Introduction

There is concern that sediment and nutrient exported from grazing lands are having a detrimental effect on the Great Barrier Reef  World Heritage Area.  CSIRO Land and Water have been monitoring the effect  of grazing land management  on sediment and nutrient export from Weany Creek  since 1999.

Site Location

Weany Creek is located on Virginia Park Station near Charters Towers in Queensland, Australia. The catchment area of 13.5 km2 has been used for cattle grazing for many decades.

Figure 2: A large cut-throat flume monitoring runoff and suspended sediment from a hillslope in the Weany Creek catchment.

Gullies and Stream Banks

Gully and stream bank erosion was measured using a combination of erosion pins (figure 3), scour chains and topographic survey.

End of Catchment

An automated stream gauge  was installed to measure water height, velocity and turbidity. The system collects 24 one litre samples across an entire hydrograph.

Figure 1: Monitoring locations within the Weany Creek catchment.

Methods

A range of field methods have been used to measure erosion and runoff from the Weany Creek catchment. (figure 1). These were targeted at specific processes and scales across hillslopes, gullies, stream banks and the catchment as a whole.

Hillslopes

Hillslope hydrology was measured using cut-throat flumes (figure 2) that also collect water samples. Erosion was measured using arrays of erosion pins, LFA transects and bed load traps.

Figure 3: Gully wall erosion being monitored with erosion pins. Measurements were made with digital calipers.