Information
Impacts of improved grazing land management on sediment yields, Part 1: hillslope processes
Level 1 General description
Purpose:
To determine the effects of improved grazing land management on hillslope runoff and sediment yields.
Methods (brief)
Bartley et al (2010) investigated hydrology and soil yields in relation to reduced utilisation and rotational wet season resting.
Ludwig et al (2005) collected runoff and sediment yield data from two sites with differing ground cover and then modelled the potential of the hillslope to retain vital soil sediments using a simple landscape leakiness index.
Key findings (brief)
Bartley et al (2010) found that there was no clear difference in percentage runoff, sediment loss or water quality evident between treatments. This is likely due to similar ground covers for each treatment.
Ludwig et al (2005) found that the uniformly grassy site lost almost no sediment (≤0.06 t/ha/y) compared to the site with a bare lower slope which lost from 2.0 to 3.1 t/ha/y. The cover-based directional leakiness index (CDLI) only applies to relatively gentle and uniform landscapes.
Table 1. Mean annual runoff, erosion and water quality exploring the impact of slope and slope length at Weany Creek Catchment from 2002 to 2007 (Bartley et al 2010)
|
Flume |
Cover % |
Slope % |
Length |
LS1 |
Runoff mm |
Soil loss t/ha |
EMC 1 gm/L |
Normalised2 Soil loss t/ha |
Normalised3 EMC gm/L |
|
1 |
57 |
3.9 |
240 |
0.9 |
58.5 |
12.2 |
20.9 |
13.6 |
23.2 |
|
2 |
55 |
3.1 |
130 |
0.4 |
- |
2.4 |
- |
6 |
- |
|
3 |
60 |
3.6 |
150 |
0.8 |
223 |
32.5 |
14.6 |
40.6 |
18.2 |
Location
Weany Creek catchment (S19 53 06.79, E146 32 06.65) with the Virgina Park Station, North Queensland
Related studies
Run-off and soil movement on mid-slopes in north-east Queensland grazed woodlands (Scanlan et al. 1996).
Pasture composition influences in soil erosion in Eucalyptus woodlands of Northern QLD (Scanlan & Mcivor 1993).
Further Access
The Weany Creek (Virgina Park station) website at http://www.ozflux.org.au/monitoringsites/virginiapark/index.html#intro