Author(s)

J. R. Harrington & S. T. Harrington

Abstract

This paper presents aspects of sediment and nutrient behaviour on the River Bandon which is located in the South Western River Basin District in Ireland; it is a relatively large sized river catchment in an Irish context with a catchment area of 608 km2. The river catchment is primarily agricultural with some pockets of urban development. The river is prone to flooding on stretches, features a number of special areas of conservation and is distinguished by both suspended and bed load transport. Continuous monitoring of turbidity commenced in February 2010. Manual sampling and testing for suspended sediment concentration and a range of species of phosphorous was also undertaken. Analysis shows that turbidity is a suitable surrogate for suspended sediment concentration allowing suspended sediment loads to be analysed from the continuous data. Similarly suspended sediment concentration has been found to correlate well with total and particulate phosphorous allowing phosphorous loads to be analysed using the continuous data. The annual suspended sediment load was 6012 tonnes, with the highest loads experienced during the winter months. The annual total phosphorous load was found to be 42.9 tonnes with particulate phosphorous accounting for approximately 64% of this total. High flow storm based events contribute disproportionately to suspended sediment and phosphorous transport. The rating curve approach applied to the sampled data can provide good estimates of the annual load which has particular relevance to Ireland where the current database of suspended sediment information is limited.

Keywords

suspended sediment, turbidity, phosphorous, loads, particulate, Strom based events, rating curve