Hydrological behaviour of a Palaeochannel system under irrigation
Small palaeochannels located in irrigated cotton fields have been identified as areas of potential high deep drainage (Triantafilis et al. 2003). Palaeochannels, being remnants of old streams and rivers, often contain a much coarser, sandier, sediment than the surrounding heavy clays. This difference is easy to see on aerial photos and there tends to be evidence of local waterlogging (T. Richards, pers. comm.). Such observations suggest differences in hydrological behaviour between the palaeochannel sediments and the surrounding clays. Other research in NSW on the hydrology of palaeochannels has either mainly looked at larger and deeper palaeochannels, such as the Namoi palaeochannel (Young et al. 2002), or looked at palaeochannels in the southern irrigation districts, which have a distinctly different origin and geomorphology (Young et al. 2002). This paper reports on the hydrological field observations as part of the project: “Geophysical and hydrological characterisation of palaeochannels in Northern NSW”.