Drought and Groundwater Levels
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The USGS National Water Information System (NWIS) contains extensive groundwater data for thousands of sites nationwide.
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Groundwater decline is a real and serious problem in many places of the Nation and the world. When rainfall is less than normal for several weeks, months, or years, the flow of streams and rivers declines, water levels in lakes and reservoirs fall, and the depth to water in wells increases.
• Water Science School HOME • Groundwater topics •
Drought and Groundwater Levels
Credit: U.S. Drought Monitor
The water levels in aquifers are not often a constant. Groundwater levels first are dependent on recharge from infiltration of precipitation so when a drought hits the land surface it can impact the water levels below ground, too. Likewise, many aquifers, especially those which don't have abundant recharge, are affected by the amount of water being pumped out of local wells. Groundwater decline is a real and serious problem in many places of the Nation and the world. When rainfall is less than normal for several weeks, months, or years, the flow of streams and rivers declines, water levels in lakes and reservoirs fall, and the depth to water in wells increases. If dry weather persists and water-supply problems develop, the dry period can become a drought.
How important is groundwater?
Groundwater, which is found in aquifers below the surface of the Earth, is one of the Nation's most important natural resources. Groundwater is the source of about 40% percent of the water that county and city water departments supply to households and businesses (public supply).
How does the water level in my well change?
The water level in the aquifer that supplies a well does not always stay the same. Droughts, seasonal variations in rainfall, and pumping affect the height of the groundwater levels. If a well is pumped at a faster rate than the aquifer around it is recharged by precipitation, streams or other underground flow, then water levels in the well can be lowered. This can happen during drought, due to the extreme deficit of rain. The water level in a well can also be lowered if other wells near it are withdrawing too much water.
What determines if a well will go dry?
A well is said to have gone dry when water levels drop below a pump intake. This does not mean that a dry well will never have water in it again, as the water level may come back through time as recharge. The water level in a well depends on a number of things, such as the depth of the well, the type (confined or unconfined) of aquifer the well taps, the amount of pumping that occurs in the aquifer, and the amount of recharge occurring. Wells screened in unconfined water table aquifers are more directly influenced by the lack of rain than those screened in deeper confined aquifers. A deep well in a confined aquifer in an area with minimal pumping is less likely to go dry than a shallow, water-table well.
Credit: Joe Leineweber, Pexels.com
How do I find out if my well will go dry?
Wells screened in unconfined water table aquifers are more directly influenced by the lack of rain than those screened in deeper confined aquifers. This means that it may be more likely for the water level in wells screened in the water table to drop below the pump level and prevent water from being obtained. This does not mean that wells in a confined aquifer will not go dry, as they are also influenced by pumping rates, lack of recharge, and possibly by the pumping rates of other wells near you that access the same aquifer your well does.
I paid to have my own private water well installed, so why can't I use the water any way I want to?
If you own a well and you pump excessive amounts of water from your well, there is a danger of your well going dry as consumption continues, and groundwater levels fall. Since aquifers can be quite extensive, the usage of your well can influence other people miles away. Groundwater that supplies your well also feeds streams during periods of low flow, so pumping from your well may also cause the water levels in streams to be lower. You can view a map of the regional aquifer systems from the USGS Groundwater Atlas of the United States. More information on aquifers may be found in the USGS Aquifer Basics website.
Want to know more about drought and groundwater levels? Follow me to the Domestic (Private) Supply Wells website!
Below are science topics related to drought and groundwater levels.
Groundwater Information by Topic
Aquifers and Groundwater
Infiltration and the Water Cycle
Groundwater True/False Quiz
Public Supply Water Use
Domestic Water Use
Groundwater decline is a real and serious problem in many places of the Nation and the world. When rainfall is less than normal for several weeks, months, or years, the flow of streams and rivers declines, water levels in lakes and reservoirs fall, and the depth to water in wells increases.
• Water Science School HOME • Groundwater topics •
Drought and Groundwater Levels
Credit: U.S. Drought Monitor
The water levels in aquifers are not often a constant. Groundwater levels first are dependent on recharge from infiltration of precipitation so when a drought hits the land surface it can impact the water levels below ground, too. Likewise, many aquifers, especially those which don't have abundant recharge, are affected by the amount of water being pumped out of local wells. Groundwater decline is a real and serious problem in many places of the Nation and the world. When rainfall is less than normal for several weeks, months, or years, the flow of streams and rivers declines, water levels in lakes and reservoirs fall, and the depth to water in wells increases. If dry weather persists and water-supply problems develop, the dry period can become a drought.
How important is groundwater?
Groundwater, which is found in aquifers below the surface of the Earth, is one of the Nation's most important natural resources. Groundwater is the source of about 40% percent of the water that county and city water departments supply to households and businesses (public supply).
How does the water level in my well change?
The water level in the aquifer that supplies a well does not always stay the same. Droughts, seasonal variations in rainfall, and pumping affect the height of the groundwater levels. If a well is pumped at a faster rate than the aquifer around it is recharged by precipitation, streams or other underground flow, then water levels in the well can be lowered. This can happen during drought, due to the extreme deficit of rain. The water level in a well can also be lowered if other wells near it are withdrawing too much water.
What determines if a well will go dry?
A well is said to have gone dry when water levels drop below a pump intake. This does not mean that a dry well will never have water in it again, as the water level may come back through time as recharge. The water level in a well depends on a number of things, such as the depth of the well, the type (confined or unconfined) of aquifer the well taps, the amount of pumping that occurs in the aquifer, and the amount of recharge occurring. Wells screened in unconfined water table aquifers are more directly influenced by the lack of rain than those screened in deeper confined aquifers. A deep well in a confined aquifer in an area with minimal pumping is less likely to go dry than a shallow, water-table well.
Credit: Joe Leineweber, Pexels.com
How do I find out if my well will go dry?
Wells screened in unconfined water table aquifers are more directly influenced by the lack of rain than those screened in deeper confined aquifers. This means that it may be more likely for the water level in wells screened in the water table to drop below the pump level and prevent water from being obtained. This does not mean that wells in a confined aquifer will not go dry, as they are also influenced by pumping rates, lack of recharge, and possibly by the pumping rates of other wells near you that access the same aquifer your well does.
I paid to have my own private water well installed, so why can't I use the water any way I want to?
If you own a well and you pump excessive amounts of water from your well, there is a danger of your well going dry as consumption continues, and groundwater levels fall. Since aquifers can be quite extensive, the usage of your well can influence other people miles away. Groundwater that supplies your well also feeds streams during periods of low flow, so pumping from your well may also cause the water levels in streams to be lower. You can view a map of the regional aquifer systems from the USGS Groundwater Atlas of the United States. More information on aquifers may be found in the USGS Aquifer Basics website.
Want to know more about drought and groundwater levels? Follow me to the Domestic (Private) Supply Wells website!
Below are science topics related to drought and groundwater levels.
Groundwater Information by Topic
Aquifers and Groundwater
Infiltration and the Water Cycle
Groundwater True/False Quiz
Public Supply Water Use