Side-channel weirs can be used for flood control to divert part of a channel's flow into detention basins, thereby reducing peak discharges and stages. After passage of the flood peak, the stored water can be released back to the channel. The Harris County (Texas) Flood Control District is planning the use of several side-channel weirs which will discharge into regional detention basins. The weirs are being designed to divert approximately 50% of peak flows of up to 25,000 cfs, with accompanying depths of up to 25 feet in the channels. A 1:25 scale model was built to investigate the hydraulic characteristics of embankment-shaped side-channel weirs. This thesis describes the model, its use, and the results obtained from the model study. Particular attention has been given to 1) quantification of the discharge which flows over a side-channel weir for given weir geometries and channel flow conditions, 2) the changes which occur in the channel stage along the length of the side-channel weir as water flows past and over the weir, 3) the effects of submergence on the side-channel weir discharge and channel stages, and 4) the effect of tapering the channel (i.e., progressively reducing its width) along the length of the weir. The standard equation for discharge over a normal broad-crested weir was modified slightly for side-weir applications and a bulk discharge coefficient (C[subscript e]) was used. C[subscript e] was correlated with channel flow parameters and weir geometric parameters. The side-weir discharge causes a head change along the weir in addition to the frictional head loss. This additional head change (h[subscript c]) is needed to determine the change in stage between the ends of the weir. The model results were used to calculate h[subscript c] using the energy equation; h[subscript c] was then correlated with channel flow conditions and weir geometric parameters. Submergence effects were characterized by determining the decrease in the bulk discharge coefficient and in the additional head change along the weir for varying values of submergence. Similar analyses were made to determine the side-weir discharge and stage change for weirs placed in tapered channels.

Side weirs are widely used to divert or discharge flows from reservoirs, rivers, artificial channels and sewers. The hydraulic behaviour of this type of weir is complex and difficult to predict accurately using simple methods and the diversity of applictions of side weirs has the potential to complicate guidance. This manual covers the fundamental hydraulic principles and discusses the practical design issues separately for each main strcuture type.

Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) * at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all con cerned if the printing and distribution of the volumes were handled by an interna tional publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Cor poration of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 34 (thesis year 1989) a total of 13,377 theses titles from 26 Canadian and 184 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this important annual reference work. While Volume 34 reports theses submitted in 1989, on occasion, certain univer sities do report theses submitted in previous years but not reported at the time.