How was value determined:

1. The regional value for Great Lakes sand dunes and beaches raw materials was calculated by dividing the total annual added value of sand and gravel mining operations (2002) by the average acreage of sand and gravel facilities across the state (U.S. Census Bureau 2005; Isely 2007).
2. This per acre value was then annualized at a 7% discount rate, which is the rate required by the U.S. Office of Management and Budget for most governmental agencies doin cost/benefit analysis.

Value estimate limitations:

1. This value estimate includes data from both sand and gravel mining operations state-wide. Sand mining data could not be separated out, and the data are not specific to the West Michigan policy region.
2. Large operations tended to be over-sampled, resulting in more conservative per acre values.
3. U.S. Census Bureau only provided data for sand and gravel used for construction purposes. It does not take into account sand and gravel mining for other purposes, which also results in more conservative value estimates.
4. These data assume that 1 acre of sand/gravel will be completely mined in 1 year.