Northeastern Section–41st Annual Meeting (20–22 March 2006)

Paper No. 4
Presentation Time: 1:00 PM-4:00 PM


JONES, Christopher R., RICH, Justin and NOVAK, Irwin D., Department of Geosciences, University of Southern Maine, Gorham, ME 04038,

The growth of gravel mining sites from 1998 to 2001 within the Presumpscot River watershed of southern Maine has been documented using ArcGIS software, Ortho-rectified Digital Images (ODIs) and digital surface water, road, watershed, town boundary and tax map data. Maine Dept. of Environmental Protection licensed site locations of five acres or more were added as a geo-referenced layer to aid in tracing and interpreting gravel pit boundaries.

The growth of the pits was calculated by hand digitizing the outlines of areas in which the surface soils have been disturbed in order to expose extractable materials as shown on 1998 ODIs. These areas were compared with the pit outlines shown derived from the 2001 ODIs. The total area of all licensed and non-licensed pits within the watershed was 445 acres in 1998 and grew to 610 acres in 2001. There was an increase of 88 acres for the 23 licensed sites from 1998 to 2001. The average growth was 3.8 acres per pit.

More detailed analysis in the Town of Gorham, Maine, reveals that 18% of the watershed falls within Gorham and that there are 21 licensed mines. This is the second largest area of coverage after Windham, Maine, which has 22% of the watershed within its boundaries, but only 13 open-pit mines.

With respect to mining within the town, Gorham has three zoning classes: (1) mineral extraction allowed, (2) allowed with special exception approval, and (3) not allowed. Combining zones 1 and 2, and subtracting road, lake, river and stream areas along with their mining-exclusionary set-backs (buffers) of 100 and 250 feet, permited the total acreage of possible mineable land within Gorham to be calculated. Gorham had approximately 215 acres of mining operations in 1998 and this grew to 278 acres in 2001. This growth was in both the licensed and non-licensed mining operations. Licensed sites increased by 22.7 percent while non-licensed pits grew by 22.6 percent over three years.