what causes changes in the groundwater level over a course of a year?

The most significant water-level changes due to recharge generally occur during springtime of the year when precipitation is generally greatest and evaporation and plant usage rates are low. Several wells in the observation well network show water-level increases due to rapid groundwater recharge following significant precipitation events.

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What causes water levels to change in groundwater?

There is very little groundwater use in the vicinity of these two wells, so changes in water levels in them are almost entirely due to natural phenomena. In most years, water levels in the two wells rise during the late winter and spring months, then decline through the summer and fall.

What causes water levels to rise and fall?

Water level rises and falls can also be caused by water wells producing groundwater in the vicinity of the observation wells. Many of the observation wells, especially those that were originally municipal water supply wells, show water-level changes that reflect municipal water use.

What happens to the water in a river when it rises?

When the water level of the river is at an elevation higher than the groundwater level, then water will move from the river into the alluvial aquifer. When the river level is lower than that of the groundwater, water flows from the aquifer back into the stream.

What happens when there is too much water in the ground?

Too much ground water. Some human activities, such as pumping water into the ground for oil and gas extraction, can cause an aquifer to hold too much ground water. Too much ground water discharge to streams can lead to erosion and alter the balance of aquatic plant and animal species. 1

What causes groundwater to change over time?

Pumping water out of the ground faster than it is replenished over the long-term causes similar problems. The volume of groundwater in storage is decreasing in many areas of the United States in response to pumping. Groundwater depletion is primarily caused by sustained groundwater pumping.

What is one cause of groundwater levels changing?

Climate change and other future developments, such as land use change and population growth, can influence not only the availability of groundwater resources for drinking water, but also the drinking water demand (Kumar et al.

What increases the level of groundwater?

Tree roots increase water saturation into groundwater reducing water runoff. Flooding temporarily increases river bed permeability by moving clay soils downstream, and this increases aquifer recharge.

What causes changes in the level of the water table?

Fluctuations in the water table level are caused by changes in precipitation between seasons and years. During late winter and spring, when snow melts and precipitation is high, the water table rises. There is a lag, however, between when precipitation infiltrates the saturated zone and when the water table rises.

What affects groundwater?

Droughts, seasonal variations in rainfall, and pumping affect the height of the under groundwater levels. If a well is pumped at a faster rate than the aquifer around it is recharged by precipitation or other underground flow, then water levels in the well can be lowered.

What is causing the groundwater change over time chegg?

Industrial waste. Effluent from "sanitary" landfills and septic tanks. Petroleum products and other chemicals that do not dissolve in water.

How does the groundwater level go down?

Groundwater depletion most commonly occurs because of the frequent pumping of water from the ground. We pump the water more quickly than it can renew itself, leading to a dangerous shortage in the groundwater supply.

Does rain increase groundwater level?

After analyzing decades of data on groundwater and precipitation, scientists at University of Wisconsin–Madison and the Wisconsin Department of Natural Resources have linked precipitation trends to groundwater levels in monitoring wells in Wisconsin. The connection seems obvious: more rain means higher water levels.

What is groundwater level?

Groundwater level is a term that is used in a relatively loose way, normally referring to the level, either below ground or above ordnance datum, at which soil or rock is saturated. This is also referred to as the water table and represents the top of the saturated zone. Above the water table lies the unsaturated zone.

What caused the level of water to decrease?

A decrease in temperature caused the water molecules to lose energy and slow down, which results in water molecules that are closer together and a decrease in water volume. When water is heated, it expands, or increases in volume. When water increases in volume, it becomes less dense.

What is groundwater fluctuation?

Groundwater-level fluctuation is an effect related to aquifer type, recharge, abstraction and regional circulation of groundwater in the area. High rainfalls above the mean are the most prominent sources of water that reach deep into the aquifers through recharge either locally or through regional circulation.

What are two factors that would alter the amount of groundwater in an area?

The availability of groundwater as a water source depends largely upon surface and subsurface geology as well as climate. The porosity and permeability of a geologic formation control its ability to hold and transmit water.

How long does it take for groundwater to change?

As part of the USGS National Water Quality Program, scientists are investigating why, in some areas and at some depths, groundwater quality changes at short timescales —years to months to days to hours, rather than decades. These fluctuations often are in areas where groundwater and surface water interact.

How many people rely on groundwater?

About 140 million people—almost one-half of the Nation’s population—rely on groundwater for drinking water. Regional assessments of groundwater quality are one component of the NWQP's ongoing efforts to assess, understand, and forecast the quality of the Nation’s groundwater.

What are regional assessments of groundwater quality?

Regional Assessments of Groundwater Quality 1 At least one inorganic constituent exceeded a human-health benchmark in all of the 15 Principal Aquifers surveyed to date, ranging from 3 to 50 percent of samples. 2 At least one organic constituent exceeded a human-health benchmark in 2 of the 15 Principal Aquifers surveyed to date, ranging from 3 to 5 percent of samples. 3 Contaminants from geologic sources—primarily trace elements such as arsenic, fluoride, and manganese—most commonly exceeded human-health benchmarks. The Floridan aquifer system was an exception, where strontium was the only trace element to exceed human-health benchmarks. 4 At least one radioactive constituent exceeded a human-health benchmark in a small percentage of samples—1 to 10 percent—in most of the 15 Principal Aquifers studied. The exceptions were the Piedmont and Blue Ridge crystalline-rock aquifers and the Cambrian-Ordovician aquifer system, where exceedances were 30 and 45 percent, respectively. 5 The nutrient nitrate was the only constituent from manmade sources that exceeded its human-health benchmark, typically in a low percentage of samples (1 or 2 percent). These exceedances occurred in the Floridan aquifer system, the Glacial aquifer system, the Rio Grande aquifer system, and the Valley and Ridge and Piedmont and Blue Ridge carbonate-rock aquifers.

When was the 2017 aquifer report published?

Date published: December 7, 2017. Groundwater Quality in the North: The Glacial Aquifer System. A regional assessment of untreated groundwater in the Glacial aquifer system, which includes parts of 25 states across the northern contiguous United States, is now available from the U.S. Geological Survey.

What is corrosive water?

Corrosivity. Corrosivity describes how aggressive water is at corroding pipes and fixtures. Corrosive water can cause lead and copper in pipes to leach into drinking water and can eventually cause leaks in plumbing. Surface water and groundwater, both sources of drinking water, can potentially be corrosive.

What are the constituents of groundwater?

Using the web tool, users can easily visualize changes in both inorganic and organic constituent concentrations in groundwater, including chloride, nitrate, several pesticides, and some drinking-water disinfection byproducts.

Is drinking water from a well regulated?

The quality and safety of water from domestic wells are not regulated by the Federal Safe Drinking Water Act or, in most cases, by state laws. Instead, individual homeowners are responsible for maintaining their domestic well systems and for monitoring water... Contacts: Leslie A DeSimone.

What are the physical changes that affect the flow of ground water?

Stressors that affect the extent of ground water—such as withdrawal or injection—can change ground water velocity and flow. These physical changes can affect patterns of discharge to surface waters and the movement of water and contaminants within the ground. Top of Page.

Why do people rely on ground water?

In many parts of the United States, people rely on ground water for drinking, irrigation, industry, and livestock. This is particularly true in areas with limited precipitation, limited surface water resources, or high demand from agriculture and growing populations.

What are the effects of land subsidence?

Land subsidence and sinkhole formation in areas of heavy withdrawal. These changes can damage buildings, roads, and other structures and can permanently reduce aquifer recharge capacity by compacting the aquifer medium (soil or rock). Salt water intrusion. Changes in ground water flow can lead to saline ground water migrating into aquifers ...

What causes aquifers to hold too much water?

Too much ground water. Some human activities , such as pumping water into the ground for oil and gas extraction, can cause an aquifer to hold too much ground water.

How long does it take for aquifers to replenish?

Some deep aquifers may take thousands of years to replenish. Some consequences of aquifer depletion include: Lower lake levels or—in extreme cases—intermittent or totally dry perennial streams. These effects can harm aquatic and riparian plants and animals that depend on regular surface flows.

What is the extent of ground water?

The extent of ground water refers to the amount available, typically measured in terms of volume or saturated thickness of an aquifer (body of ground water). Concerns related to extent include aquifer depletion and excessive ground water in aquifers.

What are the causes of aquifer depletion?

Stressors that can deplete aquifers include changes in precipitation and snowmelt patterns; withdrawal of ground water for drinking, irrigation, and other human uses; and impervious paved surfaces that prevent precipitation from recharging ground water. Some deep aquifers may take thousands of years to replenish.

How do earthquakes affect groundwater levels?

Groundwater-level responses to earthquakes have been investigated for decades, and have been documented close to and far from earthquake epicenters. The most common groundwater-level response is a water-level oscillation.

Changes in groundwater hydrographs after an earthquake

Over time, USGS has observed a network of groundwater wells monitored by USGS and cooperating agencies where water-level changes have been observed after large earthquakes around the world. Not all wells show water-level changes after every quake, and the response can vary from well to well.

How does precipitation affect groundwater?

Wells pump water from an aquifer, an area that holds a lot of groundwater. If groundwater levels are low, you'll have the expense of digging a deeper well.

Why is groundwater important?

Groundwater is essential to life and a key consideration when planning land development . Before beginning the development process make sure to determine the quality and quantity of the groundwater on your property and take the necessary actions to ensure health, comfort and a successful development project.

How to monitor groundwater levels?

There are a variety of techniques used to monitor groundwater levels. Metal tape sounding devices can be lowered into the well until they contact water. The length of tape that was submersed in water is subtracted from the total length of tape inserted in the well to determine the level.

What is the most important source of water?

One of the most important sources of our water is a natural resource we call groundwater. Groundwater makes up 98 percent of the usable water on Earth [source: Groundwater Foundation ]. Not to be confused with surface water that we see in lakes, rivers and oceans, groundwater comes from rain, snow, sleet and hail that soaks into the ground.

Why is water corrosive to plumbing?

There are also problems with high groundwater levels. Water coming from a shallow well is more acidic than water from a deeper well, making it more corrosive to plumbing. It can dissolve your metal pipes and fittings, and cause leakage.

What can help with groundwater analysis?

Local health agencies can assist in obtaining a water analysis. In addition to groundwater quality, consider groundwater quantity when making your development plans. Low and high groundwater levels each come with their own set of issues.

What is the source of contamination in a city sewer system?

Septic systems used by those not connected to a city sewer system are another source of contamination and landfills can leak contaminants through cracks in their bottom layer. Rain even washes fertilizers, pesticides and road salts into the groundwater.

What causes water level to change?

Water-level changes due to aquifer deformation are commonly due to either Earth tides, orearthquakes. Other external stresses caused by heavy trucks and trains can also causegroundwater fluctuations in some aquifers.

How does rain affect groundwater?

Rainfall is not the only weather factor that can affect groundwater levels. Changes inatmospheric pressure can also cause groundwater levels to fluctuate. Atmospheric pressure iscaused by the Earth’s gravitational attraction of air in the atmosphere. At sea level, the weight ofthe atmosphere exerts a pressure of about 14.7 pounds per square inch on the Earth’s surface.This is equivalent to the pressure exerted by a column of mercury that is 29.92 inches high. Mostweather forecasters report barometric pressure using the units “inches of mercury”, but there areseveral other units that can also be including “feet of water”. The weight of the atmosphere atsea level exerts the same pressure as a column of water 34 feet high. When discussing theeffects of atmospheric pressure change on groundwater levels it is convenient to use feet ofwater as the units. To convert atmospheric pressure measured in “inches of mercury” to “feet ofwater”, simply multiply it by 1.133. Atmospheric pressure decreases with altitude, so for weatherreporting purposes it is corrected to what it would be at sea level, regardless of the elevation ofthe reporting station.

Is groundwater static or dynamic?

Groundwater is not static. It is part of a dynamic flow system. It moves into and through aquifersfrom areas of high water-level elevation to areas of low water-level elevation. Groundwater-levelfluctuations due to aquifer storage changes involve either the addition or extraction of water fromthe aquifer, both through natural means and human involvement.