Chap 17 geo 3

Groundwater Quality

The condition of groundwater, often assessed by the presence of dissolved solids; potable water typically contains about 150 mg/L of dissolved solids.

Potable water

Water that is agreeable to taste and safe for human consumption.

Contamination

The presence of harmful substances in water, often from sources such as sewage, highway salt, and pesticides.

Sewage

Wastewater that contains bacteria and nitrates, often emanating from septic tanks or broken sewer lines.

Maximum allowable concentrations

Limits set by the U.S. Environmental Protection Agency for toxic compounds in drinking water.

Natural treatment

Natural sediment processes that filter bacteria from contaminated water, effective only in low-permeability areas.

Pumping well

A well that can reverse groundwater flow to capture contamination sources like septic tank water.

Groundwater flow

The movement of water through the underground layers of soil and rock compared to surface water flow.

Rainwater leaching

The process where rainwater dissolves and transports toxic compounds into groundwater.

Pump-and-treat

A method of cleaning contaminated aquifers that is often ineffective for organic compounds.

Biodegradation

A process where microbes break down hazardous organic compounds in contaminated water.

Cone of depression

A cone-shaped depression in the water table around a pumping well that affects groundwater flow.

Limestone composition

Limestone is primarily composed of calcite (CaCO3), which can dissolve in acidic water.

Caves formation

Caves above the water table formed by the dissolution of calcite from acidic infiltrating rainwater.

Speleothems

Drip stone formations in caves, including stalactites, stalagmites, and soda straws.

Karst topography

A landscape characterized by sinkholes and underground drainage systems, often resulting from limestone erosion.

Sinkhole

A depression that forms when the roof of a limestone cave collapses, often enlarging over time.

Soil piping

A process where soil is washed away, potentially leading to the formation of sinkholes, particularly in areas like Guatemala City.

Sewage pipe break

An event that can lead to large underground holes as seen in Guatemala City, distinct from traditional sinkholes.

Guatemala City sinkholes

Large depressions caused by the collapse of volcanic ash due to water flow from a broken sewage pipe.