Baker Range Drain, near Mount Burr
2014 Aquatic Ecosystem Condition Report
- Dry in autumn and spring
- Likely to be enriched with nutrients when wet due to the extent of vegetation clearance and agriculture in the catchment
- Riparian vegetation limited to a few gum trees over introduced grasses and weeds
About the location
Baker Range Drain is a large, northerly flowing drain with a catchment area of nearly 800 square kilometres that follows a natural watercourse along the interdunal flats in the South East. It rises as a series of smaller drains about ten kilometres east of Mount Burr in the South East and drains northwards past Lucindale where it can reach the Watervalley wetlands during wet years. The drainage has been modified in the past decade to allow water to be diverted from Drain M (including Mosquito Creek flow) via the REFLOWS western floodway to the northern Baker Range wetlands, West Avenue watercourse, Tilley Swamp or other locations as required for wetland watering projects as part of cross-catchment water transfers.
Baker Range Drain is an artificially constructed drain where the primary function is to remove surface water to improve agricultural productivity in the region (Department for Water 2010). Given its artificial character, the drain is not expected to be in a highly rated aquatic ecosystem condition, although it does provide significant habitat for many aquatic species in the region.
The major land uses in the catchment include agricultural grazing and cropping, blue gum plantation forestry and minor areas of remnant native vegetation. The monitoring site was located in the upper catchment on the Millicent-Penola Road, about 13 kilometres north-east of Mount Burr.
The drain was given a fair rating because the site sampled showed moderate changes in ecosystem structure and some changes to the way the ecosystem functions. There was evidence of human disturbance, including nutrient enrichment and the presence of a limited, weedy riparian zone. The 12 metre wide drain was dry in autumn and spring 2014, so macroinvertebrate and water quality data was not available for the site inspected. Small puddles were present in spring but were too small to sample.
The sediments were dominated by detritus, gravel and sand, and also included smaller amounts of cobbles, pebbles, boulder, clay and silt; samples taken from below the surface were aerobic grey sands but would be expected to become anaerobic on occasions due to the large amount of organic matter present. No sign of any significant erosion was noted on the banks despite the presence of cattle droppings throughout the drain in 2014.
Over 35% of the drain was covered by plants, including grasses (Paspalum), sedges (Eleocharis), knotweed (Persicaria) and dock (Rumex).
Introduced grasses and a sparse cover of gum trees were growing in the narrow (<5m wide) riparian zone. The surrounding vegetation at the site was mostly grazed introduced grasses with a few scattered gum trees.
Special environmental features
Pressures and management responses
|Livestock having direct access (causing sediment erosion and adding excessive nutrients).||Drains have been constructed since the 1860s as an engineering solution to support agricultural development and it is South Eastern Water Conservation and Drainage Board practice to lease drain reserves for grazing in certain circumstances. Not all drains are subject to grazing and leases for grazing are only approved following an engineering and environmental assessment. Lease conditions require the lessee to fulfil pest plant, pest animal and CFS management requirements, thereby relieving the Board of these responsibilities.|
|Limited riparian zone vegetation (reducing habitat quality, increasing sediment erosion).||The South Eastern Water Conservation and Drainage Board has undertaken a limited revegetation program at key locations, and has the ability to undertake further revegetation works when resources allow. Revegetation at biological hotspots is recognised as a mechanism to reduce nutrient input and soil erosion, and can be undertaken if it does not impede access for management and maintenance.|