City of Cape Town PIP desalination plant

The City of Cape Town water supply network is under increasing pressure. Rainfall projections indicate that the Western Cape Province is expected to experience longer and more frequent dry spells, while the region has also experienced substantial population growth and socio-economic development, increasing the demand for drinking water. This proposed desalination plant will be the first large-scale seawater reverse osmosis facility to augment existing water sources . Various engineering feasibility and environmental screening studies have been undertaken to identify suitable locations for the proposed plant along the Table Bay, West Coast and False Bay coastlines. The Paarden Eiland Desalination site, previously the Cape Town Port Industrial Park (PIP) site, is located near Paarden Eiland and is one of the sites chosen for a desalination plant development. The proposed size of the Desalination Plant is 70Ml/day.
Development on the site will necessitate the demolition of the existing building which is at least 75 years old (please see the Section 34 Demolition Permit attached in Appendix D).
Four possible seawater intake options are being considered at the site:
Eliot Basin in the Port of Cape Town (culvert intake):
Intake Pipeline Option 1: This pipeline will run from the Elliot Basin and cross Erven 10256RE (which includes Eastern Mole and Duncan Road), 16387 (which includes Marine Drive), 15201RE and 14809 (which includes Duncan Road and Marine Drive), Cape Town.
Ben Schoeman Basin Port of Cape Town (culvert intake):
Intake Pipeline Option 2: This pipeline will run from the Ben Schoeman Basin and cross erven 14805, 17899 (includes Marine Drive and Duncan Road), 16387 (Marine Drive) and 15201RE, Cape Town.
Seaward site of the Ben Schoeman Dock (offshore piled platform and offshore riser intake):
Option 3 and 4 for intake and outfall (for all options) pipelines: Erven 148405 (includes Container Road), 17899 (includes Marine Drive), 17898 (includes Marine Drive), 149437RE and 15201RE, Cape Town.
There will be dual marine intake pipelines for both the culvert and the offshore options to provide the necessary redundancy for maintenance. The intake pipelines will probably be manufactured from HDPE material and will be fitted with concrete weight collars, or buried or encased, which will provide the pipelines with stability and keep them submerged in all conditions.
Seawater intake risers will be designed to allow the entry of seawater into the pipeline system. Water will be received at a height of at least 2.0m above the seabed and at least 10m depth. The maximum design velocity of the incoming water will be 0,1m/s in a horizontal direction.
A network of existing surface and underground culverts exist around the PIP site. These will be used as seawater and brine pipeline corridors linking the desalination plant to the shore. All corridors are located in the harbour and are thus previously disturbed.
Three intake pump stations, two duty and one standby pump station, will be installed to supply seawater to the raw seawater holding tanks. If it is found necessary the number of pumps may increase.
The proposed bulk water pipeline routes would be located on the industrial site proposed for the location of the desalination plant. A pipeline that forms part of the CCT bulk water supply system passes on the southern boundary of the site. Injection into this pipeline is proposed and would connect the desalination plant to a 915mm bulk pipeline.
Other infrastructure include assess roads, car parks & paved areas, pump station building & services, lighting and fencing and construction of a new culvert.
WESTERN CAPE
Province(s): Western Cape, Offshore