THE PROPOSED INSTALLATION OF THE SWELLENDAM BULK WATER RETICULATION, PURIFICATION AND DISTRIBUTION SYSTEM ON MULTIPLE ERVEN IN SWELLENDAM, WESTERN CAPE.

Guillaume Nel Environmental Consultants (GNEC) was appointed by the Swellendam Municipality to facilitate the Environmental Authorisation process in terms of the National Environmental Management Act, 1998 (Act No. 107 of 1998) for the proposed installation of a bulk water reticulation, purification, and distribution system. The development is located on the following properties in Swellendam, Western Cape:
Erven nr: 3611, 9546, RE/157, RE/249, 6504, 2363, RE/1
Road Reserves: 3641, RE/159, RE/1197, RE/1, RE/2389
Swellendam is located in the Overberg District and covers a geographical area of approximately 3,001 km². The main town is situated adjacent to the N2 national road, approximately 220 km east of Cape Town.
Development proposal:
Bulk distribution pipelines to the zone reservoirs are also under sized and the pipes have reached the end of its design life expectancy. Regular pipe bursts occur and contribute to major water losses and water interruptions to the consumers. Distribution pipelines, reservoirs and pump stations need to be upgraded to supply the potential future demands.
The bulk water line will be approximately 2.15km long. The pipeline route will be as follows:
1. The proposed pipeline will start at the pump station located on Erf 3611;
2. Whereafter it will cross Stasie Street towards the Southwest;
3. The pipeline will then run along Stasie Street towards Cooper Street in a Northwestern direction, travelling under the N2;
4. It will then cross Cooper Street into Murray Street, where it will run in a Northwestern direction for 0.85 km. The pipeline will also cross the Koringlandse river culvert in Murray Street;
5. The pipeline will then run in a Northeastern direction along Buitekant Street for 0.18km;
6. Whereafter it turns in a Northwestern direction into Aanhuizen Street and runs within that road reserve for 0.49km;
7. The pipeline then turns Southwest and runs for 15.28m in Panorama Way;
8. It will then run in a Northern direction through Erf 2363 into Erf RE/1 for 38.77m;
9. The pipeline then turns in a Northeastern direction for 26.35m;
10. Whereafter it again turns in a northern direction and runs for 0.11km into the forest area;
11. The pipeline then turns in a Northeastern direction and runs for 0.09km;
12. The pipeline then turns in a Northern direction and runs for 0.08km towards the Swellendam WTP when the pipeline then ends.
The master plan indicated that the existing Railton reservoirs water distribution zone has a current average annual daily demand (AADD) of approximately 1020 kL/d. The existing peak daily demand is calculated at approximately 1 840 kL/d.
Our hydraulic analysis indicated that the existing feeder main has an existing capacity of 12.5 L/s, which accounts to a daily capacity of 1 080 kL/d.
The capacity of the 200 mm Ø feeder main is however increased to 41.0 L/s (3 540 kL/d) when the existing Railton booster pump station is operational. During peak demand conditions the Railton booster PS should be operational 13 hours a day in order to supply peak demand to the Railton reservoirs.
It is proposed that the 200 mm Ø feeder main is replaced with a new 355 mm Ø bulk pipeline. This will improve the capacity of the bulk system under gravity from the Hermitage reservoirs to Railton to 29.0 L/s (2 500 kL/d). The system will then be able to supply peak demand to Railton for roughly the next 15 years before pumping will be required to boost supply.
When the Railton booster PS reached capacity, it is proposed that the capacity of the PS is upgraded to 80 L/s. This will be required in 25 to 35 years’ time, depending on the growth rate of the Railton water demand.
Water Demand:
• Current demand: 3,506 kL/day
• Future demand: 8,092 kL/day
Present Water Source:
• Raw water is abstracted from a weir on the Klip River (1,279,690 kL/year),
• Stored in the Grootkloof Dam (capacity: 574,000 m³), dependent on sufficient rainfall.
Existing Infrastructure:
• Water is conveyed via a 600 mm pipeline and open canal to Grootkloof Dam, then pumped through a 250 mm pipeline to the Swellendam Water Treatment Plant (WTP).
• The water reticulation system is operated in 5 zones. There are 4 sets of reservoirs, and 1 Pressure Reducing Valve zone.
• Reservoir supply system:
o Bakenskop reservoir is supplied with water from the Bakenskop PS, situated at the Hermitage reservoirs.
o Bethel reservoir is supplied partly from Bakenskop reservoir through the network and from the WTP via a connection on the rising main to Bakenskop reservoir. From here, water is distributed through the Bethel reservoir zone.
o Railton reservoir is supplied from the bulk system. From the weir on the Klip River to the Grootkloof dam, from the dam to the Hermatige raw water pump station, from the pump station to the Swelendam WTP, to the WTP holding reservoirs, through a dedicated 200mm line and boosted by the Railton booster pump station to the Railton Reservoirs. From here, water is distributed through the Railton reservoir to the distribution zone.
The existing 200 mm Ø feeder main has a base capacity of 12.5 L/s (1,080 kL/day). When the Railton Booster Pump Station is operational, capacity increases to 41.0 L/s (3,540 kL/day), but this setup requires extended daily pump operation.
Future Upgrades:
• Replace the 200 mm Ø feeder main with a 355 mm Ø bulk pipeline, improving gravity-fed capacity to 29.0 L/s (2,500 kL/day)—sufficient for the next 15 years.
• Upgrade the Railton Booster Pump Station to 80 L/s @ 40 m, anticipated to be necessary in 25–35 years based on demand growth.
• Install new telemetry systems at reservoirs, pump stations, and bulk meters for enhanced control and monitoring.
• Additional new pipelines:
o 480 m (400 mm Ø) pipeline to Railton and Bethel reservoirs.
o 565 m (355 mm Ø) pipeline to Railton reservoirs.