Toward innovative management of canal systems: determining fundamental properties governing channel flow and transport.
Abstract
This research investigates current and future influences on the water quality of canal systems with the aim of designing innovative management strategies for their improvement. The implementation of the Water Framework Directive (WFD) will be particularly significant for canals as it is the first legislation to include artificial impoundments. The WFD requires that the quality of all water bodies is characterised and that ultimately they achieve “good ecological potential”; for such engineered artificial water bodies this potential is as yet undefined. The hydraulic properties of canals are uniquely different from that of natural river systems, influencing factors of particular importance are: the extremely low flow rates (enabling flow directions to be reversed during rainfall events or high winds); the multiple overflow discharge points; the interaction with groundwater; and the regular channel dredging. These lead to unpredictable flow directions, long residence times for pollutants, a lack of rapid dispersion processes and sudden mixing of bed sediment into the water column. This research uses the Union Canal, central Scotland as a case study for fundamental research of advection-dispersion processes in artificial channels. Detailed velocity profiles and dilution gauging experiments have produced unusual results: for example, maximum velocity measurements near the bed of the canal as opposed to just beneath the surface. Research is also focused on understanding the mechanisms governing canal baseline water quality: Sampling data show low levels of DO, coupled with ortho-phosphate concentrations up to 10 times greater than those normally found in rivers. Determining the hydraulic properties of canals and understanding the origins of canal water quality are fundamental to designing improved management strategies to meet the requirements of the WFD. Results of this research, in combination with channel flow and water quality modelling, will be used to provide both operational guidelines for canal systems and innovative strategies for water quality improvement.
- Publication:
-
EGS - AGU - EUG Joint Assembly
- Pub Date:
- April 2003
- Bibcode:
- 2003EAEJA.....6052S