Streamflow variability can provide valuable information for nonpoint source pollution monitoring program planning. The research papers presented in this thesis examine selected properties of streamflow variability in Oregon to advance its application in regional planning of water quality monitoring programs. The products of this research depict Oregon streams by their relative streamflow variability and evaluate factors that may influence that variability. The three manuscripts examine the application of streamflow variability in the context of regional strategic planning by addressing three related questions: 1.) What is the relationship in Oregon between streamflow variability and watershed size, which is often described as a proxy for streamflow variability?, 2.) What geographic factors in Oregon influence streamflow variability, and are regionalscale factors adequate to efficiently predict streamflow variability on ungaged streams?, and 3.) How is streamflow variability in Oregon affected by seasonal climatic variation? Examination of these questions regarding the behavior of streamflow variability of river systems in Oregon is used to assist in the design of regional and local water quality monitoring programs. Data are from historical records of established US Geological Survey gaging stations. Simple linear regression depicts the relationship of streamflow variability to basin size on a statewide basis and stratified by ecoregions. The results indicate that basin area is not an appropriate indicator of streamflow variability. Multiple regression is used to develop regional models of streamflow variability. Three models are developed for natural flow streams and streams with upstream diversions. Regional and watershed scale variables are evaluated for their potential contributions to the models. Watershed scale variables do not increase the predictive capacity of the models; therefore, the regional scale is appropriate for efficiently modeling streamflow variability. Seasonal investigation of streamflow variability in Oregon develops its application for seasonal monitoring programs. Spatial and temporal analysis reveal a weak relationship between annual and monthly streamflow variability, indicating potential for refined application of the variability index. Streamflow variability is an accessible tool for developing water quality monitoring programs. The regional scale distribution of streamflow variability in Oregon demonstrates the ease at which streamflow variability may be estimated on ungaged streams. / Graduation date: 1998

A simple correlation analysis was used to investigate the linear relationships between sea surface temperature (SST) and monthly flow of Ganges and Brahmaputra at the borders of Bangladesh and India using approximately 50 years of river discharge data. Strong correlations were found between the equatorial Pacific SST and boreal summer Ganges discharge from three-month lag to two-month lead times. The El Nio-Southern Oscillation (ENSO) explains Ganges flow variance exceeding 0.95 significance level using both the Nino 3.4 SST correlation and the composites made for El Nio (La Nina) periods. The May SST of the southwest Pacific Ocean to the east of Australia continent has a strong correlation (>0.6) with early summer Ganges discharges. Using a lag correlation analysis of Ganges discharge and SST, we found a steady and continuous development in the Nino 3.4 SST relationship, and a strong correlation with the southwest Pacific SST which is most pronounced three-four months prior to the onset of Asian summer monsoon. These relationships mean that at least 25% of the interannual summer Ganges River discharge variability can be explained by antecedent equatorial and southwest Pacific SST. It provides a possible statistical method for linear forecasting two or three months in advance. The Brahmaputra River discharge, on the other hand, shows weak relationships with tropical SST variability except for the Bay of Bengal and the higher northern latitudes of the Pacific.

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published_or_final_version / abstract / toc / Mechanical Engineering / Master / Master of Philosophy

No description available.

Project Completion Report, OWRT Project No. A-051-ARIZ / Agreement No. 14-31-0001-5003 / Project Dates: July 1974 - June 1975 / Acknowledgement: The work upon which this report is based was supported by funds provided by the United States Department of the Interior, Office of Water Research and Technology, as authorized under the Water Resources Research Act of 1978. / Bio-physicochemical measurements were made on treated sewage effluent releases at established locations within the channel of an ephemeral stream, the Santa Cruz River of Southern Arizona. Water samples were taken in chronological sequence as the effluent moved downstream, to trace changes in quality parameters during low and high hydrograph stages. Results indicate that dissolved oxygen (DO) concentrations at low effluent flows were higher than DO concentrations at high effluent flows; while, conversely, biochemical oxygen demand (BOD) concentrations at low effluent flows were generally lower than BOD concentrations at high effluent flows. Biochemical oxygen demand concentrations are affected by waste loadings, flow conditions, phytoplankton growth and nitrification. Mean river deoxygenation rates (k ) in sewage flows after six river miles from the Tucson Sewage Treatment Plant were always negative or increasing, indicative of nitrification, algal growth, and concentration of organic constituents through seepage losses.

Demands on the water resources of South Africa are ever increasing owing to population growth and increased development of urban, peri-urban and rural communities. Problems in terms of water quantity and quality are likely to be experienced during baseflow recessions. It is therefore imperative that water resources managers not only understand these baseflow periods of streamflow, but are able to model them with confidence. Research for this study thus included a comprehensive literature survey of the factors which affect baseflow as well as the approaches that previous studies have utilised to analyse and model baseflow recession. The primary aims of this study were to establish a streamflow database, to construct master recession curves (MRCs) for each catchment under consideration, evaluate the assumption that South African rivers recede exponentially, to determine a representative set of catchment characteristics for use in the baseflow recession analysis, to attempt to explain the MRC trends using these catchment characteristics and to investigate the feasibility of establishing a rule based model for baseflow recession. A streamflow database for South Africa was therefore established. This consisted initially of 202 catchments which were deemed to be recording natural streamflow. MRCs were established for 134 of these catchments. Those MRCs which were established indicate that the majority of South African rivers do not conform to an exponential model of recession. In order to account for the trends defined by the MRCs, catchment area, average catchment slope, drainage density, mean annual precipitation, rainfall concentration, rainfall seasonality, two independent estimates of groundwater recharge and a geological index were calculated for each catchment. Limited success was achieved when the data set was divided into subsets in order to group catchments with similar baseflow recession responses. The geological composition of the catchments appeared to provide the best results in that those trends exhibited by the MRCs could be explained by the types and proportions of the lithologies present. Owing to the lack of readily useable results it was concluded that until further results were forthcoming the development of a rule based model for baseflow recession analysis in South Africa would be premature. The establishment of a readily accessible database containing streamflows and associated catchment characteristics lends itself to future research. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1997.

The aim of this research project was to estimate parameters for the distribution of annual maximum flood levels for the Zambezi River at Katima Mulilo. The estimation of parameters was done by using the maximum likelihood method. The study aimed to explore data of the Zambezi's annual maximum flood heights at Katima Mulilo by means of fitting the Gumbel, Weibull and the generalized extreme value distributions and evaluated their goodness of fit.

Thesis (Ph. D.)--University of Newcastle, 1999. / Department of Civil, Surveying and Environmental Engineering. Includes bibliographical references (leaves 246-255). Also available online.

Thesis (M.S.)--University of Tennessee, Knoxville, 2008. / Title from title page screen (viewed on Mar. 12, 2009). Thesis advisor: Carol Harden. Vita. Includes bibliographical references.