Kingston Main Drain, southeast from Kingston SE
2014 Aquatic Ecosystem Condition Report
- Dry in autumn and spring 2014
- Likely to be nutrient enriched when wet due to the surrounding land uses
- Riparian vegetation consists of a few paperbark trees over introduced grasses
About the location
Kingston Main Drain is a small drain in the lower South East with a catchment area over 100 square kilometres. It rises south-east of Kingston and flows in a north-westerly direction into the Maria Creek estuary in Kingston SE.
Kingston Main Drain is an artificially constructed drain where the primary function is to remove surface water and draining saline groundwater 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 use is grazing with small patches of remnant native vegetation in the catchment. The monitoring site was located in the upper catchment near Salt Well Road, about 17 kilometres south-east from Kingston.
The drain was given a poor rating because the site sampled showed evidence of major changes in ecosystem structure and moderate changes to the way the ecosystem functions. There was considerable evidence of human disturbance, including nutrient enrichment, poor aquatic and riparian habitat structure, and the presence of cattle droppings on the banks and in the channel.
The sediments were dominated by detritus and sand, with smaller amounts of clay, boulder, bedrock, cobble and gravel also present; most rocks were slightly black on the underside which indicates that the sediments are anaerobic and lacking in oxygen when the drain was last wet.
The only aquatic plant seen were patches of water buttons (Cotula) that covered about 35% of the dry channel. The presence of some dried filamentous algal mats indicated that the drain had recently held water.
The narrow riparian zone consisted of a few scattered paperbark trees (Melaleuca) over introduced grasses. The surrounding vegetation at the site was mostly paperbark woodland over introduced grasses.
Special environmental features
The drain occasionally provides habitat for the Small-mouthed Hardyhead, a type of salt-tolerant fish, which was previously recorded at the site in 2009.
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.|