Groundwater 14.1 Water in the Ground 14.2 Conserving Groundwater 14.3 Groundwater and Geology

Water in the Ground Groundwater The amount of water that rocks or soil can hold depends on their porosity and permeability. VOCABULARY groundwater porosity The water table is the top of the water-saturated region of the ground. The depth of the water table depends on climate, season, and location. permeability water table capillary action Zone of aeration Capillary fringe Zone of saturation Impermeable layer Zone of aeration saturation Water table ordinary well spring aquifer artesian formation geyser

Zone of saturation : All the pores and cracks filled with water Zone of aeration : Area above the water table mostly filled with air

How groundwater moves Groundwater usually travels slowly underground seeping and filtering through particles of soil and pores within rocks. Gravity is the prime factor in the movement of groundwater from higher to lower locations The rock material can retard (impermeable rock) and divert flow. As the groundwater flows, pollutants follow the flow and spread out. Though gravity is the prime factor in the movement of groundwater, other factors can contribute to the way and direction of movement. Water moves from higher locations to lower locations. It can be diverted by rocks, roots, and various soil types. Cracks in rocks can produce rapid flows. Exit points such as springs, lakes, streams, or pumping locations can draw water towards these locations.

Groundwater: Water that enters and is stored in the ground. Water in the Ground Groundwater reaches the surface through natural springs and through wells. Aquifers are permeable layers of rock and sediment that have groundwater in enough quantity to supply wells. In areas associated with volcanic activity, groundwater may be very hot, resulting in the formation of springs and geysers. Groundwater: Water that enters and is stored in the ground. Porosity: The percent of a material’s volume that is pore space. Permeability: The rate at which water or other liquids passes through the pore spaces of a rock.

Porosity: The percent of a material’s volume that is pore space.                                                                     Porosity: The percent of a material’s volume that is pore space.

                                                                    Permeability: The rate at which water or other liquids passes through the pore spaces of a rock.

Groundwater: aquifers What would be the properties (porosity/permeability) of conglomerate? High porosity, high permeability

Groundwater: aquifers What would be the properties (porosity/permeability) of unfractured granite? Low porosity, low permeability

Water in the Ground Water table: The surface below which the ground is saturated with water. Capillary action: A phenomenon whereby groundwater rises because the water molecules are attracted to soil particles. Spring: A small stream of water whose source is groundwater that has reached the surface. Aquifer: A permeable layer of rock and sediment that stores and carries groundwater in enough quantities to supply wells. Geyser: A hot spring that intermittently shoots columns of hot water and steam into the air.

The Water Table

Spring: A small stream of water whose source is groundwater that has reached the surface.

The Water Table Spring: A small stream of water whose source is groundwater that has reached the surface.

Artesian formation: An arrangement of a permeable layer of rock sandwiched between two layers of impermeable rock.

Artesian Well Artesian formation: An arrangement of a permeable layer of rock sandwiched between two layers of impermeable rock.

Geyser: A hot spring that intermittently shoots columns of hot water and steam into the air.

Formation of a Water Table To view this animation, click “View” and then “Slide Show” on the top navigation bar.

Groundwater and Geology As water moves through the ground, it dissolves minerals. When the groundwater cools or evaporates, the dissolved minerals are often left behind as deposits such as travertine, geyserite, petrified wood, stalactites, stalagmites, and the cement that binds sedimentary rocks. VOCABULARY mineral deposit cavern karst topography Travertine is a calcite deposit.

Groundwater and Geology Groundwater containing carbonic acid dissolves limestone, forming caverns and features of karst topography. 1. Rainwater containing carbonic acid seeps into the ground. 2. Limestone dissolves, forming underground caves. Limestone Cave Formation 3. Below the water table, the cave is filled with water.

Groundwater and Geology Mineral deposits: A deposit that is left behind when groundwater that contains minerals cools or evaporates. Cavern: A large underground chamber. Karst topography: Topography characterized by sinkholes, sinkhole ponds, lost rivers, and underground drainage; forms in areas with bedrock made of calcite, dolomite, or other minerals that dissolve easily.

Cavern: A large underground chamber.

Karst topography: Topography characterized by sinkholes, sinkhole ponds, lost rivers, and underground drainage; forms in areas with bedrock made of calcite, dolomite, or other minerals that dissolve easily.

Mineral deposits: A deposit that is left behind when groundwater that contains minerals cools or evaporates.

Conserving Groundwater A water budget relates the recharge, surplus, usage, and deficit of soil water to the moisture needs and the moisture supply of an area. Overuse of groundwater leads to problems such as subsidence. Groundwater pollution is a serious threat to supplies of usable water. VOCABULARY water budget recharge surplus usage A worker sorting hazardous waste for safe disposal. deficit

Conserving Groundwater Water budget: Describes the income and the spending of water in a region. Recharge: The refilling of soil water supply at times when plants need little moisture. Surplus: The condition of having rainfall greater than the need for moisture when the soil is already saturated. Usage: The condition where plants draw water from the soil at times when the need for moisture is greater than the rainfall. Deficit: The condition in which stored soil water is gone and the need for moisture is greater than the rainfall.

Usage: The condition where plants draw water from the soil at times when the need for moisture is greater than the rainfall.

Formation of a Cone of Depression To view this animation, click “View” and then “Slide Show” on the top navigation bar.

Pollution in Water When pollutants enter the ground, they spread out in the groundwater. If there is no movement of the groundwater, they disperse evenly in all directions. Thought provoking question: How can pollution move in water and how does pollution get into the water?

What happens when a new well here is heavily pumped?

Flow direction can change