• Latest News

    Sunday, 27 August 2017

    The tortuous road to the completion of Tokwe – Mukorsi Dam


    MASVINGO – Tokwe – Mukorsi Dam presents the next tourism and agricultural hope not only for Masvingo but for the whole country.
    Located in a hilly area about 100km south of Masvingo, the imposing shiny feature amidst countless partially submerged hills is gradually bringing modernity to poverty stricken Chivi and Masvingo Rural Districts. The completion of the dam with a giant wall standing at 89 metres high, 351 metres long, a throwback which goes 25km and its subsequent commissioning by President Mugabe in May this year is having a knock on effect on development at the site.
    What has already picked up and is unstoppable is the flow of local tourists to the dam. The 8km dirty strip road that branches off from Triangle – Ngundu Highway is now a bustle with traffic and in particular five to eight school buses arriving at the dam wall every day. This is still just the dam wall to see and it's already creating encouraging tourist arrivals.
    Three weeks ago, members of Masvingo Publicity Association comprising managers of lodges and hotels dotted around the province paid a visit to Tokwe Mukorsi as key stakeholders. The objective of the visit was to familiarise themselves with the project and thereafter make informed contributions to the formulation of the master plan for investments at the dam.
    A Government taskforce comprising representatives of various ministries is leading the process of producing the master plan and MBB Consultants of South Africa is doing the work.
    The .....member delegation was told by Paul Dengu the Resident Engineer how the 1,8 billion cubic metres water body which is now Zimbabwe's largest inland dam came about including the long and tortuous 19 years of its construction. Contrary to widely held misconceptions, Tokwe Mukorsi is not many times larger than Lake Mutirikwi which it displaced from position one as the largest water reservoir in the country but is about one-and-half times bigger. Mutirikwi holds 1,3m billion cubic metres of water at full capacity or 72,2% of what Tokwe Mukorsi takes.
    Although Tokwe – Mukorsi took 19 years to complete, the normal construction time for such a dam had resources been readily available is a mere three-and-half to four years.
    Tokwe Mukorsi also has the largest catchment area for any internal dam in the country. Its catchment area is 7 120km2 compared to Lake Mutirikwi which has a catchment area of 3 200km2 square kilometres. Tokwe – Mukorsi's catchment stretches from as far as Gweru through Shurugwi in the Midlands and three major rivers; Shashe, Tugwi and Mukorsi are the sources of the dam's water. Tugwi stretches from Gweru while Mukorsi comes from Masvingo Rural starting near Ngomahuru. Shashe starts near Driefontein. Tugwi supplies most of the water into the dam because of its huge catchment area. 
    Tokwe-Mukorsi's catchment is however, insignificant compared to Kariba dam whose water comes from as far as Angola, Namibia, Zambia and other countries to the north of Zimbabwe. 
    The first water inflows into Tokwe Mukorsi dam were in December 2014 and the engineers were forced to allow all that water which amounted to 1 billion cubic metres or slightly above 50 percent of the dam's capacity to escape because they had not yet finished building the wall. Engineer Dengu told Masvingo Publicity Association members that they finished building the dam in 2016 and they had expected the dam to fill up in three to four seasons judging by the average 430mm of rains that are received in the catchment area. However this last season (2016/2017) Zimbabwe received heavy rains of 1 990mm in the catchment area and this brought 1,3 billion cubic metres of water into the dam leaving it at 72% full.
    The total surface area covered by the water when the dam is full is 10 000 hectares or a third of the total area that is covered by sugarcane fields in Chiredzi.
    The history of the dam stretches back to the 1950s' when some farmersin the area saw the confluence of the rivers Tugwi and Mukorsi and realised the potential of a dam as the two rivers meet just above a narrow gorge. They proposed the idea to Government and engineers were fascinated by the site after realising that a dam there can be used for both irrigation and power generation. In 1955 initial studies of the place were made and in 1965 these studies became serious.
    In 1967 the French designed the dam but this was the time that the war of liberation started in Zimbabwe and further studies could not continue. The project was shelved until after independence. In 1984 further serious studies continued leading to a decision in 1989 to build the dam.  In 1990 Cabinet approved proposals to start construction of the dam and in 1998 Salini Imbreglio, an Italian company that won the contract in 1996 started building Tokwe Mukorsi.
    The project was stopped after one year because of critical foreign currency shortages and in 2004 the Government gave piece jobs to various local companies to carry out some of the work on the dam. In 2006 work on the project was stopped completely only to resume in 2010. The project was stopped again in 2015 only to resume in 2016.
    The Dam was finally completed in 2016 and President Robert Mugabe commissioned it on 18 May 2017. During the commissioning President Mugabe could not avoid mentioning the details of the long construction period of the dam and thanked the Italians for being patient inspite of the challenges they faced because of problems of money. 
    Tokwe Mukorsi Dam has broken a number of records including that it is now the biggest inland dam. It is the only concrete-faced-rock-fill dam in the country. It is called concrete-faced-rock-fill because the wall is all rock and the face is concrete to stop water from seeping through the rock. The percentage of concrete on the wall compared to stone is minute.
    Engineer Dengu said there are 7 million tonnes of rock that build Tokwe – Mukorsi Dam wall and its cost at $ 260m is 50% cheaper than the same dam  wall built with concrete. Dams with concrete walls like Kariba are called concrete arch dams. Rock-fill dams have many advantages compared to concrete in that they are cheaper to build; 50% less expensive than the concrete arch.
    They are also strong and they support the weight on their foundation while the concrete arch transfers the weight of the water to the sides where one normally finds mountains.
    It also takes a much shorter time to build rock-fill dams because you don't need to wait for rock to dry before building, with concrete you built and from time to time wait for concrete to dry before you proceed with construction.
    "The concrete-faced-rock-fill dam is one of the safest in the World, its stable and it loads water on the foundation. It is safer than the concrete arch. The only danger is in leakages but new technology from China and other countries has since overcome this problem.   The construction of Tokwe Mukorsi Dam cost US$260m and 65% of this amount was to be paid in Euros and 35% in US$. All the rock used on the dam wall is from hills around here and the cement came from local companies. The manpower used in the construction of the dam is also far less than would have been used in the other method of building a dam wall.
    "The construction of Tokwe-Mukorsi was safe compared to other dams. There was just one fatality, Kariba had tens of workers killed and Lake Mutirikwi also had many.
    "Tokwe – Mukosi is also the only dam in Zimbabwe with saddle dams and it has five. The saddle dams are built to ensure that water does not escape through low-lying areas on the sides of the dam. Instead if that water escapes, it escapes into the saddle dams.
    "There were 2 million man-hours that went into the construction of the dam and most of it from Chivi and at $5 and hour it means Chivi benefitted a lot from the construction of this dam," said Engineer Dengu.
    Tokwe Mukorsi has three spillways and they are unique compared to those common on other Zimbabwean dams.
    The main investment projects so far mooted for the dam are airstrips, hotels, a museum, school of engineering, some harbours, ecotourism, power generation, irrigation, and cable cars.
    While the dam covers a total surface area of 10 000 hectares, an eco-tourism area covering another 15 000 hectares has been mooted around the dam and this will see an estimated 5 000 to 6 000 families being displaced. This would bring the total number of families relocated as a result of the construction of the dam to about 9 000 including those displaced from the dam area when floods rose in 2014. The ecotourism project will ensure that people are not settled too close to the dam for the purpose of conservation. The area will also be used for tourism including holding game.
    One of the dam's key economic purposes is water harvesting for irrigating sugarcane. Some 25 000 hectares will be irrigated by the dam. The dam will also generate 15mW of power and this is enough to cater for Masvingo town's needs. A $30 million hydro power station is expected to be built soon.
    Tokwe – Mukorsi is shared by two rural district councils, Chivi RDC on the west and Masvingo Rural on the east. The fight for rights at the dam had almost erupted and Chivi RDC in particular was already preparing to sell stands around the dam but this was stopped because Government has to organise development there through a master plan.
    There is also simmering fights over the islands that are found at the dam but the suggestions by Zinwa is that the dam must be treated like a commercial venture where investors who can bring the highest returns are allocated land.
    local news
    • Comment on The Mirror
    • Facebook Comments


    Post a Comment

    Item Reviewed: The tortuous road to the completion of Tokwe – Mukorsi Dam Rating: 5 Reviewed By: Webmaster
    Scroll to Top