scholarly journals Macroplastic Debris Transfer in Rivers: A Travel Distance Approach

2021 ◽  
Vol 3 ◽  
Author(s):  
Robert A. Newbould ◽  
D. Mark Powell ◽  
Michael J. Whelan
Keyword(s):  
Field Measurements ◽  
River System ◽  
Tracer Experiment ◽  
Travel Distance ◽  
Plastic Debris ◽  
Pet Bottles ◽  
Different Types ◽  
Plastic Displacement ◽  
Distance Approach ◽  
Travel Distances

Plastic accumulation in the marine environment is a major concern given the harmful effects and longevity of plastics at sea. Although rivers are likely to significantly contribute to the flux of plastic to marine systems, the behaviour of plastic debris in fluvial systems remains poorly understood and estimates of riverine plastic flux derived from field measurements and modelling efforts are highly uncertain. This paper presents a new probabilistic model of plastic transport in rivers which describes the main processes controlling plastic displacement and which predicts the statistical distribution of travel distances for individual items of buoyant macroplastic debris. Macroplastic transport is controlled by retention in temporary stores (or traps) created by vegetation, bank roughness elements and other obstacles. The behaviour of these traps is represented in the model via a series of Bernoulli trials conducted in a Monte Carlo simulation framework. The model was applied to a tracer experiment in a small 1.1 km river reach. Three replicates were used for calibration and three for validation. For each replicate, 90 closed air-filled polyethylene terephthalate (PET) bottles were introduced at the upstream end of the reach and the location of each bottle was recorded after 24 h. Bottles were chosen as “model” macroplastic litter items given their high usage and littering rate. Travel distances were low. The average and maximum distances travelled over 24 h were 231 m and 1.1 km, respectively. They were also variable. The coefficient of variation of travel distances was 0.94. Spatial patterns were controlled by the location and characteristics of discrete traps. The model was able to describe the observed travel distance distributions reasonably well, suggesting that modelling plastic behaviour in longer reaches and even whole catchments using a stochastic travel distance approach is feasible. The approach has the potential to improve estimates of river plastic flux, although significant knowledge gaps remain (e.g., the rate and location of plastic supply to river systems, the transport behaviours of different types of plastic debris and trap effectiveness in different types of river system, season, and discharge).

Macroplastic Debris Transfer in Rivers: A Travel Distance Approach 

2021 ◽  
Author(s):  
Robert Newbould ◽  
Mark Powell ◽  
Mick Whelan
Keyword(s):  
Average Distance ◽  
Field Measurements ◽  
River System ◽  
Tracer Experiment ◽  
Travel Distance ◽  
Distance Distributions ◽  
Different Types ◽  
Meander Bends ◽  
Distance Approach ◽  
Travel Distances

<p>Plastic accumulation in the marine environment is a major concern given the harmful effects and longevity of plastics at sea. Although rivers significantly contribute to flux of plastic to marine systems, plastic transport in rivers remains poorly understood and estimates of riverine plastic flux derived from field measurements and modelling efforts are highly uncertain. In this study, a new probabilistic model of plastic transport in rivers is presented which describes the main processes controlling displacement to predict the statistical distribution of travel distances for individual items of buoyant macroplastic debris. Macroplastic transport is controlled by retention in temporary stores (or traps) created by vegetation, bank roughness elements and other obstacles. The behaviour of these traps is represented in the model via a series of Bernoulli trials conducted in a Monte Carlo simulation framework. The probability of retention or release from traps is described using physical characteristics such as the type of vegetation, channel width or channel sinuosity index. The model was calibrated using a tracer experiment with six replicates, conducted in a small 1.1 km river reach. For each replicate, 90 closed air-filled plastic bottles were injected at the upstream end of the reach and the location of each bottle was recorded several times over a 24-hour period. Bottles were chosen as ‘model’ macroplastic litter items given their high usage and littering volume. Travel distances were low (the average distance travelled over 24 hours was 231 m and no bottles travelled more than 1.1 km, the length of the study reach) and variable (the coefficient of variation for the replicates ranged between 0.54 and 1.41). The travel distance distributions were controlled by the location and characteristics of discrete traps. The numerical model described the observed travel distance distributions reasonably well (particularly the trapping effect of overhanging trees and flow separation at meander bends), which suggests that modelling plastic transport for longer reaches and even whole catchments using a stochastic travel distance approach is feasible. The approach has the potential to improve estimates of total river plastic flux to the oceans, although significant knowledge gaps remain (e.g. the rate and location of plastic supply to river systems, the transport behaviours of different types of plastic debris in rivers and the effectiveness of different traps in different types of river system).</p>

scholarly journals Examining dispatching practices for Interagency Hotshot Crews to reduce seasonal travel distance and manage fatigue

2018 ◽  
Vol 27 (9) ◽  
pp. 569 ◽  
Author(s):  
Erin J. Belval ◽  
David E. Calkin ◽  
Yu Wei ◽  
Crystal S. Stonesifer ◽  
Matthew P. Thompson ◽  
...  
Keyword(s):  
United States ◽  
The United States ◽  
Travel Distance ◽  
Simulation Process ◽  
Fatigue Management ◽  
Potential Benefits ◽  
Management Policies ◽  
Optimisation Model ◽  
Fatigue Mitigation ◽  
Travel Distances

Interagency Hotshot Crews (IHCs) are a crucial firefighting suppression resource in the United States. These crews travel substantial distances each year and work long and arduous assignments that can cause accumulated fatigue. Current dispatching practices for these crews are supposed to send the closest resource while adhering to existing fatigue-management policies. In this research, we designed a simulation process that repeatedly implements an optimisation model to assign crews to suppression requests. This study examines the potential effects of using an optimisation approach to shorten seasonal crew travel distances and mitigate fatigue. We also examine the potential benefits of coordinating crew-dispatch decisions to meet multiple requests. Results indicate there is substantial room for improvement in reducing travel distances while still balancing crew fatigue; coordinating crew dispatching for multiple requests can increase the assignment efficiency, particularly when both fatigue mitigation and travel distances are jointly optimised. This research indicates implementing an optimisation model for dispatching IHCs is promising.

Weather Conditions, Travel Distance, Rest, and Running Performance: The 2014 FIFA World Cup and Implications for the Future

2017 ◽  
Vol 31 (1) ◽  
pp. 27-43 ◽  
Author(s):  
Nicholas Watanabe ◽  
Pamela Wicker ◽  
Grace Yan
Keyword(s):  
High Intensity ◽  
Weather Conditions ◽  
Travel Distance ◽  
Heat Index ◽  
Host Countries ◽  
World Cup ◽  
Policy Makers ◽  
Running Performance ◽  
Clear Sky ◽  
Travel Distances

The awarding of the hosting of the Football World Cup to Russia and Qatar initiated discussions about temperature and travel distances related to the game. This study examines the effect of weather conditions, travel distances, and rest days—three factors potentially causing fatigue—on running performance using player-level and teamlevel data from the 2014 World Cup. The results show that the heat index (combining temperature and humidity) significantly decreased running performance (number of sprints, high-intensity running), while a clear sky was positively associated with distance covered at high intensity. Travel distance and rest were insignificant. When these models are used to predict running performance at the 2022 Qatar World Cup, the projections show that the combination of heat and wind could hinder the performance of both players and teams and create potentially dangerous conditions. The present study has implications for policy makers regarding the choice of future host countries.

scholarly journals Assessment of Siltation Processes of the Koronowski Reservoir in the Northern Polish Lowland Based on Bathymetry and Empirical Formulas

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1681 ◽  
Author(s):  
Dawid Szatten ◽  
Michał Habel ◽  
Luisa Pellegrini ◽  
Michael Maerker
Keyword(s):  
Flood Control ◽  
Field Measurements ◽  
Suspended Sediments ◽  
River System ◽  
Empirical Formulas ◽  
Filtration Method ◽  
Transport Dynamics ◽  
Sediment Budgets ◽  
The Impact ◽  
Artificial Reservoirs

Artificial reservoirs have an important role in water management of river systems in terms of flood control, water supply and sediment budgeting. Therefore, it is important to maximize the time of their effective functioning. Sediment budgeting mainly depends on sediment transport dynamics. This article illustrates the impact of the Koronowski Reservoir on suspended sediments transported by the Brda River. The river system and the reservoir represent a typical lowland river environment. Our research is based on hydrological and sedimentological investigations on the reservoir and the river system. Field measurements were used to create the respective hydrological and sediment budgets. Moreover, we carried out bathymetric measurements to generate present day bathymetry and to calculate the reservoir’s capacity. We assessed the silting of the reservoir following the approaches proposed by Goncarov and Stonawski. We show that the size and dynamics of suspended sediments are mainly determined by the hydrological conditions. Moreover, we illustrate that the suspended sediment measurements made with the filtration method correlate with the nephelometric results. Generally, we show that the Koronowski Reservoir is mainly filled up by suspended sediments. We further illustrate that the level of siltation estimated with the empirical formulas deviates significantly from calculations made by bathymetric measurements.

An exploration of predictive football modelling

2020 ◽  
Vol 16 (1) ◽  
pp. 27-39
Author(s):  
Mitchell Pearson ◽  
Glen Livingston Jr ◽  
Robert King
Keyword(s):  
Statistical Models ◽  
Travel Distance ◽  
Predictive Capability ◽  
Academic Literature ◽  
Probability Score ◽  
Football Match ◽  
Different Types

AbstractPredictive football modelling has become progressively popular over the last two decades. Due to this, numerous studies have proposed different types of statistical models to predict the outcome of a football match. This study provides a review of three different models published in the academic literature and then implements these on recent match data from the top football leagues in Europe. These models are then compared utilising the rank probability score to assess their predictive capability. Additionally, a modification is proposed which includes the travel distance of the away team. When tested on football leagues from both Australia and Russia, it is shown to improve predictive capability according to the rank probability score.

Input of plastic debris in an urban tropical river system

2019 ◽  
Vol 144 ◽  
pp. 235-242 ◽  
Author(s):  
Anne Bauer-Civiello ◽  
Kay Critchell ◽  
Mia Hoogenboom ◽  
Mark Hamann
Keyword(s):  
River System ◽  
Tropical River ◽  
Plastic Debris

Longitudinal and Angular Drill-String Vibrations With Damping

1968 ◽  
Vol 90 (4) ◽  
pp. 671-679 ◽  
Author(s):  
D. W. Dareing ◽  
B. J. Livesay
Keyword(s):  
Viscous Friction ◽  
Field Measurements ◽  
Computer Programs ◽  
Drill String ◽  
Recording Instrument ◽  
String Vibration ◽  
String Vibrations ◽  
Different Types ◽  
Drilling Operations ◽  
Computer Calculations

This paper discusses longitudinal and angular drill-string vibrations and supporting field measurements taken with a special downhole recording instrument. Computer programs based on the theory are used to calculate longitudinal and angular vibrations (caused by periodic bit motions) along the drill string; field measurements made during actual drilling operations are used to check computer calculations. The main difference between this and other theory on the same problem is the inclusion of friction, which acts along the length of a drill string and impedes longitudinal and angular vibrations. For the sake of simplicity, the effect of different types of friction, such as fluid, rubbing, and material, which act along the string, is approximated by the effect produced by viscous friction. This approximation is generally accepted and appears to give adequate results for the drill-string vibration problem.

Fluid mechanics of plastic debris clogging the hydraulic structures in Indonesia

2020 ◽  
Author(s):  
Vesna Bertoncelj ◽  
Wim Uijttewaal ◽  
Mohammad Farid ◽  
Jeremy Bricker
Keyword(s):  
Water Level ◽  
Monsoon Season ◽  
Optimal Solution ◽  
Field Measurements ◽  
Hydraulic Structures ◽  
Field Observations ◽  
River Systems ◽  
Plastic Debris ◽  
Experimental Modelling ◽  
Driving Mechanisms

<p>The frequent urban floods in Jakarta and Bandung, Indonesia affect the lives and livelihoods of millions of people. Floods cause damage and casualties, while climate change, unchecked development and land subsidence are worsening the problem. One factor contributing to these floods is floating debris clogging the city's drainage structures. A major proportion of floating debris consists of macro plastics which are extremely persistent in the environment. Trash racks that are clogged due to continuous accumulation of plastics in front of them can block the water flow in the river, leading to an increase in upstream water level and causing floods. </p><p>The understanding of transport and accumulation of the macro plastics in the river systems is limited as the field surveys are difficult to perform and the variety of properties of plastic debris is enormous. However, understanding of the origin, fate and pathway of plastic waste is required in order to come up with an optimal solution for plastic collection and prevention of harmful accumulation in front of the hydraulic structures. With this urge in mind field observations will be conducted on the selected river sections in Bandung and Jakarta during the monsoon season in 2020. Field observations will include the measurements of bathymetry, velocity profiles, concentrations and the characterization of floating debris, as well as identifying the accumulation hot spots of floating debris. Furthermore, experimental and numerical modelling will be performed based on the data collected during the field campaign in order to couple different debris classes to a range of riverine situations and understand the differences in their driving mechanisms.</p><p>Using a combination of field measurements, experimental modelling and empirical relations we aim to investigate the driving mechanisms of riverine plastic transport and changes in hydraulic properties due to local disturbances of the current. We will therefore link the type of hydraulic structures and the extend of obstructions due to accumulation of plastic debris to the changes in the upstream water level. This will lead to a better understanding of plastic transport in the river systems in Bandung and Jakarta, to formulate design criteria for structures in trash-laden streams and devise ways to pass trash during floods.</p>

scholarly journals Estimating greenhouse gas emissions from travel – a GIS-based study

2015 ◽  
Vol 70 (3) ◽  
pp. 185-192 ◽  
Author(s):  
S. Kuonen
Keyword(s):  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Ghg Emissions ◽  
Travel Behaviour ◽  
Travel Distance ◽  
Gas Emissions ◽  
Return Trip ◽  
Scientific World ◽  
Annual Congress ◽  
Travel Distances

Abstract. Conferences, meetings and congresses are an important part of today's economic and scientific world. But the environmental impact, especially from greenhouse gas emissions associated with travel, can be extensive. Anthropogenic greenhouse gas (GHG) emissions account for the warming of the atmosphere and oceans. This study draws on the need to quantify and reduce greenhouse gas emissions associated with travel activities and aims to give suggestions for organizers and participants on possible ways to reduce greenhouse gas emissions, demonstrated on the example of the European Geography Association (EGEA) Annual Congress 2013 in Wasilkow, Poland. The lack of a comprehensive methodology for the estimation of greenhouse gas emissions from travel led to an outline of a methodology that uses geographic information systems (GIS) to calculate travel distances. The calculation of travel distances in GIS is adapted from actual transportation infrastructure, derived from the open-source platform OpenStreetMap. The methodology also aims to assess the possibilities to reduce GHG emissions by choosing different means of transportation and a more central conference location. The results of the participants of the EGEA congress, who shared their travel data for this study, show that the total travel distance adds up to 238 000 km, with average travel distance of 2429 km per participant. The travel activities of the participants in the study result in total GHG emissions of 39 300 kg CO2-eq including both outward and return trip. On average a participant caused GHG emissions of 401 kg CO2-eq. In addition, the analysis of the travel data showed differences in travel behaviour depending on the distance between conference site and point of origin. The findings on travel behaviour have then been used to give an estimation of total greenhouse gas emissions from travel for all participants of the conference, which result in a total amount of 79 711 kg CO2-eq. The potential for reducing greenhouse gas emissions by substituting short flights with train rides and car rides with bus and train rides is limited. Only 6 % of greenhouse gas emissions could be saved by applying these measures. Further considerable savings could only be made by substituting longer flights (32.6 %) or choosing a more central conference location (26.3 %).

A Role for a Simple Discrete-Time Model to Describe Dispersion in an Estuary

1985 ◽  
Vol 17 (6-7) ◽  
pp. 991-1000
Author(s):  
T. Wood
Keyword(s):  
Parameter Estimation ◽  
Discrete Time ◽  
Field Measurements ◽  
River System ◽  
Tidal Amplitude ◽  
Salinity Distribution ◽  
Time Model ◽  
Discrete Time Model ◽  
Modelling Procedure ◽  
Fresh Water Input

A simple discrete-time model is proposed to describe dispersion in an estuary, based on tidal exchanges between neighbouring segments. A procedure for parameter estimation and model validation is described which can be implemented with a minimum of field measurements; and the application of the model is demonstrated with data collected from the Hawkesbury River system, near Sydney. The results indicate that the modelling procedure described is capable of producing useful predictions of the response of salinity distribution to changes in fresh water input and tidal amplitude. The method could be most useful in circumstances where limitations on experimental resources preclude the undertaking of a more detailed investigation.

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