The Cape Winelands are dry. While the rest of South Africa is receiving generous downpours, the Cape is hot, dry and very windy – and as a result, prone to veld fires. We are of course a winter rainfall area and the South Easter is expected to blow during summer, but with the 2016 winter also being drier than usual, water restrictions are widely implemented and everyone is and should be much more water-conscious.
Bluenorth.co.za clearly explains why we are in trouble: “By March of 2016, the low-point of the total storage of the W. Cape’s major dams was just 28%, more than 10% lower than in 2015. Again, insufficient winter rains in 2016 have not been enough to drive a recovery of the W. Cape’s dam levels, and the total water stored reached its maximum point of just 63% of capacity in September 2016 – 30% lower than the maximum point reached in 2014 (and 10% lower than 2015).” (Detailed report here)
At the same time however, the 2017 wine grape harvest is upon us. Irrigation at veraison is of the utmost importance and in the summer heat, most vineyards rely on supplementary irrigation. Water is also a crucial part of the cellar and wine-making process – the production of 1 litre of wine requires approximately 7 litre of water.
There is a joke about drinking wine to save water… but there are more ways in which we can be water-wise when it comes to wine.
Water usage in the vineyards can be reduced through mulching, night irrigation and by proper maintenance of infrastructure. A computerised water demand management system is helpful and effluent water should be treated to enhance the quality of the winery effluent.
Here are a few pointers:
- Use mulching to encourage rainfall infiltration and reduce runoff.
- Employ a demand irrigation system using automatic soil moisture probes and leaf moisture meters (tension-meters) to determine plant needs.
- Use micro-drip irrigation systems (replacing the micro-jet sprays).
- Irrigate at night to prevent evaporation.
- Regularly inspect and maintain all water supply and water distribution infrastructure.
- Use a computerised water demand management system based on weekly soil and leaf moisture data and climatic information.
- Clear invasive alien plants and re-establish indigenous plants – especially next to water sources, such as rivers.
- Fit nozzles to hoses used in the cellar.
- Use a system in the cellar that disinfects incoming water. This ensures bacteria-free water to clean tanks and bottles and reduces the risk of contamination. The life of the bottling unit’s water filters will be extended and no strong cleaning agents will be required to remove contaminant on the winery floor.
- Implement a system that improves the final treated effluent quality. The COD in the effluent can be significantly reduced and it will lessen the pollution risk from winery effluent.
- Use treated effluent water for irrigation and to keep compost heaps moist.