Kevin R. Hall

Evaluating the Environmental Impacts of Water Distribution Systems by Using EIO-LCA-Based Multiobjective Optimization

Climate change has made environmental impact a factor of growing importance in decision making for municipalities. Increasingly, the environmental impacts of expanding and operating a water distribution system (WDS) are considered alongside the cost and hydraulic design. This paper presents a nondominated sorting genetic algorithm (NSGA-II) that minimizes capital costs, annual pumping energy use, and environmental impacts in WDS design that adheres to hydraulic constraints. A previously developed environmental impact (EI) index is included in the environmental objective function of the optimization program. The EI index normalizes and aggregates multiple environmental measures evaluated with an economic input-output life-cycle assessment (EIO-LCA) model. The EIO-LCA-based NSGA-II was applied to the Anytown network. Annual pumping energy use was found to dominate the EI index while capital cost and the EI index were inversely related, and the annual pumping energy use and the EI index followed a near linea...

Wave Attenuation by Emergent Wetland Vegetation

Though there is agreement that shoreline and aquatic plants are an integral part of more environmentally compatible shore protection techniques, there is little data or design information available to ensure successful implementation. The value of shoreline wetlands has become increasingly recognized. One of the important functions of shoreline wetland vegetation is its ability to absorb wave energy; however, considerable questions regarding the magnitude and importance of this process exist. In order to address these concerns, a research study was undertaken to assess, qualitatively and quantitatively, wave attenuation by emergent wetland plants. A Lake Ontario shoreline wetland was monitored over a 3 year period and an extensive series of complementary laboratory flume tests were performed. The laboratory experiments were conducted using irregular waves and live vegetation taken from the field site. Several key parameters and trends, with respect to wave attenuation and emergent wetland vegetation, were identified. A pair of empirically based equations was developed that predicted wave attenuation through the emergent, freshwater, wetland plants.

TRENDS IN STABILITY OF DYNAMICALLY STABLE BREAKWATERS

Tanah Lot Temple is situated in Tabanan Regency - Bali, on the coast of the Indonesian Ocean. Due to continuous wave attack, wind force, and weathering of the rock bank where the Temple stands, abrasion has occured which is more and more threatening the existence of the Temple. Considering that Tanah Lot Temple is a sacred place for the Hindu Balinese people and a place of high cultural value, and also an important tourism, steps to save the Temple are imperative. The Central as well as the Regional Authorities, and also the Bali nese community are very much interested in the effort to keep the Temple intact. Measures have been undertaken to protect both the seaside and land-side banks of the Temple rock bank. This paper only discusses counter measures of the sea —side bank of the Temple.

Human health risk assessment from exposure to trihalomethanes in Canadian cities.

Lifetime exposure to trihalomethanes (THMs) through ingestion, inhalation and dermal contacts may pose risks to human health. Current approaches may under predict THMs exposure by using THMs in cold water during showering and bathing. Warming of chlorinated water during showering may increase THMs formation through reactions between organics and residual chlorine, which can increase human health risks. In this study, THMs concentrations in shower water were estimated using THMs rate increase model. Using cold water THMs, exposure through ingestion was estimated, while THMs exposure during showering was estimated using THMs in warm water. Human health cancer risks and additional expenses for 20 most populated Canadian cities from exposure to THMs were estimated. Inhalation and dermal contact during showering contributed 30% to 50% of total cancer risks, while risks from inhalation and dermal contacts were comparable for all cities. Overall cancer risks were estimated between 7.2 x 10(-6) and 6.4 x 10(-5) for these cities. Cancer incidents were estimated highest for Montreal (94/year) followed by Toronto (53/year), which may require additional medical expenses of 18.8 and 10.7 million dollars/year for Montreal and Toronto respectively. Cancer risks from exposure to THMs can be controlled by reducing THMs in water supply and varying shower stall volume, shower duration and air exchange rate in shower stall.

Comparison of oscillatory and stationary flow through porous media

Abstract Experiments were conducted in an oscillatory water tunnel to investigate what effects temporal inertia has on the resistance of a granular medium. The flow law governing stationary porous media flow is reasonably well accepted and understood but the effects of unsteady flow have commonly been neglected. The present research was designed to assess the magnitude of the acceleration effects on media of uniformly packed spheres of equal diameter and on one sample of randomly placed stone. Oscillatory flow tests were made in a large oscillatory flume tunnel with periods varying from 3 to 12 seconds. The influence of properties of the medium (grain size and porosity) were tested by using spheres with two different diameters and packing each size sphere in different geometric arrangements. Tests made on a stone sample provided a qualitative assessment of the effects of more random material properties. For the experiments described in this paper, the Forchheimer unsteady-stationary flow law described the oscillatory measurements well when velocities and energy losses were maximum. Empirical coefficients determined from steady-stationary flow were generally found to apply to the unsteady flow, however some evidence of dependency on the period of oscillation was noted.

The influence of armour stone gradation on dynamically stable breakwaters

Abstract Dynamically stable or berm breakwaters are structures in which the armour layer is comprised of a wide range of stone sizes and undergoes reshaping in response to wave action. As a result of this wave action, a stable profile is achieved. The effect of gradation of armour stones and the amount of rounded stones in the armour on dynamically stable breakwaters was assessed in a two-dimensional wave flume. A total of 52 series of tests were undertaken at the Coastal Engineering Research Laboratory of Queens University, Kingston (Canada), using irregular waves. Profiles of the structure during the various stages of reshaping were measured using a semi-automatic profiler developed for this study. Four gradations of armour stones were used giving a range in uniformity coefficient ( D 85 / D 15 ) of 1.35 to 5.4. The core of the breakwaters was relatively permeable. The volume of stones and the initial berm width required for development of a stable profile along with the extent to which the toe of the structure progressed seaward were chosen as representative parameters of the reshaped breakwater. The results indicated that the toe width formed as a result of reshaping and the volume of stones required for reshaping were dependent on the gradation of the armour stone. The initial berm width required for reshaping was also found to be dependent on the gradation and the percentage of rounded stones in the armour.

WAVE TRANSMISSION AT SUBMERGED RUBBLEMOUND BREAKWATERS

Detailed studies have been undertaken to assist in the design of major extensions to the port of Haifa. Both numerical and physical model studies were done to optimise the mooring conditions vis a vis the harbour approach and entrance layout. The adopted layout deviates from the normal straight approach to the harbour entrance. This layout, together with suitable aids to navigation, was found to be nautically acceptable, and generally better with regard to mooring conditions, on the basis of extensive nautical design studies.Hwa-Lian Harbour is located at the north-eastern coast of Taiwan, where is relatively exposed to the threat of typhoon waves from the Pacific Ocean. In the summer season, harbour resonance caused by typhoon waves which generated at the eastern ocean of the Philippine. In order to obtain a better understanding of the existing problem and find out a feasible solution to improve harbour instability. Typhoon waves measurement, wave characteristics analysis, down-time evaluation for harbour operation, hydraulic model tests are carried out in this program. Under the action of typhoon waves, the wave spectra show that inside the harbors short period energy component has been damped by breakwater, but the long period energy increased by resonance hundred times. The hydraulic model test can reproduce the prototype phenomena successfully. The result of model tests indicate that by constructing a jetty at the harbour entrance or building a short groin at the corner of terminal #25, the long period wave height amplification agitated by typhoon waves can be eliminated about 50%. The width of harbour basin 800m is about one half of wave length in the basin for period 140sec which occurs the maximum wave amplification.Two-stage methodology of shoreline prediction for long coastal segments is presented in the study. About 30-km stretch of seaward coast of the Hel Peninsula was selected for the analysis. In 1st stage the shoreline evolution was assessed ignoring local effects of man-made structures. Those calculations allowed the identification of potentially eroding spots and the explanation of causes of erosion. In 2nd stage a 2-km eroding sub-segment of the Peninsula in the vicinity of existing harbour was thoroughly examined including local man-induced effects. The computations properly reproduced the shoreline evolution along this sub-segment over a long period between 1934 and 1997.In connection with the dredging and reclamation works at the Oresund Link Project between Denmark and Sweden carried out by the Contractor, Oresund Marine Joint Venture (OMJV), an intensive spill monitoring campaign has been performed in order to fulfil the environmental requirements set by the Danish and Swedish Authorities. Spill in this context is defined as the overall amount of suspended sediment originating from dredging and reclamation activities leaving the working zone. The maximum spill limit is set to 5% of the dredged material, which has to be monitored, analysed and calculated within 25% accuracy. Velocity data are measured by means of a broad band ADCP and turbidity data by four OBS probes (output in FTU). The FTUs are converted into sediment content in mg/1 by water samples. The analyses carried out, results in high acceptance levels for the conversion to be implemented as a linear relation which can be forced through the origin. Furthermore analyses verifies that the applied setup with a 4-point turbidity profile is a reasonable approximation to the true turbidity profile. Finally the maximum turbidity is on average located at a distance 30-40% from the seabed.

BREAKING WAVES: REVIEW OF CHARACTERISTIC RELATIONSHIPS

The analysis of the water wave breaking phenomenon has been on-going for almost 150 years, and many research papers have been published approximating both the local geographic and geometric characteristics of breaking waves. This review of original empirical work, the relationships theorized by each author, and their regions of applicability are detailed to give a historical perspective of wave breaking research but also to illustrate advances in recent years. Subsequently published validity investigations by other authors show the variability and limitations of each approximation and illustrate that the level of understanding in wave breaking parameters has progressed considerably. The understanding of the defining variables in wave breaking progresses annually, however predicting the location, depth and shape of the wave at breaking is still not universally defined. This is in part due to the inherent variability in nature of breaking waves; however, it is compounded by a lack of a collective measurement and definition system for wave breaking parameters.

Humanitarian engineering placements in our own communities

There is an increasing interest in the humanitarian engineering curriculum, and a service-learning placement could be an important component of such a curriculum. International placements offer some important pedagogical advantages, but also have some practical and ethical limitations. Local community-based placements have the potential to be transformative for both the student and the community, although this potential is not always seen. In order to investigate the role of local placements, qualitative research interviews were conducted. Thirty-two semi-structured research interviews were conducted and analysed, resulting in a distinct outcome space. It is concluded that local humanitarian engineering placements greatly complement international placements and are strongly recommended if international placements are conducted. More importantly it is seen that we are better suited to address the marginalised in our own community, although it is often easier to see the needs of an outside populace.

Prediction of Incipient Breaking Wave-Heights Using Artificial Neural Networks and Empirical Relationships

The accurate prediction of shallow water breaking heights is paramount to better understanding complex nonlinear near shore coastal processes. Over the past 150 years, numerous empirical relationships have been proposed based on scaled laboratory datasets. This study utilizes a newly available field collected full-scale dataset of breaking wave conditions to investigate the accuracy of published empirical models and a novel artificial neural networks (ANN) model in predicting the final breaking wave-height for laboratory-scaled and full-scaled ocean waves. Performance is measured by comparison against both the field datasets and 465 separate datasets from 11 independent laboratory studies. The relationship of Rattanapitikon and Shibayama [2000 “Verification and modification of breaker height formulas,” Coastal Eng. J. 42 (4), 389–406.] outperformed all available empirical models when tested against only laboratory datasets, but was superseded by the relationship of Robertson et al. [2015 “Remote sensing of irregular breaking wave parameters in field conditions,” J. Coastal Res. 31 (2), 348–363.] when tested against only field datasets. However, this study noted that models developed based on scaled laboratory tests tend to underestimate the ocean full-scale breaking wave-heights. The training and testing of the ANN model were accomplished using 75% and 25% of the combined field and laborartory datasets. The ANN models consistently outperformed predictive accuracy of empirical models. Sensitivity analysis of the trained ANN models quantified the relative impact of individual wave parameters on the final breaking wave-height.