Muddied waters: estimating the national economic cost of soil erosion and sedimentation in New Zealand

Executive Summary

The primary objective of this project was to estimate the annual national costs of soil erosion and sedimentation as a means of developing a comprehensive inventory and relative ranking of their impacts. Secondary objectives included:

• identifying data that currently exist on New Zealand soil erosion costs;
• ascertaining where there are knowledge gaps and providing some guidance to future policy by identifying the relative contribution of individual effects to the aggregate costs of soil erosion.

Highlighting categories of greatest economic cost indicates where research, advice or incentives may be targeted for greatest marginal damage reduction. Conversely, identifying knowledge gaps will show the 'holes' in current policy that need addressing. A national estimate of costs will also raise awareness of, and trigger increased discussion on, soil erosion issues.
The economic cost component of this project is not definitive. The annualised cost estimate should demonstrate the areas in which erosion causes economic damage and should provide an order of magnitude estimation of these costs. but does not represent a precise final figure.