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Author Heaton, T.H.E.; Talma, A.S.; Vogel, J.C.
Title (up) Origin and history of nitrate in confined groundwater in the western Kalahari Type Journal Article
Year 1983 Publication Journal of Hydrology Abbreviated Journal
Volume 62 Issue 1 Pages 243-262
Keywords
Abstract Data are presented for nitrate, dinitrogen and argon concentrations and 15N14N ratios in groundwater, with radiocarbon ages up to 40,000 yr. for three confined sandstone aquifers in the western Kalahari of South West Africa/Namibia. The nitrate is probably generated within the soil of the recharge areas, and its production rate during the period 3000-40,000 B.P. has remained between 0.5 and 1.6 meq NO−3l−1 of recharge water, with ° 15N between + 4 and + 8‰. Variations in the amount of nitrate and of “excess air” in groundwater recharge are found, and can only reflect changes in the environmental conditions during recharge. They must therefore be caused by the climatic changes that have taken place during the past 25,000 yr.
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ISSN 0022-1694 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ Heaton1983243 Serial 282
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Author Rusli, S.R.; Weerts, A.H.; Mustafa, S.M.T.; Irawan, D.E.; Taufiq, A.; Bense, V.F.
Title (up) Quantifying aquifer interaction using numerical groundwater flow model evaluated by environmental water tracer data: Application to the data-scarce area of the Bandung groundwater basin, West Java, Indonesia Type Journal Article
Year 2023 Publication Journal of Hydrology: Regional Studies Abbreviated Journal
Volume 50 Issue Pages 101585
Keywords Aquifer interaction, Multi-layer groundwater abstraction, Environmental water tracers, Groundwater flow model, Bandung groundwater basin
Abstract Study Region: Bandung groundwater basin, Indonesia. Study focus: Groundwater abstraction of various magnitudes, pumped out from numerous depths in a multitude of layers of aquifers, stimulates different changes in hydraulic head distribution, including ones under vertical cross-sections. This generates groundwater flow in the vertical direction, where groundwater flows within its storage from the shallow to the underlying confined aquifers. In the Bandung groundwater basin, previous studies have identified such processes, but quantitative evaluations have never been conducted, with data scarcity mainly standing as one of the major challenges. In this study, we utilize the collated (1) environmental water tracer data, including major ion elements (Na+/K+, Ca2+, Mg2+, Cl−, SO42−,HCO3−), stable isotope data (2H and δ18O), and groundwater age determination (14C), in conjunction with (2) groundwater flow modeling to quantify the aquifer interaction, driven mainly by the multi-layer groundwater abstraction in the Bandung groundwater basin, and demonstrate their correspondence. In addition, we also use the model to quantify the impact of multi-layer groundwater abstraction on the spatial distribution of the groundwater level changes. New hydrological insights for the region: In response to the limited calibration data availability, we expand the typical model calibration that makes use of the groundwater level observations, with in-situ measurement and a novel qualitative approach using the collated environmental water tracers (EWT) data for the model evaluation. The analysis in the study area using EWT data and quantitative methods of numerical groundwater flow modeling is found to collaborate with each other. Both methods show agreement in their assessment of (1) the groundwater recharge spatial distribution, (2) the regional groundwater flow direction, (3) the groundwater age estimates, and (4) the identification of aquifer interaction. On average, the downwelling to the deeper aquifer is quantified at 0.110 m/year, which stands out as a significant component compared to other groundwater fluxes in the system. We also determine the unconfined aquifer storage volume decrease, calculated from the change in the groundwater table, resulting in an average declining rate of 51 Mm3/year. This number shows that the upper aquifer storage is dwindling at a rate disproportionate to its groundwater abstraction, hugely influenced by losses to the deeper aquifer. The outflow to the deeper aquifer contributes to 60.3% of the total groundwater storage lost, despite representing only 32.3% of the total groundwater abstraction. This study shows the possibility of quantification of aquifer interaction and groundwater level change dynamics driven by multi-layer groundwater abstraction in a multi-layer hydrogeological setting, even in a data-scarce environment. Applying such methods can assist in deriving basin-scale groundwater policies and management strategies under the changing anthropogenic and climatic factors, thereby ensuring sustainable groundwater management.
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ISSN 2214-5818 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ Rusli2023101585 Serial 222
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Author Leeuwen, Z.R. van; Klaar, M.J.; Smith, M.W.; Brown, L.E.
Title (up) Quantifying the natural flood management potential of leaky dams in upland catchments, Part II: Leaky dam impacts on flood peak magnitude Type Journal Article
Year 2024 Publication Journal of Hydrology Abbreviated Journal
Volume 628 Issue Pages 130449
Keywords Nature based solutions, Large wood, Empirical, Hydrograph analysis, Ecosystem services, Transfer function noise model
Abstract Leaky dams are an increasingly popular natural flood management measure, yet their impacts on flood peak magnitude have not yet been empirically quantified for a range of event types and magnitudes, even at the stream scale. In this study, the novel application of a transfer function noise modelling approach to empirical Before-After-Control-Impact stage data from an upland catchment allowed leaky dam effectiveness in reducing flood peak magnitude to be quantified. Flood peak stage and discharge magnitude changes were assessed from empirical data for 50 single and multi-peaked high flow events with return periods ranging from less than one year to six years. Overall, event peak magnitude was significantly reduced following the installation of eight leaky dams on the impact stream. Effectiveness was highly variable, but on average, flood peak magnitude was reduced by 10% for events with a return period up to one year. Some of the variability was explained by the size of the event and whether it was a single or multi-peaked event. This finding emphasises the need to manage expectations by considering both a range of event magnitudes and types when designing or assessing leaky dam natural flood management schemes.
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ISSN 0022-1694 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ Vanleeuwen2024130449 Serial 228
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Author Tamagnone, P.; Comino, E.; Rosso, M.
Title (up) Rainwater harvesting techniques as an adaptation strategy for flood mitigation Type Journal Article
Year 2020 Publication Journal of Hydrology Abbreviated Journal
Volume 586 Issue Pages 124880
Keywords Rainwater harvesting techniques, Extreme rainfall, Runoff, Hydraulic modelling, Flood mitigation, Arid and semi-arid climate
Abstract The development of adaptation and mitigation strategies to tackle anthropic and climate changes impacts is becoming a priority in drought-prone areas. This study examines the capabilities of indigenous rainwater harvesting techniques (RWHT) to be used as a viable solution for flood mitigation. The study analyses the hydraulic performance of the most used micro-catchment RWHT in sub-Saharan regions, in terms of flow peak reduction (FPR) and volume reduction (VR) at the field and basin scale. Parametrized hyetographs were built to replicate the extreme precipitations that strike Sahelian countries during rainy seasons. 2D hydrodynamic simulations showed that half-moons placed with a staggered configuration (S-HM) have the best performances in reducing runoff. At the field scale, S-HM showed a remarkable FPR of 77% and a VR of 70% in case of extreme rainfall. Instead at the basin scale, in which only 5% of the surface was treated, 13% and 8% respectively for FPR and VR were obtained. In addition, the reduction of the runoff coefficient (Rc) between the different configuration was analyzed. The study critically evaluates hydraulic performances of the different techniques and shows how pitting practices cannot guarantee high performance in case of extreme precipitations. These results will enrich the knowledge of the hydraulic behavior of RWHT; aspect marginally investigated in the scientific literature. Moreover, this study presents the first scientific application of HEC-RAS as a rainfall-runoff model. Despite some limitations, this model has the effective feature of using very high-resolution topography as input for hydraulic simulations. The results presented in this study should encourage stakeholders to upscale the use of RWHT in order to lessen the flood hazard and land degradation that oppresses arid and semi-arid areas.
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ISSN 0022-1694 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ Tamagnone2020124880 Serial 240
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Author Xu, W.D.; Burns, M.J.; Cherqui, F.; Duchesne, S.; Pelletier, G.; Fletcher, T.D.
Title (up) Real-time controlled rainwater harvesting systems can improve the performance of stormwater networks Type Journal Article
Year 2022 Publication Journal of Hydrology Abbreviated Journal
Volume 614 Issue Pages 128503
Keywords Real-time control, Rainwater harvesting systems, Stormwater control measures, Flood mitigation, Source Control, Climate change
Abstract Real-Time Control (RTC) technology is increasingly applied in Rainwater Harvesting (RWH) systems to optimise their performance related to water supply and flood mitigation. However, most studies to date have focussed on testing the benefits at an individual site scale, leaving the potential benefits for downstream stormwater networks largely untested. In this study, we developed a methodology to predict how at-source RTC RWH systems influence the behaviour of a stormwater network. Simulation was enabled by coupling the drainage model in SWMM with an RTC RWH model coded using the R software. We modelled two different RTC strategies across a range of system settings (e.g. storage size for RWH and proportion of storage to which RTC is applied) under two different climate scenarios—current and future climates. The simulations showed that RTC reduced flooding volume and peak flow of the stormwater network, leading to a potential mitigation of urban flooding risks, while also providing a decentralised supplementary water supply. Implementing RTC in more of RWH storages yielded greater benefits than simply increasing storage capacity, in both current and future climates. More importantly, the RTC systems are capable of more precisely managing the resultant flow regime in reducing the erosion and restoring the pre-development conditions in sensitive receiving waters. Our study suggests that RTC RWH storages distributed throughout a catchment can substantially improve the performance of existing drainage systems, potentially avoiding or deferring expensive network upgrades. Investments in real-time control technology would appear to be more promising than investments in detention volume alone.
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ISSN 0022-1694 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ Xu2022128503 Serial 233
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Author Sedghi, M.M.; Zhan, H.
Title (up) Semi-analytical solutions of discharge variation of a qanat in an unconfined aquifer subjected to general areal recharge and nearby pumping well discharge Type Journal Article
Year 2020 Publication Journal of Hydrology Abbreviated Journal
Volume 584 Issue Pages 124691
Keywords Analytical solution, Laplace domain, Screen segmentation, Qanat, Areal recharge, Constant head
Abstract Qanat is a type of drain that extract water from aquifers by gravity. Significant amount of fresh water used in Middle East and other parts of the world are supplied by qanats. Despite their importance, discharge variation of these type of wells received almost no attention. The aim of this research is to obtain a Laplace domain solution of discharge variation of a qanat installed in an anisotropic unconfined aquifer subjected to arbitrary areal recharge and nearby pumping well(s) discharge. A new semi-analytical solution of drawdown is obtained first to implement the effects of arbitrary areal recharge and nearby pumping well(s) using the principle of superposition. Then, the discharge variation solution of the qanat is obtained from the drawdown solution. To establish a constant-head boundary condition at the qanat periphery, the qanat is discretized into several segments. The results of this study are presented in dimensionless discharge-dimensionless time curves. The effects of hydraulic as well as geometric parameters on the discharge variation of the qanat due to arbitrary areal recharge, falling of water table from its initial position and discharge of nearby wells are explored. We also investigate the influences of distance and screen depth and location of the nearby well on the discharge variation of the qanat. The results of this study can be utilized for multiple purposes: 1) to predict discharge of qanat in response to rainfall and nearby pumping well(s); 2) to estimate the aquifer parameters using hydrograph of the qanat; 3) to determine optimal location and pumping pattern of the nearby wells to minimize their influences on the discharge of the qanat; 4) to calculate water budget of aquifers drained by a qanat. The equation presented in this work can also be used to estimate discharge of a horizontal drain installed in cropland subjected to arbitrary irrigation pattern.
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Call Number THL @ christoph.kuells @ Sedghi2020124691 Serial 261
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Author Heaton, T.H.E.
Title (up) Sources of the nitrate in phreatic groundwater in the western Kalahari Type Journal Article
Year 1984 Publication Journal of Hydrology Abbreviated Journal
Volume 67 Issue 1 Pages 249-259
Keywords
Abstract Elevated levels of nitrate occur in phreatic groundwater in the western Kalahari, Namibia. Nitrate in water containing 0.4–3.1 meq NO−3l−1, of widespread occurrence, has δ15N values in the range +4.9 to +8.0‰, suggesting natural derivation from the soil. The sporadic occurrence of very high levels of nitrate (> 4 meq NO−3l−1), which has δ15N between +9.3 to +18.7‰, reflects pollution derived from animal waste. The importance of considering the possible isotopic effects of denitrification, and the significance of leaching in the nitrogen budget of the Kalahari soil, are also discussed.
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ISSN 0022-1694 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ Heaton1984249 Serial 278
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Author Müller, M.; Alaoui, A.; Külls, C.; Leistert, H.; Meusburger, K.; Stumpp, C.; Weiler, M.; Alewell, C.
Title (up) Tracking water pathways in steep hillslopes by δ18O depth profiles of soil water Type Journal Article
Year 2014 Publication Journal of hydrology Abbreviated Journal
Volume 519 Issue Pages 340-352
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Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
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Call Number THL @ christoph.kuells @ Mueller2014tracking Serial 20
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Author Nijsten, G.-J.; Christelis, G.; Villholth, K.G.; Braune, E.; Gaye, C.B.
Title (up) Transboundary aquifers of Africa: Review of the current state of knowledge and progress towards sustainable development and management Type Journal Article
Year 2018 Publication Journal of Hydrology: Regional Studies Abbreviated Journal
Volume 20 Issue Pages 21-34
Keywords Africa, Assessment, Governance, Indicators, Transboundary aquifers
Abstract Study region Transboundary aquifers (TBAs) of Africa. Study focus Review of work on TBAs in Africa, including an overview of assessments and management efforts that have taken place over the last half century. New hydrological insights Seventy-two TBAs have been mapped in Africa. They underlie 40% of the continent, where 33% of the population lives, often in arid or semi-arid regions. TBA inventories have progressed since 2000 and remain work in progress. Despite their importance only eleven TBAs have been subjected to more detailed studies. Cooperation has been formalised for seven TBAs. Most of these TBAs are in North Africa and the Sahel. The recent global Transboundary Waters Assessment Programme compiled information at the national level to describe TBAs in terms of key indicators related to the water resource, socio-economic, and legal and institutional conditions. Availability of data at national level is low, hampering regional assessment. Comparing indicators, from questionnaire surveys, with those from a global water-use model showed variable levels of agreement, calling for further research. Reports on agreements scoping TBA management, indicate that this may be dealt with within international river/lake agreements, but reported inconsistencies between TBA sharing countries also indicate that implementation is limited. Increasing awareness and support to joint TBA management is noticeable amongst international organisations. However, such cooperation requires long-term commitment to produce impacts at the local level.
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Series Editor Series Title Abbreviated Series Title
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ISSN 2214-5818 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ nijsten_transboundary_2018 Serial 93
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Author Seidl, C.; Wheeler, S.A.; Page, D.
Title (up) Understanding the global success criteria for managed aquifer recharge schemes Type Journal Article
Year 2024 Publication Journal of Hydrology Abbreviated Journal
Volume 628 Issue Pages 130469
Keywords Managed Aquifer Recharge (MAR), Fuzzy-set Qualitative Comparative Analysis, Water banking, Groundwater, Water management, Water storage
Abstract Water availability and quality issues will only gain importance in the future, with climate change impacts putting increasing pressure on global water resources. Dealing with these challenges requires drawing on all available water management tools, including Managed Aquifer Recharge (MAR). Although MAR has seen increasing global implementation during the last half a century, it is still often overlooked as a management tool. While technical, bio-physical, and hydrogeological aspects of MAR are well researched, this cannot be said for socio-economic and other governance factors. Where information is available, this study seeks to understand the conditions necessary for MAR success. We apply fuzzy-set Qualitative Comparative Analysis on 313 world MAR applications, and also model separately for high- and low-middle-income countries. Results show that sophisticated hydrogeological site understanding and scheme operation is paramount for MAR success, as is utilizing natural water sources for high value end uses. Successful high-income country MAR schemes tend to be large and utilize natural water sources and sophisticated water injection and treatment methods to augment potable water supply; while successful low-middle-income country schemes are not large, older than 20 years, and use gravity infiltration methods and (limited) no water treatment. These findings will help inform the future suitability of MAR application design and its likely success within various contexts.
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Call Number THL @ christoph.kuells @ Seidl2024130469 Serial 273
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