| Records |
| Author |
Johnson, R.S.H.; Alila, Y. |
| Title |
Nonstationary stochastic paired watershed approach: Investigating forest harvesting effects on floods in two large, nested, and snow-dominated watersheds in British Columbia, Canada |
Type |
Journal Article |
| Year |
2023 |
Publication |
Journal of Hydrology |
Abbreviated Journal |
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| Volume |
625 |
Issue |
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Pages |
129970 |
| Keywords |
Probabilistic physics, Forest hydrology, Attribution science, Flood Frequency Analysis, Stochastic hydrology, Nonstationarity |
| Abstract |
Drawing on advances in nonstationary frequency analysis and the science of causation and attribution, this study employs a newly developed nonstationary stochastic paired watershed approach to determine the effect of forest harvesting on snowmelt-generated floods. Moreover, this study furthers the application of stochastic physics to evaluate the environmental controls and drivers of flood response. Physically-based climate and time-varying harvesting data are used as covariates to drive the nonstationary flood frequency distribution parameters to detect, attribute, and quantify the effect of harvesting on floods in the snow-dominated Deadman River (878 km2) and nested Joe Ross Creek (99 km2) watersheds. Harvesting only 21% of the watershed caused a 38% and 84% increase in the mean but no increase in variability around the mean of the frequency distribution in the Deadman River and Joe Ross Creek, respectively. Consequently, the 7-year, 20-year, 50-year, and 100-year flood events became approximately two, four, six, and ten times more frequent in both watersheds. An increase in the mean is posited to occur from an increase in moisture availability following harvest from suppressed snow interception and increased net radiation reaching the snowpack. Variability was not increased because snowmelt synchronization was inhibited by the buffering capacity of abundant lakes, evenly distributed aspects, and widespread spatial distribution of cutblocks in the watersheds, preventing any potential for harvesting to increase the efficiency of runoff delivery to the outlet. Consistent with similar recent studies, the effect of logging on floods is controlled not only by the harvest rate but most importantly the physiographic characteristics of the watershed and the spatial distribution of the cutblocks. Imposed by the probabilistic framework to understanding and predicting the relation between extremes and their environmental controls, commonly used in the general sciences but not forest hydrology, it is the inherent nature of snowmelt-driven flood regimes which cause even modest increases in magnitude, especially in the upper tail of the distribution, to translate into surprisingly large changes in frequency. Contrary to conventional wisdom, harvesting influenced small, medium, and very large flood events, and the sensitivity to harvest increased with increasing flood event size and watershed area. |
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0022-1694 |
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THL @ christoph.kuells @ Johnson2023129970 |
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245 |
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Klaus, J.; Külls, C.; Dahan, O. |
| Title |
Evaluating the recharge mechanism of the Lower Kuiseb Dune area using mixing cell modeling and residence time data |
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Journal Article |
| Year |
2008 |
Publication |
Journal of Hydrology |
Abbreviated Journal |
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| Volume |
358 |
Issue |
3-4 |
Pages |
304-316 |
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Elsevier |
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THL @ christoph.kuells @ Klaus2008evaluating |
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28 |
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Morin, E.; Grodek, T.; Dahan, O.; Benito, G.; Külls, C.; Jacoby, Y.; Van Langenhove, G.; Seely, M.; Enzel, Y. |
| Title |
Flood routing and alluvial aquifer recharge along the ephemeral arid Kuiseb River, Namibia |
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Journal Article |
| Year |
2009 |
Publication |
Journal of Hydrology |
Abbreviated Journal |
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368 |
Issue |
1-4 |
Pages |
262-275 |
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Elsevier |
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THL @ christoph.kuells @ Morin2009flood |
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26 |
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Müller, M.; Alaoui, A.; Külls, C.; Leistert, H.; Meusburger, K.; Stumpp, C.; Weiler, M.; Alewell, C. |
| Title |
Tracking water pathways in steep hillslopes by δ18O depth profiles of soil water |
Type |
Journal Article |
| Year |
2014 |
Publication |
Journal of hydrology |
Abbreviated Journal |
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| Volume |
519 |
Issue |
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Pages |
340-352 |
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Elsevier |
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THL @ christoph.kuells @ Mueller2014tracking |
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20 |
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Musy, S.; Meyzonnat, G.; Barbecot, F.; Hunkeler, D.; Sültenfuss, J.; Solomon, D.K.; Purtschert, R. |
| Title |
In-situ sampling for krypton-85 groundwater dating |
Type |
Journal Article |
| Year |
2021 |
Publication |
Journal of Hydrology X |
Abbreviated Journal |
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| Volume |
11 |
Issue |
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Pages |
100075 |
| Keywords |
Noble gases, Tracers, Groundwater, Dating, Sampling Methodology |
| Abstract |
Krypton-85 and other radioactive noble gases are widely used for groundwater dating purposes. 85Kr analysis require large volumes of water to reach the analytical requirements. Conventionally, this water is pumped to the surface to be degassed with a gas extraction system. The large pumping rate may disturb the natural flow field and requires substantial field logistics. Hence, we propose a new in-situ degassing method, in which membrane contactors are used to degas the groundwater directly in the well and gas is collected at the surface. This way, field work is facilitated, groundwater system disturbance is minimized, and the gas sample is collected at a specific depth. We demonstrate the tightness of the system regarding atmospheric air contamination for a collection times of 24 h, which is sufficient for both low-level counting and laser-based counting methods for 85Kr. The minimal borehole diameter is 7.5 cm for the prototype presented in this research but can easily be reduced to smaller diameters. In a case study, we compare the results obtained with the new passive method with those from a conventional packer setup sampling. Additionally, 3H/3He samples were collected for both sampling regimes and the dating results were compared with those from 85Kr. A good agreement between tracer ages is demonstrated and the age stratigraphy is consistent with the expected age distribution for a porous unconfined aquifer. In addition, our study emphasizes the differences between the age information sampled with various methods. In conclusion, we demonstrate that the new in situ quasi-passive method provides a more representative age stratigraphy with depth in most cases. |
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2589-9155 |
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no |
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THL @ christoph.kuells @ Musy2021100075 |
Serial |
215 |
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Naghedifar, S.M.; Ziaei, A.N.; Naghedifar, S.A.; Ansari, H. |
| Title |
A new model for simulation of collection and conveyance sections of Qanat |
Type |
Journal Article |
| Year |
2020 |
Publication |
Journal of Hydrology |
Abbreviated Journal |
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| Volume |
590 |
Issue |
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Pages |
125218 |
| Keywords |
Richards’ equation, Saint-Venant equation, Numerical modeling, Qanat-aquifer system |
| Abstract |
In this paper, a new numerical model has been developed for simulation of Qanat-aquifer system. This model employs quasi-3D mixed-form of Richards’ equation and 1D fully-hydrodynamic form of Saint-Venant equations to simulate subsurface and overland flow, respectively. In order to handle non-orthogonal grids, subsurface flow module benefits from coordinate transformation technique. Using the above-mentioned governing equations, the presented model is able to simulate water flow inside both collection and conveyance sections of the gallery as well as dynamics of groundwater and vadose zone from impermeable bed rock to the soil-air interface. Since measured data corresponding to the hydraulics of Qanats is scarce, the overland and subsurface modules have been validated with analytical, numerical and experimental benchmarks in the literature. Subsequently, the model was employed to simulate ten different hypothetical aquifer-Qanat systems with different properties including the depth of groundwater aquifer, roughness of the gallery and saturated hydraulic conductivity of the gallery-aquifer boundary and the influence of each the parameters was monitored on the outflow rate at the appearance point of each Qanat. Furthermore, the advance of water inside two initially dry galleries were simulated at different time levels up to steady state. Eventually, the streamlines have been shown at the steady state for two Qanat-aquifer systems. Although, the presented study sheds light on some aspects of Qanat-aquifer hydraulics, the validation of the presented model with in-lab or on-field data remains ongoing for the future researches. |
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0022-1694 |
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THL @ christoph.kuells @ Naghedifar2020125218 |
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254 |
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Nijsten, G.-J.; Christelis, G.; Villholth, K.G.; Braune, E.; Gaye, C.B. |
| Title |
Transboundary aquifers of Africa: Review of the current state of knowledge and progress towards sustainable development and management |
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Journal Article |
| Year |
2018 |
Publication |
Journal of Hydrology: Regional Studies |
Abbreviated Journal |
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20 |
Issue |
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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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2214-5818 |
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no |
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THL @ christoph.kuells @ nijsten_transboundary_2018 |
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93 |
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Pavelic, P.; Srisuk, K.; Saraphirom, P.; Nadee, S.; Pholkern, K.; Chusanathas, S.; Munyou, S.; Tangsutthinon, T.; Intarasut, T.; Smakhtin, V. |
| Title |
Balancing-out floods and droughts: Opportunities to utilize floodwater harvesting and groundwater storage for agricultural development in Thailand |
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Journal Article |
| Year |
2012 |
Publication |
Journal of Hydrology |
Abbreviated Journal |
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470-471 |
Issue |
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Pages |
55-64 |
| Keywords |
Water scarcity, Flooding, Drought, Managed aquifer recharge, Floodwater harvesting, Chao Phraya River Basin |
| Abstract |
Summary Thailand’s naturally high seasonal endowment of water resources brings with it the regularly experienced problems associated with floods during the wet season and droughts during the dry season. Downstream-focused engineering solutions that address flooding are vital, but do not necessarily capture the potential for basin-scale improvements to water security, food production and livelihood enhancement. Managed aquifer recharge, typically applied to annual harvesting of wet season flows in dry climates, can also be applied to capture, store and recover episodic extreme flood events in humid environments. In the Chao Phraya River Basin it is estimated that surplus flows recorded downstream above a critical threshold could be harvested and recharged within the shallow alluvial aquifers in a distributed manner upstream of flood prone areas without significantly impacting existing large-medium storages or the Gulf and deltaic ecosystems. Capturing peak flows approximately 1year in four by dedicating around 200km2 of land to groundwater recharge would reduce the magnitude of flooding and socio-economic impacts and generate around USD 250M/year in export earnings for smallholder rainfed farmers through dry season cash cropping without unduly compromising the demands of existing water users. It is proposed that farmers in upstream riparian zones be co-opted as flood harvesters and thus contribute to improved floodwater management through simple water management technologies that enable agricultural lands to be put to higher productive use. Local-scale site suitability and technical performance assessments along with revised governance structures would be required. It is expected that such an approach would also be applicable to other coastal-discharging basins in Thailand and potentially throughout the Asia region. |
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0022-1694 |
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no |
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THL @ christoph.kuells @ Pavelic201255 |
Serial |
246 |
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Rooyen, J.D. van; Watson, A.W.; Miller, J.A. |
| Title |
Using tritium and radiocarbon activities to constrain regional modern and fossil groundwater mixing in Southern Africa |
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Journal Article |
| Year |
2022 |
Publication |
Journal of Hydrology |
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614 |
Issue |
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Pages |
128570 |
| Keywords |
Radiocarbon, Residence time, SADC, Tritium |
| Abstract |
This study combines historical records of 14C and 3H in the atmosphere and soil with renewal rate and groundwater lumped parameter models to predict the abundance of 14C and 3H in groundwater over time. 624 groundwater samples from numerous studies, over four decades (1978–2019), in South Africa, Namibia, Botswana and Mozambique were collated to compare with predicted groundwater activities of 14C and 3H within the South African Development Community (SADC) region. Spatial datasets of carbonate bearing lithology, C3/C4 vegetation, summer/winter rainfall and coastal proximity were used to apply corrections to 14C and 3H data. Corrected values of 14C and 3H were compared with the theoretical abundance of these tracers, derived from the lumped parameter models, to estimate the general mean residence times and presence of groundwater mixing between modern recharge and older groundwaters. This study found that corrected values produced varying mean residence times derived from 14C ages (∼500–28500 years) and a wide range of potentially mixed waters within each aquifer system (0–100 % of tested wells) across the study area. The largest proportions of mixed groundwater, as well as the youngest mean residence times, were found in alluvial and primary fractured rock aquifers (e.g., western coast of South Africa and southern Mozambique). The smallest proportions of mixed groundwater were predicted in deep confined clay-rich aquifers as well as layered coal bearing carbonate sequences (e.g., Orapa, Malwewe and Serowe, Botswana). Insights into the proportions of mixed groundwater and mean residence times can help assess hydrological resilience on a regional scale. Such information is pertinent in promoting socio-economic development and increased water/food security in the SADC region. By understanding the resilience of groundwater resources, robust and informed strategies for water equality and GDP growth in the SADC region can be envisioned and implemented. |
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0022-1694 |
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THL @ christoph.kuells @ rooyen_using_2022 |
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94 |
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Rosen, M.R.; Burow, K.R.; Fram, M.S. |
| Title |
Anthropogenic and geologic causes of anomalously high uranium concentrations in groundwater used for drinking water supply in the southeastern San Joaquin Valley, CA |
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Journal Article |
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2019 |
Publication |
Journal of Hydrology |
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577 |
Issue |
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Pages |
124009 |
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California, Central Valley, Geochemistry, Groundwater San Joaquin Valley, Uranium |
| Abstract |
Concentrations of uranium (U) \textgreater30 µg/L in groundwater are relatively uncommon in drinking water in the United States but can be of concern in those areas where complex interactions of aquifer materials and anthropogenic alterations of the natural flow regime mobilize U. High concentrations (\textgreater30 µg/L) of U in the southeastern San Joaquin Valley, California, USA, have been detected in 24 percent of 257 domestic, irrigation, and public-supply wells sampled across an approximately 110,000 km2 area. In this study we evaluated mechanisms for mobilization of U in the San Joaquin Valley proposed in previous studies, confirming mobilization by HCO3 and refuting mobilization by NO3 and we refined our understanding of the geologic sources of U to the scale of individual alluvial fans. The location of high concentrations depends on the interactions of geological U sources from fluvial fans that originate in the Sierra Nevada to the east and seepage of irrigation water that contains high concentrations of HCO3 that leaches U from the sediments. In addition, interactions with PO4 from fertilized irrigated fields may sequester U in the aquifer. Principal component analysis of the data demonstrates that HCO3 and ions associated with high total dissolved solids in the aquifer and the percentage of agriculture near the well sampled are associated with high U concentrations. Nitrate concentrations do not appear to control release of U to the aquifer. Age dating of the groundwater and generally increasing U concentrations of the past 25 years in resampled wells where irrigation is prevalent suggests that high U concentrations are associated with younger water, indicating that irrigation of fields over the past 100 years has significantly contributed to increasing concentrations and mobilizing U. In some places, the groundwater is supersaturated with uranyl-containing minerals, as would be expected in roll front deposits. In general, the interaction of natural geological sources high in U, the anthropogenically driven addition of HCO3 and possibly phosphate fertilizer, control the location and concentration of U in each individual fluvial fan, but the addition of nitrate in fertilizer does not appear control the location of high U. These geochemical interactions are complex but can be used to determine controls on anomalously high U in alluvial aquifers. |
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THL @ christoph.kuells @ rosen_anthropogenic_2019 |
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158 |
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