By Petronella Sibeene
Minister of Agriculture, Water and Forestry, Dr Nickey Iyambo, together with an entourage of hydrology experts yesterday travelled to Mariental to assess the water situation at the Hardap Dam, amid residents’ fears that the 2006 flood scenario might repeat itself.
The dam level has risen above NamWater’s limit of 70 percent, prompting NamWater to open the sluice gates.
The sluice gates have been releasing between 100 and 300 cubic metres of water per second since Saturday.
When the delegation visited the dam yesterday morning, the water level stood at 70.6 percent and the gates released 180 cubic metres of water per second, with an inflow of 20 cubic metres per second.
NamWater Karas Area Manager, Andries Kok, said the gates would remain open as long as the dam level is over 70 percent full.
The dam will be kept at that level because stakeholders feel it would still be able to sustain life until the next rainy season, the minister added.
According to Iyambo, flooding in Mariental cannot be ruled out especially since it is a phenomenon highly determined by nature.
Most residents at Mariental live in fear that the area might get flooded, as was the case two years ago.
The minister said, “The forces of nature can not be stopped. However, we want to assure you that everything possible is being done to minimise, if not totally prevent, flooding in the area.”
NamWater Manager of Hydrology, Andre Mostert, said: “Priority remains that Mariental does not get flooded and no damage is caused to property.”
The minister added that a flood mitigating committee together with other stakeholders are on alert, monitoring changes in weather conditions and dam levels in the area. These authorities have been alerting the residents of Mariental on the flood situation in the area and will continue to do so, the minister said.
Hydrologists said the dam could not be allowed to be 100 percent full as that poses a great danger to the wall that is nearing its lifespan.
The Hardap Dam was built 46 years ago.
Since the 2006 floods that caused damage to property with losses estimated at over N$80 million, the minister said, monitoring stations have been increased in the catchment areas of the dam.
At a meeting attended by the governor of the region, Katrina Hanse-Himarwa, hydrology experts in the Ministry of Agriculture, Water and Forestry and NamWater, local and regional councillors and farmers in the area, Iyambo said two measures in the medium term are soon to be implemented.
He said experts recommended that the dam wall currently at 39.2 metres be extended upwards by 10.4 metres in order to increase its holding capacity.
Considering its lifespan, the minister said, the upward extension or redesign of the dam will not be carried out from the old wall and as such, the entire wall will have to be re-worked on.
Although he could not indicate when the project will kick-start, the minister told New Era that as soon as the technical report on the dam is complete, the Government will embark on the project that will cost over N$200 million.
Another solution in the interim will be the clearing of reeds in the Fish River.
The Government has appointed a company based in Mariental to carry out the reed project. The company is in the process of procuring chemicals that will be used to kill the reed and its roots biologically, the minister said.
“In the past, the Government sprayed the reeds but the roots never died,” he added.
Other proposals made in the past were to dig the river deeper to allow it to hold more water but consultants have advised against it saying that would temper with the rock formation of the river, which could spell more flood disasters for Mariental.
“It is not the sand that causes flooding but the way the reeds grow and entangle, in the process obstructing the flow of water,” the minister explained.
The river can also not be diverted as some sections of society have proposed. According to Iyambo, that would disturb nature.
“We should not attempt to excavate the river but remove the artificial interferences,” he reiterated.
During the meeting, some farmers expressed concern over flood cover insurance, saying it has been two years since the town was flooded and yet no clear indication or explanation has been given regarding the matter.
Tersius Basson, an engineer in the ministry, said the matter was handed over to a Cabinet committee that further referred it to the Ministry of Finance.
However, Minister of Finance, Saara Kuugongelwa-Amadhila, said the Government would not get involved in insurance issues as that would mean that it takes care of all such related matters in all flood-prone areas of the country.
The Hardap Dam is the biggest of its kind in Namibia, with a water surface area of about 25 square kilometres. It dams up the waters of the Fish River, the only river in the country’s interior that flows just about all year round, although carrying very low quantities of water during the dry season.
Since the Hardap Dam was built in 1962, floods have taken place in 1972, 2001 and 2006.