ESTIMATION OF WATER TEMPERATURE EXCEEDANCE PROBABILITIES USING THERMO-HYDRODYNAMIC MODELING1

ABSTRACT: A continuous simulation approach is proposed for estimating water temperature exceedance probabilities using thermo-hydrodynamic modeling. The approach uses (1) a deterministic unsteady flow and heat transport model, (2) continuous hydrological and meteorological data for a long historical period, and (3) synthetic records of tributary water temperatures and other model inputs. Representative historical records of streamflow, air temperatures, and other hydrometeorological variables are obtained from nearby gages. Stochastic modeling methods are used to construct synthetic records for other model inputs, including inflow water temperatures. An application of this deterministic-stochastic approach is presented for a complex waterway in northeastern Illinois with heat discharges from several power plants and wastewater treatment plants. Statistical results from the continuous simulations are compared to results obtained from traditional event simulations. The application illustrates the information that engineers and biologists can obtain for (1) evaluating compliance with water temperature standards, and (2) assessing the effect of water temperatures on aquatic habitat.     

Fixed bed adsorption of acid dyes onto activated carbon

The context of the study here is the adsorption of acid dyes from wastewater arising from a nylon carpet printing plant which currently receives no treatment. Since nylon is a particularly difficult fibre to dye, acid dyes are required for successful coloration. However, their presence, in high concentrations, in aqueous effluent arising from the plant can create major problems with respect to disposal. A treatment method based on adsorption onto granular activated carbon (GAC F400) in a fixed column configuration is described and breakthrough data of the dyes determined. The breakthrough data were correlated using a model based on liquid and pore diffusion with a good fit of experimental results obtained. Trends in the effective diffusivity used in the model correlated with other authors. A slight decrease in effective diffusivity was found with decrease in particle size and was attributed to interactions between the relatively large molecular sized dye and the microspore structure found in granular activated carbon.     

Economic assessment of dredging operations in Mobile Bay,USA and some additional notes on sustainable management of dredged material

This paper describes a study that was performed to determine the cost-effective method of dredging in Mobile Bay in the United States and to explore the possibility of utilizing the dredged materials in an environmentally sustainable way. An analysis of the historical cost and working time data for hopper dredging and pipeline dredging for Mobile Bay showed that there was not a substantial difference in unit costs between the two methods. However, while the disposal methods for dredged materials were taken into consideration, the pipeline dredging seemed to be a more desirable and environmentally friendly option for dredging in Mobile Bay. In addition to cost analysis, the paper discusses several possible ways of sustainable management of dredged materials. The paper also indicates that if the sediment in Mobile Bay is found to be contaminated by the Deepwater Horizon oil spill, the pipeline dredging will become a more desirable dredging alternative.     

The effects of personal music devices on pedestrian behaviour

It has been suggested that pedestrians listening to personal music devices (PMD) are more likely to be involved in accidents than those not listening to PMDs. Though it has been demonstrated that pedestrians on cell phones exhibit less cautionary behaviour when street crossing ( [Hatfield and Murphy, 2007], [Nasar et al., 2008] and [Stavrinos et al., 2009]), little research has been conducted with PMD users. In the present study, cautionary behaviour (e.g., looking before crossing a road) was observed and recorded for pedestrians with or without PMDs. Amongst males, pedestrians listening to PMDs displayed more looking behaviour than those not listening to PMDs. Females showed no differences between the two conditions. Thus, unlike cell phones, PMDs do not decrease the cautionary behaviour of pedestrians. This suggests that cell phones and PMDs are two different types of distractions, and this needs to be taken into account when developing methods to prevent pedestrian accidents in the future.     

Developing the understanding of underlying causes of construction fatal accidents

A study of a small sample of construction fatal accidents was used to pilot a potential method of analysis for the UK Health and Safety Executive (HSE) Construction Division. The work was conducted in the context of a Governmental Inquiry into construction fatalities in 2009, but has been developed further since. The sample of 26 accidents (28 fatalities) was drawn from the 211 fatal accidents in the years ending 2006–2008, to be broadly illustrative of the range of accident characteristics. The accidents were analysed on the basis of available inspectorate reports and structured interviews with the investigating inspectors. A standard method of classification on four levels was developed, based on the Human Factors Analysis and Classification System (HFACS) classification of errors and task level factors, with additional categories covering the organisational and regulatory/market levels of the system. The results showed a concentration of underlying factors associated with inadequacies in planning and risk assessment, competence assurance, hardware design, purchase and installation, and contracting strategy. These findings were partially validated by comparing them with another sample of 50 accidents analysed earlier by the HSE. This paper describes the development and testing of the investigation and classification method and how it is being further developed since the initial study. It also provides a summary of the findings relating to underlying causes.     

Local‐level governance of risk and resilience in Nepal

This paper explores the circumstances in which communities may effectively reduce risks. It draws on the example of two ‘Risk and Resilience Committees’ (RRCs) that were established in Nepal as part of an action research project: one in Panchkhal in the central region, operating as a community‐based organisation (CBO); and the other in Dhankuta in the eastern region, embedded in municipal government. In‐depth interviews were conducted with RRC members. Wider community preferences for risk reduction were examined through a questionnaire survey. In Dhankuta, the RRC obtained further funding, developed strong upward and downward institutional links, and applied a ‘disaster risk reduction lens’ to existing local government responsibilities. In Panchkhal, RRC activities have been limited by funding and have focused on the strengthening of livelihoods. It may be concluded tentatively that community‐based disaster risk reduction activities are more successful when they are institutionally embedded in local government structures.