No description available.

No description available.

No description available.

Spatial and temporal variations in channel morphology, near-bed velocity, shear stress, bedload transport rate, pebble tracer movement, and bedload and bed material size distribution were measured in seven different channel patterns in two gravel-bed rivers in the Scottish Highlands (the Dubhaig and Feshie) and a proglacial stream in Norway (the Lyngsdalselva). The results showed that there were discernible links between the channel processes and changes which were consistent for all river types. 169 shear stress estimates from velocity profiles with changing discharge showed that Keller's (1971) velocity-reversal hypothesis holds true in different channel patterns of gravel-bed rivers and can be extended to include subunits of the pool/riffle cycle. At discharges near bankfull there is a decrease in the flow strength and amount of bedload movement from the poolhead down to the pooltail (and then riffle). On a broader scale 72 Helley-Smith bedload samples and the movement of over 3700 pebble tracers showed that the entrainment of different size fractions from heterogeneous bed material is inefficient and is overpredicted by the traditional bedload transport equations. Empirical analyses showed that when the armour is mobile/broken large and small particles have almost equal mobility as first proposed by Parker et al. (1982) and Andrews (1983). However for the majority of flow conditions the armour is static and entrainment is selective to a greater or lesser degree depending on the availability of appropriate-sized sediment at the surface and from bank erosion. The magnitude and direction of flow strength and bedload transport helps to explain the location and mode of channel development as revealed by repeated levelling and mapping. The accelerating convergent/decelerating divergent cells of flow alter the channel morphology in predictable ways. The positions of these cells can change with increasing discharge as the channel becomes generally, rather than locally, competent to move coarse sediment. The rates of bank erosion and volumetric scour and fill decreased from the active multi-braided system through to the stable straight channel type.

No description available.

No description available.

This thesis comprises the first systematic application of the theory of public goods to the study of the economics of Egypt during the 5000 years of its history. That history has provided an unparalleled experiment under quasi laboratory conditions. From the period of great coincidence that introduced agricultural technology in the Nile Valley, to the present day, that river with its system of irrigation has been an essentially indivisible instrument of production, a public good that has almost always dominated the economy. Over the ages, the country has been controlled by various rulers representing a number of very different civilizations: Pharaohs, Persians, Greeks, Romans, Arabs, Turks and British. Each new conquest influenced Egypt in its own way and introduced an element of foreign culture. Despite the diversity of these external influences, the qualities of timelessnes and changelessness have never ceased to mark the Egyptian scene. There has been a unique continuity in basic institutions and in the form and functions of government. In examining the economic history of Egypt, marked as it is by this same continuity, the present thesis proves to constitute a confirmation of the theory of public goods.

Graduation date: 1979

Drawdown is the lowering of the water level, and can refer to the groundwater, or the level of a river. In this thesis it will generally refer to a river going from a high flow condition to a lower flow condition. The rate of drawdown is expressed as either the change in flow per unit time, or the change in stage per unit time. The later is of most importance in terms of bank stability. (For complete abstract open document)

This research attempts to fill in some specific gaps in the area of economic valuation of non-market goods and services with respect to development projects, and the integration of those values in the policy decision-making process. The concept and theory of non-market valuation and project appraisal are examined. In a developing country context, the conventional contingent valuation method is extended to include respondents’ contribution in terms of time, irrespective of their decision to contribute money. This extension of the conventional contingent valuation method allows the inclusion of economic activities that are non-monetized and transactions in the form of ‘barter exchange’, which are typical for developing countries such as Bangladesh. The values generated by this new approach are integrated into an extended cost-benefit analysis, which reveals that the cleanup of dying rivers is not only an environmental imperative, but is also socially and economically justifiable. Apart from the theoretical investigation, another important dimension of this research is to contribute to the policy decision-making process with regard to public sector investment in developing countries. The Buriganga River, which passes through Dhaka City, the capital of Bangladesh, has been selected as the case study for this research. Although considered to be the lifeline of the capital, the city part of the Buriganga River has become biologically and hydrologically dead because of the indiscriminate dumping of domestic and industrial wastes, encroachment by unscrupulous people, and negligence on the part of the authority to enforce rules and regulations pertaining to the ecological health of the river. A cleanup programme has been designed for the Buriganga River to restore its water quality and develop new facilities in and around the river. This hypothetical cleanup programme is used: (i) to estimate the non-market benefits of an environmentally healthy waterway; (ii) to measure the total benefits; and (iii) to examine the desirability of public funding for the cleanup programme. An extended contingent valuation (ECV) survey of 400 households was carried out in Dhaka City in 2001. It reveals that not only are a significant proportion of the respondents willing to contribute direct cash for the environmental improvement of the river, they are also willing to contribute their time. When the contribution in terms of time is monetized, it is estimated to represent about 60 percent of the total contribution (the remaining 40 percent being cash payment). The total non-market benefits from the Buriganga River cleanup programme are estimated at Tk 388 million (US$ 6.80 million) in the first year, rising to Tk 1805 million (US$ 31.66 million) by the 10th year of the programme. The public decision making process in Bangladesh does not consider such benefits. Failures to do so lead to gross under-estimation of the potential for, and contribution of, undertaking environmental improvement activities. The total benefits of the cleanup programme are estimated within the framework of total economic value: the non-market benefits are estimated using the ECV survey inputs, and the market benefits are measured using secondary information, market methods and a benefit transfer approach. The cost estimate of the cleanup programme is made using market and secondary information with appropriate adjustments. The extended cost-benefit analysis (ECBA), which integrates the non-market benefits of the cleanup programme, shows that such public funding is worth undertaking. The study also reveals that a significant portion (68 percent) of this investable funding can be generated from the community. The need for a cleanup programme of the Buriganga River is not an isolated case in Bangladesh. Many rivers in that country, and also throughout the developed and developing world are under threat of becoming biologically and hydrologically dead. This study provides a framework for addressing such environmental problems. It demonstrates that the ECV survey is a useful tool in estimating economic values of resources even in extremely poor economies. The modification of the contingent valuation method takes into account the local context, including cultural, economic, social and political settings. The extended cost-benefit analysis, which integrates better resource values could provide important information for the policy decision-making process. This is particularly useful for countries where the democratic system is not fully developed and there is limited experience in integrating the environment into the decision making.