Like other wetlands, geographically isolated wetlands continue to be threatened by many human activities. Habitat destruction (e.g., filling, land-leveling, drainage for agriculture, mining, and excavation), altered hydrology (e.g., ground-water withdrawals and drainage), and water pollution (e.g., runoff from developed areas and farmland and direct discharge of contaminated water) have already destroyed or degraded many isolated wetlands and put many of the remaining ones at risk.