admintreatment plant, along with the small Prince Edward water works, simply cannot cope with the demand for treated water as the population of the metropolitan area remorselessly rises year after year, mostly through internal migration.
The last major addition to capacity was almost exactly 10 years ago, when Morton Jaffrey was doubled in size, ending what had become an intolerable shortage of treatment capacity but not really creating much in the way of spare capacity for future population expansion.
Since then, the choices have largely been either further expansion of Morton Jaffrey or a completely new treatment plant on a new supply dam on a different river to anything in the Manyame River basin.
The commissioning of new sewage treatment works in the 1980s and 1990s meant that the previous looming problem, the shortage of raw water in the dams along the Manyame River, was shelved for the time being.
With more than half the water pumped up from the dams now returned to the downstream and larger dams there was a possibility that Morton Jaffrey could be extended yet again, although a multi-year drought could endanger Harare.
So the old plans for the Kunzvi Dam were dusted off.
This scheme is far more than a dam; that is the easy and cheap part.
The bulk of the money has to go on a new treatment works and a long pipeline, around 90km, to bring that treated water to Harare. The water would have to be pumped uphill.
Technically, the Kunzvi scheme had many pluses. It used a different water source to the Manyame River, ending a near total dependence on just one river.
It meant that treated water pipelines would enter Harare from two opposite directions, the present south-west gate for Morton Jaffrey water and a north-east gate for Kunzvi water.
This made the design of a distribution grid for the city simpler since far less water would have to be pumped right across the huge built up area.
Even the one technical minus, the fact no existing or potential sewage treatment works would allow any augmentation of Kunzvi raw water was not that much of a problem.
Kunzvi water could be recycled through the Manyame River dams, allowing a possible and cheap increase in the size of the Morton Jaffrey works.
The serious downside of the Kunzvi scheme was not technical; it was financial.
The scheme is expensive, costing around US$370 million.
Neither the Government nor the Harare City Council has that sort of money, nor can either borrow that money at reasonable rates.
Pumping water close on 90km also adds to the cost of the water, costs that have to be recovered from consumers.
Expensive capital just makes those costs even higher.
So around a year ago a public-private partnership was introduced.
The Kunzvi scheme would be built and operated by a private consortium but eventually come into public ownership.
Little has happened on th ground, but apparently negotiations continue.
The one critical element, which so far as we know has yet to be settled, is the eventual wholesale price of Kunzvi water – what Harare and the satellite towns will have to pay for this water.
Clearly it will, at least for accounting purposes and in large swathes of the city in fact, be mixed with Manyame River water.
The eventual retail price of water will thus be based on the treatment and pumping price of Morton Jaffrey water, where the dams are already paid for, and the wholesale price of Kunzvi water, which contains higher capital elements plus higher operating costs, plus the need for a reasonable profit for the developers.
Water prices will go up, although no one at the moment knows by how much.
But the choice is likely to be between that new price, and worsening water shortages.
The population of Harare is not going to drop.
So far as we know, no one has come up with a cheaper alternative to Kunzvi as a new source of water for Harare, and the potential for expansion of the Manyame River water is severely limited, even with more efficient recycling.
There are some obvious tweaks that can be done in pricing, such as a lower rate for the first block of water, effectively rationing Morton Jaffrey’s cheaper water, followed by higher prices for the rest of a month’s supply.
But whether such tweaking is desirable is dubious.
If we are all serious about Kunzvi we need to move to a decision; that in the first instance needs fixing a price for water that makes the scheme viable.
So let us at least find out what that price is and how it will affect the water bills of the Harare metropolitan area.
The residents can then start thinking carefully about the trade-off between higher prices and guaranteed supplies.
Online Reporter