SCIENCE JSS 3 - Environmental Hazard, Soil Erosion and Flooding

Today on Science for Junior Secondary Class 3, Ms. Irene will be teaching on 'Environmental Hazard, Soil Erosion and Flooding'

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Episode Transcript

(00:00):
Hello there, welcome to another interestingedition of the podcast for Education exclusively brought
to you by Africa Business Radio.Taking us on the science subject today is
Miss Iron and she'll be treating thetopic environmental hazards, soil erosion and flooding.
Hello learners, welcome to another funtime of learning. My name is

(00:24):
Miss irone. We are learning aboutenvironmental hazards looking at soil erosion and flooding
in science for JSS three. ForJSS three, first we have to first
establish what is soil erosion. Whenwe are talking about environmental azard, we
are talking about things that impede oraffect the environment negatively. Okay, we

(00:47):
are looking at things that impede oraffect the environment negatively, and today we
are talking about soil erosion and flooding. First we have to define what soil
erosion is. Soil erosion is definedas the removal of the top layer of
the Earth's surface through the different agentof weathering. Okay, through the different

(01:07):
agent of weathering. And soil erosionusually are caused by excessive rainfall. Okay,
they are caused by excessive rainfall.And due to excessive rainfall, the
top fatal soil is washed away.Okay, the top fatile soil is washed
away. Then also soil erosion isusually caused by human activity, and what

(01:30):
we have is different human activity tendto accelerate the disappearance of the protective cover
of natural vegetation. An example ismost time when areas or a large piece
of land are clad for farming purposes. You know, the soil cover is
removed that and these soil covers inform of the grasses, in form of

(01:52):
the plant help preserve the top layerof the soil from wind activity. So
when this space is cleared, youhave that the surface of the soil is
exposed to very very high wind speedand win activity, which causes soil erosion.
Other human activity that help accelerate thedisappearance of the protetic covering are also

(02:15):
farming activity. Okay, areas thatare clad for building and sometimes when people
move or movement of people from onearea to the other in terms of vihicular
movement, in terms of even walkingaround, they tend to clear off the
surface of the soil and this alsoexposes the soil to agents of wed rain

(02:37):
like rainfall, excessive rainfall, excessivewind speed. And you also have that
overgrazing. Overgrazing leads to the absenceof ground vegetation and causes grad blood depollution
of soil organism and also results insoil erosion. When we have animals are
farm animals. When the graze beyondcontrol, what we have is the vegetation

(03:02):
are removed, are completely depleted.And when the vegetation are depleted, you
have the organism that are found inthe soul, organism that helped replenish the
nutrient of the cell. They tendto migrate and move away from that environment,
and in their movement away from theenvironment, the old or the activities,
their biological activities that help hold thesoil particles together are lost. And

(03:28):
when this is lost, it makethe soil susceptible to easy weathering. And
because of this you are very deepditches. You have very very deep ditches
resulting from this. And all theseare the different ways or the different causes
of soil erosion. And another veryimportant thing to note is they had different

(03:51):
types of soil erosion. We havedifferent types of soil erosion, and you
have different things that causes soil erosion. And one of the reason why you
have this erosionally that you have sometimeyou have deep cotton into the soil where
you have large galli curvises being cutinto the soil by rainfall movement, carrying

(04:13):
away the top soil, carrying awaylarge particles of soil, and it makes
the soil very inhabitable. And sometimesyou can even use the soil again.
And these are great hazard because sometimesit can tilt the land or change the
topography of an area in such away that the animal and plant life in

(04:33):
such an area are greatly affected.Then moving on, we are also going
to be looking at flooding. Okay, now we'll be looking at flooding extensively.
Now, think about what will happenif water continues to flow into a
river that its bank is full.Now, this may happen if it starts

(04:54):
to rain again and again and thesurface runoff true flow continue in a process
called over bank flow. All right, the water will spill over the top
of the river bank and this waterwill then flood the surrounding land. Now,
what usually happened is when you havewater continues to flow, a river

(05:15):
has its level, it has it'sa bank, and when the water continue
to flow on into the runoff,it overflows the bank, and when this
happened, the water floods into thesurrounding land. Its bank is majorly where
the river is supposed to hand andthe edge of the river. And when
you have the spilling, it spillsinto surrounding land. It fills into surrounding

(05:41):
villages, surrounding towns, and thisland is called the flood plain. So
a flood or cause when the dischargeof a river is too great for it
channels to old. So we havethat flood or cause when the discharge of
a river is too rate for itschannel to old. We know that a

(06:02):
river has its life cycle. Itstarts from the head of the river,
goes through its channel and continue toflow on until it deposits into the large
water bodies such as the ocean ofthe sea. But what usually happened that
we have flooding a cause when thelarge body of water or when the water

(06:24):
flows so much into a river thatits channel cannot hold it that it spills
into surrounding area. The water wesimply flow over the top of the river
bank, causing flooding. This isa particular problem in the middle course of
a river. Like I mentioned thatthe river has its course. Okay,
we have the top of the river, the head of the river, and

(06:46):
then we have the middle course ofthe river, and then we have it
flowing into the large body of water. Because the land is relatively flat,
the water can spread long distances,just like spilled drinks across a water table.
Like now, I want wherever youare. Now, just try and
experiment. Take a cup of waterand pour it on the table. If

(07:12):
you observe, you will say thatthe water spills in different direction, moving
in different directions. This is whathappened when a river overflows it banks,
it begins to spread all around.Now, all these are different things that
happen now. Building on a floodplanewhat flooding changes the landscape, sometime temporary,

(07:32):
sometime permanently. However, flooding canalso affect people and community. We
have houses that are located in floodplain. Most times in areas a lot of
people build their house along floodplaine.And the reason is not fat fed.
Because land along floodplaine are usually veryfatal. They usually have very fatal soil

(07:56):
which are good for agriculture. Andbecause this soil is very rich and very
good for agriculture. People tend tomigrate when they're settling, you know,
during their migration, they will settlein such an area because the land is
very productive and when they're develop whencities or when communities develop along this floodplain,

(08:16):
it's become a riks when the riverflows along. Now, living close
to navigable river also help trade andcommerce. You know, most of African
community, they exchange commerce and economicdevelopment between towns, extially around areas that
have rivers, where you can easilymove from one town to the other and

(08:39):
exchange good A lot of cities,a lot of countries all over the world
enjoy great economic boom because of theircloseness to a body of water. Because
of their closeness to a body ofwater, today houses are built on floodplain
and because of the shortage of affordableland for home. Addition, anally,

(09:00):
a river location can be sought afterbecause it's afford a householder. A very
picturistic view. We have so manyof that happening in countries all over the
world. A lot of people wantto build houses are long seashores. They
want to build houses along river plains. You know, because you have a
lot of trees, you have verythe weather, the surroundings are very conducive,

(09:24):
so most of those areas and alsobecause of the shortage of land,
more people are choosing to build housesalong river plain. This as a potential
eye risk. Okay, these havegreat potential eye risk because when we build
along flood plains, when we buildalong floodplain, when the rivers over spills

(09:46):
is banned, its pills into ourhomes and areas. So these are different
situations. We've ad cities, youknow, being submerged in water. You've
had large cities being submerg urge inwater. Now every rainfall also result in
river flooding as a whole. Wehave something like in the UK almost eight

(10:09):
thousand houses we're flooded in an areathat most cities were flooded. And you
also have cases being reported even inthe United States, in the Indies,
in Pakistan where great monsoon rain submergewhole cities and when this happened is resolved
because rivers overflows their bank. Andwhen this happened, a lot of damage

(10:33):
okay, a lot of damage arecaused because the materials and so many things
are destroyed. And most times alsoflooding also resolved from when you have a
dam in an area, maybe dueto the overflow of the river due to
rains, mostly due to every rainyou have that the dam overflows is bank

(10:54):
called the damn breaks out, andthen the water from the dams feels into
towns and surrounding cities, spills intotowns and surrounding cities. And something about
flooding is that there is nothing tostop floodwaters. What can just be done
as building barriers, creating barriers ifa flood is imminent with the best that

(11:18):
can be done are to provide sandbagby the local areas and all to build
up, what to proof, tocreate and evacuate people that are along such
areas. These are the best thatcan be done to protect against flooding.
Now, soil erosion and flooding,they are very strong environmental azard in that

(11:41):
they affect the environment, in thatthey affect the entire relationship. And there
are things that we can do.There are ways we can advocate. Even
as a young person, there arethings that you can do in your community
as you're listening, as you're learningabout them, you've learned the consequences of
them, and there are ways youcan encourage people around you to take better

(12:05):
options. There are things that youcan do to take better option. We
already know that soil erosion is causedwhen large areas are clad of cover trees.
Okay, when large areas are cladof cover trees. So wherever you
are in the part of the world, all over the world, I want
you to use this opportunity encouract peoplearound you. When a tree is fallen

(12:26):
or a tree is called plant anotherone. When a large area is clad
for farmland, try to plant aperennial. Try to plant a perennial around
so that it creates windbreak for theseareas and then reduces the exposure to soil
erosion. Also for flooding, youknow, for flooding, majorly, our

(12:50):
use of water some time tend toaffect the amount of water that is available.
Try to advocate and encourage people notto build houses along floodplain. And
then for even those that are doingbuilding development around or all provisions should be
made for proper channeling of water.In the class that you are. You

(13:11):
can create an advocacy with your friendsyou know, to encourage your local councels
you know, to encourage and toaffect laws there are laws that are in
place already all over the world,but you can create that awareness as a
young person, you know, toencourage them to put those laws into effect

(13:33):
to reduce the people building in floodplainand also help them educate people around.
Educate your mom, educates your dad, educate your grandparents or your uncle's,
your aunt. Because yes, weknow that soil in floodplain are very fertile,
so there is that temptation to wantto settle around floodplain. And even

(13:54):
when you do such, you mustprotect your building. And a way we
can do that against flooding is creatingsandbags. Is creating sandbags to protect the
movement or the devastating effect of flooding. Okay, and also always seek out

(14:15):
more information, share information with everyonethat you come across. Any way that
we can help make the head abetter place and prevent all this environmental hazard
is always add encouragement. So untilwe meet again for another exciting time of
learning, to have a wonderful timeby thank you for listening to this episode

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