Groundwater, A Source To Streams in the Ozark Plateaus

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Detailed Description

Groundwater or surface water interaction in the Ozark Plateaus aquifer system. Includes examples of thermal imagery used to see groundwater entering streams.

Details

Image Dimensions: 480 x 360

Date Taken:

Length: 00:03:18

Location Taken: Fayetteville, AR, US

Transcript

there are many streams in the ozarks that
seem to disappear and reappear

randomly....if you walk along tributaries
of the Buffalo National River,

one minute you'll hear the familiar sounds
of running water, the next minute silence.

Where does the water go and why?

That question, which is related to the interaction
of groundwater and surface water, is one the

USGS wants to begin to answer as part of an
ongoing study.

one USGS study by imes and others estimated
about 173 tons of rock were dissolved by water

flowing
out of Big Spring each day (that's about 72

cubic yards or 2.5 large dump trucks)

this rock dissolved by groundwater can result
in caverns beneath land surface.

in other instances, when enough of the rock
is removed to create an unstable

condition above the cavern, the overlying
rock will collapse forming a sinkhole.

As is the case with Big Spring, groundwater
flowing through the openings created by dissolution

typically emerge at the surface, often in
or near a surface water body.

the existence of these features underscores
the role of groundwater

in the ozark system

evaluating where or how much groundwater enters
or leaves the streams can be tricky.

one method to estimate the gain or loss of
groundwater to streams is

to measure stream discharge at multiple locations.

hundreds of such measurements have been made
throughout the ozarks,

and the USGS has compiled these into a single
data set

for use in a geographic information system.

another method to literally see groundwater
entering a stream uses thermal

imaging. because groundwater is insulated
from rapid shifts in surface

temperature, it tends to emerge from the ground
at temperature either above

or below surface water.

In our case, thermal imaging was taken during
the winter,

so groundwater is actually warmer than the
surrounding surface water.

groundwater can emerge at single point locations
from springs adjacent to or underneath

surface water bodies, or it can enter slowly
- diffusing into the surface water.

information gained through these methods help
in developing tools - such as numerical models

of the groundwater system.

These tools can then provide information regarding
the supply of water underground, and how much

flow in streams is provided by groundwater
- while helping to ensure the future sustainability

of the Ozark aquifer system.