Thesis. 1979. M.C.P.--Massachusetts Institute of Technology. Dept. of Urban Studies and Planning. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH. / Bibliography: leaves 127-130. / M.C.P.

This study assessed how logging-access roads may have contributed to observed historical increases in peak discharges associated with small and large logged basins in the western Cascades of Oregon. The study was conducted on the Lookout Creek (62km��) and the upper Blue River (118km��) basins. Potential road effects on hydrology were examined using a combination of field surveys and spatial modeling with a geographic information system (GIS). Road networks were similar in both basins with respect to hillslope position, orientation, and stream crossings, but roads in Blue River were constructed one or two decades later than roads in Lookout Creek. A total of 20% (62 km) of the road length was sampled to assess routing of surface flow, using 31 2-km transects stratified by decade of construction and hillslope position. Along each transect, ditches and culvert outlets were examined and this information used to predict the probable routing of water to (1) existing stream channels, (2) newly eroded gullies downslope of culvert outlets, or (3) subsurface flow. Nearly 60% of the surveyed road length appeared to route water directly to stream channels or into gullies. Over time, the length of road connected to stream crossings has decreased, while the length of road discharging runoff that reinfiltrates to subsurface flow has increased, as roads have progressed up hillslopes and onto ridges in Lookout Creek and Blue River. The relatively constant proportion of the road network draining to gullies over time suggests that roads have the potential to become integrated into stream networks, even when constructed on unchannelled hillslope positions. An extended stream network, assumed to exist under storm conditions, was simulated for the basins using a digital elevation model. Although gullies and ditches differ from natural channels, extrapolation of field surveys using the GIS suggested that roads might extend the stream network by as much as 40% during storm events. It is hypothesized that such an effect could decrease the time of concentration of stormflow and contribute to higher peak discharges observed after clearcutting and road construction in these basins. Differences in the magnitude of road effects on peak flow generation may occur among road systems according to hillslope position of roads, road age, soil saturation, geologic substrate, and climate. These differences may explain the range of observed results from paired-basin studies examining road effects on hydrologic response. / Graduation date: 1994

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published_or_final_version / Public Administration / Master / Master of Public Administration

published_or_final_version / Public Administration / Master / Master of Public Administration

Decisions made regarding road building have far-flung consequences. Spending money on roads means that other public goals such as farmland preservation, air quality improvement and provision of housing may be frustrated. In order for knowledgeable land-use decisions to be made, the full cost of roads needs to be examined. This thesis explores the issue of roadway land costs from a professional planning point of view. A method for calculating roadway land costs is developed and is then applied to provincially-funded roads in the Greater Vancouver region. The case study revealed that annual provincial roadway land costs amount to approximately $162 per automobile. Limited supplies of land and limited financial resources suggest that it may be time to examine approaches that would make it less necessary to add capacity to the existing road network. Expenditures on roads can be reduced by shifting from current "supply side" tactics. This thesis suggests various policies that could be enacted to effect such a change.

River stage or flow rates are required for the design and evaluation of hydraulic structures. Most river reaches are ungauged and a methodology is needed to estimate the stages, or rates of flow, at specific locations in streams where no measurements are available. Flood routing techniques are utilised to estimate the stages, or rates of flow, in order to predict flood wave propagation along river reaches. Models can be developed for gauged catchments and their parameters related to physical characteristics such as slope, reach width, reach length so that the approach can be applied to ungauged catchments in the region. The objective of this study is to assess Muskingum-based methods for flow routing ill ungauged river reaches, both with and without lateral inflows. Using observed data, the model parameters were calibrated to assess performance of the Muskingum flood routing procedures and the Muskingum-Cunge method was then assessed using catchment derived parameters for use in ungauged river reaches. The Muskingum parameters were derived from empirically estimated variables and variables estimated from assumed river cross-sections within the selected river reaches used. Three sub-catchments in the Thukela catchment in KwaZulu-Natal, South Africa were selected for analyses, with river lengths of 4, 21 and 54 km. The slopes of the river reaches and reach lengths were derived from a digital elevation model. Manning roughness coefficients were estimated from field observations. Flow variables such as velocity, hydraulic radius, wetted perimeters, flow depth and top flow width were determined from empirical equations and cross-sections of the selected rivers. Lateral inflows to long river reaches were estimated from the Saint-Venant equation. Observed events were extracted for each sub-catchment to assess the Muskingum-Cunge parameter estimation method and Three-parameter Muskingum method. The extracted events were further analysed using empirically estimated flow variables. The performances of the methods were evaluated by comparing both graphically and statistically the simulated and observed hydrographs. Sensitivity analyses were undertaken using three selected events and a 50% variation in selected input variables was used to identify sensitive variablesThe performance of the calibrated Muskingum-Cunge flood routing method using observed hydrographs displayed acceptable results. Therefore, the Muskingum-Cunge flood routing method was applied in ungauged catchments, with variables estimated empirically. The results obtained shows that the computed outflow hydrographs generated using the Muskingum-Cunge method, with the empirically estimated variables and variables estimated from cross-sections of the selected rivers resulted in reasonably accurate computed outflow hydrographs with respect to peak discharge, timing of peak flow and volume. From this study, it is concluded that the Muskingum-Cunge method can be applied to route floods in ungauged catchments in the Thukela catchment and it is postulated that the method can be used to route floods in other ungauged rivers in South Africa. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2005.

The goal of the research is to devise an equitable road pricing system which would leave the majority of routes free of tolls, so that low income people would suffer no cash loss although they would probably suffer loss of time. The aims of the dissertation are twofold. The first is to provide a numerical analysis of how urban commuters with differing abilities to pay would respond to additional road user charges. The welfare implications of such differential responses are examined and their policy implications analysed. The second aim is to develop a practical framework to model congestion pricing policies in the context of heterogeneous users. To achieve these aims, the following objectives have been set: (a) Using a simple network with two parallel competing routes, determine both welfare maximising and revenue maximising tolls under the constraint that only one route can be priced. In this setting, determine the allocation of traffic between the alternative routes, the efficiency gain, the revenue, the changes in travel cost and the distributional effects. (b) Establish a realistic model of an actual urban area to examine the impacts of selectively tolling congestible routes. As in the simple network case, assess the effects of toll policy on traffic distribution, network efficiency, revenues, and the welfare of the individual consumer and society. (c) Evaluate whether the non-identical treatment of users will enhance the acceptability of congestion pricing as a transport policy. Results from the simulations indicate that non-identical treatment of drivers? responses to toll charges provides better understanding of the differential impacts of various pricing policies. Allowing for heterogeneity in time valuation provides a better assessment of the efficiency of pricing policies and of the welfare impacts of toll charges, as it is able to capture their differential effects. More importantly, it shows that low-income commuters may not be significantly worse off with pricing especially when there is a free alternative route. This research demonstrates the need to adopt appropriate analytical techniques and assumptions when modelling the traffic equilibrium in a network with tolls. These include relaxing the homogeneity assumption, examining sensitivity to supply function parameter values and to the effect of vehicle operating cost, and using a route rather than link based measure of consumer surplus

Thesis (doctoral of philosophy)--University of Leeds, 1977. / Twenty-five plans on folded leaves in pocket. Bibliography: p. 333-350.