PUBLIC DOCUMENTS


Marine Intake and Outfall Infrastructure Servitude(s) Project, Coega Special Economic Zone, Port Elizabeth, Eastern Cape

The Coega Special Economic Zone (SEZ) is situated on the northern side of Port Elizabeth within the Nelson Mandela Bay Metropolitan Municipality (NMBM), Eastern Cape Province. Abutting the Coega SEZ on the eastern side is the Ngqura Deepwater Port, which is managed by the Transnet National Ports Authority (TNPA). The integrated SEZ and Port of Ngqura is approximately 11,500 ha in extent and comprises 14 zones designated for various light, medium and heavy industrial land uses. The purpose of the marine intake and outfall infrastructure and servitudes project is to enable the provisioning of seawater to various industries within the Coega SEZ (aquaculture, power provision and seawater desalination plant) via a number of seawater intakes; and the discharge of treated effluent into the marine environment. As such, infrastructure related to this project needs to be constructed along the coast adjacent to the Coega SEZ. The Port of Ngqura and Zone 10 within the SEZ have been proposed as the locations for the establishment of the marine servitudes.

1. Intake Infrastructure

The need for the marine seawater abstraction servitudes is driven by the water requirements for the following proposed Coega SEZ industries:

  • Cooling water for two 1000 MW LNG power stations for which the EIA is currently in progress.
  • Land based abalone and finfish aquaculture (42,370 tonnes / year).  Environmental Authorization received on the 07th of February 2018.
  • The Coega Aquaculture Development Zone includes the development of a desalination plant with a maximum capacity of 60 Ml / day.  Environmental Authorization received as part of the authorisation for the aquaculture development zone on the 07th of February 2018.

The following maximum (worse case) seawater intake requirements are projected:

  • Cooling Water: Once Through Cooling: 14.70 m3/sec
  • Cooling Water: Wet Mechanical Draft Cooling: 0.42 m3/sec
  • Aquaculture flow through system for abalone: 5.00 m3/sec
  • Aquaculture recirculation system for finfish: 0.94 m3/sec
  • Desalination: 2.03 m3/sec
  • Total: 23.09 m3/sec

There will be two seawater abstraction servitudes with associated infrastructure:

  1. Inside the Port of Ngqura for a Once Through and Wet Mechanical power station cooling water requirements; and
  2. East of the Port of Ngqura to meet the more specific water quality requirements of the aquaculture industries and for desalination.

Within each servitude, a number of different seawater abstraction technologies will be utilised, depending on industry requirements. 

  • Abstraction basin with concrete intake channels (within the Port);
  • Abstraction pipeline and jetty (within the Port);
  • Seawater abstraction pipelines;
  • Vertical beach wells;
  • Onshore pump stations and screening facility; and
  • WEROP wave pumps.

Detailed descriptions of these technologies are provided in Chapter 2 of the EIR.

2. OUTFALL INFRASTRUCTURE

The need for the marine effluent discharge servitudes is mostly driven by a corresponding need by the respective Coega SEZ industries to return effluent seawater back into the offshore marine environment. Other discharges will include wastewater treatment effluent and stormwater.

The following maximum effluent discharge requirements are projected:

  • Cooling water: once through cooling: 14.70 m3/sec
  • Cooling water: wet mechanical draft cooling: 0.30 m3/sec
  • Aquaculture flow through system for abalone: 5.00 m3/sec
  • Aquaculture recirculation system for finfish: 0.94 m3/sec
  • Desalination brine: 1.22 m3/sec
  • Wastewater: 0.93 + 0.46 m3/sec
  • Stormwater: Uncertain

Three discharge servitudes will be required:

  • Discharge servitude 1:
    • Cooling water effluent discharge servitude 200 m wide to a distance of 650 m offshore and a depth of -11 m CD.
  • Discharge servitude 2: Combined effluent discharge servitude 200 m wide with the following:
    • Brine discharge 1,000 m offshore, at a depth of -13.5 m CD.
    • Finfish aquaculture recirculation system effluent discharge 1,500 m offshore, at a depth of -16 m CD.
    • Wastewater discharge from Phase 2 of the WWTW at 3,000 m offshore, at a depth of -20 m CD.
  • Discharge servitude 3:
    • Abalone aquaculture flow-through system effluent discharge servitude 100 m wide into the surf zone.

ALL the following technologies will be implemented to discharge the various effluent streams from the various proposed land-based uses into the sea.

  • Tunnel discharge;
  • Pipeline discharge;
  • Surf zone discharge.

The time of construction of the various intake and discharge structures within the servitudes will be dictated by the demand and timing of the implementation of the various industries.

3. STORMWATER INFRASTRUCTURE

Stormwater derived from Zone 10 will be attenuated on land behind the foredune area, approximately 40-50 m from the HWM. The stormwater outlet channel will run parallel to the HWM but behind the foredune, and will comprise of gabions and reno mattresses to break the flow of water before it enters a gently sloping lined channel (0%-0.5% slope). This will attenuate the stormwater and allow for the infiltration of water into the underlying sandy substrate. The stormwater structures have been designed to attenuate the 1:5 year storm event. Three outlet channels will be constructed. A berm surrounding the outlet channel will prevent the overflow of stormwater into the surrounding beach environment. A large reno mattress and associated gabions on the far end of the outlet channel will extend to the rocky shoreline to ensure the system can accommodate major rainfall events (>1:5 year) which may result in the overflow of water from the stormwater outlet channel.

Published: 06 April 2021
Review Period: 07 April - 10 May 2021

Contact Person: Ms Nicole Wienand
Email: n.wienand@cesnet.co.za
Tel: 046-622 2364

Contact Us

FIND OUT MORE

View Gallery

FIND OUT MORE

News Flash

FIND OUT MORE