Thesis (M.S.)--Michigan State University. Dept. of Resource Development, 1976. / Includes bibliographical references (leaves 197-203).

The regulation of the Manama river, one of the major Orinoco distributary channels, has instigated changes in the hydrological and sedimentological regimes of its channel and surrounding wetlands, covering one-third of the Delta area. The dam has altered the hydrodynamics of the Manama. While the average flow of its channel was reduced from 10% to 0.5% (200 m3/s), of the annual discharge of the Orinoco River. The adjacent Macareo distributary, which is not regulated, discharges 11% (4,000 m3/s) annually. During the seasonal high-water period, the water level in the Macareo rises approximately 7 m, while in the Manama is restricted to an periodic oscillation of 0.7 to 1.2 m due mainly to the tidal influence. This flow reduction not only affects the accretion and erosive processes of the banks, due to the decrease of transport of sediments, but also the composition, distribution and diversity of aquatic plants in the region, particularly along the river shores where the species diversity tend to be lower in the regulated river than in the unregulated. The change in the hydrologic dynamic has promoted broad floating meadows to develop in the upper reaches of the Manama river creating patches of rafting meadows. The cessation of the annual flooding has allowed an extensive intrusion of saline water from the sea, which only occur during the dry season. This has enabled halophytic species, particularly mangrove communities to expand their distribution upriver and has also forced the migration of part of the Delta inhabitants Creole and Indians, resulting in a modification of the distribution of the forest and marsh ecological communities due to the overexploitation of their subsistence resources. The particular characteristics of the region that have remained mostly undisturbed since the dam construction several decades ago, permit a comparison of 30 years period of the long-term physical and biological characteristics of a regulated (Manamo) and unaltered (Maca reo) distributary. This thesis investigates these changes and propose a model of the river regulation effects on the ecosystem properties and an equilibrium model of the disturbance and the gain of a new steady state of the ecosystems compartments.

In the search for energy many proposals have been made to harness the rivers of British Columbia, but the one for the Moran canyon on the Fraser River has the widest implications. A dam on this site, 800 feet high and 2400 feet wide, could produce initially 4 million horsepower of electricity at low cost. In addition it would hold the key to flood control on the Fraser River and to expansion of navigation, industrial location and agriculture. It would be located on part of the river believed by many to have considerable potential for future salmon runs. While each of these aspects of the dam is important when considered by its proponents, together they indicate a unique possibility of widening the economic base of the province. One aspect, the effect of the dam on agriculture, is the subject of this study. Moran Dam, it is believed, will affect agriculture in three major ways: (1) It will flood the Fraser Valley for a distance of 172 miles north of Moran to a maximum elevation of 1540 feet; (2) it will provide low cost hydro-electric power for use in pumping irrigation water and for rural electrification; (3) it will provide low cost energy which may act as a factor in the location of electrically-oriented industries, and in turn through an increased work force create larger markets for agricultural products. It is these influences on agriculture related to the land and people of British Columbia that concerns this thesis. To collect the necessary data four week-long trips were made to the agricultural areas of the Fraser Basin in the fall of 1957. Land-use was mapped and location of farms, ranches and significant landforms upon which agriculture could be undertaken were mapped. Later airphotos and maps were studied. The reasons for proposing the Moran Dam along with a comparison between this dam and others within the province were reviewed. Next followed a description of the landforms, climate, soils, vegetation and hydrology, the components of the Physical Geography. A consideration of the present value, location and nature of agricultural activity and the extent to which foodstuffs have been imported into the province was made. Another aspect studied was the human geography. As the Fraser River Basin was found too large to study as a whole a sub-regional breakdown was made within which the various aspects of the problem were discussed. The sub-regions were Lytton to Moran, Moran to Williams Lake River, Williams Lake River to Quesnel and the adjacent areas of the Thompson Valley, Chilcotin and Cariboo plateau. Flooding was found to be restricted because of the physical nature of the valley with its steep slopes rising from the river to a more or less continuous series of benches 100 to 800 feet above its present bed. Thus only about 3000 acres of arable land, now chiefly utilized for winter grazing would be flooded, while about 45,000 acres could be intensively cultivated with irrigation water pumped from the reservoir. If the adjacent regions were included, where flooding is not a factor, pumping plants utilizing low cost electrical energy could make available an additional 20,000 acres. Since British Columbia at present imports large quantities of foodstuffs, additional population expected to work in electrically-oriented industries would necessitate importation of even larger quantities of foodstuffs unless some of the 65,000 acres were developed. Many of these are in areas with a relatively long growing season, large accumulated temperatures and low precipitation. Soils are fertile and the prospects for the intensive cultivation of vegetables, fruits and forage crops, plus the establishment of "feed lot" type cattle operations, in place of extensive grazing of cattle, could be expected. The costs of expanding agriculture in this region, however, would have to be competitive with other areas where irrigation agriculture is undertaken. This expansion of agriculture, desirable to meet the growing deficit in foodstuffs within British Columbia, would be dependent on the advent of large scale pumping irrigation works contingent on the construction of Moran Dam. No other proposal has been made of comparable import to the diversification of the economic base of the province. The impact of the proposal on agriculture alone is impressive. / Arts, Faculty of / Geography, Department of / Graduate

This thesis describes the development of a method for determining the most efficient way to operate an upstream flood control reservoir for maximum flood peak reduction at a downstream point. Linear programming is used as the optimization technique. A simplified case is studied, namely that of a single storage reservoir approximately 500 miles upstream from the area to be protected. A channel routing method which was linear was required for use with linear programming. For this reason a Muskingum type channel routing method was chosen. The results for the three years that were studied are presented in graphical form. They indicate the extent that the downstream peak could be reduced and the operation of the upstream reservoir which would be required to bring about this reduction in peak flow. Procedures for extending the technique to more complex systems and possible applications of the method are discussed. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

No description available.

No description available.

Thesis (PhD(Engineering)(Civil Engineering)) --University of Pretoria, 2007. / Includes bibliographical references.

No description available.

No description available.

The residual flow procedure (RFP) is used to conjunction with finite element method for solution of steady state free surface seepage in dams containing open cracks. The cracks are simulated using the thin-layer element concept. A comprehensive parametric study is performed to analyze the applicability of the numerical procedure with the thin layer element. Here, vertically trending as well as horizontally trending open cracks are considered with variable lengths, widths, and conductivities. It is found that the numerical results involve oscillatory, unstable, and physically unreasonable behavior beyond critical values of the geometry and conductivities. Here, the vertically trending configurations are found to be relatively more sensitive than the horizontally trending configurations. Although additional research will be needed to analyze other factors such as different crack geometries, transient flow, and different ratios of crack conductivities to surrounding soil conductivities, the results presented here suggest that the procedure can be applied for seepage analysis in dams containing open cracks.