The Preekstoel Water Treatment Works (WTW) currently receives about 64% of its annual raw water from the De Bos Dam. The remaining 36% is being supplied from groundwater. This is drawn from two wellfields. Gateway Wellfield contributes about 17% of the total volume and Hemel and Aarde Wellfield 19%. Each wellfield includes several production and monitoring boreholes. The wellfield contribution has over the past year therefore increased from 27% to 36%.
HRA input on Water Infrastructure Monitoring: March 2026
Attendance to Quarterly Hermanus Monitoring Committee (HMC)
The Preekstoel Water Treatment Works (WTW) currently receives about 64% of its annual raw water from the De Bos Dam. The remaining 36% is being supplied from groundwater. This is drawn from two wellfields. Gateway Wellfield contributes about 17% of the total volume and Hemel and Aarde Wellfield 19%. Each wellfield includes several production and monitoring boreholes. The wellfield contribution has over the past year therefore increased from 27% to 36%.
Wellfields need very regular monitoring to ensure sustainable delivery. Umvoto, an earth-science consultancy was responsible for the establishment of these wellfields. They still perform ongoing monitoring duties of the boreholes. On a quarterly basis Umvoto gives feedback via a selected committee, the Hermanus Monitoring Committee (HMC), on the monitoring and performance of the wellfields.
I regularly attend these meetings as representative of Hermanus Ratepayers Association, with the objective to share high level feedback on the management of this important water source.
A short summary on the report back:
Gateway Wellfield
It entails 3 production boreholes with an approximate total 2025 annual yield of 741000 cubic meter. This represents 46% of the Water Use Licence for the Gateway Wellfield.
One of the original 4 boreholes has been converted to a monitoring hole over the past year.
Additionally, there are some 22 monitoring boreholes that serve the Gateway Wellfield, some near- and other far-field. Groundwater levels within the vicinity of the Gateway Wellfield are stable and do not indicate any significant impacts on other groundwater users in the area.
Lastly, as for 2024, an overview of the Gateway Wellfield hydrochemistry (metals and microbiology) did not reveal any concerning results from monitoring over this period.
Hemel and Aarde Wellfield
This is in fact a collective name for two wellfields, ie the Camphill and the Volmoed wellfields. Together they include 7 production boreholes with an approximate total annual yield of 884 000 cubic meter. This represents 69% of the Stage 2 Water Use Licence for the Hemel and Aarde Wellfield.
There are 7 monitoring boreholes that serve the Hemel and Aarde Wellfield. There were no issues of concern noted regarding flow rates and ground water levels in the 7 production boreholes across the Hemel en Aarde Wellfield.
These wellfields’ hydrochemistry also did not reveal any concerning results during monitoring.
Treated Wastewater used for Irrigation.
Overstrand Municipality distribute treated wastewater for the irrigation of various sports fields and the golf course in Hermanus. Overstrand Municipality has a Water Use Licence to allow the irrigation of treated effluent to these various sports fields. Umvoto monitors the impact of these applications via 12 monitoring boreholes, together with several private boreholes, spread across the areas of application.
There were some minor exceedances from National Standards, however these were geogenic and no clear indication of upper aquifer groundwater contamination was identified.
Ecological Monitoring of Fernkloof Nature Reserve
Umvoto also does ecological monitoring in the Fernkloof Nature Reserve, which is the Peninsula Aquifer recharge area for both Gateway and Volmoed Wellfields. Three ecological wetland sites were selected for this monitoring. These sites are linked to springs and seeps within Fernkloof Nature Reserve. Several parameters are monitored at these three sites to assist in tracking any impacts of large-scale abstraction for Hermanus municipal use.
From these reviews, it was found that that there were no significant trends or anomalies noted at the Fernkloof Nature Reserve ecological monitoring sites.
Closing remarks
The meeting was well attended by representatives of Overstrand Municipality’s infrastructure directorate as well as the Overberg Geoscientists group. Also, a few representatives of some Hemel en Aarde farms. Peter van Niekerk of Onrus Estuary Forum is the chairperson of the HMC.
As before I found the feedback information very well prepared and professionally presented by Umvoto.
The monitoring of our well fields is in my view under good management.
Prepared by Tobie Louw for HRA
March 2026
