Work begins on large-scale gully at Belmore Downs

The Landholders Driving Change project’s sixth large-scale gully remediation project has started.

Works started in April to treat a large eroding alluvial gully complex near Collinsville, on Belmore Downs. 

Remediation will focus on seven highly-active gullies that cover 19ha.  The gullies are estimated at yielding 4617 tonnes of fine sediment each year and are expanding at an accelerated rate.

Neilly Group Engineering has been contracted to design and construct the project. 

Work undertaken included:

  • a cultural heritage survey and impact assessment;
  • approvals for vegetation clearing and waterway barrier works;
  • flora and fauna surveys; 
  • soil sampling and soil mapping.
  • detailed construction designs

Remediation includes a combination of gully reshaping and rock chutes. A total of 12 rock chutes will be constructed, and a series of bunds will be constructed in association with the rock chutes.  Overland flow diversion bunds will also be built to prevent further gully growth.  

After works, the site will be revegetated using a range of pasture and legume species to promote ground cover establishment.  Hay mulch or bagasse will also be used on disturbed areas.

Following remediation, it is expected there will be:

  • Improvements in vegetation, cover and biomass, and soil condition;
  • Reductions in erosion and gully retreat rates; and
  • Improvement in water quality (sediment concentrations) because more sediment is not being mobilised or released in the first place. 

Longer term, we expect improvements in runoff and sediment loads, however this is also influenced by rainfall, so trends will take longer to detect.

The site will be monitored to monitor remediation effectiveness. The area will be fenced and stock excluded until groundcover is established.

Works are expected to be completed by August this year. Local contractors are delivering 100 per cent of on-ground works

The overall aim of this remedial work is to determine the control measures capable of permanently reducing alluvial gully erosion and associated sediment and particulate nutrient export.

An overview of the seven gully complexes at Belmore Downs (above) and (below), a 4WD parked near the head of one of the gullies provides a sense of scale.

An aerial view of the work beginning on Gully 2, one of seven being remediated on Belmore Downs.

Three of the seven Belmore Downs gullies — Gully 5, 6 and 7 — as the remediation work begins.

Earthmoving work almost complete on Gully 5 at Belmore Downs. Work thus far includes preparing a main access track to the site, forming a laydown area for soil and machinery, stripping and setting aside topsoil from Gully 2, 5, 6 and 7. The topsoil, along with gypsum and mill mud will be spread over the area in the final stage.

Baseline monitoring and observations were carried out before works began. Some of it included these pics of photo monitoring points at downwearing pegs.