Many watersheds are severely affected each year by wildfires, intensified by declines in forest health. Catastrophic fires can destroy watershed functions and stream conditions for decades. The effect of forest loss and the importance of sustaining the health of forests should be recognized as an integral part of future watershed, water quality, and pollution prevention strategies.
A Victorian Government sponsored study, for example, calculated the financial benefit of water supplied to Melbourne from forested catchments at $250 million per year. This amount is based on a study which valued water collected in the Thomson Reservoir and supplied to Melbourne at $530 per megalitre, and the fact that the bulk of water supplied to Melbourne is harvested from 80 000 ha of catchment forested with ash-type eucalypts. Annual water yields from these forests vary from six to twelve megalitres per hectare, depending on whether the forest is 30 year old regrowth or oldgrowth more than 200 years old. Presently most of the ash-type eucalypt forest in the catchments is 54 years old. Over the next 50 to 100 years, as the regrowth forests age, the value of water produced each year will increase by $150 million due to natural streamflow increases.