Carlos Barrero (left) and Scott Hardy from Whitsunday Regional Council and NQ Dry Tropics project officer Dan Hazelman (centre).
Determining how best to manage runoff on rural roads
Rural roads in the BBB directly serve thousands of rural and regional residents living along them. They provide essential market access for grazing properties, are the main access for major industries, and they play a major part in tourism, adding to the economic wealth of the region.
Roads are unnatural structures in the natural environment, and are susceptible to erosion because they collect runoff from overland flow, as well as from rain falling on the road surface.
Good road drainage and maintenance is the best way to combat water’s damaging influence – keeping water off, out of, and away from the road.
The challenge rests in simultaneously preserving our roads and environment in a safe and cost-effective manner.
That’s why LDC has approached Whitsunday Regional Council (WRC) to work on a collaborative project to monitor the sediment difference between V bottom and flat bottom drains in the BBB catchment.
The aim is to test the assumption that flat bottom drains provide water quality benefits, and lower maintenance costs.
With input from landholders and WRC council maintenance crew, several potential sites have been selected, a total of six drains to be monitored including three treatment and three control sites.
Fruition Environmental has supplied the monitoring methodology, it includes:
- Soil tests conducted at each site to obtain data about site factors that influence erosion.
- Drone survey done to allow a DEM (Digital Elevation Model) of difference to be produced to quantify erosion volume at each site over the wet season. It will also allow cross-sections to be derived to estimate discharge at the sample location, and to get basic information relevant to the USLE (Universal Soil Loss Equation) equation.
- Photo reference points collected to allow repeat monitoring photos.
- Two rising stage samplers installed at each site. The intention is to take up to three sample collections during the wet season to be analysed for sediment sample concentration and particle size distribution. This will show what concentration and particle size is moving during rainfall events. TropWATER will analyse the water samples. Fruition Environmental will collate and report the findings.
The LDC project and WRC are in discussions on how best to progress this important project.
Erosion is a problem for everybody
Erosion isn’t just an issue for graziers. The LDC project aims to involve all land managers in the BBB, including mines, utilities and government departments.
Getting the whole community working together and learning from each other will help achieve better long-term land management and improved water quality in the BBB.
That is why the project has an activity area called ‘Influencing Other Land Managers’. This activity area encourages non-graziers who manage or use land in the BBB to get involved with the project so it can truly be a whole-of-catchment effort.
Although 92 per cent of the land in the BBB is used for grazing, other areas include national parks, state forests and coal mines. Four local councils operate in the catchment, which also features major infrastructure such as power transmission lines, rail lines and local and main roads.