basin (50,000 km〈sup〉2〈/sup〉 drainage area). To do so, Total Water Storage Anomalies (TWSA) from seven global solutions based on the Gravity Recovery And Climate Experiment (GRACE) satellite mission measurements (˜300 km spatial resolution) are inter-compared with TWSA from two hydrological models, SAFRAN-ISBA-MODCOU (SIM) and Soil and Water Assessment Tool (SWAT), between January 2003 and December 2010.〈/p〉 〈/div〉 〈div〉 〈h6〉New Hydrological Insights for the Region〈/h6〉 〈p〉Despite the small size of the Garonne basin compared to GRACE spatial resolution, good agreement between GRACE solutions and hydrological model TWSA has been found (maximum correlation coefficient ˜0.9 and Nash-Sutcliffe Efficiency, NSE, ˜0.7). These datasets showed that TWSA in the Garonne basin is mainly due to water stored in the first dozen meters of soil and in the shallow aquifer. To a smaller extent, snow also influences Garonne TWSA. Open surface water TWSA is quite small and TWSA from deep aquifer is negligible. The most important drought period occurred in 2011/2012, due to low precipitation during the two hydrological years and ETR close to previous years. Important precipitation in 2013/2014 helps to refill the water stocks. This study also showed that GRACE and models mismatches should be due to GRACE poor spatial resolution, but also to its monthly time resolution (rarely shown in previous studies).〈/p〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 25〈/p〉 〈p〉Author(s): D.A. Hughes〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉South Africa, Lesotho and Swaziland.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The focus of this study is on the development of simple transmission loss functions that can account for channel evaporation and alluvial storage losses from upstream flows in the downstream sub-basins of large river systems.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for this region〈/h6〉 〈p〉The importance of channel evaporation (and hence the relevance of the proposed model) is quite variable depending on the climate variations within the basins. While the model is validated using a site in the USA, it is difficult to fully assess the importance of alluvial losses in the southern Africa region, as there are almost no appropriate observed data, and few studies that quantify alluvial material extent or properties. Where existing information on transmission losses is available for South Africa, the model generated results that are in broad agreement.〈/p〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 21〈/p〉 〈p〉Author(s): Stefan Liersch, Samuel Fournet, Hagen Koch, Abdouramane Gado Djibo, Julia Reinhardt, Joyce Kortlandt, Frank Van Weert, Ousmane Seidou, Erik Klop, Chris Baker, Fred F. Hattermann〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉The Upper Niger and Bani River basins in West Africa.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The growing demand for food, water, and energy led Mali and Guinea to develop ambitious hydropower and irrigation plans, including the construction of a new dam and the extension of irrigation schemes. These two developments will take place upstream of sensible ecosystem hotspots while the feasibility of development plans in terms of water availability and sustainability is questionable. Where agricultural development in past decades focused mainly on intensifying dry-season crops cultivation, future plans include extension in both the dry and wet seasons.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Today’s irrigation demand corresponds to 7% of the average annual Niger discharge and could account to one third in 2045. An extension of irrigated agriculture is possible in the wet season, while extending dry-season cropping would be largely compromised with the one major existing Sélingué dam. An additional large Fomi or Moussako dam would not completely satisfy dry-season irrigation demands in the 2045 scenario but would reduce the estimated supply gap from 36% to 14%. However, discharge peaks may decrease by 40% reducing the inundated area in the Inner Niger Delta by 21%, while average annual discharge decreases by 30%. Sustainable development should therefore consider investments in water-saving irrigation and management practices to enhance the feasibility of the envisaged irrigation plans instead of completely relying on the construction of a flow regime altering dam.〈/p〉 〈/div〉

Description: 〈p〉Publication date: April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 22〈/p〉 〈p〉Author(s): Jonathan Spinoni, Paulo Barbosa, Alfred De Jager, Niall McCormick, Gustavo Naumann, Jürgen V. Vogt, Diego Magni, Dario Masante, Marco Mazzeschi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉This study has three spatial scales: global (0.5°), macro-regional, and country scale. The database of drought events has specific entries for each macro-region and country.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉We constructed a database of meteorological drought events from 1951 to 2016, now hosted by the Global Drought Observatory of the European Commission's Joint Research Centre. Events were detected at macro-regional and country scale based on the separate analysis of the Standardized Precipitation-Evapotranspiration Index (SPEI) and the Standardized Precipitation Index (SPI) at different accumulation scales (from 3 to 72 months), using as input the Global Precipitation Climatology Centre (GPCC) and Climatic Research Unit (CRU) Time Series datasets. The database includes approximately 4800 events based on SPEI-3 and 4500 based on SPI-3. Each event is described by its start and end date, duration, intensity, severity, peak, average and maximum area in drought, and a special score to classify 52 mega-droughts.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region under study〈/h6〉 〈p〉We derived trends in drought frequency and severity, separately for SPI and SPEI at a 12-month accumulation scale, which is usually related to hydrological droughts. Results show several drought hotspots in the last decades: Amazonia, southern South America, the Mediterranean region, most of Africa, north-eastern China and, to a lesser extent, central Asia and southern Australia. Over North America, central Europe, central Asia, and Australia, the recent progressive temperature increase outbalanced the increase in precipitation causing more frequent and severe droughts.〈/p〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 21〈/p〉 〈p〉Author(s): Essayas K. Ayana, Yihun T. Dile, Balaji Narasimhan, Raghavan Srinivasan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Upper Blue Nile, Ethiopia〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The recent availability of high-resolution soil data offers a better representation of spatially varying hydrologic parameters and could help in building accurate models. Despite the release of the AfSIS 250 m resolution soil data in 2015, its benefits in improving streamflow prediction accuracy is yet to be evaluated. The focus of this study is to evaluate the improvement in prediction accuracy of an uncalibrated hydrologic model built using the recently released AfSIS 250 m soil database in comparison to four other soil databases which are under use for the last decade.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Limited streamflow data availability has been a major impediment to assessing water resources potential of watersheds. Recently the Africa Soil Information Service (AfSIS) provided 250 m resolution datasets with soil properties for up to six soil depth layers. The objective of this study is to evaluate the flow prediction accuracy gains from the AfSIS 250 m if any, in comparison to previously availed databases using un-calibrated SWAT (Soil and Water Assessment Tool) hydrologic models. The performance of the un-calibrated models was evaluated using streamflow at two of the gauging stations. Evapotranspiration output from the respective models was also compared to remote sensing derived evapotranspiration estimates (MOD16 ET and ALEXI). Only marginal improvements in streamflow simulation were achieved by using the most detailed AfSIS soil. A satisfactory agreement was found in most of the area between SWAT simulated ET and MOD16 ET during the wet seasons whereas ALEXI ET products are seasonally more consistent and comparable to SWAT estimates over wide land cover types. Robust evaluation of these datasets in different landscapes and geographic regions is warranted before a specific application.〈/p〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 21〈/p〉 〈p〉Author(s): Korbinian Breinl, Giuliano Di Baldassarre〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Study region: This study focuses on two study areas: the Province of Trento (Italy; 6200 km²), and entire Sweden (447000km²). The Province of Trento is a complex mountainous area including subarctic, humid continental and Tundra climates. Sweden, instead, is mainly dominated by a subarctic climate in the North and an oceanic climate in the South.〈/p〉 〈p〉Study focus: Hydrological predictions often require long weather time series of high temporal resolution. Daily observations typically exceed the length of sub-daily observations, and daily gauges are more widely available than sub-daily gauges. The issue can be overcome by disaggregating daily into sub-daily values. We present an open-source tool for the non-parametric space-time disaggregation of daily precipitation and temperature into hourly values called spatial method of fragments (S-MOF). A large number of comparative experiments was conducted for both S-MOF and MOF in the two study regions.〈/p〉 〈p〉New hydrological insights for the region: Our experiments demonstrate the applicability of the univariate and spatial method of fragments in the two temperate/subarctic study regions where snow processes are important. S-MOF is able to produce consistent precipitation and temperature fields at sub-daily resolution with acceptable method related bias. For precipitation, although climatologically more complex, S-MOF generally leads to better results in the Province of Trento than in Sweden, mainly due to the smaller spatial extent of the former region.〈/p〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 21〈/p〉 〈p〉Author(s): Rajith Mukundan, Nachiketa Acharya, Rakesh K. Gelda, Allan Frei, Emmet M. Owens〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉The New York City water supply watersheds〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉This study is a modeling analysis on climate change impact on streamflow using a stochastic weather generator (SWG), a hydrologic model, and downscaled future climate scenarios. Streamflow generated using synthetic time series of precipitation and air temperature from a SWG were compared to those simulated from observed historical and projected future weather.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrologic insights for the region〈/h6〉 〈p〉Synthetic weather was able to mimic the observed annual streamflow cycle for the six watersheds studied, including the seasonal pattern as well as magnitude and occurrence of extreme hydrologic events. Streamflow simulations using projected climate from 20 global climate models (GCM) for one of the New York City water supply watersheds indicate the potential for changes in the hydrologic regime in this region. The models indicate a shift in the timing of spring melt runoff from a distinct peak in late March and April under historical (1950–2009) conditions towards earlier in the year for mid-century (2041–2060) period. Results indicate that the region may experience an overall increase in mean streamflow in the future due to the combined effect of decreasing spring runoff peak and increasing streamflow during other seasons. More importantly, the magnitude and frequency of extreme hydrological events are projected to increase under future scenarios. These results have implications for future operation and management of the water supply.〈/p〉 〈/div〉

Description: 〈p〉Publication date: April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 22〈/p〉 〈p〉Author(s): Iulii Didovets, Valentina Krysanova, Gerd Bürger, Sergiy Snizhko, Vira Balabukh, Axel Bronstert〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Tisza and Prut catchments, originating on the slopes of the Carpathian mountains.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The study reported here investigates (i) climate change impacts on flood risk in the region, and (ii) uncertainty related to hydrological modelling, downscaling techniques and climate projections. The climate projections used in the study were derived from five GCMs, downscaled either dynamically with RCMs or with the statistical downscaling model XDS. The resulting climate change scenarios were applied to drive the eco-hydrological model SWIM, which was calibrated and validated for the catchments in advance using observed climate and hydrological data. The changes in the 30-year flood hazards and 98 and 95 percentiles of discharge were evaluated for the far future period (2071–2100) in comparison with the reference period (1981–2010).〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉The majority of model outputs under RCP 4.5 show a small to strong increase of the 30-year flood level in the Tisza ranging from 4.5% to 62%, and moderate increase in the Prut ranging from 11% to 22%. The impact results under RCP 8.5 are more uncertain with changes in both directions due to high uncertainties in GCM-RCM climate projections, downscaling methods and the low density of available climate stations.〈/p〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 24〈/p〉 〈p〉Author(s): Michael T. Kiefer, Jeffrey A. Andresen, Dana Doubler, Aaron Pollyea〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Great Lakes region of North America〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Reference Evapotranspiration (ETo) is a key variable in water use management and irrigation of agricultural crops. This study describes the development of a gridded historical ETo dataset for the period 1983–2012 derived from North American Data Assimilation System Phase 2 (NLDAS-2) forcing fields for the Great Lakes region of North America. The gridded dataset is intended to fill a gap in the resource toolbox available to growers in this region of rapidly expanding irrigation. As a prerequisite for development of the ETo dataset, a correction procedure is applied to the NLDAS-2 downward solar radiation to account for overall bias and a tendency to underestimate the range of solar radiation on hourly and daily timescales.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights〈/h6〉 〈p〉Analyses of spatial and temporal variability reveal that the lakes play an important role in modulating seasonal and geographical variability in evaporative demand. An example application of the gridded historical ETo dataset to irrigation management is provided. A 30-year climatology of crop irrigation for field maize is developed from the ETo dataset and is applied in a hypothetical irrigation-scheduling scenario. Overall, the study illustrates the utility of the NLDAS-2 ETo dataset in describing spatial and temporal patterns of evaporative demand across the Great Lakes region, and as a source of reference climatological information for irrigation management.〈/p〉 〈/div〉

Description: 〈p〉Publication date: April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 22〈/p〉 〈p〉Author(s): Jing Tao, Ana P. Barros〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Southeast US (SE US).〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉This study probes the propagation of errors in standard remote-sensing vegetation products caused by cloud contamination and the impact of time-variant radiative properties for correctly describing land-surface properties in hydrologic models. Spatiotemporally-varying quality-controlled vegetation attributes (i.e., leaf area index and fractional vegetation coverage) and surface radiative properties (i.e., longwave broadband emissivity and shortwave broadband albedo) were derived from MODIS (Moderate Resolution Imaging Spectroradiometer) products over the SE US at 1 km × 1 km and hourly resolutions from 2007 to 2013. The data sets are publicly available. The impact of uncorrected standard vegetation products and static treatments of radiative properties was assessed systematically clearly illustrating improvements in simulated water and energy fluxes using the developed landscape attributes with a fully-distributed uncalibrated hydrologic model.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Through simulations in the Southern Appalachian Mountains, we found that the spatiotemporal variability of radiative properties significantly influences the diurnal cycle of the surface energy budget with marked differences in sensible heat fluxes (up to 10–20%). Better performance of streamflow simulations achieved by using the improved vegetation attributes is tied to changes in rainfall interception and evapotranspiration, reflecting the importance of SE forests in the regional water cycle. The largest improvements in streamflow simulations result from larger corrections to MODIS products in the inner mountain region where cloudiness is persistent.〈/p〉 〈/div〉

Description: 〈p〉Publication date: April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 22〈/p〉 〈p〉Author(s): Samuale Tesfaye, Gebeyehu Taye, Emiru Birhane, Sjoerd EATM van der Zee〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉This study focuses on Tekeze river basin of northern Ethiopia, and it is characterized by a typical dry biogeophysical environment.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉In recent years, recurrent droughts are having an adverse impact on agricultural production and water resources in northern Ethiopia. Climate change through changes on temperature, precipitation and streamflow, may further strain this critical situation. This study has investigated the observed (1961–2014) and potential (2006–2099) hydro-climatic changes in Tekeze river basin of northern Ethiopia. Artificial Neural Networks (ANNs) are used to downscale temperature and precipitation predicated by 30 General Circulation Models (GCMs) as well as the projected streamflow changes for two Representative Concentration Pathways (RCP4.5 and RCP8.5) scenario.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Results indicate that the variability of climatic factors as temperature and precipitation was observed to be both spatially and temporally diverse for the considered Tekeze river basin. Accordingly, the response of streamflow was also spatiotemporally complex. GCMs were evaluated with several performance indictors regarding patterns in hydro-climatic variables. The analysis showed the superiority of the multimodel ensemble means compared with individual GCM output. GCM projections for the 21century indicate a gradual reductions in streamflow attributed to the combined effect of increasing temperature and decreasing precipitation. The persistent increase of temperature and decrease of precipitation will have negative impacts on water availability and agriculture, hence site specific adaptation strategies are necessary.〈/p〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 21〈/p〉 〈p〉Author(s): K.J. Rattan, E.A. Blukacz-Richards, A.G. Yates, J.M. Culp, P.A. Chambers〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉The study area is located in southern Manitoba, in the prairie region of Canada〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉This study examined the impact of hydrological variability on the timing and magnitude of nutrient export from seven agriculturally-dominated watersheds in the Red River Valley, Manitoba, Canada.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉In 2013, discharge showed a seasonal pattern typical of streams traversing the Canadian prairies: high discharge during snowmelt followed by cessation of flow in early June due to lack of precipitation. In 2014, discharge still peaked during snowmelt but, compared to 2013, was 49% lower during snowmelt yet 21% higher during summer and fall due to greater rainfall. These hydrologic differences were associated with differences in fractionation of nutrients between years. Thus, higher concentrations and loads of particulate phosphorus (P) and nitrogen (N), and a greater (p 〈 0.05) share of the total nutrient pool in particulate forms (particularly for P), were observed during the snowmelt- dominated year (2013). Our findings show that the nutrient concentrations, fractionation and export from prairie watersheds differ between years, and amongst hydrological seasons, in relation to hydrological conditions. Additional management actions may be required to address changes in the quantity, timing and fractionation of nutrient export associated with rainier summers forecasted under future climate scenarios.〈/p〉 〈/div〉

Description: 〈p〉Publication date: April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 22〈/p〉 〈p〉Author(s): Poulomi Ganguli, Paulin Coulibaly〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Southern Ontario, Canada.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The evaluation of possible climate change consequence on extreme rainfall has significant implications for the design of engineering structures and socioeconomic resources development. To date, there has been no comprehensive comparison or evaluation of intensity-duration-frequency (IDF) statistics at a regional scale, considering both stationary versus nonstationary models for the future climate projection. To understand how extreme precipitation may affect future IDFs, we used an ensemble of three regional climate models (RCMs) participating in the NA-CORDEX domain over eight selected rainfall stations across Southern Ontario, one of the most densely populated and major economic regions in Canada. We modeled precipitation extremes, at different durations using extreme value distributions considering parameters that are either stationary or nonstationary, as a linear function of time.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Extreme precipitation intensity driven by future climate forcing shows a significant increase in intensity for 10-year events in the 2050s (2030–2070) relative to 1990s (1970–2010) baseline period across most of the locations. For longer return period (i.e., 25-year), we note detectable changes in design storm considering a nonstationary model than that of the stationary ones. Finally, the results of this study are not only limited to develop nonstationary IDFs for the future emission scenario but the proposed framework can serve as a basis to improve weather generator accounting nonstationary nature of extreme precipitation.〈/p〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 25〈/p〉 〈p〉Author(s): Lan Cuo, Ning Li, Zhe Liu, Jin Ding, Liqiao Liang, Yongxin Zhang, Tongliang Gong〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉The Yarlung Tsangpo Basin (YB) on the Tibetan Plateau.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Characteristics and changes of air temperature, precipitation, snow cover, snow depth, glacier, streamflow during 1979–2015, land cover/use in 1990 and 2015, and the responses of streamflow to the changes are analyzed. The objective is to understand the major factors that influence streamflow in the YB at both intra-annual and inter-annual time scales.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights〈/h6〉 〈p〉The YB experiences significant warming but spatiotemporally varying precipitation changes. Snow decreases and glaciers retreat in the YB but with heterogeneous spatial patterns. Streamflow shows strong annual and decadal variability. In the cold and dry season, streamflow is positively correlated to air temperature in the upper sub-basin non-significantly; whereas in the warm and wet season, precipitation influence dominates the streamflow changes in both high and low elevations. Human activity induced 2-fold residential area and 5-fold tree nursery area expansions come at the expense of cropland, dense forest and grassland. In the upper sub-basin, snow depth and streamflow display significant concurrent and lagged correlations for several months. Streamflow in April–May, a melting and seedling season, is positively affected by snow depth of the previous year. Warming induced degradation in cryospheric elements, low precipitation during the cold and dry season, together with land cover/use change could result in water resource conflict in April - May for the YB.〈/p〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 25〈/p〉 〈p〉Author(s): Dagnachew Adugna, Brook Lemma, Marina Bergen Jensen, Geremew Sahilu Gebrie〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Addis Ababa, Ethiopia.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Addis Ababa is undergoing rapid urbanization with unprecedented high rate of road and building constructions, resulting in a sudden upsurge of sealed surfaces and generation of significant amounts of stormwater. The present study therefore aims to investigate the hydraulic capacity of existing drains and stormwater management challenges using detailed field surveys, and stakeholders' interview. 469 road segments (74 km) and 202 drain segments (42.76 km) in two representative case sites confined in 564.54 ha boundary areas were physically surveyed.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Results showed that 14% of the drains in new city parts and 28% in old city parts were in conditions inadequate for removal of stormwater, resulting in flash flooding and infrastructure degradation in the associated watersheds. Further, although more than 72% of the surveyed drains were oversized, stormwater overtopping reoccur as a season-to-season problem, ascribed to illegal dumping of waste into drains, reducing their hydraulic capacity. The challenges of stormwater management were related to lack of city-wide drainage master plan, absence of hydrologic data considerations during designing drains, and weak enforcement on solid and liquid waste dumping into drains. The present study recommends that building practices that minimize surface sealing and critical hydrologic and hydraulic considerations during designing drains, and educating the local community and stakeholders regarding waste management.〈/p〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 25〈/p〉 〈p〉Author(s): Nelson Canuto, Tiago B. Ramos, Ana R. Oliveira, Lucian Simionesei, Marta Basso, Ramiro Neves〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Guadiana international catchment, located in the Iberian Peninsula.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The Guadiana River catchment has registered an intense and speed up modification of its natural regime over the last few decades to cope with water scarcity. Such modifications pose a serious challenge to the development of improved management tools as information on available water resources is often not detailed enough. This study aimed to simulate the flow regime of the Guadiana River using the MOHID-Land model during a 30 years period. Two scenarios were defined by considering (or not) inputs from reservoirs. Model performance was assessed by comparing simulated and measured monthly streamflow at 24 hydrometric stations influenced (9 stations) or not (15 stations) by reservoir management.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Streamflow simulations produced quite acceptable estimates for most of the hydrometric stations not influenced by reservoirs. However, results also showed the importance of non-simulated processes (〈em〉e.g〈/em〉., groundwater abstractions) to the accurate prediction of the Guadiana flow regime. For the stations influenced by reservoir management, model simulations generally overestimated streamflow measurements. Information related to reservoir management needs thus to be made clearer for achieving better results, which can only be accomplished when national water agencies improve their cooperation protocols. Further model limitations were also addressed as well as the necessary developments for improving streamflow estimates in future modeling applications.〈/p〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 26〈/p〉 〈p〉Author(s): Suraj Lamichhane, Narendra Man Shakya〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Kathmandu Valley, Nepal.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The focus of this study is to project future LULC, delineate potential recharge areas, and evaluate encroachment in recharge areas due to future changes in LULC.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for this region〈/h6〉 〈p〉The consequences of urbanization in Kathmandu Valley (KV) have been observed in various forms such as change in runoff, groundwater recharge, water scarcity, and others. To sustainably utilize groundwater resources by ensuring adequate supply/recharge to groundwater system, land use/cover (LULC) management is required. A set of models and tools such as the Conversion of Land Use and its Effects at Small regional extent (CLUE-S) model for future LULC projection; geographic information system (GIS) for spatial data management and analysis; analytical hierarchy process (AHP) to estimate appropriate weights for different layers that influence groundwater recharge; and in-situ field test and analysis for infiltration rate were used to achieve the objectives. Results showed that built-up area in the KV watershed is projected to change by +21.4%, agricultural land by -20.5%, and forest areas by -0.9%. between 2020 and 2050. In terms of recharge area, 6% of open land is projected to convert into impervious area every decade. The projected changes are expected to have implications in terms of depletion in groundwater levels and subsequent consequences in urban water environment, including base flows in rivers.〈/p〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 26〈/p〉 〈p〉Author(s): Alix Toulier, Benjamin Baud, Véronique de Montety, Patrick Lachassagne, Véronique Leonardi, Séverin Pistre, Jean-Marie Dautria, Heru Hendrayana, M. Haris Miftakhul Fajar, Azwar Satrya Muhammad, Olivier Beon, Hervé Jourde〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉The Bromo-Tengger volcanic aquifer system, (East Java, Indonesia).〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Andesitic volcanic aquifers in Indonesia are an important source of groundwater supply for the population. The artesian flow from high discharge springs facilitates the access for irrigation and drinking water but continuously flowing artesian wells exert an increasing pressure on the groundwater resource. Given the complexity of the volcanic edifice, a multidisciplinary approach including geological, hydrometeorological, hydrochemical and isotopic measurements was performed to characterise the hydrogeological functioning of the volcano’s northern flank.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrogeological insights for the region〈/h6〉 〈p〉Two main hydrogeological systems are identified: a system with perched aquifers in the lava flows and pyroclastic complex, supplying low discharge springs or infiltrating to a deep flow system. The latter system is unconfined and provides groundwater to the downstream plain that hosts a confined multi-layer volcano-sedimentary aquifer. The joint implementation of a quantitative isotopic approach and a groundwater budget allows characterising aquifer recharge along the whole volcano flank. It is mainly controlled by the rainfall distribution that peaks around 1200 m elevation. The caldera basin on the top of the volcano has a very limited contribution to recharge. A conceptual hydrogeological model is proposed and compared to the main concepts of volcanic islands. This study is a first step for further scientific and management discussions to implement protection policies on the Bromo-Tengger aquifer system.〈/p〉 〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 27〈/p〉 〈p〉Author(s): Mahtab Nazari, Seyed Mohammad Moein Sadeghi, John Toland Van Stan, Mohammad Reza Chaichi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Maize farmland in Varamin, located southwest of Tehran (Iran).〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The aims of this study were to: (1) monitor throughfall and stemflow during rainstorms beneath maize canopies over two growing seasons (2015, 2016); (2) evaluate the effect of maize canopy structure (leaf area index, plant height) on throughfall, stemflow, and interception; and (3) develop an analytical model of rainfall partitioning by maize from controlled rainfall simulations.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Rainfall or irrigation interception by crops and residues has often been overlooked in hydrologic modelling in Iran. However, our results confirm that interception by maize canopy can significantly reduce total water input to the surface (19.9 % and 11.2 % of natural and simulated rainfalls, respectively). Although rainfall amounts and rates were similar between simulations and natural rainfall, differences in interception value may still exist between simulated and natural conditions due to the formation, size distribution, and movement of water droplets emitted from simulation systems 〈em〉vs〈/em〉. natural rainfall water droplets. Throughfall and interception significantly correlated with LAI and height of the maize canopy above thresholds of 2.5 (LAI) and 180 cm (height). The analytical model performed well under natural rain conditions. These results may help farmers’ irrigation scheduling achieve higher irrigation water use efficiency for maize fields, particularly in arid agricultural lands.〈/p〉 〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 27〈/p〉 〈p〉Author(s): Ignacio Fuentes, R. Willem Vervoort〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉This study was conducted in the Namoi catchment, Australia.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Managed aquifer recharge (MAR) site suitability has been widely studied through multicriteria decision analysis (MCDA). However, the selection of areas for MAR project implementation can be a vague process with different validation approaches. The aim of this study was to create a site suitability map for MAR projects and conduct a sensitivity analysis for the selection of an area of interest (AOI) by combining highly suitable and low sensitive areas. Ten hydrologic and hydrogeologic criteria were chosen for the selection of sites for the MAR project. All criteria were reclassified and used in a MCDA that combined Analytic Hierarchy Processes (AHP) and pairwise comparisons to construct a site suitability map. Validation of the map and the AOI selected was performed using hydrograph data. Based on the AOI map, water availability and frequency were analysed using gauging station data.〈/p〉 〈/div〉 〈div〉 〈h6〉New Hydrological Insights for the Region〈/h6〉 〈p〉The selected AOI represents high spatio-temporal variability in natural recharge rates, highly dependent on the Namoi River streamflow. Moreover, all recharge rates in the AOI are high, particularly in the paleochannel surrounding the current Namoi River. The selected AOI coincides with an area of thick coarse sediments underlying the riverbed and demonstrates the usefulness of the proposed methodology.〈/p〉 〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 27〈/p〉 〈p〉Author(s): Vadim Yapiyev, Grzegorz Skrzypek, Anne Verhoef, David Macdonald, Zhanay Sagintayev〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Burabay National Nature Park (BNNP) of North Kazakhstan is located between humid boreal forests and an arid steppe of Central Asia.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The stable hydrogen and oxygen isotope analyses of precipitation, stream, lake and ground waters were used for water budget calculations of the BNNP endorheic lake system to assess the impact of increasing aridity on lakes in this most continental part of the Earth.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉The stable isotope results confirmed two different types of lakes in BNNP: Burabay and Shortandy Lakes are more similar to higher latitude lakes (e.g. South Siberia), while Kishi and Ulken Shabakty Lakes are more comparable to the steppe lakes of Central Asia. The slopes of evaporation lines for this region, obtained by regression analysis of lake water samples, ranged from 4.57 (steppe lakes) to 6.21 (forest lakes). The evaporation over inflow ratios (0.34 Burabay, 0.69 Ulken Shabakty, and 0.53 Shortandy) are in good agreement with catchment water budget calculations reflecting different groundwater inputs and water retention times. The recent water level rise in the Ulken Shabakty Lake terminal basin was observed for the first time in a decade. This increase can be explained by the ‘fill and spill’ hypothesis and suggest that a single unusually wet year may significantly replenish water resources despite long-term increasing aridity of the region.〈/p〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S2214581819301740-ga1.jpg" width="360" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 24〈/p〉 〈p〉Author(s): Kongmeng Ly, Graciela Metternicht, Lucy Marshall〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉The management of transboundary river basins is challenging given frequent divergences in political, cultural, developmental and conservation priorities of countries that make up the basin. In the Lower Mekong River Basin where multiple countries are beneficiaries of its water resources, ensuring good quality of the river waters is crucial for sustainable development, and for protecting the integrity of its ecosystems.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The focus of this paper is on identifying an appropriate decision support tool for assisting the management of in-stream nutrients and sediment concentrations taking into account the abilities to (i) satisfactory simulate hydrological processes and pollutant loadings in a time continuous manner; (ii) simulate the effects of various land use change scenarios; (iii) handle issues of data scarcity and compatibility stemming from different development policies and priorities of each administrative jurisdiction; (iv) have a record of previous applications in a large transboundary river basin; and (v) have a track record of use by government agencies to support decision making. These criteria guide in-depth analysis of 250 peer-reviewed journal papers.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Four models meet the pre-determined criteria, with eWater Source providing a comparative advantage of prior use in a transboundary catchment larger than the Lower Mekong River Basin.〈/p〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 24〈/p〉 〈p〉Author(s): Tesfa Gebrie Andualem, Girum Getachew Demeke〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Guna Tana Landscape, Upper Blue Nile Basin, Ethiopia.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉This paper aimed to delineate the groundwater potential zones using GIS and remote sensing. Multi-Criteria Decision Analysis (MCDA) technique is used to develop the groundwater potential prospect zones by integrating different groundwater contributing thematic layers. The thematic layers of land cover, drainage density, lineament density, soil, geology, slope, and geomorphology were prepared and used for groundwater potential map development by assigning weights to each thematic layer and features. The weights of each thematic layer were assigned and normalized based on their characteristic and relationship with groundwater recharge. Finally, the thematic maps were integrated by a weighted sum overlay analysis tool to develop groundwater prospect zones.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉It was found that the downstream parts of the Landscape showed excellent groundwater potential covering about 833.49 km〈sup〉2〈/sup〉 area with a flat and lacustrine sediment characteristic. About 469.12 km〈sup〉2〈/sup〉 of the landscape showed very good groundwater potential zone. Northern, northeastern and southeastern parts of the area presented very poor groundwater prospect covering about 553.68 km〈sup〉2〈/sup〉 area. The groundwater potential map was validated using the existing pumping wells and it indicated a good prediction accuracy of 70.5%. Thus, the potential zones identified in the study area by the MCDA technique are reliable.〈/p〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 26〈/p〉 〈p〉Author(s): Jennifer Solakian, Viviana Maggioni, Adnan Lodhi, Adil Godrej〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study Region〈/h6〉 〈p〉The Washington D.C area.〈/p〉 〈/div〉 〈div〉 〈h6〉Study Focus〈/h6〉 〈p〉This work investigates the potential of using satellite-based precipitation products in a hydrological model to estimate water quality indicators in the Occoquan Watershed, located in the suburban Washington D.C area. Three (3) satellite-based precipitation products based on different retrieval algorithms (the Tropical Rainfall Measuring Mission Multi-satellite Precipitation Analysis, TMPA 3B42-V7; the Climate Prediction Center’s CMORPH product; and the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks Cloud Classification System, PERSIANN−CCS) are compared to gauge-based records over a 5-year period across the study region. The 3 satellite-based precipitation products and the gauge-based dataset are used as input to the Hydrologic Simulation Program FORTRAN (HSPF) hydrology and water quality model. Each satellite precipitation-forced simulation is compared to the reference model simulation forced with the gauge-based observations, in terms of streamflow and water quality indicators, i.e., stream temperature (TW), total suspended solids (TSS), dissolved oxygen (DO), and biological oxygen demand (BOD).〈/p〉 〈/div〉 〈div〉 〈h6〉New Hydrological Insights for the Region〈/h6〉 〈p〉Results indicate that the spatiotemporal variability observed in the satellite-based precipitation products has a quantifiable impact on both modeled streamflow and water quality indicators. All 3 satellite products present moderate agreements with the reference precipitation and simulation; CMORPH presenting the best overall performance followed closely by TMPA, and PERSIANN presenting a comparatively inferior performance in terms of correlation, root-mean-square error and bias for streamflow and water quality indicators, such as TW, TSS, DO and BOD concentrations.〈/p〉 〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 27〈/p〉 〈p〉Author(s): S.S. Wanniarachchi, N.T.S. Wijesekera〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Considering the availability of gauged data, the Karasnagala watershed of Attanagalu Oya located in the Gampaha district in the Western province of Sri Lanka was modeled with EPA SWMM 5.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉This study analyses the effect of the catchment field approximations for accurate flood hydrograph prediction. Following an event based approach, 3 days Minimum Inter event Time (MIT) and 0 mm/day Minimum inter Event Depth (MED) were used as the threshold. Fifty events were separated from 1971 to 1982 period. Four major field approximation types were identified: stream geometrical parameters approximations, soil infiltration parameter approximations, approximation of watershed intermittent storages, and subcatchment delineation approximation. Soil parameter approximations and the stream network geometry parameter approximations were verified by the field observations.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Model calibration and verification revealed that EPA SWMM5 can be successfully used to develop regional Karasnagala watershed model with mean ratio of absolute error (MRAE) 0.289 for calibration, and 0.375 MRAE for verification. Incorporation of intermittent storages with optimized model layout obtained the best fitting of hydrograph recession MRAE 0.167. Subcatchment lumping with a 16 sub basin configuration showed the marginal increment of modeling error when compared with distributed modeling. Stream parameter approximations revealed that the head water streams/lesser order streams parameters sensitivity is higher than that of the higher order streams. In soil parameter approximations, saturated hydraulic conductivity of the soil was the most influencing parameter.〈/p〉 〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 27〈/p〉 〈p〉Author(s): Dayal Buddika Wijayarathne, Paulin Coulibaly〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Waterford River watershed, St. John’s, Newfoundland and Labrador (NL), Canada.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉This study investigates five hydrological models to identify adequate model(s) for operational flood forecasting at Waterford River watershed. These models included three lumped conceptual models (SAC-SMA: Sacramento Soil Moisture Accounting, GR4J: modèle du Génie Rural à 4 paramètres Journalier, and MAC-HBV: McMaster University Hydrologiska Byråns Vattenbalansavdelning), a semi-distributed model (HEC-HMS: Hydrologic Engineering Center’s Hydrologic Modeling System) and a fully distributed physically-based model (WATFLOOD: University of Waterloo Flood Forecasting System). The best model(s) were chosen by comparison of performance criteria. To verify the potential of the best performing hydrological models for operational use, deterministic hydrologic forecasts were performed.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉All five models are capable of simulating streamflow reasonably well in both calibration and validation periods. The SAC-SMA and GR4J models perform equally well and perform better than the other three models for all low, medium, and peak flows. The SAC-SMA and GR4J models generally perform better for peak flows, followed by HEC-HMS. Streamflow forecast experiment using deterministic weather prediction shows that SAC-SMA, GR4J, and HEC-HMS models perform well for up to 1–3 days ahead forecasts and are recommended for operational use. However, due to the good performance of all five models, an ensemble forecasting using continuous, multiple hydrological models is also recommended.〈/p〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 26〈/p〉 〈p〉Author(s): Kurt C. Solander, Katrina E. Bennett, Sean W. Fleming, Richard S. Middleton〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Future climate impacts on streamflow are of critical concern due to its importance for water and energy supplies. However, rigorous studies of such impacts involve complicated modeling chains that can be time-consuming and costly to implement. We examine an alternative approach by developing a method to predict the 21〈sup〉st〈/sup〉 century peak March-May (MAM) streamflow response to warming from historical data alone, specifically, past observations of the Snow-to-Precipitation ratio divided by basin Area (SPA).〈/p〉 〈/div〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Using the Colorado River Basin (CRB) as a proving ground, we test this empirical relationship over 23 basins ranging in size from 9728 to 639,806 km〈sup〉2〈/sup〉 within the CRB. Data was derived from hydrology model simulations forced by a suite of climate models, run under two emissions scenarios.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights〈/h6〉 〈p〉Our proof-of-concept study revealed useful predictive capability (r〈sup〉2〈/sup〉 = 0.58) and additionally identified three response types: rain- (basin SPA 〈 1.2 × 10〈sup〉−3〈/sup〉 km〈sup〉-2〈/sup〉), snow-rain- (1.4 × 10〈sup〉−3〈/sup〉 to 3 × 10〈sup〉−3〈/sup〉 km〈sup〉-2〈/sup〉), and snow-dominant (〉3 × 10〈sup〉−3〈/sup〉 km〈sup〉-2〈/sup〉). The most dramatic changes occurred in snow-dominant basins where streamflow increased up to 320 % in MAM, but decreased by up to 60 % in the critical high demand months of July-September (JAS). By quantifying the relationship between historical data and future streamflow projections, our findings suggest this empirical relationship is useful to quickly and cheaply determine where and when large changes in hydrology will occur from future warming.〈/p〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 24〈/p〉 〈p〉Author(s): Venkataramana Sridhar, Syed Azhar Ali, Venkataraman Lakshmi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Chesapeake Bay is the largest estuary in the United States, and its catchment has heterogeneous hydrological and geomorphologic characteristics. It includes seven major river basins: James, Patuxent, Potomac, Rappahannock, Susquehanna, Western Shore, Eastern Shore, and York. Remote sensing data, along with in-situ observations of streamflow and simulated water budget components, can provide significant understanding of variability in water resources availability in this diverse watershed. In this study, we quantify the terrestrial water storage using both remote sensing and in-situ data and hydrologic model outputs in the Chesapeake Bay watershed. Total water storage change (TWSC) was calculated based on the combination of three methods to identify the best approach in estimating TWSC. These methods evaluated different sources of data, including Parameter elevation Regression on Independent Slopes Model (PRISM) precipitation, MODIS ET, U.S. Geological Survey observed streamflow, and the Variable Infiltration Capacity (VIC) model. Estimated TWSC were in close agreement with GRACE-derived TWSC when we employed VIC-simulated streamflow after calibration with observed streamflow. However, the use of VIC-simulated ET or MODIS-derived ET yielded similar results for TWSC. Assessment of TWSC during extreme events (drought) during the summer months revealed that predicting ET is critical for TWSC in June–August and that VIC-simulated TWSC could be a reliable proxy for GRACE data to assess the water availability in the watershed.〈/p〉〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 27〈/p〉 〈p〉Author(s): O.E. Adeyeri, P. Laux, J. Arnault, A.E. Lawin, H. Kunstmann〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study Area〈/h6〉 〈p〉The discharge of the transboundary Komadugu-Yobe Basin, Lake Chad Area, West Africa is calibrated using multi-objective optimization techniques.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The GR5J hydrological model parameters are calibrated using six optimization methods i.e. Local Optimization-Multi Start (LOMS), the Differential Evolution (DE), the Multi-objective Particle the Swarm Optimization (MPSO), the Memetic Algorithm with Local Search Chains (MALS), the Shuffled Complex Evolution-Rosenbrock’s function (SCE-R), and the Bayesian Markov Chain Monte Carlo (MCMC) approach. Three combined objective functions i.e. Root Mean Square Error, Nash- Sutcliffe efficiency, Kling-Gupta efficiency are applied. The calibration process is divided into two separate episodes (1974–2000 and 1980–1995) so as to ascertain the robustness of the calibration approaches. Runoff simulation results are analysed with a time-frequency wavelet transform.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉For calibration and validation stages, all optimization methods simulate the base flow and high flow spells with a satisfactory level of accuracy. For calibration period, MCMC underestimate it by -0.07 mm/day. The performance evaluation shows that MCMC has the highest values of mean absolute error (0.28) and mean square error (0.40) while LOMS and MCMC record a low volumetric efficiency of 0.56. In all cases, the DE and the SCE-R methods perform better than others. The combination of multi-objective functions and multi-optimization techniques improve the model’s parameters stability and the algorithms’ optimization to represent the runoff in the basin.〈/p〉 〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 27〈/p〉 〈p〉Author(s): Eunice Maia Andrade, Maria João Simas Guerreiro, Helba Araújo Queiroz Palácio, Diego Antunes Campos〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉This study was developed in two paired catchments under a tropical dry climate with a tropical dry forest landcover subject to vegetation management in the Brazilian northeastern region. Water input is mostly from rainfall, concentrated in three to four months of the year and with a potential evaporation that is over twice the amount of rainfall that characterizes its hydric deficit.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Interactions between hydrological functions, services and human actions to minimize environmental impacts, improve the availability of water of good quality and decrease degradation of the ecosystems; land use management effect on systems resilience, impact on surface runoff, soil loss, herbaceous and radicular biomass production, soil humidity and total organic carbon under altered vegetation cover.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Strategies to improve ecosystem services should rely on adequate management of vegetation to reduce surface flow. This reduction contributes to higher soil moisture contents, less intense erosive processes and resulting higher stocked soil carbon. The many techniques that improve resilience and ecosystem services in tropical dry forests lack an integrated view on how ecohydrological processes may be managed to favor the system. Vegetation thinning promotes underbrush development that dissipates rainfall and surface flow kinetic energy, increasing soil moisture content and carbon fixation and reducing soil loss.〈/p〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S2214581819300485-ga1.jpg" width="357" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 27〈/p〉 〈p〉Author(s): Yuheng Yang, Baisha Weng, Zihao Man, Zhilei Yu, Jinle Zhao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Region〈/h6〉 〈p〉The Nagqu River Basin in the Qinghai-Tibet Plateau.〈/p〉 〈/div〉 〈div〉 〈h6〉Focus〈/h6〉 〈p〉Climate change and human activities have altered the type of land use in the Qinghai-Tibet Plateau (QTP), which has affected the variation laws of water resources. We calibrated and verified the Water and Energy Transfer Process for a Large basin model (WEP-L), and calculated the impacts of climate change and human activities on runoff change and separated the impact of land use.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights〈/h6〉 〈p〉The Archimedean Copula function was used to diagnose the variance between precipitation and runoff. The contribution of climate change to the runoff in the Dasa and Jiayuqiao subbasin was 81.7% and 71.5%, of which the contribution of land use was 39.3% and 32.6%, respectively. Human activities contributing to the runoff in the Dasa and Jiayuqiao subbasins were 18.3% and 28.5%, of which the contribution of land use is 7.9% and 2.8%, respectively. Climate change has led to the melting of glaciers, permanent permafrost and the shift of the vertical distribution of vegetation, which is the main reason for the runoff variation in the NRB. This research provides a scientific basis for the rational protection and utilization of water resources, as well as soil and water conservation work.〈/p〉 〈/div〉

Description: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 27〈/p〉 〈p〉Author(s): Balbhadra Thakur, Ajay Kalra, Sajjad Ahmad, Kenneth W. Lamb, Venkat Lakshmi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Sacramento San Joaquin River Basin, California〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The study forecasts the streamflow at a regional scale within SSJ river basin with largescale climate variables. The proposed approach eliminates the bias resulting from predefined indices at regional scale. The study was performed for eight unimpaired streamflow stations from 1962–2016. First, the Singular Valued Decomposition (SVD) teleconnections of the streamflow corresponding to 500 mbar geopotential height, sea surface temperature, 500 mbar specific humidity (SHUM〈sub〉500〈/sub〉), and 500 mbar U-wind (U〈sub〉500〈/sub〉) were obtained. Second, the skillful SVD teleconnections were screened non-parametrically. Finally, the screened teleconnections were used as the streamflow predictors in the non-linear regression models (K-nearest neighbor regression and data-driven support vector machine).〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights〈/h6〉 〈p〉The SVD results identified new spatial regions that have not been included in existing predefined indices. The nonparametric model indicated the teleconnections of SHUM〈sub〉500〈/sub〉 and U〈sub〉500〈/sub〉 being better streamflow predictors compared to other climate variables. The regression models were capable to apprehend most of the sustained low flows, proving the model to be effective for drought-affected regions. It was also observed that the proposed approach showed better forecasting skills with preprocessed large scale climate variables rather than using the predefined indices. The proposed study is simple, yet robust in providing qualitative streamflow forecasts that may assist water managers in making policy-related decisions when planning and managing watersheds.〈/p〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 26〈/p〉 〈p〉Author(s): Ying Ouyang, Wei Jin, Johnny M. Grace, Sunday E. Obalum, Wayne C. Zipperer, Xiaoqing Huang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Lower Mississippi River Alluvial Valley (LMRAV) is located in the humid subtropical region of mid-south USA, and Lower Yazoo River Watershed (LYRW) in Mississippi is within the LMRAV.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Groundwater depletion due to anthropogenic activities is an issue of water resource concern in the LMRAV. Some studies suggested that forest lands reduce water recharge from land surface into aquifers as compared to agricultural lands. However, very few efforts have been devoted to investigating the relationship of water recharge and land use in the LMRAV. This study was designed to meet this need.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Using the HSPF (Hydrological Simulation Program-FORTRAN) model along with the LYRW, we found that the annual average water recharge from the land surface into the deep aquifer over the 10-year simulation period for the three land uses was: agriculture 〈 forest 〈 wetland. Only 1.1, 1.2, and 1.4% of the precipitation water from the agriculture, forest, and wetland, respectively, recharged into the deep aquifer in the LYRW. Results demonstrated that forest land slightly increased rather than reduced water recharge from the land surface into the groundwater as compared to that of the agricultural land. These finding could change the traditional scientific view on how forests affect water recharge into groundwater in the humid subtropical region around the world.〈/p〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 26〈/p〉 〈p〉Author(s): J.J. Gibson, Y. Yi, S.J. Birks〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Surveys of stable isotopes of water in 50 boreal lakes were conducted during 2002–2017 as a component of Alberta’s Oil Sands acid sensitivity program in northeastern Alberta.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Using an isotope mass balance approach, watershed, climatic and isotopic data were applied to estimate evaporation losses and residence time of lakes, as well as to estimate water yield from watersheds.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Site-specific differences in water yield to 50 lakes over 16 years were found to be controlled by latitudinal gradients in climate, wetland type, lake/watershed configuration and permafrost. 19 plateau watersheds located northeast of Fort McMurray and in the Birch and Caribou Mountains which contained significant permafrost were found to have similar water yield to permafrost-poor watersheds if fen-dominated (159 mm/yr: n = 5 vs. 166 mm/yr; n = 31), and enhanced water yield (405 mm/yr; n = 14) if bog-dominated. Water yield was found to be systematically dependent on permafrost extent, yielding up to several hundred millimetres of additional runoff in bog-dominated systems. Temporal trend analysis indicates systemic momentum of change in hydrologic drivers over the 16-year period, although few are statistically significant. A new conceptual framework is proposed for classification of site-to-site permafrost thaw stage to improve water yield prediction, which is expected to influence lake water quality including observed pH increases noted previously for many lakes in the region.〈/p〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 26〈/p〉 〈p〉Author(s): Jhan Carlo Espinoza, Anna A. Sörensson, Josyane Ronchail, Jorge Molina-Carpio, Hans Segura, Omar Gutierrez-Cori, Romina Ruscica, Thomas Condom, Sly Wongchuig-Correa〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Upper Madeira Basin (975,500 km〈sup〉2〈/sup〉) in Southern Amazonia, which is suffering a biophysical transition, involving deforestation and changes in rainfall regime.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The evolution of the runoff coefficient (Rc: runoff/rainfall) is examined as an indicator of the environmental changes (1982–2017).〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉At an annual scale, the Rc at Porto Velho station declines while neither the basin-averaged rainfall nor the runoff change. During the low-water period Rc and runoff diminish while no changes are observed in rainfall. This cannot be explained by increase of evapotranspiration since the basin-averaged actual evapotranspiration decreases. To explain the decrease of Rc, a regional analysis is undertaken. While the characteristic rainfall-runoff time-lag (CT) at Porto Velho basin is estimated to 60 days, CT is higher (65–75 days) in the south and lower (50 days) over the Amazon-Andes transition regions. It is found that 1) the southern basin (south of 14 °S) best explains low-level Porto Velho runoff, 2) in the south, rainfall diminishes and the frequency of dry days increases. Both features explain the diminution of the runoff and the Rc in Porto Velho. Moreover, the increasing dryness in the south compensates for the rainfall and frequency of wet days (〉10 mm) increase north of 14 °S and explains the lack of basin-averaged rainfall trends of the upper Madeira basin.〈/p〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 26〈/p〉 〈p〉Author(s): Alemayehu A. Shawul, Sumedha Chakma, Assefa M. Melesse〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Upper Awash basin at the headwater of Awash River.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Comprehensive assessment of land cover (LC) change effect on the water balance components using integrated approaches of hydrologic modeling and partial least squares regression (PLSR) provides better understandings of the impact of recent development activities on water resources. The SWAT model was validated at five subbasins and used to simulate the water balance and hydrologic response to LC changes at multiple temporal and spatial scales. PLSR was used to evaluate the significance of the relative influence of LC classes on the hydrologic components.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Based on the multitemporal LC change detections, Upper Awash basin is characterized by the decline of natural vegetation due to the swelling rise of cropland and urbanization. The monoplot of PLSR components exhibited that groundwater is highly correlated with the forest areas and lateral flow is strongly correlated with pasture, whereas, surface runoff is significantly attributed to the change in urban and cropland. The Variable Importance for the Projection (VIP) and PLSR weight (w) revealed that the decline of groundwater is mainly due to urban (VIP = 1.34 and w=-0.55), whereas, the change in forest area enhanced groundwater (VIP = 1.04 and w = 0.47). The study provides valuable information on the contribution of particular LC to change in water balance which is vital for improved water resources management.〈/p〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 26〈/p〉 〈p〉Author(s): Henrique M.L. Chaves, Douglas R. Lorena〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Considering that most water supply reservoirs were designed and are operated with limited streamflow records, and that persistence (long-memory) is often present in reservoir inflows, it not surprising that reservoirs designed and operated with 100% reliability have failed, due to unaccounted uncertainties. The Descoberto reservoir (Central Brazil) failed to supply the water demand in 2017, although mass balance analyses indicated a failure-free condition during its previous 31 years of operation. The objective of the present study was to identify the presence of long-memory processes in the Descoberto reservoir inflows and to reassess its reliability with alternative methods and statistics. After persistently low inflows were detected in the years preceding reservoir failure, autocorrelation and rescaled-range analyses were performed in the inflow series, confirming the presence of long-term process-LTP (Hurst coefficient = 0.655). Reservoir reliability was then reassessed for the pre-failure period (1986–2016), using three storage-yield-reliability (S-Y-R) methods and LTP statistics. The reassessed pre-failure reservoir reliability was 96.05%, very close to the observed (post failure) reliability (96.87%), estimated by mass balance analysis. The 3% difference observed between the reliabilities using classical and LTP statistics resulted from a higher standard deviation in the reservoir inflows, capturing the long-term variability not evident in the classical analysis. If persistence occurs in inflows, reservoir reliability could be assessed using a similar approach, improving reservoir behavior forecast and management.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 26〈/p〉 〈p〉Author(s): Hamed Zamani Sabzi, Hernan A. Moreno, Rachel Fovargue, Xianwu Xue, Yang Hong, Thomas M. Neeson〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Red River Basin of the South, United States of America.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉We investigated the projected changes in water availability and demand across the Red River to identify regions of potential future water stress. The VIC model was calibrated, validated and then run with ensemble forcing from regionally representative global circulation model (GCM) outputs. For different combinations of representative concentration pathways (RCPs) we evaluated the impacts of climate change on streamflows and water availability throughout the basin. To estimate future water demand, we integrated a series of sector-specific regression models fit to historical water usage per county.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Despite discrepancies among GCMs projections, all future scenarios include a strong west-east gradient in water availability. Joint consideration of projected water demand and availability reveals that the distribution of future hotspots of water stress is spatially patchy and generally driven by changes in water demand, rather than availability. These hotspots of future water stress highlight locations of potential water conflicts. Our approach is likely to be applicable to drought-prone river basins worldwide where the spatial patterns of future water availability differ from spatial patterns of future water demand.〈/p〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 26〈/p〉 〈p〉Author(s): Shannon Ulrich, Jeffrey Gillow, Shawn Roberts, Gregory Byer, Julie Sueker, Kathryn Farris〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Lower San Mateo Creek Basin (SMCB), New Mexico〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Groundwater in the alluvial aquifer of the lower SMCB has a high concentration of total dissolved solids, alkalinity, and dissolved uranium at concentrations above USEPA limits; the source of the water quality was investigated through evaluation of geology, mineralogy, and geochemistry of sediments and groundwater. Surface-expressing bedrock in the larger Basin is dominated by uranium-bearing units such as the Morrison Formation and Dakota Sandstone; erosion of these units contributed sediment to Quaternary alluvium valley fill in the Basin with heterogeneous distribution of uranium. The potential for uranium-bearing alluvial fill to affect the groundwater quality was investigated upgradient of the Grants Reclamation Project (GRP), a former uranium milling facility in the lower SMCB, by hydrogeochemical and geophysical methods.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Uranium is primarily associated with fine-grained materials (clay/silt) and is labile depending upon sediment geochemical conditions. Natural occurrence of uranium minerals in SMCB alluvial sediments here results in concentrations in groundwater greater than the USEPA water quality standards; as such, site-specific standards are established and supported by the findings of this work. Regional groundwater systems, derived from weathered mineralized bedrock, require careful evaluation of water quality to understand background conditions; uranium in groundwater results from hydrogeochemical processes at the interface of fine and coarse grained sediments within the aquifer.〈/p〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 26〈/p〉 〈p〉Author(s): Amélie Dausse, Véronique Leonardi, Hervé Jourde〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study Region〈/h6〉 〈p〉The Lez aquifer is a Mediterranean karst system located in southern France, which supplies groundwater to the Montpellier urban area.〈/p〉 〈/div〉 〈div〉 〈h6〉Study Focus〈/h6〉 〈p〉Multi-scale hydrodynamic investigations were carried out in a fractured and karstic aquifer in order to identify the flow-bearing structures and evaluate their hydraulic properties. The study is based on an extensive dataset developed from several hydraulic tests, performed at different spatial and temporal scales. The scales ranged spatially from a few meters to more than 15 km and temporally from a few minutes to a few months.〈/p〉 〈/div〉 〈div〉 〈h6〉New Hydrological Insights for the Region〈/h6〉 〈p〉The data analysis shows that the hydraulic connectivity at both local and regional scales is mainly due to sub-horizontal flow-bearing structures, in which a conduit network has developed. This structure appears mainly to be located at the interface between two stratigraphic units, at the transition between Jurassic and Cretaceous limestones (Kimmeridgian-Berriasian interface). At the regional scale, this flow-bearing structure plays a major role in large-scale connectivity since a compartmentalization of the Lez aquifer appears where the continuity of this structure disappears. The hydraulic properties estimated appear to be strongly dependent on the investigated geological structures and on the different hydrogeological methods used for the borehole, local and regional scale of investigations.〈/p〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 26〈/p〉 〈p〉Author(s): Fabien Rizinjirabake, Petter Pilesjö, David E. Tenenbaum〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉Rukarara River Watershed (RRW), Rwanda.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉DOC leaching has important environmental consequences for both terrestrial and aquatic ecosystems. This paper measures leached dissolved organic carbon (LDOC) and the factors controlling its variation in the RRW, a mixed agriculture and forest watershed in Rwanda. The study describes the relationship of LDOC with land use/land cover (LULC), soil properties, rainfall characteristics, and stream DOC using linear regression and linear mixed effects models.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights〈/h6〉 〈p〉The annual LDOC flux from topsoil to deeper soil horizons was 13.62 tonnes of carbon for the study area. This annual LDOC flux represents approximately 2% of the net primary productivity and 0.02% of the soil carbon stock. The plantation forest and natural forest sites showed higher LDOC fluxes than other LULC classes. Soil TOC, TN, rainfall intensity and amount positively affected LDOC flux (7 ≤ R〈sup〉2〈/sup〉 ≤ 30%) in the RRW. Cation exchange capacity, runoff, and rainfall storage negatively affected the RRW (7 ≤ R〈sup〉2〈/sup〉 ≤ 23%). LDOC flux explained 14% of the variation of stream DOC in the RRW. Our results imply that, under ongoing climate and LULC changes, an increase of the proportion of plantation forest and rainfall intensity throughout the watershed will increase LDOC flux, and will have a weak positive effect on stream DOC.〈/p〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S221458181930031X-ga1.jpg" width="337" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉