ILISO Consulting has proven itself an integral part of a water solution for neighbouring Botswana. An ambitious water project, acknowledged as one of the largest in the engineering world, will ensure the country has enough water to sustain industrial and mining development in the future.

For the last five years, ILISO Consulting’s Environmental Management business unit, together with Botswana-based Water Resource Consultants, has been involved in the massive Chobe/Zambezi Water Transfer Scheme. The scheme was commissioned by the Botswana government as part of its national water management strategy. To date, ILISO Consulting has successfully completed both the pre-feasibility and feasibility studies; it is now working on the preliminary design of the R12 billion (BWP10 billion) project. Once established, the scheme will be used to meet the ever increasing agricultural, industrial and urban demand for water, creating sustainability in water supply—it will also contribute to Botswana’s GDP and create further employment.

Sourcing potential
“Botswana has two major river systems, the Okavango and Zambezi,” explains Martin van Veelen, Director of Environmental Management, ILISO Consulting. “From preserving tourism to maintaining sound political ties with its neighbours, the Botswana government are naturally reluctant to touch any part of the Okavango Delta to ease water supply, especially with its delicate eco system.” The other viable option, he points out, was identified as the Zambezi River. Botswana owns only 200 meters of riverfront riparian to the Zambezi, but has some rights to water from the Zambezi as the catchment of the Chobe River, a tributary of the Zambezi, is partially situated in Botswana. “The Chobe is an unreliable source of water, but it does make a contribution to the average flow in the Zambezi” Van Veelen says. The Zambezi Commission has approved the use of 495 million cubic metres per year of raw water from the Zambezi/Chobe scheme. “Botswana needs this water delivered for irrigation use at Pandamatenga and for industrial and domestic use in the southern parts of the country,” he says.

Seizing opportunities
“Botswana has the opportunity to make the most of their coal production and to use their carbon credits more effectively with this project,” says Van Veelen. “In Francistown and the Selebi-Phikwe mines, we’re seeing massive coalfield developments. The country can either export the coal or, more astutely, use it to generate and sell power to other countries. However, in order to commoditise their resources, they need water.” At present, the country has only groundwater in these areas, but no river water as a resource. In terms of the Chobe/Zambezi Transfer Scheme, 150 million cubic metres of water will be carried south of the country, and 345 million cubic metres of water will be used for irrigation in Pandamatenga.

ILISO expertise on pipeline
To carry this influx of raw water requires a pipeline of significant proportions; it also demands innovative engineering expertise. Initially, ILISO was appointed by the Botswana Department of Water Affairs to put together an environmental impact study on the proposed pipeline, which would run 550km south, starting at Pandamateng and ending at Selebi Phikwe. ILISO was subsequently appointed to conduct an engineering feasibility study, and was then tasked to draw up the preliminary design for the scheme. Subsequently ILISO was also made responsible for the first 80km of 3.5m diameter pipeline, two 12MW pump stations and two major reservoirs that constitute Phase I of the scheme that was previously designed by others.

Meeting logistical challenges
The logistics of the project present a daunting engineering challenge, he points out. To mitigate the risk of pipes deforming during transportation, steel sheets will be taken to site. Spiral welding will be used to manufacture the pipes, which will then be placed in  the trenches—trenches deeper and wider than an average conference room—and then backfilled. “For ILISO Consulting, it has been highly gratifying to take this contract into the design stage,” comments Van Veelen.  In effect, this means that ILISO will play a critical role in the construction of the Chobe/Zambezi Transfer Scheme for the next three to four years. “We will have to pre-select contractors and suppliers with care, as this is a highly specialised process,” he adds. However long the process, there is no mistaking that this is one of the most prestigious and ambitious contracts ILISO Consulting has taken on. “It’s an engineer’s dream come true,” says Van Veelen. “If you’re lucky, a project like this comes along once in a lifetime,” he concluded.