Valuing the water purification/filtration service of temperate coastal rainforests in southwestern British Columbia

In British Columbia, a lack of understanding exists concerning the tradeoffs between timber harvesting and maintaining ecosystem services, where losses of these services can occur as externalities from the timber harvest. This study provides insight into such tradeoffs by estimating the value of a change in a forest’s water purification/filtration service, focusing on the quality of water as it becomes degraded from timber harvesting activities. I use an integrated economic-ecological model to quantify the economic impact of forest road induced sedimentation on raw water quality prior to its arrival at a municipal drinking water utility. I find that the economic value of the water purification/filtration service is more sensitive to traffic volume than aggregate road length and, therefore, should be subjected to more regulation in those watersheds that must consider the tradeoffs between the supply of clean drinking water and timber harvesting.