Hydrotechnical studies of Peter's River

• Published in: Canadian Journal of Civil Engineering
• Main Authors: Lye, Leonard M., Sharp, James J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1994
• Subjects: General Environmental Science; Civil and Structural Engineering; Weir; Newfoundland
• Online Access: http://dx.doi.org/10.1139/l94-012; http://www.nrcresearchpress.com/doi/pdf/10.1139/l94-012

Peter's River in central Newfoundland supplies water to the town of Botwood from an intake located at a point just upstream of a right-angled bend. The pumphouse is situated on the outer bank of the river and is constructed on a foundation of sandy silt. In 1983, a large flood eroded part of the bank and removed vegetation which had provided a protective cover. Progressive erosion then threatened the pumphouse and forced an engineering assessment of the situation. This was conducted in the winter of 1984–1985 and included the prediction of the 50- and 100-year floods from the minimal data (4 years of records) which were then available. Estimates were made of velocities and flood levels, and various protection schemes were considered.The installation of a revetment in 1986 stabilized the bank, but icing on the intake had always caused problems and these continued unabated. In winter, frazil ice adhered to the submerged intake structure and was drawn into the pumps causing frequent shutdowns. Various solutions, including electrical heating, were considered. However, in 1991, a decision was made to install infiltration pipes below the stream bed, to raise water levels with a small broad crested weir and to disconnect the existing intake. Flow estimates were again required, both for construction purposes and for responding to the Department of Fisheries requirement that there would be no immediate or long-term harm to fish habitat.This paper provides a brief description of the general problems, but focuses primarily on the methods used, 8 years apart, to estimate flood data. These methods were intended to be relatively unsophisticated, but were consistent with the magnitude of the river and the relatively small scale of the proposed works. In the study conducted in 1984–1985, only 4 years of records were available and the estimation of the 50- and 100-year floods relied strongly on the use of regional equations, the development of unit hydrographs, and one large recorded flood. The more extensive record available in ...