EIA for bulk water project

ROB KNOWLES

THE supply of water to Ndlambe is a critical factor in the future prosperity of the entire area, according to Dr Cherie-Lynn Mack of Cesnet, a company commissioned to assess the impact a proposed project to resolve water issues.

Following the recent prolonged period of drought, Ndlambe municipality in conjunction with various provincial and national governmental departments, commissioned a bulk water project to ensure the sustainability of the water supply to the area.

Amatola Water was appointed by the Department of Water Affairs (DWA), on behalf of Ndlambe municipality, to implement a regional bulk water supply project within the municipal boundaries.

In terms of regulations an environmental impact assessment (EIA) will be required for each of the three major areas affected. These areas include the abstraction of water from the Fish River to supply Ndlambe East (up to Port Alfred), groundwater abstraction northeast of Port Alfred to supply Port Alfred, and centralised desalination of groundwater at Canon Rocks to supply Alexandria, Cannon Rocks, Boknes, Bushman's River and Kenton-on-Sea.

For the abstraction of water from the Fish River the proposal includes the construction of a weir across the Fish River, upstream of the estuary. About 30 megalitres (ML)/day raw water will be abstracted via the weir infrastructure located on the East bank of the river, which will be transferred to large settling channels alongside the river.

From there, the water will be pumped to the existing Dabi Dam. The water treatment works at Dabi Dam are to be upgraded to a brackish water reverse osmosis (BWRO) system capable of treating raw water to Class 1 potable standards. The brine generated will be reticulated via a pipeline of approximately 17km, to be discharged to sea via an outfall situated east of the Fish River Sun.

Potable water will be reticulated to the water supply reservoirs at Port Alfred via approximately 57 km of pipeline. This pipeline will follow a route inland of the R72 and will cross a number of rivers.

For the groundwater abstraction project for Port Alfred, test boreholes northeast of Port Alfred on the farm, Oliveburn, have already indicated a sustainable supply of approximately 2.5 ML/day is possible. Pump infrastructure will be installed at the borehole sites, with reticulation of the raw water to the balancing dam outside of Port Alfred.

A new BWRO water treatment plant will be constructed in the vicinity of the balancing dam in order to provide the area with 1.8 ML/day of Class 1 potable water. The brine generated of around 0.5 ML/day by the BWRO plant will be reticulated to a sea outfall, where it will be discharged.

As for the centralised desalination to supply Alexandria and surrounding areas up to Kenton-on-Sea, existing and new boreholes, located predominantly on municipal land in Cannon Rocks, will be exploited in order to provide up to 7.5 ML/day of raw water to the existing BWRO water treatment works, which will be upgraded.

The plant will supply up to 5.5 ML/day of potable water, which will be reticulated to Alexandria via an existing refurbished pipeline which passes through the Woody Cape section of the Addo Elephant National Park, Boknes, Bushman's and Kenton.

The brine generated of approximately 1.5 ML/day by the BWRO plant will be reticulated to a sea outfall, where it will be discharged.

There are a number of alternate routes proposed for the pipelines, and the EIAs will focus attention on the impact of each, as well as the overall impact of each of the systems proposed. Such considerations include;

• Ecological impacts of the proposed weir on the Fish River along with the impact of water abstraction,
• Ecological impacts of the infrastructure on the surrounding ecology and heritage resources
• Impacts of brine discharge on the marine environment
• Impacts of infrastructure on the beach/rocky shores and upgrading infrastructure on river crossings
• Wetland delineation and impact assessment as well as surface water/ groundwater interaction assessment

Residents and all other interested parties are encourage to participate, and, for that purpose, comments and attendance of public meetings are essential to the success of the public participation process, said Mack.

Correspondence should be addressed to either Mack or Dr Alan Carter, PO Box 8145, Nahoon, East London 5210. Alternatively, e-mail Mack on c.mack@cesnet.co.za or contact her on (043) 742-3302.