Central Oklahoma’s Bedrock

Groundwater is water located beneath the earths surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water.

In Central Oklahoma, the major bedrock aquifer is the Garber-Wellington aquifer, a subset of the larger Central Oklahoma Aquifer system. The aquifer is named after the two rock formations that the water flows through: the Garber Sandstone and the Wellington Formation.

Introduction to the Aquifer

The world is a watery place. According to estimates from the United States Geological Survey (USGS), over 70 percent of the earth is covered in water, with 96.5 percent of the water in the oceans. But it is the freshwater resources – lakes, rivers, and aquifers –that provide life. It is this water, which is constantly moving from one place to another and from one form to another, which is of the most concern to people (USGS, 2012).

The graphic above is an illustration of how water moves through our world. Commonly referred to as the water cycle, water generally starts out as precipitation which has condensed from water vapor in clouds. The water falls as rain, which can become runoff, ground water, or immediately be evaporated again.

Runoff water eventually becomes stream, river, or lake water. It can also infiltrate into the near surface to be transpired by plants, thus becoming water vapor once again. Stream, river, or lake water can also evaporate to become water vapor. It can also move to the ocean, a large reservoir of water which is where much evaporation takes place.

Water that infiltrates down deep into the ground is usually referred to as groundwater. Groundwater generally moves much slower than surface water because rock has pores which the water must now travel through. Water that enters the ground is generally called recharge; the rock that is permanently wet below the ground is called the saturated zone.

Ground water can stay in the ground thousands of years or it can discharge quickly. This depends on the rock type (geology), the rate of movement the water is flowing through the ground, and the distance to the nearest discharge point such as a water well. Ground water can discharge naturally into lakes and oceans, or become surface water in the form of springs.

Staff Contacts

John Harrington, P.G., CFM
Director, Water Resources

Anita Kroth
Administrative Assistant


Water Cycle

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Aquifers in Oklahoma

Many people refer to “the aquifer” as simply water under the ground and usually conceptualize it as a large underground lake or stream. This is probably due to the fact that most people are familiar with large bodies of water in the form of rivers and lakes. Many people refer to “streams” of water under the ground. Continue Reading…

Water Well Construction

Well construction is an important consideration for anyone who uses groundwater since the construction directly affects the chemistry of the water sampled in many cases. Several styles of well construction are found in the central Oklahoma area. Continue Reading…

Aquifers and Rock Types

A lot of people think that a rock is a pretty solid thing. But on closer examination, many rocks have cracks and holes that allow water to exist in and pass through a rock – an astonishing amount of water in some cases. It is the holes and cracks – called porosity and permeability – that determine how fast the water moves and how much water can come out of a water well. Think of a sponge – it is the holes in the sponge that fills with water (porosity) and the interconnected pores (permeability) that allow the water to go through the sponge. Continue Reading…

Water Quality

When people think of groundwater, a common reaction is that it is clean, refreshing, sweet water.  Many bottled water companies display language that refer to their product as artesian well water, mineral water, spring water, or well water.  The implication is that groundwater is superior to tap or surface water and tastes better. Continue Reading…

Garber-Wellington Aquifer

The Garber-Wellington Aquifer is a major bedrock sandstone aquifer in Central Oklahoma. Also referred to as part of the Central Oklahoma Aquifer System, it is comprised primarily of rocks from the Lower Permian-age Garber Sandstone and Wellington Formations (Simpson, 1973). The total thickness of the combined formations is about 1,000 feet. Depth to water varies from less than 100 feet to 350 feet; saturated thickness ranges from 150 to 650 feet. Non-domestic wells completed in the aquifer can yield as much as 600 gallons per minute (gpm) but generally yield from 200 to 400 gpm. Continue Reading…


Please review our list of helpful water references.

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