Date of Award

1-1-2016

Document Type

Master Thesis

Degree Name

Master of Engineering (Research)

Department

Civil, Structural, & Environmental Engineering

First Advisor

Dr Joseph Harrington

Abstract

Sediment behaviour and transport in river systems has been studied for centuries and potentially impacts on river capacity, navigation, water quality, ecology and flooding. This thesis investigates sediment behaviour and transport on the River Bandon, a river system which has experienced severe flooding on a periodic basis. The River Bandon is located in the South Western River Basin District with a total catchment area of 608km“. The River Bandon offers a positive environment for biodiversity, facilitating habitats for some endangered species. This thesis presents a literature review on the River Bandon and its catchment, on sediment behaviour and transport and on numerical modelling in the riverine environment. A detailed river flow extreme analysis is presented, for the two long term hydrometric station on the river, at Bandon Bridge and further downstream at Curranure. A suspended sediment and bed sediment sampling programme at five river locations was undertaken and the results are presented. Suspended sediment data was supplemented by data gathered from a turbidity sensor and an automatic water sampler. Bed load traps were also installed. Detailed sediment analyses are presented. The river sediment behaviour may be characterised as dynamic in nature with low suspended sediment concentrations punctuated by high values on higher river flows. Bed load transport of coarse sediment is also a feature of the system. A HEC-RAS numerical model was calibrated, validated and applied to the river system. Hydraulic calibration and validation was completed satisfactorily; sediment calibration was limited in extent. The model was applied to the current river conditions to predict deposition and erosion mass and sediment transport rates; it was also applied to assess the potential impacts of the proposed river improvement works planned by the Office of Public Works. Model results indicate current deposition patterns which are consistent with historic data and field observation. The model results indicate, in general, a significant reduction in predicted deposition patterns after completion of the river improvement works and also some potential reduction in bed load transport rates.

Access Level

info:eu-repo/semantics/openAccess

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