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Good practice Imported

Melbourne's Protected Forested Water Catchments (Australia)

Australia · Melbourne · See the Australia profile · See the Melbourne profile

Evidence: Observational / pre–post Top 18% 60/100 · Ask Evidence Copilot about this practice

Melbourne has kept the public and farming out of its mountain-ash forest catchments since 1879, so over 65% of its drinking water now needs only minimal treatment — a policy Melbourne Water calls cheaper than fully treating all supply, though bushfires remain a recurring risk.

163,000 hectares
Total protected catchment area (current)
80,500 hectares
National park within catchment (current)
68,500 hectares
State forest within catchment (current)
>65 %
Share of water needing only disinfection (not full filtration) (current)
Melbourne's Protected Forested Water Catchments (Australia)

Details

Maturity
Established
Promoter
Melbourne Water
Period
1879–present
Keywords
water utility, forest conservation, catchment management

Context

Melbourne draws the majority of its drinking water from forested mountain catchments in the Yarra Ranges and Central Highlands rather than from rivers running through farmland or cities. Public access restrictions on the Yan Yean catchment date to 1879, after poor water quality forced the Melbourne and Metropolitan Board of Works to act; by 1928 a formal agreement reserved 45,000 acres of Upper Yarra state forest for water supply, and today catchment areas have been closed to the public for over a century.

Activities

Melbourne Water's roughly 163,000-hectare total catchment area includes 80,500 ha of national park, 68,500 ha of state forest, 7,900 ha of Melbourne Water freehold land, 4,100 ha of Crown land and 2,000 ha of private freehold, kept closed to public access and farming.

Results

Because these closed, largely undisturbed mountain-ash forests act as a natural filter, over 65% of Melbourne's water requires only disinfection rather than full filtration - Melbourne Water states this is 'more effective and less costly' than treating all of the city's supply to the same standard as unprotected catchments.

Conclusions

The approach is not without risk: the 2009 Black Saturday and 2019 bushfires burned close to Melbourne's Upper Yarra and Thomson catchments, and post-fire ash and sediment can force reservoirs offline for months, illustrating that avoided-cost watershed protection still requires active, ongoing fire and erosion management rather than passive conservation alone.

Implementation
Indicative cost
Medium (€50k–€500k) — No published cost figures; an avoided-cost model in which Melbourne Water states closed-catchment protection is 'more effective and less costly' than fully treating water to the standard required from unprotected catchments; active bushfire and erosion management represents an ongoing cost.
Time to results
Long (> 3 years) — Public access restrictions in place since 1879 (Yan Yean), formalised in 1928 (Upper Yarra reservation); catchments have been closed to the public for over a century and remain so today.
Staffing & skills
Melbourne Water land and catchment management staff responsible for ongoing fire and erosion management

Conditions for success

  • Statutory closed-catchment public-access restriction sustained over more than a century
  • Large intact native mountain-ash forest cover acting as a natural water filter
  • Diversified land tenure (national park, state forest, utility freehold, Crown land) under coordinated management

Common failure modes

  • Bushfires (2009 Black Saturday, 2019) burned close to key catchments, and post-fire ash/sediment forced reservoirs offline for months, showing that passive conservation alone is not sufficient without active fire and erosion management

Where it fits

Governance type
Public water utility (Melbourne Water) operating under statutory land-access controls
Scale
Regional, approximately 163,000 hectares of catchment

Commonly funded by

National / regional programmes

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Data sources

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