2 Renmark to border LAP area assessment - EPA - Sa.gov.au

River Murray and Lower Lakes catchment risk assessment for water quality: Results and management options
5 Mid Murray LAP area assessment
5.1 Description of the area
The Mid Murray Local Action Planning (MM LAP) area extends along from Lock 1 at Blanchetown to
Mannum (Figure 5.1). The area is characterised by limestone cliffs and floodplain wetlands and includes
the townships of Blanchetown, Swan Reach, Nildottie and Purnong. The area has a small permanent
resident population (approximately 4000 people) but this can increase significantly during holiday
periods, as up to 80% of all river shacks are located within this area (MM LAP 2000). Popular shack areas
such as Walker Flat and Bowhill are also associated with significant recreational river craft activity. The
MM LAP area encompasses approximately 1600 ha of irrigated horticultural areas (mostly vegetables,
vines, citrus and stone fruit). Other land uses within the area include sheep and cattle grazing, and
cropping.
The MM LAP committee has identified a number of key issues in the area that are of concern, including
natural habitat degradation, unsustainable agriculture, unsustainable recreational use and declining
water quality (MM LAP 2000). Current8 key implementation activities are focused around:
• revegetation and biodiversity plans
• improvement of wetland habitat through surveys, management plans and on-ground works
• education and awareness including irrigation efficiency training workshops.
Within the MM LAP area, water quality monitoring sites are located at the raw water off-takes for the
Swan Reach town supply and the Mannum–Adelaide pipeline respectively. Monitoring is carried out
regularly on a wide range of parameters.
Water quality within the region is fair compared to the rest of the river. Nutrient levels are generally
steady, with slight increases in soluble nitrogen, phosphorus and E coli levels towards Mannum. Total
heavy metals at the monitoring stations in this area were generally at a low level and pesticides were
generally at or below detection levels. Turbidity levels in the river are high from where the river enters
South Australia to the mouth, significantly influenced by contributions from the Darling River (which has
a high clay colloid level) and flood events (MDBC 1988).
‘Run of the river’ data collected by DWLBC indicates that saline groundwater inputs entering the river in
this area are lower than in the Riverland. The MM LAP committee commissioned an in-stream salinity
survey of the river from Wellington to Blanchetown in 2005, which will provide additional information
about salt accessions to the river.
8 See
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