Abstraction of Water from Abenab Mine : PROJECTS : LCE

Abstraction of Water from Abenab Mine and the Supply to the Eastern National Water Carrier

Engineering Discipline Hydraulic Modelling / Water Supply / Feasibility Study
Location Grootfontein
Client Namibia Water Corporation Ltd (NamWater)
Project Value Not Available
End Date 2000
Start Date 1997

Water Transfer Consultants, a joint venture partnership between LCE, Bicon Namibia and Parkman Namibia, undertook this project, which comprised a Feasibility Study on and the detailed design of infrastructure needed for the abstraction of water from Abenab Mine, the required treatment and transfer thereof to the Eastern National Water Carrier (ENWC) canal at Grootfontein, as an emergency water supply measure for the Central Area of Namibia. The proposed scheme entailed the abstraction of water from two, 200 m deep disused mine shafts via 250 mm diameter steel pipes, the 250 m above-ground transfer of this water, via a 500mm diameter steel pipeline, to a water treatment scheme and thence to a storage reservoir. From the storage reservoir, a booster pump station would transfer 650 m³/h through a 500 mm diameter, 38 km long, glass reinforced plastic (GRP) pipeline into an existing 1,700 mm diameter and 14 km long concrete pipeline, which terminates in the ENWC canal at Grootfontein. LCE carried out a very detailed and intricate surge analysis on the proposed scheme, including the analysis of different pipeline materials. The route of the proposed 38 km pipeline required that water be lifted 170 m over a large hill, which caused the separation of water columns as well as large vacuum pressures in the pipeline. Intricate surge mitigation measures such as bypass pipelines, dividing the pipeline into several sub-sections using non-return valves, the use of self-generating surge vessels and the exact placement of air valves were therefore required.