Impacts of Desalinated Irrigation Water in the Abu Dhabi surficial aquifer

Author(s):  
Claudia Cherubini ◽  
Sathish Sadhasivam ◽  
Nicola Pastore ◽  
Monica Ghirotti

<p>Abu Dhabi is one of the arid regions in the world having less than 100 mm of rainfall per annum. The renewability of freshwater occurs only in the eastern part. The groundwater resources under desirable quality are very concise due to limited dilution/rainfall and higher rate of evaporation. Hence, in recent decades, desalinated water has been introduced for agriculture activities and surplus desalinated water is injected into the aquifer as artificial recharge. This study is conducted to understand the impacts in the aquifer system caused by the introduction of desalinated water for agriculture activities and for aquifer recharge structures. The simulation was carried out from 2000 to 2050 using reported rate of groundwater pumping and of desalinated water with 0.1 g/l, 0.5 g/l, 1 g/l, 1.5 g/l and 2 g/l degrees of salinity. A wide range of decline in the groundwater table is noticed in the western part of the aquifer due to less rainfall recharge. The results confirm that this region demands either reduction in agricultural activities or additional usage of desalinated water by which the pumping of groundwater can be reduced further. The improvement in the groundwater quality is noticed in the aquifer due to the addition of less saline desalinated water into the aquifer. This study confirms the long term suitability of existing aquifer recharge structure. Also, it expresses the need of further management practices in quantifying the desalinated water contribution for agriculture activities.</p><p> </p>

2020 ◽  
Author(s):  
Silvio Janetz ◽  
Christoph Jahnke ◽  
Frank Wendland ◽  
Hans-Jürgen Voigt

<p>In recent years, deep aquifers (> 50 m below ground level) have become increasingly interesting for the supply of drinking and irrigation water or geothermal use. Understanding the regional flow processes between near-surface and deep aquifer systems is an important criterion for the sustainable management of deep groundwater resources. However, hydrogeological conditions, regional flow rates and aquifer recharge in deep aquifers are largely unknown in many cases. The aims of the present study are therefore to determine (i) groundwater flow velocities in a Cenozoic multi-aquifer system, and (ii) proportion of aquifer recharge into the individual Cenozoic aquifers and timescales to completely replace water in the Cenozoic aquifers (turnover time).  </p><p>The numerical study was carried out in three adjacent groundwater catchment areas in the region of Eastern Brandenburg. In a first step, a hydrogeological 3D model of the entire Cenozoic aquifer system (85 km × 73 km and down to a depth of 0.5 km) was developed, which comprises up to 12 unconsolidated sandy aquifers and 10 confining units (glacial tills, silts and clays). In a second step, a steady-state flow modelling was performed including calibration using natural hydraulic head data from both regional main and deep aquifers.</p><p>The modeling results show that the average groundwater flow velocities decrease from 20-50 m/a in the near-surface Pleistocene main aquifers to 1-2 m/a in the deep Oligocene aquifers. At the same time, the aquifer recharge in the aquifer system decreases substantially with increasing depth. Depending on the catchment geology, the Pleistocene main aquifers are recharged by 65-70 % of infiltration water, while the aquifer recharge of the deep Oligocene aquifers is only 4.5-9.5 %. The calculations of turnover time indicate that the time periods to completely flush the deep aquifers are very long (approx. between 90 and 4600 years). The results thus allow a first quantification of the flow processes between near-surface and deep aquifers as well as the identification of flow paths to develop a utilization concept for deep groundwater resources in the region of Eastern Brandenburg.</p>


Author(s):  
Lorenzo Altissimo ◽  
Silvia Bertoldo ◽  
Francesca Campagnolo ◽  
Giancarlo Gusmaroli ◽  
Teresa Muraro ◽  
...  

In recent decades, groundwater resources of the high Vicenza plain were subjected to an increasing extraction rate and, at the same time, to a lower quantity of groundwater recharge. The result is a decreasing flow from the plain springs and a high reduction in piezometric levels of the middle and lower Venetian aquifers. In order to restore the balance of groundwater resources in the Vicenza area, the Vicenza Province has promoted experimental activities aimed to increase the recharge of the aquifer in the high Vicenza plain and in the River Agno valley, using infiltration wells, forested infiltration areas, infiltration trenches, subsurface fields and infiltration canals. All recharge plants are fed by irrigation water, managed by agricultural consortia only during periods of water surplus. Construction works were preceded by specific geological and hydrogeological investigations to verify the suitability for recharge, with the purpose of optimizing the available economic resources. For the protection of the aquifer system, a chemical background of infiltration water was assessed with periodical chemical-physical and microbiological surveys. After the activation date, a monthly monitoring program started to verify the quality of both surface and groundwater, collecting samples in monitoring wells downstream the infiltration structures. The input flow rate entering the various systems, monitored by automatic instruments either in the superficial structure and in groundwater, have provided interesting information about the volumes and the quality of water. These scientific experiences appear to be very helpful in case of future applications for other sites, especially during critical hydrologic period.


Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2853
Author(s):  
Sadhasivam Sathish ◽  
Claudia Cherubini ◽  
Nicola Pastore ◽  
Concetta I. Giasi ◽  
Dimitra Rapti

In Abu Dhabi, one of the most arid regions in the world, in recent decades, desalinated water has been identified as a prime solution in solving the water demand issues. In this study, a three-dimensional coupled density-dependent flow and solute transport model was set up in order to study the effect of the artificial recharge using desalinated water and the influence of nonconventional water with a salt concentration in the range 0.1–2 g/L The results confirm that this region demands the adoption of a more rational use of irrigation water or additional usage of desalinated water and recycled water together with optimizing groundwater pumping at locations that are vulnerable to further quality degradation and depletion. The long-term storage of desalinated freshwater with a maximum radial distance of 653 m in the dune surface is ensured with the formation of the transition zone, and change in the groundwater head up to 5 km. The maximum recovery obtained by immediate recovery is 70%. The study expresses the long-term feasibility of desalinated freshwater storage and the need for further management practices in quantifying the contribution of desalinated and recycled water for agriculture activities which might have improved groundwater quality and increased hydraulic head at some locations.


2013 ◽  
pp. 35-64 ◽  
Author(s):  
Giovanna Michelon

The aim of this paper is to study if and how impression management varies during different phases of the legitimation process, in particular during the legitimacy building and legitimacy repairing phases (Suchman, 1995). We aim at understanding whether and how the disclosure tone adopted by a company in the two different moments is diverse and thus functional to the intrinsic objective of the each phase. The empirical analysis focuses on the case of British Petroleum Plc. We investigated the impression management practices undertaken by the company both during the preparation of the rebranding operation, i.e. a situation in which the company is trying to build legitimacy; and during the happenings of two legitimacy crises, like the explosion of the refinery in Texas City and the oil spill in the Gulf of Mexico. The evidence appears in line with the theoretical prediction of legitimacy theory. Results show that while the company tends to privilege image enhancement techniques during the legitimacy-building phase, it uses more obfuscation techniques when managing a legitimacy-repairing process. Moreover, the analysis suggests that the company makes more extensive use of impression management techniques in the disclosures addressed to shareholders, investors and other market operators than in the disclosures addressed to the wide range of other stakeholders.


2020 ◽  
Vol 28 (8) ◽  
pp. 2635-2656
Author(s):  
Samson Oiro ◽  
Jean-Christophe Comte ◽  
Chris Soulsby ◽  
Alan MacDonald ◽  
Canute Mwakamba

AbstractThe Nairobi volcano-sedimentary regional aquifer system (NAS) of Kenya hosts >6 M people, including 4.7 M people in the city of Nairobi. This work combines analysis of multi-decadal in-situ water-level data with numerical groundwater modelling to provide an assessment of the past and likely future evolution of Nairobi’s groundwater resources. Since the mid-1970s, groundwater abstraction has increased 10-fold at a rate similar to urban population growth, groundwater levels have declined at a median rate of 6 m/decade underneath Nairobi since 1950, whilst built-up areas have increased by 70% since 2000. Despite the absence of significant trends in climatic data since the 1970s, more recently, drought conditions have resulted in increased applications for borehole licences. Based on a new conceptual understanding of the NAS (including insights from geophysics and stable isotopes), numerical simulations provide further quantitative estimates of the accelerating negative impact of abstraction and capture the historical groundwater levels quite well. Analysis suggests a groundwater-level decline of 4 m on average over the entire aquifer area and up to 46 m below Nairobi, net groundwater storage loss of 1.5 billion m3 and 9% river baseflow reduction since 1950. Given current practices and trajectories, these figures are predicted to increase six-fold by 2120. Modelled future management scenarios suggest that future groundwater abstraction required to meet Nairobi projected water demand is unsustainable and that the regional anthropogenically-driven depletion trend can be partially mitigated through conjunctive water use. The presented approach can inform groundwater assessment for other major African cities undergoing similar rapid groundwater development.


Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 469 ◽  
Author(s):  
Vila-Aiub

Herbicide resistance is the ultimate evidence of the extraordinary capacity of weeds to evolve under stressful conditions. Despite the extraordinary plant fitness advantage endowed by herbicide resistance mutations in agroecosystems under herbicide selection, resistance mutations are predicted to exhibit an adaptation cost (i.e., fitness cost), relative to the susceptible wild-type, in herbicide untreated conditions. Fitness costs associated with herbicide resistance mutations are not universal and their expression depends on the particular mutation, genetic background, dominance of the fitness cost, and environmental conditions. The detrimental effects of herbicide resistance mutations on plant fitness may arise as a direct impact on fitness-related traits and/or coevolution with changes in other life history traits that ultimately may lead to fitness costs under particular ecological conditions. This brings the idea that a “lower adaptive value” of herbicide resistance mutations represents an opportunity for the design of resistance management practices that could minimize the evolution of herbicide resistance. It is evident that the challenge for weed management practices aiming to control, minimize, or even reverse the frequency of resistance mutations in the agricultural landscape is to “create” those agroecological conditions that could expose, exploit, and exacerbate those life history and/or fitness traits affecting the evolution of herbicide resistance mutations. Ideally, resistance management should implement a wide range of cultural practices leading to environmentally mediated fitness costs associated with herbicide resistance mutations.


Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 209
Author(s):  
Luiza Tymińska-Czabańska ◽  
Jarosław Socha ◽  
Marek Maj ◽  
Dominika Cywicka ◽  
Xo Viet Hoang Duong

Site productivity provides critical information for forest management practices and is a fundamental measure in forestry. It is determined using site index (SI) models, which are developed using two primary groups of methods, namely, phytocentric (plant-based) or geocentric (earth-based). Geocentric methods allow for direct site growth modelling, in which the SI is predicted using multiple environmental indicators. However, changes in non-static site factors—particularly nitrogen deposition and rising CO2 concentration—lead to an increase in site productivity, which may be visible as an age trend in the SI. In this study, we developed a geocentric SI model for oak. For the development of the SI model, we used data from 150 sample plots, representing a wide range of local topographic and site conditions. A generalized additive model was used to model site productivity. We found that the oak SI depended predominantly on physicochemical soil properties—mainly nitrogen, carbon, sand, and clay content. Additionally, the oak SI value was found to be slightly shaped by the topography, especially by altitude above sea level, and topographic position. We also detected a significant relationship between the SI and the age of oak stands, indicating the long-term increasing site productivity for oak, most likely caused by nitrogen deposition and changes in climatic conditions. The developed geocentric site productivity model for oak explained 77.2% of the SI variation.


Author(s):  
Soo-Hyoung Lee ◽  
Jae Min Lee ◽  
Sang-Ho Moon ◽  
Kyoochul Ha ◽  
Yongcheol Kim ◽  
...  

AbstractHydrogeological responses to earthquakes such as changes in groundwater level, temperature, and chemistry, have been observed for several decades. This study examines behavior associated with ML 5.8 and ML 5.1 earthquakes that occurred on 12 September 2016 near Gyeongju, a city located on the southeast coast of the Korean peninsula. The ML 5.8 event stands as the largest recorded earthquake in South Korea since the advent of modern recording systems. There was considerable damage associated with the earthquakes and many aftershocks. Records from monitoring wells located about 135 km west of the epicenter displayed various patterns of change in both water level and temperature. There were transient-type, step-like-type (up and down), and persistent-type (rise and fall) changes in water levels. The water temperature changes were of transient, shift-change, and tendency-change types. Transient changes in the groundwater level and temperature were particularly well developed in monitoring wells installed along a major boundary fault that bisected the study area. These changes were interpreted as representing an aquifer system deformed by seismic waves. The various patterns in groundwater level and temperature, therefore, suggested that seismic waves impacted the fractured units through the reactivation of fractures, joints, and microcracks, which resulted from a pulse in fluid pressure. This study points to the value of long-term monitoring efforts, which in this case were able to provide detailed information needed to manage the groundwater resources in areas potentially affected by further earthquakes.


2017 ◽  
Vol 79 (03) ◽  
pp. 289-296 ◽  
Author(s):  
Jamie Van Gompel ◽  
R. Wiet ◽  
Nicole Tombers ◽  
Anand Devaiah ◽  
Devyani Lal ◽  
...  

Background Very few studies have examined vestibular schwannoma (VS) management trends across centers and between providers. The objective of this study is to examine current practice trends, variance in treatment philosophies, and nuanced or controversial aspects of VS care across North America. Methods This is a cross-sectional survey of North American Skull Base Society (NASBS) members who report regular involvement in VS care. Results A total of 57 completed surveys were returned. Most respondents claimed to have over 20 years of experience and the majority reported working in an academic practice with an affiliated otolaryngology and/or neurosurgery residency program. Sixty-three percent of respondents claimed to evaluate VS patients in clinic with both an otolaryngologist and neurosurgeon involved. Eighty-six percent of respondents claimed to operate on VS with both an otolaryngologist and neurosurgeon involved, while only 18% of neurosurgeons and 9% of otolaryngologists performed surgery alone. There was a wide range in the number of cases evaluated at each center annually. Similarly, there was wide variation in the number of patients treated with microsurgery and radiation at each center. Additional details regarding management preferences for microsurgery, stereotactic radiosurgery, stereotactic radiotherapy, and conservative observation are presented. Conclusion VS management practices vary between providers and centers. Overall, most centers employ a multidisciplinary approach to management with collaboration between otolaryngology and neurosurgery. Overall, survey responses concur with previous studies suggesting a shift toward conservatism in management.


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