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Monitoring runoff coefficients and groundwater levels using data from GRACE, GLDAS, and hydrometeorological stations: analysis of a Colombian foreland basin | Suivi des coefficients de ruissellement et des niveaux piézométriques en utilisant les données de GRACE, GLDAS et des stations hydrométéorologiques: étude d’un bassin d’avant-pays colombien Monitoreo de coeficientes de escorrentía y niveles de agua subterránea utilizando datos de GRACE, GLDAS y estaciones hidrometeorológicas: análisis de una cuenca de antepaís colombiana 采用重力恢复和气候实验数据、全球大地数据同化系统数据以及水文气象站等数据监测径流系数:哥伦比亚沿海地区平原的分析 Monitoramento dos coeficientes de escoamento superficial e níveis das águas subterrâneas, utilizando dados do GRACE, GLDAS e estações hidrometeorológicas: análise de uma bacia de ante-país Colombiana Texte intégral
2018
Ospina M., Diana L. | Vargas J., Carlos A.
The determination of space–time variation in groundwater accumulation in Colombia’s Eastern Llanos foreland basin from 2003 to 2014 was done using terrestrial water storage (TWS) anomalies identified in two versions of the Gravity Recovery and Climate Experiment (GRACE) data—from the Global Data Center for Space Research (CSR) at the University of Texas at Austin (USA) and from the Institute of Geodesy at the Graz University of Technology (ITSG, Austria)—and also soil moisture storage (SMS) data from the Global Land Data Assimilation System (GLDAS). These data were compared to changes in groundwater storage obtained using the water-budget equation, calculated based on recorded data from hydrometeorological stations. This study confirmed the viability of using satellite information to understand and monitor temporal variation in groundwater recharge in the study area. Temporal variations in TWS, SMS, and groundwater level were shown to correspond to regional rain and drought periods, which are sensitive to climate phenomena such as El Niño and La Niña. Comparing changes in TWS and groundwater level to changes in infiltration and recharge revealed correlation coefficients of 0.56 and 0.98 with CSR data and 0.71 and 0.86 with ITSG data, respectively.
Afficher plus [+] Moins [-]Seasonal variability of oxygen and hydrogen isotopes in a wetland system of the Yunnan-Guizhou Plateau, southwest China: a quantitative assessment of groundwater inflow fluxes | Variabilité saisonnière des isotopes de l’oxygène et de l’hydrogène dans un système de zones humides du Plateau de Guizhou au Yunnan, dans le sud-ouest de la Chine: une évaluation quantitative des flux des apports des eaux souterraines Variabilidad estacional de isótopos de oxígeno e hidrógeno en un sistema de humedales de la meseta de Yunnan Guizhou, suroeste de China: una evaluación cuantitativa de los flujos de entrada del agua subterránea 中国西南部云贵高原一个湿地系统氧氢同位素的季节性变化:地下水流入通量定量评价 Variação sazonal de isótopos de oxigênio e hidrogênio em um sistema de área úmida no planalto de Yunnan Guizhou, sudoeste da China: uma avaliação quantitativa do fluxo de recarga de águas subterrâneas Texte intégral
2018
Cao, Xingxing | Wu, Pan | Zhou, Shaoqi | Han, Zhiwei | Tu, Han | Zhang, Shui
The Caohai Wetland serves as an important ecosystem on the Yunnan–Guizhou Plateau and as a nationally important nature reserve for migratory birds in China. In this study, surface water, groundwater and wetland water were collected for the measurement of environmental isotopes to reveal the seasonal variability of oxygen and hydrogen isotopes (δ¹⁸O, δD), sources of water, and groundwater inflow fluxes. Results showed that surface water and groundwater are of meteoric origin. The isotopes in samples of wetland water were well mixed vertically in seasons of both high-flow (September) and low-flow (April); however, marked seasonal and spatial variations were observed. During the high-flow season, the isotopic composition in surface wetland water varied from −97.13 to −41.73‰ for δD and from −13.17 to −4.70‰ for δ¹⁸O. The composition of stable isotopes in the eastern region of this wetland was lower than in the western region. These may have been influenced by uneven evaporation caused by the distribution of aquatic vegetation. During the low-flow season, δD and δ¹⁸O in the more open water with dead aquatic vegetation ranged from −37.11 to −11.77‰, and from −4.25 to −0.08‰, respectively. This may result from high evaporation rates in this season with the lowest atmospheric humidity. Groundwater fluxes were calculated by mass transfer and isotope mass balance approaches, suggesting that the water sources of the Caohai Wetland were mainly from groundwater in the high-flow season, while the groundwater has a smaller contribution to wetland water during the low-flow season.
Afficher plus [+] Moins [-]Application of multiple-isotope and groundwater-age data to identify factors affecting the extent of denitrification in a shallow aquifer near a river in South Korea | Application d’un traçage multi-isotopique et de lal datation des eaux souterraines pour identifier l’extension de la dénitrification dans un aquifère superficiel près d’une rivière, en Corée du Sud Aplicación de datos de isótopos múltiples y de edad del agua subterránea para identificar los factores que afectan el grado de desnitrificación en un acuífero poco profundo cerca de un río en Corea del Sur 利用多个同位素和地下水年龄数据确定影响南韩一条河流附近浅层含水层反硝化程度的因素 Aplicação de dados de multi-isótopicos e de datação de águas subterrâneas para identificar fatores que afetam a extensão da desnitrificação em um aquífero raso nas proximidades de um rio na Coréia do Sul Texte intégral
2018
Kaown, Dugin | Koh, Eun-Hee | Mayer, Bernhard | Kim, Heejung | Pak, Tong-gyu | Park, Byeong-Hak | Lee, Kang-Kun
The extent of denitrification in a small agricultural area near a river in Yangpyeong, South Korea, was determined using multiple isotopes, groundwater age, and physicochemical data for groundwater. The shallow groundwater at one monitoring site had high concentrations of NO₃-N (74–83 mg L⁻¹). The δ¹⁵N-NO₃ values for groundwater in the study area ranged between +9.1 and +24.6‰ in June 2014 and +12.2 to +21.6‰ in October 2014. High δ¹⁵N-NO₃ values (+10.7 to +12.5‰) in both sampling periods indicated that the high concentrations of nitrate in the groundwater originated from application of organic fertilizers and manure. In the northern part of the study area, some groundwater samples showed elevated δ¹⁵N-NO₃ and δ¹⁸O-NO₃ values, which suggest that nitrate was removed from the groundwater via denitrification, with N isotope enrichment factors ranging between −4.8 and −7.9‰ and O isotope enrichment factors varying between −3.8 and −4.9‰. Similar δD and δ¹⁸O values of the surface water and groundwater in the south appear to indicate that groundwater in that area was affected by surface-water infiltration. The mean residence times (MRTs) of groundwater showed younger ages in the south (10–20 years) than in the north (20–30 years). Hence, it was concluded that denitrification processes under anaerobic conditions with longer groundwater MRT in the northern part of the study area removed considerable amounts of nitrate. This study demonstrates that multi-isotope data combined with physicochemical data and age-dating information can be effectively applied to characterize nitrate contaminant sources and attenuation processes.
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