Abstract
Mining sand and rock in low-lying, coastal plain areas forms large, often deep, lakes that can adversely affect local water resources and sensitive environments, particularly wetlands. Ground water flow modeling at a planned mine site in South Florida was used to assess the general hydrologic processes by which such lakes can impact local near-surface ground water levels. The construction of a large lake in an area with a sloping water table may result in a decreased ground water levels (drainage) in the areas up-gradient of the lake and increased water levels in down-gradient areas. Lakes also add storage to the hydrologic system, which can maintain locally higher aquifer water levels, provided that they capture excess surface water that would otherwise be lost. Mining plans can be developed to minimize potential adverse impacts to existing wetlands and to take advantage of down-gradient increases in waters levels for wetland enhancement and mitigation.