ZIMBABWE – Zimbabwe National Water Authority (ZINWA) has proposed a budget of US$946,159 (over Z$342.4 million) for the rehabilitation of water infrastructure at Wenimbe dam, which is the only source of clean water in Marondera.
This comes after the main source of water for Marondera town, Rufaro dam, has become heavily polluted with raw sewer with council spending a lot of money on water treatment chemicals.
In an interview, Zimbabwe National Water Authority (ZINWA) Engineer Colleta Tundu said Wenimbe dam has two pumping stations and a 16km pipeline that runs from the dam to the water treatment works.
The full pumping capacity is 540m³ per hour (12.9 megalitres/day) consisting of two pump-sets duty and one on standby in each pump house.
“Currently, the two-pump stations each have a single pump-set running with original split casing at the dam and a multistage at the booster stations. This operation delivers 30 percent of the Marondera’s current treatment capacity,” she said.
“We are delivering 270m³/h giving shortfall of 405m³/h, because we are running with one set of pumps from both pumping stations. If we manage to run two pump sets it means we are going to run about 540m³/h leaving a shortfall of 135m³/h.”
Eng Tundu said short and mid-term stragetic plan on Wenimbe Dam water system rehabilitation will increase output of 60 percent of treated water from 30 percent.
“As an authority after we have encountered problems to deal with delivering the right and clean water required by the municipality we have come out with short and mid-term strategic plan,” said Eng Tundu.
“On mid-term strategic plan, we are going to upgrade the 3km x 400mm PVC pipeline from the Harare highway to the Treatment Works, which will add another output of 60 percent of treated water and it will cost US$634 200. However out of these six pumps only two are operational.”
ZINWA’s specifications call for the installation of new multi-stage pumps with motors at the main station and at the secondary intake. This operation is expected to cost US$312,000 (over $112.9 million Zimbabwean dollars).
ZINWA also plans to upgrade the polyvinyl chloride (PVC) pipeline linking the dam to the drinking water plant. This will increase the amount of water treated from 30 to 60 per cent. This second component of the rehabilitation project is expected to require an investment of US$634,000.