Groundwater Surface Water Interaction

Material Information

Groundwater Surface Water Interaction
Series Title:
Karst Educational Posters
Added title page title:
Poster series (Florida Geological Survey) ; no. 13A
Place of Publication:
Tallahassee, FL
Florida Geological Survey
Publication Date:


Subjects / Keywords:
Geology -- Florida ( LCSH )
Groundwater -- Florida
Water -- Florida
Groundwater ( jstor )
Water tables ( jstor )
Lakes ( jstor )


Digitized as a collaborative project with the Florida Geological Survey, Florida Department of Environmental Protection

Record Information

Source Institution:
University of Florida
Holding Location:
University of Florida
Rights Management:
The author dedicated the work to the public domain by waiving all of his or her rights to the work worldwide under copyright law and all related or neighboring legal rights he or she had in the work, to the extent allowable by law.


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Pumping water from this well drawsdown the water table. This causeswater to drain from the river. This field is being irrigated by waterpumped from the ground. Runofffrom over irrigation may draininto the lake, spring, or aquifer.Runoff can also carry fertilizerand pesticides into the surfaceand ground water. This spring issues water to thesurface. Runoff water may enterthe spring. This lake receives water fromthe aquifer. The water table isat the same level as the surfaceof the lake. Because the water table is depressedalong the flanks of the river, the rivercontributes water to the aquifer. Ifthere are pollutants in the river, theymay enter the groundwater supply. Over time, watermoves throughthe limestoneaquifer and intothe conduits,quickly makingit’s way tospring. Upper Floridan Aquifer Conduit Flow The portion of water in a streamthat comes from the groundwatersupply is referred to as base flow. If no water enters the stream fromrunoff or rain, the level of a streamat base flow stage (level of waterin a stream) marks the surface ofthe water table. The amount ofwater that an aquifer contributesto a stream varies betweenlocations. This thermographic areal photograph shows the interaction of surface andgroundwater. Cold colors (blues) represent places where cooler groundwateris coming to the surface. Existing surface water is shown by hot colors (red andorange). Warm colors (bright greens, yellows) show areas of mixing. This image shows the locations of ten streams and the percent ofgroundwater that contributes to streamflow. The blue area of thecircle is the percent of the total flow that comes from groundwatersources. Sometimes, people pump more water out of an aquifer than they should. When this happens, the water table can become lower and water maydrain out of lakes and into the aquifer to replace water that is being pumped out. In extreme cases, over pumping of an aquifer can cause lakesand wetlands to dry up and enhance the formation of sinkholes.Not only does water easily enter the groundwater system from the surface, but so does contamination. There are two types of pollution sources:point source and non-point source. Point source pollution refers to pollution that originates from a definable source such as a leaking undergroundstorage tank or a factory. Most non-point source pollution comes from fertilizers and pesticides spread on fields, lawns, and parks. Because of Florida’s unique geologic conditions,interaction of the surface water and groundwatersystems is of particular concern. As you have seen,surface water often enters the groundwater supplythrough sinkholes. Rivers, wetlands, and lakes bothcontribute water to and take water from aquifers. Ifthe water table is high, depressions in the land surfacemay fill with water creating lakes or wetlands. If thewater table is low, water from lakes may slowly seepthrough the soil into the aquifer. The amount of time water spends in an aquifer, between when it enters via recharge and leaves through discharge, is called residence time. In aquifers where water flows more slowly, likesandstone aquifers, bacteria has time to digest contaminants. Theresidence time of water in some limestone aquifers is so short that thereis not enough time for natural processes to remove the contamination. Agriculture is one of the largestsources of non-point source pollution effectingsurface and groundwater. Nitrogen, the activecomponent in fertilizer, is called a limiting nutrient. It is something thatplants need to grow, but is found in limited quantities in nature. Iffarmers over-apply fertilizers, the excess nitrates may get into surfaceand groundwater systems, enhancing growth of algae in pore spaces,springs, and streams, and damaging ecosystems. Excess nitrates andpesticides run off of crops and end up in drinking water, sometimesresulting in health problems in humans and animals. Nitrates can alsooriginate from animal manure, sewage treatment sprayfields, and sometypes of rocks. For Inquires or a copy of the poster Contact: Florida Geological Survey Gunter Building MS, 903 W. Tennessee St., Tallahassee, FL 32304-7700 (850) 488-9380