| Records |
| Author |
Christofi, C.; Bruggeman, A.; Külls, C.; Constantinou, C. |
| Title |
Isotope hydrology and hydrogeochemical modeling of Troodos Fractured Aquifer, Cyprus: The development of hydrogeological descriptions of observed water types |
Type |
Journal Article |
| Year |
2020 |
Publication |
Applied Geochemistry |
Abbreviated Journal |
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| Volume |
123 |
Issue |
|
Pages |
104780 |
| Keywords |
Isotope hydrology, Hydrogeochemical modelling, Hydrochemistry, Kargiotis, Troodos |
| Abstract |
The origin of groundwater recharge and subsequent flow paths are often difficult to establish in fractured, multi-lithological, and highly compartmentalized aquifers such as the Troodos Fractured Aquifer (TFA). As the conjunctive use of stable isotopes and hydrogeochemical data provides additional information, we established a monitoring network for stable isotopes in precipitation in Cyprus. The local meteoric water line, altitude effect and seasonal variation of stable isotopes in precipitation are derived from monitoring data. Stable isotopes and hydrogeochemical data are combined to model water-rock interactions and groundwater evolution along a complete ophiolite sequence. As a result a generic hydrogeologic description for the observed water types is developed. Isotope hydrology was applied in conjunction with hydrogeochemical modelling in Kargiotis Watershed, a major north-south transect of the TFA. PHREEQC was used for hydrogeochemical modelling to establish generic descriptions for observed water types. Mean precipitation-weighted values from 16 monitoring stations were used to calculate the Local Meteoric Water Line (LMWL), which was found to be equal to δ2H = (6.58 ± 0.13)*δ18O + (12.64 ± 0.91). A general decrease of 1.22‰ for δ2H and 0.20‰ for δ18O in precipitation was calculated per 100 m altitude. A generic groundwater evolution path was established: 1. Na/MgClHCO3, 2. MgHCO3, 3. Ca/MgHCO3, 4. Ca/MgNaHCO3, 4a. MgNa/CaHCO3/Cl, 5. NaMg/CaHCO3/Cl, 6. NaHCO3, 7. Na/MgHCO3SO4, 8. NaSO4Cl/HCO3. Hydrogeologic descriptions, consisting of groundwater origin, flow path and possible active water-rock processes, have been realised for the observed water types. The first two water types occur in serpentine and ultramafic-gabbro springs. Type 3 waters represent early stages of recharge and/or short flow paths, in gabbro whereas types 4 and 5 are typical for further percolating waters in gabbro and diabase. Water types 6 and 7 occur both in diabase and in the basal group and represent the regional flow. Water type 8 is the end member of regional, upwelling groundwater in the basal group. The presented descriptions and methods have practical applications in groundwater exploration, characterization, and protection. The methodology can be applied in other complex aquifer systems. |
| Address |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
english |
Summary Language |
english |
Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0883-2927 |
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| Area |
Cyprus |
Expedition |
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Conference  |
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| Notes |
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Approved |
no |
| Call Number |
THL @ christoph.kuells @ Christofi2020104780 |
Serial |
76 |
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| Author |
Eliades, M.; Bruggeman, A.; Djuma, H.; Christofi, C.; Kuells, C. |
| Title |
Quantifying Evapotranspiration and Drainage Losses in a Semi-Arid Nectarine (Prunus persica var. nucipersica) Field with a Dynamic Crop Coefficient (Kc) Derived from Leaf Area Index Measurements |
Type |
Journal Article |
| Year |
2022 |
Publication |
Water |
Abbreviated Journal |
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| Volume |
14 |
Issue |
5 |
Pages |
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| Keywords |
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| Abstract |
Quantifying evapotranspiration and drainage losses is essential for improving irrigation efficiency. The FAO-56 is the most popular method for computing crop evapotranspiration. There is, however, a need for locally derived crop coefficients (Kc) with a high temporal resolution to reduce errors in the water balance. The aim of this paper is to introduce a dynamic Kc approach, based on Leaf Area Index (LAI) observations, for improving water balance computations. Soil moisture and meteorological data were collected in a terraced nectarine (Prunus persica var. nucipersica) orchard in Cyprus, from 22 March 2019 to 18 November 2021. The Kc was derived as a function of the canopy cover fraction (c), from biweekly in situ LAI measurements. The use of a dynamic Kc resulted in Kc estimates with a bias of 17 mm and a mean absolute error of 0.8 mm. Evapotranspiration (ET) ranged from 41% of the rainfall (P) and irrigation (I) in the wet year (2019) to 57% of P + I in the dry year (2021). Drainage losses from irrigation (DR_I) were 44% of the total irrigation. The irrigation efficiency in the nectarine field could be improved by reducing irrigation amounts and increasing the irrigation frequency. Future studies should focus on improving the dynamic Kc approach by linking LAI field observations with remote sensing observations and by adding ground cover observations. |
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Place of Publication |
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Summary Language |
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Original Title |
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| Series Editor |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
2073-4441 |
ISBN |
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| Notes |
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Approved |
no |
| Call Number |
THL @ christoph.kuells @ Marinos2022 |
Serial |
82 |
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| Author |
Emparanza, A.R.; Kampmann, R.; Caso, F.D.; Morales, C.; Nanni, A. |
| Title |
Durability assessment of GFRP rebars in marine environments |
Type |
Journal Article |
| Year |
2022 |
Publication |
Construction and Building Materials |
Abbreviated Journal |
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| Volume |
329 |
Issue |
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Pages |
127028 |
| Keywords |
Composite FRP rebar, Durability, Service life, Marine structures, Reinforced concrete |
| Abstract |
Technologies developed over the last two decades have facilitated the use of glass fiber reinforced polymer (GFRP) bars as internal reinforcement for concrete structures, specially in coastal environments, mainly due to their corrosion resistance. To-date, most durability studies have focused on a single mechanical parameter (tensile strength) and a single aging environment (exposure to high alkalinity). However, knowledge gaps exists in understanding how other mechanical parameters and relevant conditioning environments may affect the durability of GFRP bars. To this end, this study assesses the durability for different physio-mechanical properties of GFRP rebars, post exposure to accelerated conditioning in seawater. Six different GFRP rebar types were submerged in seawater tanks, at various temperatures (23°C, 40°C and 60°C) for different time periods (60, 120, 210 and 365 days). In total six different physio-mechanical properties were assessed, including: tensile strength, E-modulus, transverse and horizontal shear strength, micro-structural composition and lastly, bond strength. It was inferred that rebars with high moisture absorption resulted in poor durability, in that it affected mainly the tensile strength. Based on the Arrhenius model, at 23°C all the rebars that met the acceptance criteria by ASTM D7957 are expected to retain 85% of the tensile strength capacity. |
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Edition |
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| ISSN |
0950-0618 |
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| Notes |
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Approved |
no |
| Call Number |
THL @ christoph.kuells @ Ruizemparanza2022127028 |
Serial |
83 |
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| Author |
Eliades, M.; Bruggeman, A.; Djuma, H.; Christofi, C.; Kuells, C. |
| Title |
Quantifying Evapotranspiration and Drainage Losses in a Semi-Arid Nectarine (Prunus persica var. nucipersica) Field with a Dynamic Crop Coefficient (Kc) Derived from Leaf Area Index Measurements |
Type |
Journal Article |
| Year |
2022 |
Publication |
Water |
Abbreviated Journal |
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| Volume |
14 |
Issue |
5 |
Pages |
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| Keywords |
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| Abstract |
Quantifying evapotranspiration and drainage losses is essential for improving irrigation efficiency. The FAO-56 is the most popular method for computing crop evapotranspiration. There is, however, a need for locally derived crop coefficients (Kc) with a high temporal resolution to reduce errors in the water balance. The aim of this paper is to introduce a dynamic Kc approach, based on Leaf Area Index (LAI) observations, for improving water balance computations. Soil moisture and meteorological data were collected in a terraced nectarine (Prunus persica var. nucipersica) orchard in Cyprus, from 22 March 2019 to 18 November 2021. The Kc was derived as a function of the canopy cover fraction (c), from biweekly in situ LAI measurements. The use of a dynamic Kc resulted in Kc estimates with a bias of 17 mm and a mean absolute error of 0.8 mm. Evapotranspiration (ET) ranged from 41% of the rainfall (P) and irrigation (I) in the wet year (2019) to 57% of P + I in the dry year (2021). Drainage losses from irrigation (DR_I) were 44% of the total irrigation. The irrigation efficiency in the nectarine field could be improved by reducing irrigation amounts and increasing the irrigation frequency. Future studies should focus on improving the dynamic Kc approach by linking LAI field observations with remote sensing observations and by adding ground cover observations. |
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Abbreviated Series Title |
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Edition |
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| ISSN |
2073-4441 |
ISBN |
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Expedition |
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Conference |
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| Notes |
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Approved |
no |
| Call Number |
THL @ christoph.kuells @ w14050734 |
Serial |
81 |
| Permanent link to this record |
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| Author |
Eliades, M.; Bruggeman, A.; Djuma, H.; Christofi, C.; Kuells, C. |
| Title |
Quantifying Evapotranspiration and Drainage Losses in a Semi-Arid Nectarine (Prunus persica var. nucipersica) Field with a Dynamic Crop Coefficient (Kc) Derived from Leaf Area Index Measurements |
Type |
Journal Article |
| Year |
2022 |
Publication |
Water |
Abbreviated Journal |
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| Volume |
14 |
Issue |
5 |
Pages |
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| Keywords |
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| Abstract |
Quantifying evapotranspiration and drainage losses is essential for improving irrigation efficiency. The FAO-56 is the most popular method for computing crop evapotranspiration. There is, however, a need for locally derived crop coefficients (Kc) with a high temporal resolution to reduce errors in the water balance. The aim of this paper is to introduce a dynamic Kc approach, based on Leaf Area Index (LAI) observations, for improving water balance computations. Soil moisture and meteorological data were collected in a terraced nectarine (Prunus persica var. nucipersica) orchard in Cyprus, from 22 March 2019 to 18 November 2021. The Kc was derived as a function of the canopy cover fraction (c), from biweekly in situ LAI measurements. The use of a dynamic Kc resulted in Kc estimates with a bias of 17 mm and a mean absolute error of 0.8 mm. Evapotranspiration (ET) ranged from 41% of the rainfall (P) and irrigation (I) in the wet year (2019) to 57% of P + I in the dry year (2021). Drainage losses from irrigation (DR_I) were 44% of the total irrigation. The irrigation efficiency in the nectarine field could be improved by reducing irrigation amounts and increasing the irrigation frequency. Future studies should focus on improving the dynamic Kc approach by linking LAI field observations with remote sensing observations and by adding ground cover observations. |
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Edition |
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| ISSN |
2073-4441 |
ISBN |
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| Notes |
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Approved |
no |
| Call Number |
THL @ christoph.kuells @ w14050734 |
Serial |
85 |
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| Author |
Ola, I.; Drebenstedt, C.; Burgess, R.M.; Mensah, M.; Hoth, N.; Okoroafor, P.; Külls, C. |
| Title |
Assessing petroleum contamination in parts of the Niger Delta based on a sub-catchment delineated field assessment |
Type |
Journal Article |
| Year |
2024 |
Publication |
Environmental Monitoring and Assessment |
Abbreviated Journal |
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| Volume |
196 |
Issue |
6 |
Pages |
585 |
| Keywords |
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| Abstract |
The Niger Delta in Nigeria is a complex and heavily contaminated area with over 150,000 interconnected contaminated sites. This intricate issue is compounded by the region’s strong hydrological processes and high-energy environment, necessitating a science-based approach for effective contamination assessment and management. This study introduces the concept of sub-catchment contamination assessment and management, providing an overarching perspective rather than addressing each site individually. A description of the sub-catchment delineation process using the digital elevation model data from an impacted area within the Delta is provided. Additionally, the contamination status from the delineated sub-catchment is reported. Sediment, surface water and groundwater samples from the sub-catchment were analyzed for total petroleum hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAHs), respectively. Surface sediment TPH concentrations ranged from 129 to 20,600 mg/kg, with subsurface (2-m depth) concentrations from 15.5 to 729 mg/kg. PAHs in surface and subsurface sediment reached 9.55 mg/kg and 0.46 mg/kg, respectively. Surface water exhibited TPH concentrations from 10 to 620 mg/L, while PAHs ranged from below detection limits to 1 mg/L. Groundwater TPH concentrations spanned 3 to 473 mg/L, with total PAHs varying from below detection limits to 0.28 mg/L. These elevated TPH and PAH levels indicate extensive petroleum contamination in the investigated sediment and water environment. Along with severe impacts on large areas of mangroves and wetlands, comparison of TPH and PAH concentrations with sediment and water quality criteria found 54 to 100% of stations demonstrated exceedances, suggesting adverse biological effects on aquatic and sediment biota are likely occurring. |
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1573-2959 |
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Approved |
no |
| Call Number |
THL @ christoph.kuells @ Ola2024 |
Serial |
290 |
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| Author |
Külls, C.H.; Eichinger, F.; Fader, H.J.; Leistert, H.; Lorenz, G.; Szakacs, E. |
| Title |
New Environmental Analytical Techniques to Monitor Carbon Sequestration |
Type |
Conference Article |
| Year |
2011 |
Publication |
1st EAGE Sustainable Earth Sciences (SES) Conference and Exhibition |
Abbreviated Journal |
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Issue |
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Pages |
268 |
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Conference |
European Association of Geoscientists & Engineers |
| Notes |
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Approved |
no |
| Call Number |
THL @ christoph.kuells @ Kuells2011new |
Serial |
47 |
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| Author |
Külls, C. |
| Title |
Resolving patterns of groundwater flow by inverse hydrochemical modelling in a semiarid Kalahari |
Type |
Conference Article |
| Year |
2000 |
Publication |
Tracers and Modelling in Hydrogeology: TraM’2000: Proceedings of TraM’2000, the International Conference on Tracers and Modelling in Hydrogeology Held at Liège, Belgium, in May 2000 |
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Issue |
262 |
Pages |
447 |
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IAHS Press |
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no |
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THL @ christoph.kuells @ Kuells2000resolving |
Serial |
62 |
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| Author |
Klock, H.; Külls, C.; Udluft, P. |
| Title |
Estimating recharge values using hydrochemical and geological data: a case study from the |
Type |
Conference Article |
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2001 |
Publication |
Impact of Human Activity on Groundwater Dynamics: Proceedings of an International Symposium (Symposium S3) Held During the Sixth Scientific Assembly of the International Association of Hydrological Sciences (IAHS) at Maastricht, The Netherlands, from 18 t |
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Issue |
269 |
Pages |
25 |
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International Assn of Hydrological Sciences |
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no |
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THL @ christoph.kuells @ Klock2001estimating |
Serial |
60 |
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| Author |
Grodek, T.; Enzel, Y.; Morin, E.; Jacoby, Y.; Dahan, O.; Benito, G.; Kulls, C.; Geller, A.; Van Langenhove, G.; Seely, M. |
| Title |
Flood hydrology, flood routing, paleohydrology and the estimation of water resources along the shallow alluvial aquifers of the Kuiseb River, Namibia |
Type |
Conference Article |
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2008 |
Publication |
Abstracts – Israel Geological Society |
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2008 |
Issue |
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Pages |
37 |
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Israel Geological Society |
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THL @ christoph.kuells @ Grodek2008flood |
Serial |
56 |
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