World News Headlines

Coverage of breaking stories

While an important source of freshwater, groundwater is not as widely used as rivers & springs. True or false?

source :

While an important source of freshwater, groundwater is not as widely used as rivers & springs. True or false?


Groundwater is water located beneath the earths surface in soil pore spaces and in the fractures of rock formations.It comes from rain, snow, sleet, and hail that soaks into the ground. The water moves down into the ground because of gravity, passing between particles of soil, sand, gravel, or rock until it reaches a depth where the ground is filled, or saturated, with water.

Water | Free Full-Text | Groundwater as a Source of Drinking Water...

Water | Free Full-Text | Groundwater as a Source of Drinking Water… – Groundwater is widely acknowledged to be an important source of drinking water in low-income The River Chief System and River Pollution Control in China: A Case Study of Foshan. However, for those using piped or packaged water, the resource supplying these systems is not consistently…About 70% of the water pumped out of underground aquifers worldwide is used for agriculture while much of the remainder quenches the thirst of cities. A new study released Wednesday says that diminishing groundwater is causing the level of streams and rivers to fall as well.A river is a moving body of water that flows from its source on high ground, across land, and then into another body of As rivers flow, they erode – or wear away – the land. Over a long period of time rivers create valleys, or gorges and canyons if If they flow from underground they are called springs.

River Flows Are Falling Worldwide as Groundwater Is… – Bloomberg – Groundwater is the source of about 37 percent of the water that county and city water Volatile organic compounds (VOCs), which are widely used in the manufacture of many products including Contrary to popular belief, groundwater does not form underground rivers. It fills the pores and…Industrial water is also used as cooling water for energy generation in fossil fuel and nuclear power plants (hydropower generation is not included in Renewable internal freshwater resources refers to the quantity of internal freshwater from inflowing river basins and recharging groundwater aquifers.Almost all water that goes through water treatment facilities to get cleaned up for use in homes, businesses This can include rivers, lakes, ponds, streams, and the oceans. However, in this article, we'll mostly be Surface water is an important part of the hydrologic cycle, just like groundwater is.

River Flows Are Falling Worldwide as Groundwater Is... - Bloomberg

Rivers – BBC Bitesize – Fresh water is not always potable water, that is, water safe to drink. Much of the earth's fresh water (on the surface and groundwater) is to a substantial degree unsuitable for human consumption Water fountain found in a small Swiss village; used as a drinking water source for people and cattle.Contaminated water can transmit diseases such diarrhoea, cholera, dysentery, typhoid, and polio. Contaminated drinking water is estimated to While this practice if done inappropriately poses health risks, safe management of wastewater can yield multiple benefits, including increased food production.Groundwater is widely used as a source of freshwater. It is a cheap source of freshwater, and also, not as much vulnerable to pollution such as surface water. Because of that, it can be commonly used as a source of freshwater.

Cliff Humphrey: Renaisassance Arising -RENAISSANCE, a ...
Ground Water — Safe Drinking Water Foundation
South Haven Tribune - 10.17.16Best buddiesProgram pairs ...
What is Groundwater?

GS 106 Week 5 Video 5 – >> Welcome back to
Week 4, and we're going to continue on with groundwater.
And in this video we are going
to talk about what aquifers are. And what the major
types of aquifers exist. And then we'll talk about hazards associated
with groundwater. So what are aquifers? Aquifers are basically
a body of rock that can easily transmit
and store water. So it has a decent
permeability and porosity. To be able to hold that water,
and be able to transmit it from one place to another. Aquifers that we
actively use are ones that we can pump water out of. So it has to have a good
permeability and porosity to be able to move that
water from place-to-place. There's three major types. There's confined aquifers. Unconfined aquifers,
and perched aquifers. So one thing to note before we
get into the types of aquifers, is to talk about
what groundwater is, and kind of show you a little
bit of what that looks like. So if we were to take
a slice into the earth, here's our surface topography. We've got surface water in
one part, and this white — sorry, blue line is showing
you where the water table is. And you can see that
water table tends to mirror the surface
topography. Where it's higher, the
water table's close to the surface up high. Where it's lower, the water
table is again lower too. So you can see how it
has that curved plane, just like the surface does. And so that water table's
right where you have all of the porous spaces in the rock
completely filled with water. So how does ground water move? Well, it's going to move from high elevations
to low elevations. So here you can see
that high elevation at either side of this river. Rainfall seeps into the ground, and then gets into
the water table. So this would be an
unconfined aquifer where the water just seeps in
and enters the water table. So we have an unconfined
aquifer here. And then transmits
slowly into that stream. And that stream is
actually flowing. It's a spot where it's an
outlet to the groundwater. And so that stream would be
considered a gaining stream. And then if we look over here,
a more complex situation. What we have is this is kind
of a little bit more realistic. What we actually have in the
earth, and what we see is on the surface of the earth
we have an unconfined aquifer. And then what's called
the confining bed. So our aquifer's going to be
a rock unit or sediment unit that has enough porous space and
permeability to transmit water. Whereas a confining bed
doesn't have the permeability to let water through it. So it's going to hold — trap
water on one side or the other. A confined aquifer is going to have those confining
beds on either side. So that confined
aquifer, the water gets in from someplace else and it
gets basically trapped there. Until you drill a well
into it to be able to pump the water out. And so the deeper you go, the
longer it takes that water to transmit from place to place. So here's just another —
a different scenario here. We've got our unconfined
aquifer on the surface here. And this one would be
emptying into this river. And then we have our confining
layer — this dark brown layer. And then we have our
confined aquifer. So up here would be
considered unconfined, because the water can
easily get into that layer. But then as it transmits
down into this bed, gravity's pulling it down, and
because it has more material on top of it, it's
under some pressure. So when you drill a well into
it, the water is going to rise in the well up to a
point where that pressure from this confined aquifer
is going to push it up to, we call it the pesiometric
[phonetic] surface. And when we have
lots of pressure on that confined aquifer, sometimes we can get
wells that are flowing. Those are called artesian wells. And here's just a
couple of examples of a pretty calm, flowing one. And then a pretty
crazy flowing well. So those are the
different types of aquifers. It might be helpful to try to
draw or sketch one of those. A diagram that has
all three on it. So some of the different hazards
associated with groundwater. Some of the main
ones that we're going to talk about are sinkholes. Disappearing water bodies. Cone of depression. Salt water intrusion
and pollution. So sinkholes are the first one. We kind of touched
on this before. So sinkholes, here you
can see some sinkholes in Florida that occurred. And these are happening because
this is limestone; bedrock. And in Florida there's
a lot of development. So you have a lot more
houses being built. So we're adding more
and more weight to the surface of the land. Destabilizing the
roofs of those caves. And we have a lot more
people using the groundwater, pumping water out of the ground. So we pump water out. The water table drops. Caves get exposed. And that water was once
a support to those caves. Once it's gone, caves
are weakened. And so we end up with kind of a
double whammy for these areas. And we can have some
sinkholes developing. Pretty scary. And here — there's a great
website here, I'll show you. I got a lot of this
information from. Oops. There we go. So a USGS water science school. You have a link to this and
it talks about sinkholes. What they are. Shows you some great
photographs. And places that are susceptible
to caves and sinkholes. We're pretty safe where we are. And then kind of how these form. So here's our — showing you
how the caves are created. And here we've got
kind of the stages. We've got places where we have
a layer of sediment on top of the limestone that gets
collapsed so that sand can fill in that cave over time. You get a depression
on the surface. Or you can have a
collapse that can happen. And then we can have
manmade ones as well. So that website's great. It has a lot of awesome
information on it. So I strongly suggest
you take a look. Another problem is increased
water withdrawals from aquifers. And this is a map here
showing you, as of 2005, the total groundwater
withdrawals by state. So the darker the blue,
the more water is used. California; high population. Pretty dry in places. Lots of groundwater use. Texas, Arkansas, Nebraska. These are also areas
that can be fairly dry. But also the breadbasket
of the United States. This is where a lot of
our agriculture happens. We have subsidence
that occurs due to groundwater withdrawals;
over-pumping. Before I get to the
subsidence here, I want to talk a
little bit about — I have an example of
Lake Chad in Africa. So if we zoom over to Lake Chad, this is an area that's
pretty dry. This is — let's go back
here to 1963, Lake Chad. All the dark areas here
are filled with water. We come up to 1972. We have our blue areas. That's the water. The green is vegetation. We come up here to 1987,
and look at Lake Chad. All we have is a lake
in this small area. And then if we come up
to 2000, even smaller. And you can see it's kind
of stayed at a steady point from in the 2000s, decreased
a little bit from 1990. This is a really dry area. People pump the groundwater out
and divert rivers and streams in this area to try
to grow crops. This Lake Chad is right on
the edge of the Sahara desert, which is expanding over time. So you have a couple different
things happening here. You guys are going to look
at an example in lab as well. So we've got increased ground
water withdrawals from humans. So we're pulling
groundwater out. So we're lowering the
water table in the area because we're using so much. And because we're pumping
out onto the surface, see it being taken up by plants. And it's also evaporating
into the air. We also have in this
area a drying happening. This is a drought. The desert's increasing in size, so we're also having natural
changes causing this area to become dryer. And hopefully that doesn't
happen in our neck of the woods. We are getting — we're
pumping a lot of water out of the Oglala aquifer. Or the High Plains aquifer. Great for studying
groundwater for your project. Great area to look at. Lots of groundwater withdrawals. It's a pretty big aquifer. We don't see major changes
in surface bodies of water, but we're seeing major
declines in that aquifer. Over in Georgia every year —
every summer, they have times when they can't water their
lawns or wash their cars. There's a couple lakes
in the area that decrease in level dramatically in the
summertime because there's so much groundwater withdrawal. And with that, in some of
these places we can also have subsidence that is a direct
result of over-pumping. And here you can see this
is Cook County, Georgia. How much decline they've
had in the water table because of so much over-pumping. And what happens is as
you pump that water out, it's kind of supporting the
structure of the subsurface. As you pump that water
out, the grains of — especially if it's loose
sediment, they start to compact. Because they're compacting
we end up — if this is our start time,
we're pumping tons of water out. We're decreasing the support
to this loose sediment and it compacts and
drops the land surface. San Juaquin Valley, as you can
see here in this photograph. We've got where the land
surface was in 1925. Where it was in 1955. And where it was in 1977. Huge. Huge amount of decline. Venice, Italy is
another example. New Orleans. These places are all locations
where we have increased removal of groundwater, causing the
land surface to subside. New Orleans we have
3 meters, or 10 feet. Las Vegas, 3 feet. And this part of
California, up to 26 feet. Pretty amazing. Just insane amount
of land subsidence. Another problem that we
see is what are called "cones of depression". So when we start
pumping ground water — so here's a well installed. We start to pump water. It creates this depression, and we are pulling water
towards this well away from maybe other
bodies of water. So here's a before picture. We have these two
wells installed. We start pumping
from the smaller one. This might be a house. This might be an
industrial facility. A factory or something. We start pumping from this well, we get a small
counter-depression. We're not pulling
that much water out. It doesn't change the
overall water table that much [inaudible]. So we start pumping from this
bigger well, and what ends up happening is we
have a major decline. We are pumping way
more water out. It's deeper. They're trying get
a lot of water. Big cone of depression forming because you're using
a lot of water. And you can see from the
start here to the finish, how much that water
level has dropped. So we can have a major decrease in the local water
table as well. And you can visit that website that I showed you
before for more details. We can also — we also
see salt water intrusion in coastal areas. So here's an example
of a normal situation. We've got fresh water. It's less dense. Floats on top of the salt
water that is in the ground. So we have this kind of boundary
between the fresh and the salt. And you can get kind of brackish
water along that boundary. Coastal areas are pretty
popular places to live. So people move in. They install wells. And then here you can
see wells installed. They start pumping water. It's too close to the coast
so they pump too much. They can start to actually
suck this interface closer to their well, and they can
get salt water being pulled up into their well. In groundwater contamination
what we see — so for salt water intrusion, around a coastal
environment this is kind of a natural situation. Here in our sea floor, to our
coast, fresh water floats on top of the sea water, because sea
water has a higher density. And we have this
interface between the two. It can be kind of
gradient sometimes. Coastal areas are
pretty popular, so people like to move there. They install a well
to have water. They pump too much, or they
put it too close to the coast. And they can pull that
interface closer to the well, and then start to pump out salt
water instead of fresh water. So people that live in
coastal environments have to be pretty careful about
where that water comes from. So groundwater pollution can
have multiple different sources. Some of the common sources, we
can have waste disposal sites. So things like landfills that aren't properly
lined or configured. We can have manure from farms. Agricultural pesticides; herbicides that can
get into the ground. Septic systems can also
be a source of pollution. And what happens is a
lot of the liquid part of that contamination can
then seep down into the ground and either get into the
wells that are being pumped, or into the nearby rivers. So for example, if we
say had a surface spill. Maybe fertilizer. Septic system. It could also be
a similar feature. Well, we have a surface spill
that gets on top of the ground. If it's allowed to sit there;
it's not dealt with immediately, it's going to seep
down into the ground. And depending on
what it is, some — especially with gasoline,
there's multiple different parts that are mixed together
in gasoline. Some of it is denser than water and will sink into
the groundwater. Maybe disperse slightly. Some of it's lighter and will
float on top of the water table. And in underground storage
tanks, you can have a hole in your storage tank, and
they can start to leak and the same thing can happen. Depending on what is leaking,
might float on the water table and like mix into
the water table. Now to kind of talk about
cleanup, what do you do? If this is a kind of a
hypothetical situation here. We've got different
houses indicated by the letters; the starts. A chemical spill. And that spill is on the
surface and it starts to seep into the ground. And here the water table's
pretty close to the surface, and it starts to travel. And the water is going to — the ground water will
flow perpendicular to the surface topography. So I have these topographic
lines drawn on here. And they're going to — the water's going to be
flowing parallel to those lines. So you can see I've
drawn this plume of contamination
parallel to those lines. And then it eventually
gets to the stream. So if this isn't dealt
with immediately, this plume could travel
all the way to this stream. And depending on what
the subsurface is like, that movement could
happen relatively fast. Or it could happen pretty slow. So depending on what
your bedrock is like, your response time might
have to be within hours. Or it could be within days. So what do you do when
something like this happens? Well, kind of figure out which
way the contamination's going to flow. If you know this
chemical spill happened. You know this spill occurred. You go and you stop the source. So you figure out
where it came from and you stop or remove
the source. And then you're going to
have to figure out, okay, which way is the
contaminate going to move to? And because of the
topography we know which way it's going to flow to. And then what we can do is
figure out, okay, who's at risk? Who do we need to warn? I would say A would
be the first to warn. C would need to know. D possibly. Depends on how much this plume
disperses in the groundwater. And then we're going to figure
out, okay, well what do I need to do to get rid
of this pollutant? Well, if the spill is not
travelling really fast, they can — they can —
it's moving pretty slow. Maybe it only has reached A.
What they'll do is they'll start to put in — install a
well where they will start to pump out the pollutant. And then install some monitoring
wells around this site. Maybe further downstream. Maybe along — maybe monitor
the stream as well to see if that pollutant gets
down to the stream. So they put in a well. They can create one of
those cones of depressions that we saw way back up here. So that all of the water's
going to flow towards the well. So the contaminant will be
pulled towards the well. So they can create an artificial
groundwater flow direction temporarily while
they're trying to get all that pollutant out
of the ground. And again, you see sometimes, depending on how
deep you're talking. How the water table's like. Sometimes these pollutants
might move within a year. Sometimes it might
move in 10 years. Sometimes 50 years. So depending on what
your bedrock's like. How deep the contaminate
goes, you're looking at a variety of timeframes. And then you can look in your
textbook for more information. So those are some of
the hazards in aquifers. So we'll stop there, and
I will see you in lab. .

04 – ground water 01 المياه الجوفية – .

Water As One Resource: How Groundwater Interacts with Lakes and Streams – Good morning everyone.
Well I'm going to
give a brief talk here about how groundwater interacts with lakes and
streams and so I'll be covering some ground water basics, maybe basic for
many people but not everyone, a little bit about stream hydrogeology and then I'll
finish up with how pumping affects pumping from wells affects streams and
lakes. I wanted to point out a couple of good publications, both from the US
Geological Survey, one of these is called groundwater and surface water a single
resource, and this makes the point that groundwater and surface water are really
quite intimately related and really need to be managed and understood as a single
resource and you can download this book at this website, and then a second
one is this recent publication circular 1376 from the US Geological Survey about
groundwater and streamflow depletion by wells and understanding and managing the
effects of groundwater and much of the information I think we'll all be
presenting today is in these two these two books. So to start out what is
groundwater? Well that's groundwater is is any of the water filling the pores
cracks fractures and other interstities of in geologic materials below the
land's surface. We usually think of groundwater as being in the saturated
zone. So the saturated zone is the zone of the earth where all the pores and
spaces in the rocks or soil or sand and gravel are filled with water and the top
of that is called the water table. Above the water table we have the unsaturated
zone where the pores are only partially filled with water although there is
water in that in that area. We need to talk about a little bit about the water
cycle, remembering that all water begins as precipitation, snow or rain falling on
the land surface percolating or infiltrating into the ground. Much of
that water runs off becomes runoff and much of that is transpires or
evapotranspires back to the atmosphere. A smaller percentage percolates into the
ground and eventually comes crosses the water table and becomes part of
the groundwater flow system. Ground water moves through the groundwater flow
system through aquifers. Aquifers are geologic units that are permeable enough
to transport and transmit and store significant quantities of groundwater.
Some of this groundwater is eventually going to discharge to a usually a
surface water body like a lake or stream or wetland, some of it gets intercepted
and discharges into wells. Groundwater moves in three dimensions. This this
diagram is is most relevant for humid climates where the water table is a
subdued representation of the topography but we have higher water levels under
hills and lower water levels near the stream. If we start taking that apart, we
see the ground water moves laterally from these divides on the tops of water
table to the low points in the streams. It also moves vertically in flow paths
that that go down and then back up to discharge to a surface water point and
the divides in the groundwater flow system are called groundwater divides. So
groundwater moves in three dimensions. So let's get to some streams. Groundwater is
important for streams and lakes because it often sustains streams, lakes and
wetlands and so the groundwater flows through the groundwater flow system, ends
up discharging to a surface water body. The slide, the picture on the right shows
that there's often a zone called the hyporheic zone right under a stream or
lake where there's a lot of biochemical and geochemical reactions go on. So a lot
of that's a very active biological and chemical zone, a lot of transformations
and chemistry happen right there. I don't have more time to talk about that today
but just be aware that there's a lot of in addition to this flow there's a lot
of chemical and biological interactions that go on between groundwater and
surface water. Streams can be gaining and losing, meaning that as streams flow
along in the upper left here, this is called a gaining stream because water
ground water is flowing into the stream and maintaining its flow and and really
increasing its flow. In contrast the stream on the lower left is a we call
that a losing stream because you can see the water table is basically below the
level of the stream or the river and so water leaks out of the stream into the
groundwater system and so that stream eventually loses water. And the diagram
on the right is just a plot of stream flow versus distance down the stream
showing if you went through a losing reach how you would get a change a
slight decrease in stream flow as you went through that losing part of the
stream or where maybe a well near the stream is causing it to be a losing
stream by pulling water out of it. Sometimes streams and lakes can become
disconnected from the groundwater system meaning that there's a unsaturated zone –
the water table drops below the bottom of the surface water body and so we have
an unsaturated zone there. Often there's a mound in the water table below that as
shown in the upper left diagram and there's still water moving from the
stream to the groundwater system but it's moving in the in the unsaturated
zone in an unsaturated way. The lower diagram shows where the system has
become completely disconnected. In fact the stream has become dry. So here's a
here's a very and this could be probably more common in that in the more arid
parts of the country. A little bit about lakes. Lakes are often, particularly here
in Wisconsin and humid parts of the country, outcrops of the water table.
In other words they're the low point in the landscape and that's where the water
table appears at the surface. Lakes can are dynamic systems. There's a lot of
ground water exchange between lakes and the groundwater systems so there's
usually three different possibilities as shown on the right upper, we have a lake
that's that's a where groundwater is discharging into the lake all the time
all around it. Second or middle diagram water is leaving the lake and the third
is what we call a flow-through lake water is groundwater is
flowing into one side of the lake and out the other side of the lake and some
of the some groundwater actually passes beneath the lake, and all these we see
all these situations pretty commonly in groundwater systems. A little bit about
base flow. Groundwater sustains streams like this trout stream shown on the
lower left by maintaining base flow. The groundwater discharge is the reason
that streams flow cool and steadily even during the hot parts of the year.
Here and here in Wisconsin we have a lot of great trout streams particularly in
the south west part of our state that flow all the time even in the middle
of the summer when it hasn't rained for for days or weeks and that's because
there's a lot of groundwater discharge. Here's a, the upper left here we have a
stream hydrograph with lots of peaks corresponding to various storms and so
forth but you can see that the base flow the black line is is what is being
sustained by groundwater. We can do things with with this sort of
information making a base flow index of looking at streams that have higher
percentage it's a base flow versus this transient storm flow and try to map that
out. Here's a map of Wisconsin and the bluer areas have higher total base flow
and then when we overlay that with where our trout streams are you can see how
important something like groundwater and base flow are to our trout fishing
industry. So it's because the trout streams correspond to whether we have
these high base flow conditions. Now a little bit about how pumping
groundwater can affect streams. Pumping from an aquifer that's near a stream or
a surface water body can cause two things: drawdown or lowering of water
levels near the well and a reduction of groundwater flow to nearby features, a
reduction of this natural discharge, and here is a fairly famous diagram just
showing a stream and an aquifer and a recharge area up here, ground water flowing
to the stream, and we put a well in there and the well has a little cone of
depression around it and you can see by the what the arrows are doing that that
well starts to diminish the flow to the stream and if we increase the pumping
from q1 to q2 here we even can reverse flow. So a
well near stream always is going to have some sort of impact on the stream and
and the amount of that impact will depend on the distance from the stream
and the amount of pumping from the well and so forth. I think Bill Alley will talk
a little bit more about that. Now a little bit about the water budget.
Remember that a water budget is kind of like a bank balance and everything has
to balance – all the inflows and outflows of water and hydrogeologists use these
days use mostly computer models to do this water budget accounting. In many
parts of the of the world when we think of a water budget deficit, that deficit
is going to be expressed as a decreased flow to our surface water features
lakes streams and wetlands because you don't get something for nothing in the
groundwater world. You, anytime we pump a well and take water out of the ground
that water is water that would have ended up somewhere else usually in a
lake stream or wetland. And a scientist named Seward who's a South African,
has illustrated this rather well I think with the concept of of the looking at
groundwater is sort of a bucket here where you have, think of this as an aquifer,
this diagram on the left, is full of water and we often see this with
aquifers. We have a, people have a whole lot of water in their aquifer and and
yet a little bit of pumping can can have a deleterious effect on ecological
resources and this is because not all that water is is really equally
available. Some of the water the very deep water is often what's called
physically unabstractable here or it's just hard or too expensive or
physically too difficult to get to. So even though the waters there, it's hard
to use. And then we have water that's maybe in the middle of the system here
that that we can pump out for use for human use or for agricultural use and
that's water that can be consumed. But right at the top we have what's often
called the ecological reserve. This is the water that would have been the first
water to discharge to a lake stream or wetland or spring and this and if we go
to the right and we start pumping that, we can see that
that's the first water that gets depleted and so the first thing we see
if we start depleting an aquifer is decreased discharge to these surface
water features and that's and that's a can be a troubling thing. So there are a
few misconceptions and this is from that USGS circular about groundwater and
streamflow depletion. First the misconception is the total development
of groundwater resources from an aquifer system is safe or sustainable at rates
to the average rate of recharge. There was an old almost a myth
of that as long as you didn't use more water than was recharged you were okay, but the problem
with that idea is that it doesn't account for the water that's needed for
to sustain ecology or for what's called environmental services – the water that
sustains its base flow. So that needs to be accounted for. The second
misconception is that depletion is depending on the rate and direction of
water movement in the aquifer. That's that's really not true. It's more the
decline in head or the decline in pressure in the aquifer is going to go
out in all directions. Third, depletion stops when pumping ceases. That's not
true either and that's because of the storage properties that I think Bill is
going to talk about in a minute, and finally if we have a confining unit or
an aquitard in our system there was some thought that pumping
below that aquitard is not going to it's going to eliminate any any groundwater
depletion and that's not completely true either. That's, you may get some delay
in the depletion but it's not going to eliminate it. And then so finally to
finish up here my main points today are that groundwater and surface water are
well connected and should be thought of as a single resource. We can't really
manage them differently. All water comes from somewhere which seems obvious but
we need to remember that the water balance is critical for management
decisions and anything anytime you perturb the water balance you're
changing something. Groundwater discharge becomes a base flow and sustains the
flow and streams and then lakes, and pumping from wells near streams can
reduce stream flow and these impacts depend on pumping rates and the local
hydrologic hydrogeologic setting. I think Bill and Thomas
will talk more about this. And that's it for me Charlotte. .