Glossary

Barton Springs Pool

Aquifer
an underground layer of soil, gravel, or porous rock that contains water.

Arachnid
a small invertebrate with four pairs of legs. Spiders, scorpions, and harvestmen – all found in the Barton Creek area – are arachnids.

Conduit
a natural opening that allows water to flow through an aquifer.

Contributing zone
land area upstream from the recharge zone where the watersheds of creeks and rivers catch rainfall.

Ecosystem
a collection of interacting plants and animals, together with their natural environment.

Edwards Aquifer
an aquifer that underlies portions of nine counties in central and south-central Texas. The central section of the aquifer supplies water to Barton Springs.

Edwards Plateau
the southern the southern extension of the Great Plains, which covers much of south Texas, from the Rio Grande River to the Colorado River.

Evaporation
changing of a liquid to a gas; for example, when water becomes water vapor.

Fertilizer
any material in the soil or water that acts as a nutrient for plant growth.

Groundwater
water that seeps down from the Earth’s surface and is stored in aquifers, porous rock or soil pores.

Karst aquifer
a geological landform typified by structures created by water, such as caves, sinkholes, and highly porous rock. The Edwards Aquifer is a karst aquifer.

Nitrate
a nitrogen compound that is a major plant nutrient.

Nonpoint source pollution
pollution caused by sediment, nutrients, organic and toxic substances; originates from land use activities; and is carried to lakes and streams and groundwater by surface runoff.

Pesticide
any chemical agent used to kill specific insects or animals.

Phosphorus
one of the primary nutrients required by plants; often is the limiting factor for the growth of aquatic plants.

Point source pollution
pollution that originates from a single, well-defined point, such as a leaking underground storage tank, a factory or a damaged sewer line.

Pollutants
toxic substances that enter the air or water.

Recharge zone
the area of land where surface water enters the ground and moves into an aquifer. The aquifer is exposed at the surface at some points in the zone.

Reservoir
any holding area used to store, regulate or control water, may be natural or man-made.

Runoff
the portion of rainfall, melted snow or irrigation water that flows across land surfaces and eventually enters a stream.

Sediment
water-transported and water-deposited particles of rock, soil, or biological material.

Silt
fine-grained sediment.

Toxic substances
poisonous materials that cause sickness, disease, and/or death in plants and animals.

Water pollution
the contamination of water by the addition of substances which degrade water quality.

Watershed
the land area that contributes surface water runoff to a given point in a drainage system.