High porosity and permeability Unconfined aquifer Aquitard Confined aquifer Low porosity and permeability An aquifer is a high-porosity,high-permeability rock.If it has access to the ground surface,it's an unconfined aquifer.If it's trapped below an aquitard,a rock with low permeability,it's a confined aquifer
An aquifer is a high-porosity, high-permeability rock.If it has access to the ground surface,it’s an unconfined aquifer.If it’s trapped below an aquitard,a rock with low permeability,it’s a confined aquifer
8.1 The Basic Concepts of Groundwater 8.1.1 The Spaces and Moisture in Rocks 3)Water table(潜水面或地下水面)： geologists define a boundary ,above which pore spaces and cracks contain mostly air and below which they contain only water. The region of the subsurface above the water table is called the unsaturated zone,and the region below the water table is the saturated zone
(3)Water table（潜水面或地下水面）: geologists define a boundary ,above which pore spaces and cracks contain mostly air and below which they contain only water. The region of the subsurface above the water table is called the unsaturated zone, and the region below the water table is the saturated zone, 8. 1 The Basic Concepts of Groundwater 8.1.1 The Spaces and Moisture in Rocks
Zone of aeration Soil Capillary fringe Moisture sticks to grain surfaces;air pockets remain. Water table Zone of Bedrock or saturation sediment All pore space is filled with water. (a) (a)The geometry of the water table,illustrating the saturated zone,the unsaturated zone,and the capilary fringe. Water table
Water table (a) The geometry of the water table, illustrating the saturated zone, the unsaturated zone, and the capilary fringe
Water table (b) (c) (b)The surface of a permanent pond is the water table. (c)During the dry season,the water table can drop substantially,causing the pond to dry up. Water table
Water table (b) The surface of a permanent pond is the water table. (c) During the dry season, the water table can drop substantially, causing the pond to dry up
8.1 The Basic Concepts of Groundwater 8.1.1 The Spaces and Moisture in Rocks Hi Pond The shape of a water table beneath hilly topography
The shape of a water table beneath hilly topography 8. 1 The Basic Concepts of Groundwater 8.1.1 The Spaces and Moisture in Rocks