Although drilling of two new boreholes at the Gateway Wellfield in Hermanus is expected to start soon, it is important that residents continue to save water, despite the Overstrand Municipality’s endeavour to secure new water sources.
The appointed drilling contractor, Steyn’s Drilling, said the equipment was being moved on site this week. Nearby properties, including the Gateway Shopping Centre management, have been informed about the planned drilling activities.
Drilling sites were selected by geohydrologists, based on available hydrogeological information and the likelihood of its delivering a good sustainable yield. The water will be pumped to the Preekstoel Water Treatment Plant to ensure a potable standard. From there, it will be distributed into the town’s water supply network.
“We will only be sure about the sustainable yield after the holes have been drilled and tested,” said the municipality’s Deputy Director of Engineering and Planning, Hanré Blignaut, adding that the boreholes would be utilised on a permanent basis, and would be monitored continuously.
Blignaut explained that Overstrand’s groundwater programmes were based on an environmentally-sensitive approach – the aim being to ensure sustainable and responsible water abstraction. The Overstrand receives its water from three dams and 15 boreholes.
The Greater Hermanus area is supplied with water from the De Bos Dam in the Hemel-en-Aarde Valley, as well as 10 boreholes spread across the Hemel-en-Aarde Valley and the Gateway area. The other boreholes include two in Stanford, two in Baardskeerdersbos and one in Buffeljagsbaai.
At this stage, Level 2 water restrictions – including the first level of water-saving tariffs – have to be maintained for the Greater Hermanus area. The De Bos Dam level was at 41.5% at the end of April 2019.
The total water demand in Hermanus for April 2019 was 228 mega-litres and Hermanus residents have been using an average of 10.9 million litres of water per day.
What to expect
If all goes according to plan, drilling is scheduled to start next week.
The boreholes are on municipal land. The one is located opposite the Gateway Shopping and the other ± 100 metres north of the Kingdom Hall of Jehovah’s Witness.
The boreholes will be drilled to a depth of approximately 300 meters and are designed to target the deeper Peninsula Formation aquifer and will therefore not affect the shallower aquifers from which most households abstract their groundwater.
It is anticipated that during the drilling process water strikes will occur, and this will result in large amounts of water being ejected from the ground, potentially in excess of 50-100 litres per second.
This non-potable water will be captured and disposed of in stormwater drains.
Drilling will only take place during the day and will result in noise and dust generation.
Drilling is estimated to last between one and two weeks per borehole. Pump testing will last a week and will be a 24-hour activity.
Small changes to your water usage can make a big difference
To save water we need to think not just about the water we use directly – for drinking and cleaning in our homes – but also to become more aware of how water is used to make the food we eat, the products we use and to generate the power for our lights and stoves. One of the top ways to prevent your household from using extra water is to re-use grey water.
What is greywater?
Greywater is defined as ‘untreated household wastewater that has not come into contact with toilet waste’. Greywater is from baths, showers and bathroom hand basins. Laundry water from washing machines can also be re-used if environmentally-friendly detergents have been used.
Greywater from the kitchen and dishwasher must not be re-used. This water may be damaging to plant life because of heavy loads of organic material: fats, oils and caustic additives. Greywater can contain the following, depending on the source: bacteria, pathogens, organic material, oil, grease, soap, detergents, pesticides, dirt, lint, sodium, nitrates, phosphates, bleach, hair, skin particles and high salt/pH levels.
Water from toilets is considered black water and must not be re-used.
Why re-use greywater?
Greywater can be successfully used for garden irrigation and toilet flushing. Our gardens consume between 30% and 50% of all domestic water used in summer.
Greywater re-use provides benefits that include:
- reducing potable water consumption;
• reducing the amount of sewerage discharged into the municipal sewer system;
• putting less strain on septic tank and conservancy tank systems;
• saving you money by reducing your municipal water and sewerage bills;
• enabling irrigation of gardens during drought periods.
Why grey water starts to smell
The most important rule of grey water re-use is that it must never be stored longer than 24 hours. The problem is that grey water has a temperature and food value for anaerobic bacteria to breed and produce methane and hydrogen sulphide, the stuff that smells so bad.
Can greywater be used for all types of plants?
Greywater can be used for almost all types of plants. Everything from the lawn to vegetables will benefit from greywater, as it contains plant nutrients. Vegetables should be washed before using them. Greywater with a high phosphate level should be avoided in a fynbos garden.
Won’t soap in greywater be harmful to plants?
Not all soaps are harmful. Quality soaps are actually good for the garden. Only soaps and soap powders with a high phosphate level must be avoided. Plants need phosphate to grow, but too much can be harmful over a period of time. Most new soap powders and biodegradable soaps will not harm your plants but try to avoid introducing bleach and harmful detergents into your greywater tank.
How can I re-use greywater?
Bucketing: The advantage is that it doesn’t require modification to the plumbing of your home, or the installation of a greywater treatment and irrigation system. The greywater can be collected directly from the bathroom and laundry into a bucket and applied to garden or lawn areas.
Basic greywater systems
The most basic greywater system employs a submersible pump that automatically extracts the greywater as soon as it enters the tank. The pump is connected to a static sprinkler head by a garden hose, which you’ll have to move regularly to ensure even watering. A float automatically switches the pump off when the tank is empty. A basic filter can also be installed before the greywater enters the tank.
Once a greywater system is installed, it becomes the homeowner’s responsibility to ensure it is operated and maintained according to the manufacturer’s instructions. Some greywater systems may require weekly cleaning or replacement of filters, desludging of tanks, the manual diversion of greywater back to the sewer in winter, flushing of the irrigation lines, and occasional replacement of pumps.
Greywater systems must never be connected to municipal drinking water systems.