A simple and efficient approach to predict reservoir settling volume: case study of Bin El Ouidane reservoir (Morocco)

The negligence of the cumulative deposit volume over years may lead to uselessness of a pre-established and efficient reservoir management method. In this objective, this paper tries to introduce a simple approach to forecast annually the volume lost from the reservoir capacity. The suggested approach employs the modified universal soil loss equation (MUSLE) and the Dendy and Bolton (J Soil Water Conserv 31:264–266, 1976) methods, in addition to the sediment consolidation process. This process permits to follow the evolution of sediment deposit volume throughout the years. For application, we selected the reservoir of Bin El Ouidane (Morocco), for which we have tried to fit a linear regression between sediment yield and observed settling volumes. The optimization process was assured by the algorithm genetic and the OptQuest methods. The results show a high significant (R²?=?0.9513, RMSE?=?8.5428, and p value?=?0.0009) linear regression between cumulative sediment yield volume and accumulated measured lost volume from the reservoir of Bin El Ouidane. The use of a linear relation is justified by the fact that all nonlinear regressions in long term are composed of multiple linear regressions in short term. Nevertheless, this method can become more efficient, and confirmed for real forecasting applications by performing modifications essentially related to in situ measures of different variables. Finally, and considering its simplicity regarding input data and application, the proposed approach converges to efficient results. Therefore, and after validation in other reservoirs, this method can be used to forecast annual reservoir settling at short term.     

Sugarcane waste straw biochar and its effects on calcareous soil and agronomic traits of okra

Biochar has been considered a safe soil additive to enhance soil fertility and agronomic traits of different crops. This study was conducted to explore the impacts of sugarcane waste straw biochar on soil characteristics and some agronomic traits of okra. The experiment was carried out with four treatments, i.e., control, sugarcane waste straw biochar (10 ton ha^?1), farmyard manure (FYM, 10 ton ha^?1), and chemical fertilizers (NPK; 120:100:80 kg ha^?1) having three replications of each treatment. Soil samples were tested for texture, bulk density, particle density, pH, electrical conductivity (EC), organic matter content, nitrate nitrogen (NO₃-N), and extractable-P. The sugarcane waste straw biochar was characterized for plant major nutrient elements. The impact of various treatments was observed on soils and agronomic traits of okra like plant height, fruit size, fruit length, and yield of okra. Results revealed that sugarcane waste straw biochar expressed higher EC value and noticeable amounts of nitrogen (N), phosphorus (P), potassium (K), sulfur (S), and magnesium (Mg). The sugarcane waste straw biochar, in comparison with FYM and NPK, significantly improved the NO₃-N, extractable-P, OM and EC of the calcareous soil, and reduced the soil bulk density. Furthermore, plant growth and yield parameters were significantly improved under biochar application over the control, FYM and NPK. Overall, sugarcane waste straw biochar proved to be a good alternative to conventional organic and inorganic fertilizers under calcareous soil conditions.     

Fingerprinting groundwater salinity sources in the Gulf Coast Aquifer System,USA

Understanding groundwater salinity sources in the Gulf Coast Aquifer System (GCAS) is a critical issue due to depletion of fresh groundwater and concerns for potential seawater intrusion. The study objective was to assess sources of groundwater salinity in the GCAS using ～1,400 chemical analyses and ～90 isotopic analyses along nine well transects in the Texas Gulf Coast, USA. Salinity increases from northeast (median total dissolved solids (TDS) 340 mg/L) to southwest (median TDS 1,160 mg/L), which inversely correlates with the precipitation distribution pattern (1,370– 600 mm/yr, respectively). Molar Cl/Br ratios (median 540–600), depleted δ²H and δ¹⁸O (?24.7‰, ?4.5‰) relative to seawater (Cl/Br ～655 and δ²H, δ¹⁸O 0‰, 0‰, respectively), and elevated ³⁶Cl/Cl ratios (～100), suggest precipitation enriched with marine aerosols as the dominant salinity source. Mass balance estimates suggest that marine aerosols could adequately explain salt loading over the large expanse of the GCAS. Evapotranspiration enrichment to the southwest is supported by elevated chloride concentrations in soil profiles and higher δ¹⁸O. Secondary salinity sources include dissolution of salt domes or upwelling brines from geopressured zones along growth faults, mainly near the coast in the northeast. The regional extent and large quantities of brackish water have the potential to support moderate-sized desalination plants in this location. These results have important implications for groundwater management, suggesting a current lack of regional seawater intrusion and a suitable source of relatively low TDS water for desalination.     

Mineral chemistry and geochemistry of ophiolitic metaultramafics from Um Halham and Fawakhir,Central Eastern Desert,Egypt

International Journal of Earth Sciences - This study is focused on ophiolitic metaultramafics from Um Halham and Fawakhir, Central Eastern Desert of Egypt. The rocks include serpentinized...     

Moho depth determination beneath the Zagros Mountains from 3D inversion of gravity data

Due to its geological and economic importance, the Zagros Mountains have been investigated by many researchers during the last decades. Nevertheless, in spite of all the studies conducted on the region, there are still some controversial problems concerning the structure of the Zagros Mountains, including crustal depths, demanding more insights into understanding the crustal constraints of the region. Accordingly, we have conducted a gravity study to determine Moho depth map of the Zagros Mountains region, including its major structural domains from the coastal plain of the Persian Gulf to central Iran. The employed data are the densest and most accurate terrestrial gravity data set observed until now with the precision of 5 μGal and resolution of 5 arc-minute by 5 arc-minute. To image Moho depth variations, gravity inversion software GROWTH2.0 is used, proposing the possibility to model stratified structures by means of a semi-objective exploratory 3D inversion approach. The obtained results reveal the crustal thickness of ~?30–35 km underneath the southwestern most Zagros Fold-Thrust Belt increasing northeastward to 48 km. The maximum Moho depth is estimated ~?62 km below the Zagros Mountains belt along the Main Zagros Thrust. Northeast of the study area, an average crustal thickness of 46 km is computed beneath Urumieh–Dokhtar magmatic arc and central Iran.     

Delineation of potential recharge area using a hybrid model,case of Djelfa Hadjia watershed

Groundwater potential map is important for environmental assessment and water resources management. In this work, a groundwater recharge potential map was established for the watershed of Oued Djelfa Hadjia in Algeria, based on new multiparameters hybrid model. The model has hydroclimatic parameters, geological settings, slope factor, and stream network density factor as inputs. The groundwater recharge estimated by the model range from 0.71 to 14 mm. The model allows delineation of potential area of recharge. The total water abstraction in Djelfa city is about of 14 hm³; however, the calculated groundwater recharge is about 3 mm/year (min 0.71 mm and max 14 mm), which correspond to an average recharge volume of 3.9 hm³ which mean that the aquifer is under over exploitation.     

Characteristics of turbulence over the semi-fixed desert area north of Xinjiang,China

As the largest fixed and semi-fixed desert in China, the Gurbantünggüt Desert undergoes a long period of snow cover in the winter and the rapid growth of ephemeral plants in the spring, presenting obvious seasonal changes in the underlying desert surface type, which can lead to variation in the turbulence of the near-surface boundary layer turbulence over the desert. In this study, gradient tower data and eddy covariance data from 2017 were analysed to investigate the turbulence characteristics of the different surface boundary layers in the hinterland of the Gurbantünggüt Desert. The results indicate that stable atmospheric conditions in the desert occur exclusively during the early morning and at night in the desert, and the onset and duration of this stable state varies seasonally. Two regimes of intermittent turbulence occur during the night, a weak turbulent regime that occurs when the wind speed is less than the threshold and a strong turbulent regime when the wind speed exceeds the threshold, and different wind speed thresholds were observed at each level. These parameters follow a seasonal pattern of summer (July) > spring (April) > autumn (October) > winter (January) in terms of magnitude. The mean turbulence intensities of the along-wind, cross-wind and vertical wind are 0.5, 0.47 and 0.14, respectively, with I_u > I_v > I_w. The normalized standard deviation of the wind velocity components (σ_u, σ_v and σ_w) generally satisfies a 1/3 power-law relation. Our results show that the night-time turbulence regime classification for the Gurbantünggüt Desert strongly depends on meteorological and orographic features, and the intermittent turbulent events have the non-stationarity of the flow in common. The results can contribute to the study of land surface processes, climate change and desertification in inland arid desert areas.     

Chronology of late quaternary glaciations in Indian Himalaya: A critical review

The timing of glaciation is an important parameter that helps in the understanding of past climate change and provides valuable information for developing the predictive futuristic models. There are evidences to suggest that during the late Quaternary, Himalayan glaciers fluctuated considerably thus implying their sensitivity to changes in past climatic conditions. Although the Himalayan region is fed by two major weather systems viz. the southwest summer monsoon and the mid-latitude westerlies, however, the existing chronology (mostly exposure ages) indicates that irrespective of the geographical position, glaciers seem to grow during increased insolation and enhanced southwest summer monsoon including the mid-latitude westerly dominated north-western Himalayan glaciers (Ladakh and Karakoram). Considering the limited geographical coverage and the dating uncertainty, the above inferences should be treated as tentative.