After the Hardap Dam level decreased, several faulty aspects needing attention in terms of rehabilitation were recently identified.
A detailed investigation on the asphalt layer was done in 2016, which concluded the asphalt layer is stressed, recommending asphalt concrete facing to be rehabilitated to a serviceable state to avoid any leakages.
In response to Jan Van Wyk of the United People’s Movement (UPM) in the National Assembly last week, Agriculture, Water and Forestry minister Alpheus !Naruseb recommended a short to medium-term rehabilitation that would extend the life of the asphaltic layer for 10 years, which will also reduce the financial burden.
“A new bitumastic rich layer should be applied after pre-treatment of cracks. Finalisation of tender documentation is in progress and a contractor is expected to be appointed soon to address these issues during the rehabilitation of the dam wall,” !Naruseb noted.
He explained a consultant was appointed to ensure the issues raised in the evaluation report were addressed, following a detailed survey of cracks in the upstream face when the water level is low.
The minister said several minor cracks were observed on the asphaltic layer on the stream and crest of the dam, most of which have not been of great concern at the time, except for one that was repaired in 2011.
Thereafter, he added there have been two studies to ascertain the safety of the dam and to identify remedial measures. The first one was a complete evaluation of the dam that was done by dam engineers from South Africa in 2013.
To avoid the 2006 flood events at Mariental, he said curtailment of water during drought periods was recommended.
He explained the curtailment rules were not implemented during this drought, as farmers opted to continue irrigating to achieve a full harvest.
To mitigate the situation in future, !Naruseb stressed curtailment will need to be enforced.
In March 2017, the Hardap Dam reached 75.9% and 80 square millimetres of water was released. In April 2014, the dam stood at 74.9% and 22 square millimetres of water was released. In April 2011, the dam reached 81.5% and 619 square millimetres of water was released.
!Narused said, with the release rate of 600 square metres, the dam was predicted to exceed 100%, and this promoted the higher release of 800 square metres to avoid the dam from exceeding 100% and potential releases that could have inundated Mariental.
Van Wyk wanted to know the assurance government could give to the currently affected residents and farmers that such irresponsible deeds would not be repeated.
!Naruseb said the decision to release water from Hardap Dam was taken in good faith.
“Failure to find water for the construction work at Neckartal dam could also lead to standing time, resulting in millions of dollars claim by the contractor. It was on the assumption that it would rain over the following rain season, but unfortunately, the country faced consecutive drought years, which is beyond human control,” he responded.