Hydrologeological and Hydrological Conditions of Dakhla Oasis

Author(s):  
Salwa F. Elbeih ◽  
Elsayed A. Zaghloul
Author(s):  
G.V. Sharukho ◽  
K.G. Oleynik ◽  
Yu.I. Raspopova ◽  
M.Yu. Zolotareva

The experience in ensuring a stable sanitary and epidemiological situationon the territory of 10 municipalities of Tyumen regionunder the aggravation of hydrological conditions in 2016 is provided. The importance of interdepartmental cooperation in ensuring sanitary and epidemiological well-being under conditions of flooding-elimination is revealed.


2016 ◽  
Vol 33 (3) ◽  
Author(s):  
Eduardo M.S. Amarante ◽  
Olivar A.L. de Lima ◽  
Susana S. Cavalcanti

ABSTRACT. To investigate the subsurface geological and hydrological conditions around the area of the Alagoinhas county cemetery – Bahia State, Brazil, 38 vertical electrical soundings using Schlumberger electrode array were performed to a maximum AB/2 spacing... RESUMO. Para investigar as condições geológicas e hidrológicas da subsuperfície na área do entorno do Cemitério Municipal de Alagoinhas, Bahia, foram realizadas 38 sondagens elétricas verticais centradas em pontos acessíveis da área. As sondagens foram...


2016 ◽  
Vol 155 (3) ◽  
pp. 729-746 ◽  
Author(s):  
SHERIF FAROUK ◽  
SREEPAT JAIN

AbstractThe Maastrichtian–Danian benthic foraminiferal diversity and assemblages through sequence stratigraphy were studied at Dakhla Oasis, Egypt. Benthic foraminifera numbers (BFN), high-flux species and characteristic benthic foraminiferal species and genera distribution are also incorporated to assess palaeobathymetry, palaeoenvironment and palaeoproductivity. All these proxies are then taken together to construct a sea-level curve and interpreted in terms of regional tectonics, climate and eustasy. Data suggest a remarkably highly equitable benthic environment deposited in a brackish littoral and/or marsh setting with moderate (?) to low oxygen conditions and reduced salinity (oligotrophic), possibly due to increased precipitation and terrestrial runoff. The interrupted dominance of calcareous forms and high-organic-flux species suggests occasional marine incursions and high palaeoproductivity, due to local upwelling. The inferred sea-level curve replicates the global eustatic curve and suggests that the curve is more influenced by the prevailing climate and global eustasy rather than by regional tectonics. The post-Cretaceous–Palaeogene boundary displays improvement in the environment in terms of diversity and number of species and specimens, with a marked reduction in the abundance of high-organic-flux species during early Paleocene (Danian) time, indicating a shift from a more mesotrophic open marine environment to much reduced oligotrophic conditions.


Eos ◽  
2013 ◽  
Vol 94 (51) ◽  
pp. 504-504
Author(s):  
Ernie Balcerak

2000 ◽  
Vol 14 (2) ◽  
pp. 195-214 ◽  
Author(s):  
Shelagh Yanni ◽  
Kevin Keys ◽  
Fan-Rui Meng ◽  
Xiwei Yin ◽  
Tom Clair ◽  
...  

2021 ◽  
Author(s):  
Steffen Birk ◽  
Johannes Haas ◽  
Alice Retter ◽  
Raoul Collenteur ◽  
Heike Brielmann ◽  
...  

<p>An integrative interdisciplinary approach is currently developed to investigate groundwater systems in alpine and prealpine environments and how they respond to hydrological extremes such as droughts, heavy rain and floods in terms of water quantity, hydrochemical quality, and ecological status. The new approach is aimed at improving the understanding of the interaction between physical, chemical, and biological processes in groundwater responses to extreme events as well as developing indicators suitable for an integrative monitoring and management of the aquifers. For this purpose, observation wells of the existing state hydrographic monitoring net have been selected within the Austrian part of the Mur river basin, stretching from the alpine origin to the national border in the foreland. The investigation area thus comprises diverse hydrogeological settings and land-use types. The selected observation wells have long-term records of groundwater levels and are used for sampling campaigns under different hydrological conditions. Groundwater level fluctuations are evaluated using drought indices and statistical approaches, such as auto-correlation and cross-correlation with precipitation and stream stages. Our hydrochemical analyses of groundwater and surface waters also consider compounds indicative of agricultural sources (e.g., nitrate), wastewater-borne micro-pollutants, and stable isotopes of water. These indicators are used to identify different drivers controlling water origin and quality. The ecological status is characterized using microbiological measures, such as total number of bacteria and microbial activity, groundwater fauna, and the qualitative composition of dissolved organic matter (DOM). First results demonstrate a deterioration of water quality from groundwater to surface water and from the alpine region towards the foreland, corresponding to the more intense agricultural and urban land use in the foreland. Linkages between water quality and hydrological conditions are currently being evaluated and will be further examined using UV-Vis spectrometry for high-resolution in-situ monitoring of water quality changes (DOM and nitrate) at selected observation wells.</p>


2021 ◽  
Author(s):  
Wei Wang ◽  
Yunzhong Shen ◽  
Fengwei Wang ◽  
Weiwei Li

<p>Climate change has led to increased droughts and floods over mainland Australia, resulting in water scarcity, excessive surplus and socioeconomic losses. Therefore, it is of great significance to comprehensively evaluate droughts and floods from the meteorological and hydrological perspective. Firstly, we determine the Standard Precipitation and Evapotranspiration Index (SPEI) by correlation analysis to represent the meteorological conditions. To characterize the hydrological conditions, we calculate the hydrological drought indices including Standard Runoff Index (SRI), Soil Moisture Deficit Index (SMDI), and Total Storage Deficit Index (TSDI), using the runoff and soil moisture data from the Global Land Data Assimilation System (GLDAS) and the Terrestrial Water Storage Change (TWSC) data from Gravity Recovery And Climate Experiment (GRACE) respectively. Results show that the most severe hydrological drought over mainland Australia during the study period occurred from May 2006 to Jan. 2009 with the drought severity of -58.28 (cm months) and the most severe flood from Jun. 2010 to Jan. 2013 is with the severity of 151.36 (cm months). The comprehensive analysis of both meteorological and hydrological drought indices shows that both meteorological and hydrological drought indices can effectively detect the droughts and floods over mainland Australia. Moreover, the meteorological drought and flood are of higher frequency, while hydrological drought and flood have a relatively longer duration. Based on the cross-correlation analysis, we find that the SPEI can firstly reflect the droughts or floods over mainland Australia, and then the SRI, SMDI and TSDI reflect with the time lags of one, three and six months respectively. Furthermore, we calculate the frequency of drought and flood at the basin scale and find that SPEI and SMDI are equally sensitive to drought and flood, while TSDI is more sensitive to flood than drought. This study reveals the relationship between meteorological and hydrological conditions in mainland Australia in the last two decades and highlights its intensifying extreme climate conditions under the circumstances of the increasing temperature and complex changing precipitation.</p>


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