scholarly journals Asphaltic Concrete Pavement Strength and the Impact of Rainfall

Author(s):  
GOC Amuchi ◽  
J.C Agunwamba

Studies have shown that moisture impacts on the strength of flexible pavement surface of asphaltic concrete. Several investigations and relevant researches treated the effect of subsurface and surface water sources, on the durability of flexible pavements. This study is focused on the surface water sources, as a result of precipitation (rainfall), on the surface of flexible pavements. To conduct this experiment, the considerations made include (i) the continuous exposure of the pavement surface to annual rainfall (ii) application of pavement exposure to moisture in the field. This study considered the amount of rainfall each day, as the duration (age) of pavement exposure to moisture (being under water during rainfall). For the purpose of this experiment, the Owerri to Onitsha about 90km of dual carriage way in south east of Nigeria, was considered. This is a flexible pavement that traverses through the rain forest belt, characterized with high amount of annual rainfall values. Flexible pavement specimens from this road were obtained, cleaned and immersed in water after weighing, to keep vital records of the necessary parameters, before further tests at 7days intervals. Values of strength obtained after days in water, that approximated to the appropriate field situation of exposure to rainfall, showed a consistent loss of strength, from the crushing strength results.

2018 ◽  
Vol 18 (6) ◽  
pp. 2108-2117 ◽  
Author(s):  
A. Hadidi ◽  
B. Remini ◽  
M. Habi ◽  
D. Saba

Abstract The oasis of Moghrar is located in the wilaya (province) of Naama, in the southwest of Algeria. It is well known for its Ksours, its palm groves and the good quality of its fruit and vegetables, especially the dates and their varieties. This region contains important groundwater and surface water resources. For several centuries, domestic water supply and irrigation have been carried out using traditional techniques of water harvesting such as pendulum wells and foggaras. Currently, this hydraulic heritage is meeting technical and social problems, particularly with the contribution of drilling and motor-pumps. The main issues are water table drawdown, the drying-up of water sources and degradation and decay of traditional techniques. The objective of this study is to make an inventory of all water sources in the study area, to study the impact of the contribution of modern techniques on ancestral techniques and finally to propose recommendations for safeguarding the hydraulic heritage.


2022 ◽  
Vol 964 (1) ◽  
pp. 012014
Author(s):  
Lam Vinh Son ◽  
Nguyen Vu Phong ◽  
Ta Trung Kien ◽  
Nguyen Thi Phu’o’ng Chau ◽  
Le Thanh Hoa ◽  
...  

Abstract In recent years, local livelihood activities in the Can Gio district have increased significantly, including aquaculture practices, aquaculture cultivation, salt-works, forest guard, farming, livestock, tourism, and etc. These livelihood activities have contributed remarkably to the local economy and the improvement of living conditions for local people. However, the burgeoning development of these activities have posed negative impacts on the mangrove ecosystem in Can Gio. In which, the use and exploitation of existing human and natural resources are paid inadequate attention. The purpose of this study is to identify livelihoods by conducting a survey with 536 questionnaire samples in both the buffer and transition zones in Can Gio Mangrove Forest. In addition, the quality of surface water sources was examined by collecting 70 surface water and wastewater samples. The results show that the quality of surface water meets the allowable limits of QCVN 08-MT:2015/BTNMT. The extent of the impact from livelihood activities on the environment of mangrove forest is at the medium level. However, the livelihood of aquaculture cultivation practices has the most affect on the environment and natural resources and is posing negative impacts on the quality of water sources in Can Gio Mangrove Forest. Therefore, these findings will be useful information for decision makers of the local authority in building an appropriate planning for aquaculture cultivation area. Further, irrigation and drainage systems for aquaculture practices need to be invested to control and handle wastes from aquaculture cultivation areas.


Author(s):  
Zeinab S. Ahmed ◽  
Esraa A. Elshafiee ◽  
Hanan S. Khalefa ◽  
Mona Kadry ◽  
Dalia A. Hamza

Abstract Background Antimicrobial resistance has become one of the most severe global threats to human and veterinary Medicine. colistin is an effective therapeutic agent against multi-drug-resistant pathogens. However, the discovery of transferable plasmids that confer resistance to colistin (mcr-1) has led to challenges in medical science. This study describes the role of wild birds in the harbouring and environmental spread of colistin-resistant bacteria, which could pose a potential hazard to human and animal health. Methods In total, 140 faecal samples from wild birds (migratory and resident birds) were tested. Twenty surface water samples were collected from the area in which wild bird trapping was conducted, and 50 human stool samples were collected from individuals residing near the surface water sources and farm buildings. Isolation and identification of Enterobacteriaceae and Pseudomonas aeruginosa from the different samples were performed using conventional culture techniques and biochemical identification. PCR amplification of the mcr genes was performed in all positive isolates. Sequencing of mcr-1 genes from three randomly selected E. coli carrying mcr-1 isolates; wild birds, water and humans was performed. Result The bacteriological examination of the samples showing isolates of Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca and P. aeruginosa. The results of multiplex PCR of the mcr genes revealed that E. coli was the most prevalent gram-negative bacterium harbouring the mcr genes, whereas a low prevalence was observed for K. pneumoniae. The prevalence of mcr-1 in resident birds, migratory birds, water sources and humans were 10.4, 20,16.6 and 9.6% while the prevalence of mcr-2 were 1.4, 3.6, 11.1 and 9.6%, respectively. Sequencing of the mcr-1 gene from the three E. coli carrying mcr-1 isolates indicated a possible correlation between the wild bird and surface water isolates. Conclusion The detection of mcr-1-positive bacteria in wild birds in Egypt indicates the possible environmental dissemination of this gene through bird activity. The impact of the interaction between domestic and wild animals on public health cannot be overlooked.


2013 ◽  
Vol 12 (2) ◽  
pp. 119-125

The present study concerns the impact of a change in the rainfall regime on surface and groundwater resources in an experimental watershed. The research is conducted in a gauged mountainous watershed (15.18 km2) that is located on the eastern side of Penteli Mountain, in the prefecture of Attica, Greece and the study period concerns the years from 2003 to 2008. The decrease in the annual rainfall depth during the last two hydrological years 2006-2007, 2007-2008 is 10% and 35%, respectively, in relation to the average of the previous years. In addition, the monthly distribution of rainfall is characterized by a distinct decrease in winter rainfall volume. The field measurements show that this change in rainfall conditions has a direct impact on the surface runoff of the watershed, as well as on the groundwater reserves. The mean annual runoff in the last two hydrological years has decreased by 56% and 75% in relation to the average of the previous years. Moreover, the groundwater level follows a declining trend and has dropped significantly in the last two years.


Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 308
Author(s):  
Kristen Almen ◽  
Xinhua Jia ◽  
Thomas DeSutter ◽  
Thomas Scherer ◽  
Minglian Lin

The potential impact of controlled drainage (CD), which limits drainage outflow, and subirrigation (SI), which provides supplemental water through drain tile, on surface water quality are not well known in the Red River Valley (RRV). In this study, water samples were collected and analyzed for chemical concentrations from a tile-drained field that also has controlled drainage and subirrigation modes in the RRV of southeastern North Dakota from 2012–2018. A decreasing trend in overall nutrient load loss was observed because of reduced drainage outflow, though some chemical concentrations were found to be above the recommended surface water quality standards in this region. For example, sulfate was recommended to be below 750 mg/L but was reported at a mean value of 1971 mg/L during spring free drainage. The chemical composition of the subirrigation water was shown to have an impact on drainage water and the soil, specifically on salinity-related parameters, and the impact varied between years. This variation largely depended on the amount of subirrigation applied, soil moisture, and soil properties. Overall, the results of this study show the benefits of controlled drainage on nutrient loss reduction from agricultural fields.


2014 ◽  
Vol 12 (3) ◽  
pp. 484-491 ◽  
Author(s):  
Andrea Crampton ◽  
Angela T. Ragusa

Agricultural runoff into surface water is a problem in Australia, as it is in arguably all agriculturally active countries. While farm practices and resource management measures are employed to reduce downstream effects, they are often either technically insufficient or practically unsustainable. Therefore, consumers may still be exposed to agrichemicals whenever they turn on the tap. For rural residents surrounded by agriculture, the link between agriculture and water quality is easy to make and thus informed decisions about water consumption are possible. Urban residents, however, are removed from agricultural activity and indeed drinking water sources. Urban and rural residents were interviewed to identify perceptions of agriculture's impact on drinking water. Rural residents thought agriculture could impact their water quality and, in many cases, actively avoided it, often preferring tank to surface water sources. Urban residents generally did not perceive agriculture to pose health risks to their drinking water. Although there are more agricultural contaminants recognised in the latest Australian Drinking Water Guidelines than previously, we argue this is insufficient to enhance consumer protection. Health authorities may better serve the public by improving their proactivity and providing communities and water utilities with the capacity to effectively monitor and address agricultural runoff.


2021 ◽  
Vol 11 (5) ◽  
pp. 2307
Author(s):  
João Lincho ◽  
Rui C. Martins ◽  
João Gomes

Parabens are widely used in different industries as preservatives and antimicrobial compounds. The evolution of analytical techniques allowed the detection of these compounds in different sources at µg/L and ng/L. Until today, parabens were already found in water sources, air, soil and even in human tissues. The impact of parabens in humans, animals and in ecosystems are a matter of discussion within the scientific community, but it is proven that parabens can act as endocrine disruptors, and some reports suggest that they are carcinogenic compounds. The presence of parabens in ecosystems is mainly related to wastewater discharges. This work gives an overview about the paraben problem, starting with their characteristics and applications. Moreover, the dangers related to their usage were addressed through the evaluation of toxicological studies over different species as well as of humans. Considering this, paraben detection in different water sources, wastewater treatment plants, humans and animals was analyzed based on literature results. A review of European legislation regarding parabens was also performed, presenting some considerations for the use of parabens.


2018 ◽  
Vol 488 (1) ◽  
pp. 277-289 ◽  
Author(s):  
Adebayo J. Adeloye ◽  
Bankaru-Swamy Soundharajan

AbstractHedging is universally recognized as a useful operational practice in surface water reservoirs to temporally redistribute water supplies and thereby avoid large, crippling water shortages. When based on the zones of available water in storage, hedging has traditionally involved a static rationing (i.e. supply to demand) ratio. However, given the usual seasonality of reservoir inflows, it is also possible that hedging could be dynamic with seasonally varying rationing ratios. This study examined the effect of static and dynamic hedging policies on the performance of the Pong reservoir in India during a period of climate change. The results show that the reservoir vulnerability was unacceptably high (≥60%) without hedging and that this vulnerability further deteriorated as the catchment became drier due to projected climate change. The time- and volume-based reliabilities were acceptable. The introduction of static hedging drastically reduced the vulnerability to <25%, although the hedging reduction in the water supplied during normal operational conditions was only 17%. Further analyses with dynamic hedging provided only modest improvements in vulnerability. The significance of this study is its demonstration of the effectiveness of hedging in offsetting the impact of water shortages caused by climate change and the fact that static hedging can match more complex dynamic hedging policies.


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