Office of Conservation
Ground Water Use Facts
Ground water is a renewable resource. In Louisiana, water removed from the ground is constantly replaced, but stress on aquifers and areas of concern give us all pause for examination of how we can conserve water. Adequate time is needed to allow replenishment of underlying ground water reservoirs (aquifers) and proper ground water management will help prevent water-soluble waste products stored in these areas from infiltrating and polluting the underground supply. As water users, the two "C's" can serve as a valuable guideline: DO Conserve and DON'T Contaminate.
Ground Water Facts
- Did you know, although over 70 percent of the Earth's surface is covered with water, less than 1 percent of this water is available for human consumption?
- Ground water is found in aquifers and our state has eleven major aquifers. These are permeable, saturated zones of rock, sand or gravel that contain sufficient water to yield usable amounts to wells.
- Everyday water is withdrawn from our aquifers for the public's use, industry's use, as well as for power-generation, farm and irrigation and aquaculture purposes.
- Generally speaking - water consumption is on the rise and that is stressing available water supplies and distribution systems. Indeed, water is a renewable natural resource, but climate change, prolonged drought conditions and extensive demand can be reason for concern.
- There are nearly 16 million water wells in the U.S., supplying ground water for public supply, private supply, irrigation, livestock, manufacturing, mining, thermoelectric power, and other purposes.
- A recent government survey points to at least 36 states that expect to experience local, regional, or statewide water shortages by 2013. But, by using water more efficiently, we all can help preserve water supplies for future generations, save money, and protect the environment.
- Louisiana is blessed with an abundance of high quality ground water. In fact, ground water is the primary source of drinking water for 61 percent of Louisiana's residents. Of this 61 percent, 12 percent use domestic wells and 49 percent rely on public water supplies. (DOTD/USGS, 1995)
- Louisiana and the rest of the nation are looking to establish best management practices and policies to protect this most important natural resource.
Frequently Asked Questions br>
Why is water important?
All humans and animals need water to survive. Both water availability and water quality are critical issues. At a basic level, pretty much everything we eat has some water in it. It takes water to either grow or make our foods. This water is either supplied by nature as precipitation or added by man during the growing/production process. You can't tell by the size or texture of a food how much water was used to actually produce the food item.
What is most of the fresh water in the U.S. used for?
In 2000, about 408,000 million gallons per day of fresh water was withdrawn from our surface and ground water sources, such as wells, rivers, lakes, and reservoirs. Breakdown by water-use category:
- Thermoelectric Power....48%
- Public Supply...........11%
What is ground water?
Ground water is water that flows or seeps downward and saturates soil or rock, supplying springs and wells. Ground water often begins as precipitation and soaks into the ground where it is stored underground in rock crevices and in the pores of geologic materials (these are aquifers), the same way as water fills a sponge. The upper surface of the saturated zone is called the water table.
How important is ground water?
Ground water, which is found in aquifers below the surface of the Earth, is one of the Nation's most important natural resources. Ground water is the source of about 38 percent of the water that county and city water departments supply to households and businesses (public supply). It provides drinking water for more than 97 percent of the rural population who do not get their water delivered to them from a parish or city water department or private water company.
What is an aquifer?
An aquifer is a geologic formation that can store and transmit water to wells, springs and some streams. An aquifer is more like a sponge than an underground river: geologic materials have connected pores that allow water to move from one space to another, but unless the rock is fractured, water does not move through large, hollow tunnels at rapid rates. Wells can be drilled into aquifers and water can be pumped out. Precipitation adds water (this is recharge) into the porous rock of the aquifer. The rate of recharge is not the same for all aquifers, though, and that must be considered when pumping water from a well. Pumping too much water too fast draws down the water in the aquifer and might eventually cause a well to yield less water or run dry. Pumping your well too fast or too often might also cause your neighbor's well to run dry if you both are pumping from the same aquifer. Aquifers can be quite extensive, possibly stretching for tens of miles, feeding hundreds of ground water wells and streams. This is why usage of your well can influence other people miles away.
How does water get underground?
A portion of the precipitation (rain, hail, snow) that lands on the ground will enter the soil. This process is called infiltration. Because of gravity, the filling or saturation of spaces between soil particles, and the pressure of the overlying water, water may continue to move down through the soil layer. As water moves past the root zone, the movement is referred to as percolation. Layers of soil and rock that are saturated with water are called aquifers. Aquifers are able to transport water and supply water to wells, rivers, springs and marshes. A ground surface area that provides a water entry port for a confined aquifer is called a recharge area or zone.
What is the difference between a confined and a water-table (unconfined) aquifer?
A confined aquifer is an aquifer below the land surface that is saturated with water. Layers of impermeable material are both above and below the aquifer, causing it to be under pressure so that when the aquifer is penetrated by a well, the water will rise above the top of the aquifer. A water-table, or unconfined, aquifer is an aquifer whose upper water surface (water table) is at atmospheric pressure, and thus is able to rise and fall. Water-table aquifers are usually closer to the Earth's surface than confined aquifers are, and as such are impacted by drought conditions sooner than confined aquifers.
Where does artesian water come from?
Artesian water is a phrase found on many bottled water containers and other refreshment products. Artesian water comes from an artesian water source - a confined aquifer in which the water is under enough pressure that, when tapped by a well, the underground water rises above the level of the aquifer surface. In some cases, the water in the aquifer is under sufficient pressure to push the water right up and over the ground surface. Such wells are called flowing artesian wells.
Why does the water level in a 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 underground water 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. This is what is happening during drought periods. The water level in a well can also be lowered if other wells near it are withdrawing too much water.
What determines when 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 your well will never have water in it again, as the water level may come back through time as recharge increases. The water level in your 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 this 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.
Why doesn't a drought go away when it rains?
There are a few reasons for this. During a drought, a lot of rain is needed to make up for water deficits, and to fill our reservoirs and recharge our aquifers. During hot summers, a lot of rain gets evaporated before getting the chance to replenish our water supplies. In terms of replenishing our ground-water supplies, it may take a long time for water that falls on the Earth's surface to reach and recharge the aquifers. The deeper the aquifer, the longer it takes for rainfall to get there.
How does water reach my home?
All of the water that we use in our homes comes from either a ground-water source, such as a well, or from a surface-water source, such a river, lake, or reservoir. Precipitation falls on the Earth's surface and eventually adds water (recharge) into an aquifer. This water may be pumped into your home from a well that taps into the aquifer. If your water source is a reservoir, precipitation and other surface water collects in the reservoir. This water is piped to homes from a public supplier.
How much water does the average person use at home per day?
Estimates vary, but each person uses about 75-100 gallons of water per day. Are you surprised that the largest use of household water is to flush the toilet, and after that, to take showers and baths? That is why in these days of water conservation, we are starting to see toilets and showers that use less water than before.
Does a little leak in my house really waste water?
It's not the little leak that wastes water ... it is the little leak that keeps on leaking that wastes water. And the fact that the leak is so little means that maybe you ignore it. So, how can a little leak turn into a big waste? Many of our toilets have a constant leak - somewhere around 22 gallons per day. This translates into about 8,000 gallons per year of wasted water, water that could be saved. Or think of a leaky water line coming into your house. If it leaks 1 gallon of water every 10 minutes that means that you are losing (and paying for) 144 gallons per day, or 52,560 gallons per year.
Why does my water smell like rotten eggs?
You would know it if you had this problem! In some parts of the country, drinking water can contain the chemical hydrogen sulfide, which smells just like rotten eggs. This can occur when water comes into contact with organic matter or with some minerals, such as pyrite. The situation mostly occurs as ground water filters through organic material or rocks.
Why does it take so long to rinse the soap off my hands?
The terms "soft water" and "hard water" are important here. Water is said to be "soft" if it has a low concentration of calcium and magnesium ions in it, and "hard" water has a higher concentration. The ions react with the soap you use to produce a scummy residue that is hard to wash off. If you use "hard" water you also will have a harder time working the soap up into a lather. "Hard" water is prevalent in some parts of the country, and sometimes "water softening" chemicals, that reduce the amount of calcium and magnesium, are added to the water.
Why is our porcelain sink stained brown?
The brown stain is from too much iron in your water. It is closely related to simple rust you see on metal, which is iron oxide. Probably the source of the water you use is ground water, and the water has filtered through rocks containing iron-rich minerals on the way to the well.
What can I do to conserve water being drawn from aquifers and reservoirs?
The Louisiana Department of Natural Resources recommends these water conservation tips.
Where can I find a summary of Louisiana water resources law?
To view a summary of law governing water resources in Louisiana, see sections 2.4.1 and 2.4.2 (Volume II) of the December 2002 Report, Assistance in Developing the Statewide Water Management Plan
Additionally, the Louisiana Attorney General's Office recently provided several legal opinions on the commercial use of surface water. A link to the opinions are as follows:
Subsequent to issuance of these opinions, an Interagency MOU was issued.
Click here for Act 955 and Cooperative Endeavor Agreements related to withdraw of surface water from state owned water bodies.
Ground water well registration data can be retrieved from the DNR SONRIS Lite menu at www.sonris.com by searching Water Wells by Longitude Latitude
For additional water well registration database information, please contact our office at (225) 342-8244.