scholarly journals Design and construction of the barrier system for the Halton Landfill

2000 ◽  
Vol 37 (3) ◽  
pp. 662-675 ◽  
Author(s):  
R Kerry Rowe ◽  
Chris J Caers ◽  
Glenn Reynolds ◽  
Cliff Chan
Keyword(s):  
Hydraulic Conductivity ◽  
Impact Assessment ◽  
Concentration Profile ◽  
Organic Contaminants ◽  
Laboratory Experiments ◽  
Chloride Concentration ◽  
Design Concept ◽  
Good Prediction ◽  
Air Pocket ◽  
The Impact

Considerations related to the design of the Halton Landfill as a "hydraulic trap" are summarized together with the research that was conducted to support the design concept. The interrelationship between hydrogeology and the engineered design is examined. Laboratory experiments demonstrated that there can be diffusion away from a source, even with significant inward velocity. Existing theory was found to provide a good prediction of the observed concentration profile in these experiments. It is also shown that a pressurized air pocket below the clay effectively acts as a zero-flux boundary and hence, with respect to migration of chloride, could be conservatively neglected in the impact assessment. The results of the impact calculations predict only a small increase in chloride concentration in the receptor aquifer while there is negligible predicted impact due to organic contaminants. The landfill was designed and constructed with a granular "sub-liner contingency layer" (SLCL) beneath the compacted liner. The operation of this layer is discussed. Finally, the construction of the compacted clayey liner with a hydraulic conductivity of 1 × 10-8 cm/s is documented.Key words: landfill, hydraulic containment, liner, field case, construction.

scholarly journals Characterization of stony soils' hydraulic conductivity using laboratory and numerical experiments

SOIL ◽  
2016 ◽  
Vol 2 (3) ◽  
pp. 421-431 ◽  
Author(s):  
Eléonore Beckers ◽  
Mathieu Pichault ◽  
Wanwisa Pansak ◽  
Aurore Degré ◽  
Sarah Garré
Keyword(s):  
Hydraulic Conductivity ◽  
Water Flow ◽  
Predictive Models ◽  
Laboratory Experiments ◽  
Saturated Hydraulic Conductivity ◽  
Experimental Conditions ◽  
Rock Fragments ◽  
Unsaturated Hydraulic Conductivity ◽  
The One ◽  
The Impact

Abstract. Determining soil hydraulic properties is of major concern in various fields of study. Although stony soils are widespread across the globe, most studies deal with gravel-free soils, so that the literature describing the impact of stones on the hydraulic conductivity of a soil is still rather scarce. Most frequently, models characterizing the saturated hydraulic conductivity of stony soils assume that the only effect of rock fragments is to reduce the volume available for water flow, and therefore they predict a decrease in hydraulic conductivity with an increasing stoniness. The objective of this study is to assess the effect of rock fragments on the saturated and unsaturated hydraulic conductivity. This was done by means of laboratory experiments and numerical simulations involving different amounts and types of coarse fragments. We compared our results with values predicted by the aforementioned predictive models. Our study suggests that it might be ill-founded to consider that stones only reduce the volume available for water flow. We pointed out several factors of the saturated hydraulic conductivity of stony soils that are not considered by these models. On the one hand, the shape and the size of inclusions may substantially affect the hydraulic conductivity. On the other hand, laboratory experiments show that an increasing stone content can counteract and even overcome the effect of a reduced volume in some cases: we observed an increase in saturated hydraulic conductivity with volume of inclusions. These differences are mainly important near to saturation. However, comparison of results from predictive models and our experiments in unsaturated conditions shows that models and data agree on a decrease in hydraulic conductivity with stone content, even though the experimental conditions did not allow testing for stone contents higher than 20 %.

Modelling of Solute Transfer to Surface Runoff

1992 ◽  
Vol 26 (7-8) ◽  
pp. 1851-1856 ◽  
Author(s):  
J. L. Lai ◽  
K. S. L. Lo
Keyword(s):  
Potassium Chloride ◽  
Surface Runoff ◽  
Laboratory Experiments ◽  
Overland Flow ◽  
Chloride Concentration ◽  
Runoff Water ◽  
Mixing Depth ◽  
Change Rate ◽  
Solute Transfer ◽  
The Media

A mixing-based model for describing solute transfer to overland flow was developed. This model included a time-dependent mixing depth of the top layer and a complete-mixed surface runoff zone. In a series of laboratory experiments, runoff was passed at various velocities and depths over a medium bed. The media were saturated with uniform concentration of potassium chloride solution. Runoff water was sampled at the beginning and end of the flume and the potassium chloride concentration analyzed. Using this model, dimensionless ultimate mixing depth and dimensionless change rate of mixing depth from experimental data were investigated and implemented. The results showed that the Reynolds number and relative roughness are two important factors.

From Silent Spring to The Frog of War

2017 ◽  
Author(s):  
David K. Skelly
Keyword(s):  
Natural History ◽  
Laboratory Experiments ◽  
Wild Populations ◽  
Rachel Carson ◽  
Chemical Agents ◽  
Silent Spring ◽  
The World ◽  
History Information ◽  
Wildlife Populations ◽  
The Impact

This chapter presents two examples to demonstrate that natural history is the necessary basis of any reliable understanding of the world. More than a half century ago, Rachel Carson revolutionized the public’s view of pesticides. The foundation of her success was the careful use of natural history data, collated from across North America. The examples she assembled left little doubt that DDT and other pesticides were causing a widespread decline in birds. More recently, the case for the impact of atrazine on wildlife was based on laboratory experiments, without the advantage of natural history observations. For atrazine, natural history observations now suggest that other chemical agents are more likely to be responsible for feminization of wildlife populations. Developing expectations for scientists to collect natural history information can help to avoid over-extrapolating lab results to wild populations, a tendency often seen when those lab results conform to preconceptions about chemicals in the environment.

scholarly journals Development of a Rapid Risk and Impact Assessment Tool to Enhance Response to Environmental Emergencies in the Early Stages of a Disaster: A Tool Developed by the European Multiple Environmental Threats Emergency NETwork (EMETNET) Project

2021 ◽  
Author(s):  
Emma-Jane Goode ◽  
Eirian Thomas ◽  
Owen Landeg ◽  
Raquel Duarte-Davidson ◽  
Lisbeth Hall ◽  
...  
Keyword(s):  
Public Health ◽  
Impact Assessment ◽  
Assessment Tool ◽  
The European Union ◽  
Protection Mechanism ◽  
Environmental Threats ◽  
Environmental Disasters ◽  
Early Stages ◽  
Potential Risks ◽  
The Impact

AbstractEvery year, numerous environmental disasters and emergencies occur across the globe with far-reaching impacts on human health and the environment. The ability to rapidly assess an environmental emergency to mitigate potential risks and impacts is paramount. However, collating the necessary evidence in the early stages of an emergency to conduct a robust risk assessment is a major challenge. This article presents a methodology developed to help assess the risks and impacts during the early stages of such incidents, primarily to support the European Union Civil Protection Mechanism but also the wider global community in the response to environmental emergencies. An online rapid risk and impact assessment tool has also been developed to promote enhanced collaboration between experts who are working remotely, considering the impact of a disaster on the environment and public health in the short, medium, and long terms. The methodology developed can support the appropriate selection of experts and assets to be deployed to affected regions to ensure that potential public health and environmental risks and impacts are mitigated whenever possible. This methodology will aid defensible decision making, communication, planning, and risk management, and presents a harmonized understanding of the associated impacts of an environmental emergency.

scholarly journals Forest and Society’s Welfare: Impact Assessment in Lithuania

2021 ◽  
Vol 13 (10) ◽  
pp. 5598
Author(s):  
Stasys Mizaras ◽  
Diana Lukmine
Keyword(s):  
Impact Assessment ◽  
Forest Policy ◽  
Assessment Model ◽  
Dimensional Model ◽  
Important Goal ◽  
Welfare Impact ◽  
Global Problem ◽  
Five Dimensional Model ◽  
Welfare Index ◽  
The Impact

Effective formation and implementation of forest policy can only be achieved with orientation to the most important goal—increasing society’s welfare. The global problem is, at present, that the impact of forests on society welfare indexes have not been identified. The aim of the study is to design an assessment model and assess the impact of Lithuanian forests on the society welfare index. The impact of forests was determined by multiplying the country’s welfare of society index by the forest contribution coefficient. In this study, to assess the index of the welfare of Lithuanian society, a five-dimensional model with 16 indicators was applied. The study is based on the Eurostat database and on Lithuanian forestry statistics. The Lithuanian welfare of society index calculated according to the model was 51.4% and the contribution of forests in this index was 3.9%. It represented 7.6% of the index of the welfare of society. Forests have the greatest impact in the environmental dimension, according to the assessment results.

scholarly journals Adding value to the use of Health Impact Assessment and social return on investment technologies

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
L Green ◽  
K Ashton ◽  
M Dyakova ◽  
L Parry-Williams
Keyword(s):  
Impact Assessment ◽  
Return On Investment ◽  
Health Impact Assessment ◽  
Grey Literature ◽  
Health Impact ◽  
Social Value ◽  
Decision Makers ◽  
Structured Interviews ◽  
Social Return On Investment ◽  
The Impact

Abstract Health Impact Assessment (HIA) and Social Return on Investment (SROI) are beneficial public health methodologies that assess potential effects on health including social, economic and environmental factors and have synergies in their approaches. This paper explores how HIA and SROI can complement each other to capture and account for the impact and social value of an assessed intervention or policy. A scoping review of academic and grey literature was undertaken to identify case studies published between January 1996 and April 2019 where HIA and SROI methods have been used to complement each other. Semi-structured interviews were carried out with nine international experts from a range of regulatory/legislative contexts to gain a better understanding of past experiences and expertise of both HIA and SROI. A thematic analysis was undertaken on the data collected. The review identified two published reports which outline when HIA and SROI have both been used to assess the same intervention. Interview results suggest that both methods have strengths as standalone processes i.e. HIAs are well-structured in their approach, assessing health in its broadest context and SROI can add value by monetizing social value as well as capturing social/environmental impact. Similarities of the two methods were identified i.e. a strong emphasis on stakeholder engagement and common shared principles. When questioned how the two methods could complement each other in practice, the results indicate the benefits of using HIA to explore initial impact, and as a platform on which to build SROI to monetarize social value. HIA and SROI methodologies have cross-over. The research suggests potential benefits when used in tandem or combining the methods to assess impact and account for health and social value. Innovative work is now being carried out in Wales to understand the implications of this in practice and to understand how the results of the two methods could be used by decision-makers. Key messages HIA and SROI methods can be used in tandem to capture both the health impact and social value of policies and proposed interventions. HIA and SROI when used together can provide valuable information to inform decision makers around the health impact and social value of proposed policies and interventions.

scholarly journals Natural dimethyl sulfide gradients would lead marine predators to higher prey biomass

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Kylie Owen ◽  
Kentaro Saeki ◽  
Joseph D. Warren ◽  
Alessandro Bocconcelli ◽  
David N. Wiley ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Dimethyl Sulfide ◽  
Zooplankton Biomass ◽  
Foraging Success ◽  
Spatially Correlated ◽  
Prey Biomass ◽  
Marine Predators ◽  
Predator Foraging ◽  
The Impact

AbstractFinding prey is essential to survival, with marine predators hypothesised to track chemicals such as dimethyl sulfide (DMS) while foraging. Many predators are attracted to artificially released DMS, and laboratory experiments have shown that zooplankton grazing on phytoplankton accelerates DMS release. However, whether natural DMS concentrations are useful for predators and correlated to areas of high prey biomass remains a fundamental knowledge gap. Here, we used concurrent hydroacoustic surveys and in situ DMS measurements to present evidence that zooplankton biomass is spatially correlated to natural DMS concentration in air and seawater. Using agent simulations, we also show that following gradients of DMS would lead zooplankton predators to areas of higher prey biomass than swimming randomly. Further understanding of the conditions and scales over which these gradients occur, and how they are used by predators, is essential to predicting the impact of future changes in the ocean on predator foraging success.

Measuring Entrepreneurial Self-efficacy: A Comprehensive Scale

2021 ◽  
pp. 239395752110196
Author(s):  
Neha Taneja Chawla ◽  
Hitesh Bhatia
Keyword(s):  
Impact Assessment ◽  
Statistical Methods ◽  
Self Efficacy ◽  
Reliability And Validity ◽  
Entrepreneurship Education ◽  
Education Programs ◽  
Entrepreneurial Behaviour ◽  
Indian Context ◽  
The World ◽  
The Impact

With the increasing popularity of entrepreneurship education programs across the world, the impact assessment of such programs has gathered considerable interest of the researchers. Growing number of studies are including entrepreneurial self-efficacy (ESE) as a key predictor of future entrepreneurial behaviour and hence the scale for measuring ESE is central to majority of studies pertaining to entrepreneurship education and entrepreneurial behaviour. This study attempts to refine the existing instruments for measuring ESE by extensively reviewing the notable scales of ESE in literature and develops a comprehensive scale of ESE relevant in the Indian context. The additional components are added to the existing scales through expert discussions with the academicians as well as entrepreneurs. The scale is further verified for its reliability and validity by using appropriate statistical methods.

scholarly journals Treated wastewater irrigation effects on soil hydraulic conductivity and aggregate stability of loamy soils in Israel

2015 ◽  
Vol 63 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Karsten Schacht ◽  
Bernd Marschner
Keyword(s):  
Hydraulic Conductivity ◽  
Chemical Properties ◽  
Aggregate Stability ◽  
Treated Wastewater ◽  
Soil Aggregate Stability ◽  
Irrigation Effects ◽  
Physical And Chemical ◽  
The Impact

Abstract The use of treated wastewater (TWW) for agricultural irrigation becomes increasingly important in water stressed regions like the Middle East for substituting fresh water (FW) resources. Due to elevated salt concentrations and organic compounds in TWW this practice has potential adverse effects on soil quality, such as the reduction of hydraulic conductivity (HC) and soil aggregate stability (SAS). To assess the impact of TWW irrigation in comparison to FW irrigation on HC, in-situ infiltration measurements using mini disk infiltrometer were deployed in four different long-term experimental orchard test sites in Israel. Topsoil samples (0-10 cm) were collected for analyzing SAS and determination of selected soil chemical and physical characteristics. The mean HC values decreased at all TWW sites by 42.9% up to 50.8% compared to FW sites. The SAS was 11.3% to 32.4% lower at all TWW sites. Soil electrical conductivity (EC) and exchangeable sodium percentage (ESP) were generally higher at TWW sites. These results indicate the use of TWW for irrigation is a viable, but potentially deleterious option, as it influences soil physical and chemical properties.

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