Surface Water Quality Indicator Results for Willinga Lake Catchment 2004

Willinga Lake Catchment - 2004

What does the Data tell us for 2000/2004

The water quality at Willinga Lake fluctuated over the 2000-04 period, from poor in the 2000/01 period up to excellent in the 2001/02 period, and settled on medium for the 2003/04 period.

This index was supported by the results of monitoring Dissolved Oxygen, nutrients levels, faecal coliform levels and pH. At site 91, Nitrogen was relatively high over the period, exceeding the Australian guideline standards in 7 of the 10 samples (70%) with the highest recorded level of 1.42 mg/L reached in the 2001/02 period, which is also when the Water Quality Index (WQI) was the lowest. pH, a measure of acidity or alkalinity, was below 5 on two occasions in the 2001/02 period. However at site 91, the low was reached in the 2002/03 period, when pH fell below 4 (3.99). In contrast to this, pH became alkaline in the 2003/04 period when pH reached 9.1 in correlation to the increase in nutrients, with Phosphorus reaching 0.08 mg/L and Nitrogen recording a 0.90mg/L level, exceeding the recommended levels of 0.05 mg/L and 0.5mg/L respectively.

Faecal coliform count was generally insignificant and apart from one sample in 2000/1 at both site 91 and 92, all readings were below the threshold level for swimming, that of 150 cfu/ml.

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Willinga Lake Catchment - 2004

What does the Data tell us for 2000/2004

Figure 46 - Water Quality Sampling Locations for Willinga Lake Catchment

Graph 120 - Water Quality Index Willinga Lake

Graph 121 - Dissolved Oxygen Levels Willinga Lake

Graph 122 - Faecal Coliform Levels Willinga Lake

Graph 123 - Nutrient Levels (Phosphorus) Willinga Lake

Graph 123a - Nutrient Levels (Nitrogen) Willinga Lake