Any material (concrete blocks, reeds, wood, dirt, gravel, etc.) used for the primary purpose of replacing an aquatic area with dry land or of changing the bottom elevation of a waterbody. The term does not include any pollutant discharged into the water primarily to dispose of waste.

---

From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.