Welcome rains fell in the City last month, but this month has been largely dry. As the City enters a long, hot Summer Season, all sources of water need to be exploited. Water security is critical for the City’s sustainability, economic growth and job creation.
Recognising the impact that a lack of rainfall will have on the medium to long-term plans of the City, the Municipality began to explore alternative water sources. Borehole water was identified as a key alternative source for augmenting the City’s water supply.
A number of boreholes have been explored and availed as an alternative source of non-drinking water supply.
Now the City has taken the borehole exploration to another level with the the biggest borehole exploration site within the City.
On completion, the borehole will provide up to 26 mega-litres. In addition, a water treatment works will be constructed to integrate the water into the main drinking water supply.
This more than R200 million project will go a long way towards securing water resources for the City.
The NMBM performed numerous groundwater investigation studies inside and outside of the municipal boundary as part of its Groundwater Augmentation programme. This initiative was identified in the NMBM Water Master Plan and prioritised as part of the 2010 drought intervention plan.
While the total estimated yield from all groundwater sources within a reasonable radius of NMBM’s bulk supply infrastructure is approximately 80 M?/day, the maximum potential of the Groot Winterhoek Aquifer is estimated to be 26 M?/day including the flow from the Uitenhage Springs (which is currently ~6 M?/day). The most favourable area for drilling, extraction and treatment of the Groot Winterhoek Aquifer was identified to be located at the foot of Coegakop. The proposed borehole site was therefore named the Coegakop Wellfield. A license application to DWS for this flow (26 M?/day) has been submitted and approved.
A phased approach was taken for the implementation of the scheme due to the limited funds being available each year on the capital budget.
The implementation of the groundwater abstraction from the Coegakop Wellfield was split into four phases to accommodate the work requirements and budget limitations.
Phase 1: Groundwater Identification – R10 Million
During the 2009-2012 drought period, various potential groundwater sources were identified, investigated and the results documented. The Groot Winterhoek Aquifer was found to be the most favourable and preparation was made to commence with drilling exploration and probe boreholes in the Coegakop Area.
Phase 2: Drilling of Exploration Probe Boreholes – R20 Million
In February 2014 the drilling of the probe and exploration boreholes commenced. 2011-2012 saw drilling of Probe and Exploration Boreholes in Coegakop During this contract a total of 36 exploration probe boreholes were drilled in order to finally site the 5 production boreholes that would ultimately provide the system with raw borehole water.
The contract was completed successfully in July 2015 with all production holes, interconnecting pipelines and the new treatment works positions having been finalized.
Phase 3: Drilling Production Boreholes and Construction of Pipelines – R50 Million
The NMBM awarded the following contract to deal with the Phase 3 aspect of the works: Coega Kop Wellfield Phase 3a: Drilling of Production Boreholes Construction of Pipelines – This contract will deal with the 72 week contract period for the drilling of the production boreholes and the construction of the raw and final water rising mains from the borehole site to the water treatment works inlet and from the treatment works outlet to the Coegakop Reservoir respectively. The contract is currently under construction with a commencement date of 4 April 2018 and a planned completion date of 25 September 2019.
Phase 4: Construction of Treatment Works – R220 Million
This portion of the works entails the construction of the water treatment works and all mechanical and electrical equipment and still needs to go out to tender. Detailed designs and tender document preparation is well underway and is estimated to be completed in the October 2018.
Through Drought Funding applications the NMBM has been provided with R212,800 (Inclusive of VAT) by National Treasury through CoGTA and the Municipal Disaster Recovery Grant to implement Coegakop Wellfields: Phase 4. The funding allocations will be made public in the 2018 Adjustment Budget, thereafter the funding will be transferred to the NMBM.
In order for the NMBM to be ready to utilize the funding once it has been transferred and placed on the Budget by council the tender for Phase 4 must be advertised before the end of November 2018. The utilization of the full amount of the funding will require a roll over process for the 2019/20 financial year as per the table below. In order for National Treasury through CoGTA to look favourably on the roll over application a committed contract for the works is required and will be in place.
The cost estimate is for the water treatment works at in the Coega Kop Wellfield is based on a continuous potable water supply of between 15 – 20M?/day including all relevant infrastructure required to treat and distribute the treated water into the Municipal system.
The current capital cost estimate for the project is R 230mil, which equites to about R 7mil per M?/d of water compared to about R 13mil per M?/d for the Nooitgedagt Low Level Scheme.
Due to the quality of the water, operational cost is estimated at a very low R 1.30 per k? compared to the operational costs of NMBM’s other conventional water treatment works.
Compared to other current augmentation projects it remains the cheapest source of water for NMBM.
The main conclusions thus far are:
- The Phase 2 drilling in the Coegakop area was successful in that very high-yielding exploration boreholes were drilled. Arguably the highest in South Africa.
- Some boreholes in the Coegakop area are strongly artesian, and therefore the pumping costs will be relatively low.
- The water quality is good (very low salinity) although iron and manganese will need to be removed.
- The Phase 3 production boreholes still have to be drilled with the contract now in construction stage.
- The comprehensive water sampling schedule has been completed to re-establish the quality of the water for the final treatment works design.
- The Phase 4 treatment works designs are currently being finalized
- Funding for the Phase 4 portion of the works has been received and the tender for the work will be tendered in 2018.
- The estimated completion date for the Coegakop Wellfields project as a whole is June 2020.
- The Environmental Authorisation and WULA were received and are in place.
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