Superelevation transition is often used to help balance the centrifugal forces on vehicles through curved roadway sections. Such transitions have regions with near-zero cross-slope as the pavement cross-section rotates from a negative to positive grade. For drainage of roadway surfaces, regions with near-zero slope constitute 'irregular topography'. This condition promotes extended stormwater runoff drainage path lengths and may result in excessive splash from vehicles and hydroplaning. A critical concern is the effect of longitudinal slope on stormwater drainage through superelevation transition. The overall goal of this study is to provide design guidance on longitudinal slope at superelevation transitions through application of a numerical simulation model of highway drainage. Sheet flow on urban pavement surfaces is very shallow, typically measuring a depth less than one centimeter. For modeling of such flow conditions, any small discontinuity or over-simplification of the surface geometry may result in failure in the flow computation. The kinematic wave approximation to the full Saint-Venant equations is often used in many surface and subsurface water models due to its simplicity in application. However, this model fails when backwater effects, ponding, or flow on reverse slope occurs in the local scale. Furthermore, due to the complexity in the surface geometry and the existence of drainage systems, the kinematic wave model is not sufficient for modeling urban stormwater runoff. On the other hand, the full dynamic wave (DW) model usually requires more computational effort. The long computation time of DW model often compromises the accuracy of the model, making the model practically inefficient. In this study, an algorithm was developed to properly represent the irregularly shaped roadway surfaces near superelevation transition areas with unevenly spaced curvilinear grids based on the geometry profile provided by a roadway design software package such as MicroStation CAD. With this accurately defined geometric representation, a nonlinear hydrodynamic diffusion wave model for hydraulic analysis developed in this research estimates the flow depth and runoff volume on the pavement surfaces. The model computes the flow responses for rising hydrographs using a preconditioned general Conjugate Gradient method. Kinematic boundary conditions developed for the open boundaries at the upstream and downstream boundaries compute the boundary values explicitly at each time step. The result of a numerical experiment shows that the spread and concentration of sheet flow is closely related to the transition in cross slope, longitudinal slope, rainfall intensity, and the width of the road. The characteristics of the sheet flow on superelevation transition areas are analyzed to find the optimal longitudinal slope. It is found that the longitudinal slope in the range of 0.3%-0.4% is the optimal slope at superelevation transition areas which minimizes the depth of stormwater runoff. An example application of the model on a rural highway in Texas is also presented. It is found that a significant amount of stormwater may exist on traffic lanes at the superelevation transitions tested. The predicted ponding depth exceeds the minimum value for potential hydroplaning, and the pattern of the flow concentration may cause differential drag forces on traffic vehicles. / text

Two locations, Lake Ivanhoe and the Maitland interchange of Interstate 4, were selected to study the impact of bridge runoff on receiving water bodies. The Lake Ivanhoe location includes two similar bridges, one without scuppers and one with scuppers. The Maitland interchange site has several borr ponds which drain to Lake Lucien. Samples were collected from Lake Ivanhoe below the bridges and in the open lake away from the bridges. Also samples were collected from the east pond, west pond, and lake Lucien, at the Maitland interchange. Samples included water, sediments, plants and benthos to detect differences, if any, in heavy metal concentration due to sampling location. Heavy metals tested included: ZN, Cu, Cr, Cd, Pb, As, Fe, and Ni. Dissolved oxygen, temperature profiles and secchi desk transparency were measured in the field. Additional water quality parameters such as pH, turbidity, carbon and phosphorus were evaluated. Results indicated significant differences in specific heavy metal concentrations exist between samples collected beneath a bridge with scuppers compared to samples collected beneath a bridge without scuppers. Also, the drainage ponds appear to contain more heavy metals than the adjacent Lake Lucien at the Maitland interchange.

M.S.

ABSTRACT Continuous flow column studies were conducted to characterize suspended sol ids and heavy metal reduct ions through sedimentation with varying overflow rates. The heavy metals tested were cadmium, zinc, copper, iron, lead, nickel and chromium. Stormwater derived samples spiked with street sweepings categorized into particle size ranges less than 500 microns in diameter were utilized in the research. Overflow rates investigated ranged from 28 to 3600 gallons per day per square foot. Theoretical predictions of suspended solids reductions with the application of Stoke's Law exceeded observed reductions for the continuous flow system. Performance curves for all reductions over the observed range of overflow rates are described by a parabolic relationship with the general equation as follows: Reduced fraction= a+ b(Overflow Rate - c) 2 where a, b and c are constants specific to each parameter. Similarities in performance curves for all metals indicate a dependence on suspended solids for reductions. Cadmium and chromium reductions were a function of overflow rate, but did not show a statistically significant dependence on initial total suspended solids concentration. Lead, copper, zinc and iron reductions were a function of initial total suspended solids concentration as well as overflow rate. Iron and nickel exhibited dependence on initial concentration of the specific metal for reductions, as well as dependence on overflow rate and initial total suspended solids concentration. The steady-state models selected from the results of this research for total suspended sol ids and each of the heavy metals are limited to the mixture, specific experimental conditions, and range of overflow rates observed in this research. Observed reductions of total suspended solids and heavy metals are considered to be 1 imited to physical sedimentation processes, in that processes that may effect reductions of these elements in a natural system are not factors in the results of this research.

Copper and zinc are heavy metals commonly present in highway stormwater runoff. Discharge of these metals to surface waters inhabited by sensitive aquatic species including threatened and endangered salmonids has necessitated the need for improved treatment techniques. Although copper is of the greater toxicological concern, zinc is often present at concentrations several times higher than copper and may compete with copper during adsorptive treatment processes. In the current study, the ability biogenic fish-bone based alternative adsorbent, Apatite II™, for copper and zinc removal from synthetic stormwater runoff was evaluated. Batch experiments were employed to examine equilibrium removal and rapid small scale column tests (RSSCT) were used to simulate dynamic operation in continuous systems. In both batch and continuous systems, the release of phosphate and calcium were observed, and Apatite II™ achieved high removal efficiencies. The removal of copper and zinc was likely due to a combination of processes including adsorption, ion exchange and precipitation. Precipitation played a dominant role in copper removal and the release of phosphate and pH buffering appear to drive this process. While precipitation was also quite important for zinc removal, adsorptive removal also played a role. The findings from the current study provide a general understanding of the performance of copper and zinc removal from stormwater runoff using Apatite II™. / Graduation date: 2012

Les routes sont normalement pourvues de systèmes de drainage dimensionnés et exécutés conformément aux règles de l’art en vue d’évacuer, le plus rapidement possible de l’emprise de la route, les eaux des précipitations à considérer sur la base des périodes de retour prises en compte. Toutefois, il subsiste souvent des écoulements d’eau indésirables au niveau des talus et parfois dans les accotements et/ou les surfaces de roulement non imperméabilisées. Une succession de pluies entraîne des infiltrations d’eau qui varient notamment en fonction des conditions climatiques et suivant la texture et la structure du sol. De telles infiltrations ont pour conséquence la réduction des coefficients de sécurité des talus.<p><p>Bien qu’il existe plusieurs publications scientifiques traitant de pluies qui ont conduit à des glissements de terrain (Lim et al. 1996 ;Cho et al. 2001 ;Kim et al. 2004 ;Xue et al. 2007 ;Gavin et al. 2008), les incidences des infiltrations résultant de pluies successives sur le comportement des couches superficielles des sols non saturés ne sont généralement pas prises en compte. Les modèles permettant le calcul de la stabilité de talus des massifs de sols non saturés exigent beaucoup de paramètres parfois difficiles à évaluer et se rapportent ordinairement aux cas d’instabilité provoqués par une remontée du niveau piézométrique des nappes phréatiques.<p><p>Sur la base des essais réalisés en laboratoire, une méthodologie adaptée permettant d’évaluer la variation spatio-temporelle de la teneur en eau du sol en fonction d’une suite de pluies a été développée. Cette méthodologie facilite la prise en compte des effets cumulés des taux d’infiltration associés aux évènements pluvieux et permet d’en déduire le profil de succion ainsi que celui de la cohésion apparente à utiliser en vue de calculer, pour une inclinaison β du talus, l’intervalle de variation du coefficient de sécurité Fs. La méthodologie développée présente un intérêt particulier dans le cas de budgets et infrastructures limités.<p><p>ABSTRACT<p><p>Roads are normally equipped with drainage systems sized and implemented in accordance with the rules of art to evacuate as quickly as possible to the right of way, water precipitation to be considered on the basis of return periods taken into account. However, there are often water flows at the slope side and sometimes in the shoulders and / or running surfaces that are not waterproof. A succession of rain causes a certain amount of water infiltration, which varies according to climatic conditions and depending on the soil texture and structure. Such infiltrations have resulted in reduced safety factor of slopes.<p><p>Although there are several scientific publications on rainfall leading to landslides (Lim et al. 1996; Cho et al. 2001, Kim et al. 2004; Xue et al. 2007; Gavin and al. 2008), impacts resulting from infiltration of successive rains on the behavior of surface layers of unsaturated soils are usually not taken into account. Models for calculating the slope stability of unsaturated soils require many parameters that can be, in certain circumstances, difficult to assess and refer generally to cases of instability caused by a rise in groundwater level.<p><p>Based on laboratory tests, a suitable methodology for assessing the spatial and temporal variation of soil water content induced by a set of rains has been developed. This methodology facilitates the inclusion of the cumulative effects of the infiltration rates associated with rain events and infers from them the profile of suction and that of the apparent cohesion to be used to calculate, for a slope angle β, the range of variation of the safety factor Fs. This methodology is particularly relevant in the case of limited budgets and infrastructures. / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished