Hello everybody my name is Zohir Chowdhury, and right now we'll talk about the hydrologic cycle
so what is the hydrologic cycle of the water cycle water is in continuous motion the natural
cycle by which water evaporates from oceans and other water bodies accumulates as water vapor
and clouds and returns to oceans and other water bodies as precipitation is known as the hydrologic
cycle without continuous evaporation from the oceans precipitation on land and runoff back
to the oceans no surface or groundwater recharge can take place and we would eventually exhaust our
available freshwater supplies this figure provides an overview of the hydrologic cycle and dominant
flows and the critical reservoirs the her logic cycle teaches us to view water and health with
a holistic perspective the compartments of the hydrologic cycle are either directly or indirectly
connected and perturbation in one compartment is likely to affect all other compartments
and therefore both human and ecological health so this water cycle we humans have been have centered
around us and so we know that available fresh water supplies are often conceptually divided
into surface water and groundwater surface water includes all water naturally open to the
atmosphere like such as rivers lakes reservoirs ponds and streams impoundment seas and estuaries
groundwater is a supply of freshwater from found beneath the earth's surface usually in aquifers
groundwater supplies groundwater supplies wells as well as Springs ideally water used as drinking
water source should be of the highest quality reducing the cost of water treatment and the risk
of contamination groundwater has traditionally been considered a high quality resource because
as rainfall and other surface water percolates - soil into groundwater they claim by physical
chemical and microbial processes in the soil however groundwater is not always available and
municipalities may have no choice but to use surface water requiring extensive and costly
water treatment surface water may be considered suitable for agriculture industrial recreational
users with no or limited treatment different criteria are therefore developed and applied
to source waters depending on on their ultimate use surface water that are used as drinking water
sources are regulated by far stricter criteria for example than waters used to irrigate crops
in this chart we can see the water cycle as it makes its way through the river into the ocean
human have created dams and as a result of the dam the water is stored and this has permitted
humans to use water year-round to supply water to municipalities such as the one shown in here and
in this case because it is surface water water has to be treated pumped into homes and businesses and
once it is utilized humans produce sewage and in this case the sewage gets collected treated again
and then pumped into water reservoirs rivers or oceans thus completing the water cycle with
the human component incorporating it global water availability this map shows that the global water
availability Poynting availability pointing at areas where water is over exploited that over
exploited regions are in maroon heavily exploited regions in red and moderately exploited regions
in orange of course the arid regions face the most severe problems in fact 85 85 percent of
the world population lives in the driest half of the planet water availability is expected to
decrease in many regions due to climate change population growth and increase demand for water
from agriculture it has been shown that future global the cultural water consumption alone is
estimated to increase by about 19 percent by 2050 and be even greater in the absence of any
technological progress or policy intervention this graph in here shows the residential usage
around the globe in the state of California and in the County of San Diego so as you can see around
the globe agriculture is the major consumer of water whereas for the state of California it's
more or less evenly distributed almost over 30 to 40 percent between agriculture industry and
residential but as we move to Southern California this is that every drier place of California and
San Diego County is an example 60% is used in residential homes and only 17% for agriculture and
23% by industry so San Diego County as compared to the globe definitely has a very different
approach in residential water usage and here is how this residential water uses user is divided a
big chunk of the water inside your county is used for landscaping and then the remaining is used for
other purposes for home in California water the water cycle of course provides more water in the
northern part of the state because of increased precipitation and snowmelt on the other hand the
southern part of the state there is not enough precipitation making it very dry and from an
engineering perspective of course you think about that if people are living a la in the drier part
you'd have to bring water from the northern part of the southern part in fact the map in here shows
that population a lot of the publishing lives in the southern half of the state especially in Los
Angeles San Diego County and significant people also live in San Francisco and Sacramento counties
with a little bit in the Central Valley area so most of the water is in the northern part where
population is rated this spare sparse whereas in the southern part water is not as widely available
but population is pretty dense okay so let's do some quick check the natural cycle by which water
evaporates from oceans and other water bodies accumulates as water vapor in clouds and returns
to oceans as water bodies as precipitation is known as the hydrologic cycle another concept
check water availability is expected to decrease in many regions of the world due to climate
change population growth and increased water demand for agriculture true or false true ok