The McLaren Vale district is less than an hours drive south of Adelaide, capital of the state of South Australia. It has been a premium wine growing region since the mid 1800s and enjoys a distinct Mediterranean climate. The vineyard in our case study is situated in Blewett-Springs which is a small township sitting at the highest altitude in the area.
The Hard Water Problems
The vineyards rely mostly on rainfall for irrigation but growers have limited large storage capacity. Especially during peak irrigation season of October – February there is a need to draw on bore (well) water from the large underground reservoir, the Willunga Basin. The water from this basin has a range of iron and salt content with the most severe being in McLaren Vale where the iron levels are from 5mg – 10mg/litre, which is extremely high.
In an attempt to overcome the iron hard water problem many different methods of pre-treating the water have been tried.
- A spray filter with a spinning disc is used in an attempt to collect the iron. These units work but require constant cleaning.
- Sand bed filters have been used with very little success.
- The aeration of water in an elevated water tank where settling can occur before water is pumped to the irrigating system. This is very expensive to setup and maintain.
- The only method that had any degree of success was to maintain an extra supply of drippers that can be exchanged often during an irrigation. The blocked drippers are then soaked in hydrochloric acid before being manually cleaned. This is a very labour intensive and costly exercise.
- Used with the acid cleaning of the drippers, injecting chlorine into the irrigation system to remove the iron scale build up has proved to be slightly successful.
Flushing the mains and sub-mains, along with changing and cleaning the drippers at least 3 times during the irrigating season has proven to be essential even though it is extremely labour intensive and costly.
The SofterWater Conditioners Hard Water Solution
Year One – A SofterWater Conditioner was installed in December.
- No extra major cleaning was done to the lines before installation.
- The usual procedure of cleaning drippers and flushing the lines continued.
- A month later – the number of blocked drippers was declining and those that were blocked were much easier to clean. There was also a large amount of iron sludge and waste being discharged from the sub-mains.
At the end of the irrigation season in March it was very evident changes had occurred.
- Large decrease in the number of blocked drippers, and
- Large increase in the output of the pump due to the fact the drippers were operating at their correct output without obstruction.
Year Two results
- Further improvement was noticed with the level of maintenance being cut by 75%.
- With maintenance being cut so dramatically the grower reported significant savings.
- The flushing of the mains and sub-mains continues as the accumulated scale is gradually removed.
Given the many, many years of accumulated scale that had built up in the mains and sub-mains of this vineyards irrigation system, the result has been outstanding. With continued use over following years and as more iron scale flakes come away from the pipes, the results will be even better.