Why It Assists Water Security — But Cannot Solve It Alone
Mossel Bay’s desalination plant forms an important part of the town’s water-security strategy.
However, desalination must be understood correctly.
It is not a complete solution to Mossel Bay’s long-term bulk water challenges.
It is a support mechanism — an expensive and energy-intensive supplement designed to assist the system during periods of pressure, drought, or reduced dam availability.
That distinction is critical.
The Reality of Mossel Bay’s Water System
Mossel Bay continues to experience:
• rapid urban growth;
• increasing development pressure;
• rising peak-demand periods;
• and growing infrastructure costs.
At the same time, the town remains heavily dependent on finite surface-water resources and rainfall patterns.
The desalination plant helps reduce immediate pressure during low-rainfall periods — but it does not replace the need for sustainable long-term bulk water planning.
The Numbers Matter
The desalination plant is capable of producing approximately 15 ML/day under optimal operating conditions.
Mossel Bay’s average daily demand is already estimated at approximately 23–25 ML/day.
Historically recorded peak demand has reached approximately 32 ML/day.
This means:
• the desalination plant cannot replace total municipal demand during prolonged drought conditions;
• it cannot independently sustain the town if dam levels collapse;
• and it provides less than half of historically recorded peak demand capacity.
Desalination therefore functions as supplementary augmentation — not as a replacement for the town’s primary water resources.
Why This Matters
Water systems require operating buffers.
That buffer is what protects a town during:
• drought periods;
• peak tourism seasons;
• infrastructure failures;
• heatwaves;
• fire-fighting demand;
• and future population growth.
When those buffers shrink, the entire system becomes more vulnerable.
The concern is not simply whether water exists today.
The concern is whether the system remains sustainable, affordable, and resilient as demand continues to increase.
Desalination Comes at a Cost
Desalination is significantly more expensive than conventional dam abstraction because it requires large amounts of electricity and specialised treatment processes.
If desalination becomes a permanent primary supply mechanism rather than a controlled supplementary tool:
• operating costs increase;
• tariff pressure increases;
• infrastructure dependency deepens;
• and long-term financial exposure shifts onto ratepayers.
That is why desalination should not be viewed as a “problem solved” solution.
It is an emergency and support technology — not a substitute for balanced long-term water-resource management.
The Bigger Water-Security Question
A resilient water strategy must include:
• leak reduction;
• protection of catchment systems;
• groundwater optimisation;
• responsible demand management;
• transparent infrastructure planning;
• and alignment between development growth and proven sustainable supply.
Desalination should support that strategy — not replace it.
MossRates’ Position
MossRates is not opposed to desalination.
In fact, the plant plays an important role in improving short-term resilience during periods of low rainfall and supply pressure.
However, MossRates believes the public discussion must remain realistic and transparent.
Desalination alone cannot carry Mossel Bay’s future growth requirements.
Long-term water security depends on responsible planning, sustainable infrastructure expansion, transparent cost management, and ensuring that growth does not outpace proven bulk water capacity.
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