The natural flows and stores within both the global and local water cycles



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  1. The natural flows and stores within both the global and local water cycles



The global/local water cycle has many flows and stores. It has no starting point, but we could say it begins with oceans. The sun drives the cycle, heating the water. Some of that water evaporates as vapor into the air. Rising air currents take the vapor up into the atmosphere, and the vapor rises into the air where cooler temperatures cause it to condense into clouds. Air currents move around the globe, and cloud particles collide, grow, and fall out of the sky as precipitation. Some of the precipitation falls as snow and can accumulate as ice caps and glaciers. Most precipitation falls back into the oceans or onto the land, where it flows over the ground as surface runoff. A portion of the runoff enters rivers in valleys, with streamflow moving towards the oceans. Runoff and groundwater seepage then accumulate and are stored as freshwater in lakes. Much of the runoff soaks into the ground as infiltration. Some water infiltrates into the ground and replenishes aquifers. Some infiltration stays close to the land surface and can seep back into surface-water bodies and the ocean as groundwater discharge, and some groundwater finds openings in the land surface and emerges as freshwater springs. More groundwater is absorbed by plant roots to end up as evapotranspiration from the leaves. Over time, the water keeps moving and some of it reenters into the ocean, where the cycle continues over again. The Conveyor Belt: There is constant motion in the ocean in the form of a global ocean conveyor belt. This motion is caused by a combination of thermohaline currents (thermo = temperature; haline = salinity) in the deep ocean and wind-driven currents on the surface. Cold, salty water is dense and sinks to the bottom of the ocean while warm water is less dense and remains on the surface. The ocean conveyor gets its “start” in the Norwegian Sea, where warm water from the Gulf Stream heats the atmosphere in the cold northern latitudes. This loss of heat to the atmosphere makes the water cooler and denser, causing it to sink to the bottom of the ocean. As more warm water is transported north, the cooler water sinks and moves south to make room for the incoming warm water. This cold bottom water flows south of the equator all the way down to Antarctica. Eventually, the cold bottom waters return to the surface through mixing and wind-driven upwelling, continuing the conveyor belt that encircles the globe.

The Ganges Basin: this basin begins in semi-arid valleys in the rain shadow of the Himalaya and the Shiwalik foothills and fertile Gangetic Plains. The Ganges is made up of the Bhagirathi and Alaknanda rivers, which are formed by snowmelt. The surface water potential of the basin has been assessed as 525 km in India. There are water related issues of the basin due to high and low flows. The Indian states of Uttar Pradesh, Bihar and West Bengal are affected by flooding, and suffer from them almost every year. The discharge of the Ganges also differs by source and described frequently of the Meghna River resulting in the combination of the Ganges with Brahmaputra and Meghna.

The Amazon Basin: This basin is bounded by the Guiana Highlands to the north and the Brazilian Highlands of the south. The Amazon River rises in the Andes Mountains at the west of the basin and covers about 6,400 km before it drains into the Atlantic Ocean. At its highest point the Amazon watershed peaks at Yerupajá at 6,635 m. The basin originally flowed west to the Pacific Ocean until the Andes formed which caused the basin to flow east toward the Atlantic Ocean.

The Mississippi Basin: The Mississippi River has the world’s fourth largest drainage basin and covers 31 states and 2 Canadian provinces. The drainage basin empties into the Gulf of Mexico and part of the Atlantic Ocean. The highest point within the watershed is Mount Elbert, the highest point of the Rocky Mountains. The Mississippi River drains the area between the crest of the Rocky Mountain and the crest of the Appalachian Mountains. It eventually empties into the Gulf of Mexico about 100 miles downstream from New Orleans.




  1. The global system includes the transfer between ocean/ seas, atmosphere and the land;

    1. It should refer to the conditions under which the volume of solid, liquid and gaseous water will change.

Due to global warming the ice caps are melting at high rates and the now liquid water takes up more volume due to thermal expansion. The salinity of the ocean changes resulting in a shift and acceleration in the global rainfall and evaporation cycle tied to climate change. Saltwater intrusion is also occurring which takes away the amount of drinking water from freshwater aquifers and contaminates them so they are not drinkable. The rising temperatures increase heat and moisture which have profound effects on the atmospheric processes near and over the ocean. There is an increase in water vapor in the atmosphere, leading to higher temperatures in turn causes more water vapor to be absorbed into the atmosphere. This amplifies the warming effects of other greenhouse gases, which in turn CO2 allows for more water vapor to enter atmosphere. Due to the warming of the Earth, weather patterns change causing more extreme weather which affects everything on the planet. In the oceans liquid water is increasing in temperature resulting in man negative things such as not only higher sea levels but also worse weather and easier spread of invasive species and marine disease.


    1. The local water cycle includes evaporation, precipitation, interception, runoff, infiltration,percolation and groundwater. Explain cycle starting in ocean.

It begins with oceans. The sun drives the cycle, heating the water. Some of that water evaporates as vapor into the air. Rising air currents take the vapor up into the atmosphere, and the vapor rises into the air where cooler temperatures cause it to condense into clouds. Air currents move around the globe, and cloud particles collide, grow, and fall out of the sky as precipitation. Some of the precipitation falls as snow and can accumulate as ice caps and glaciers. Most precipitation falls back into the oceans or onto the land endless it is intercepted, where it flows over the ground as surface runoff. A portion of the runoff enters rivers in valleys, with streamflow moving towards the oceans. Runoff and groundwater seepage then accumulate and are stored as freshwater in lakes. Much of the runoff soaks into the ground as infiltration. Some water infiltrates into the ground and replenishes aquifers. Some infiltration stays close to the land surface and can seep back into surface-water bodies and the ocean as groundwater discharge, and some groundwater finds openings in the land surface and emerges as freshwater springs. More groundwater is absorbed by plant roots to end up as evapotranspiration from the leaves. Over time, the water keeps moving and some of it reenters into the ocean, where the cycle continues over again.

    1. Groundwater stores are to include the features of natural aquifers:

        1. Confined, define and 3 examples

        2. Unconfined, define and 3 examples

        3. Perched, define and 2 examples

Confined aquifers- are aquifers in which an impermeable dirt/rock layer exists that prevents water from seeping into the aquifer from the ground surface located directly above and water from below. When an artesian (or confined) aquifer is pumped there is no dewatering of saturated zone by gravity discharge. A well that taps an unconfined aquifer above a confined aquifer can dewater the former by gravity drainage and not affect the artesian aquifer if the confining bed between them has negligible permeability. An artesian well is pumpless water source that uses pipes to allow underground water that is under pressure to rise to the surface. Impermeable rocks consists of rocks that water cannot seep through such as sandstone and limestone.

Example: Brown’s Creek Watershed aquifer, Madison aquifer, Piney Point Aquifer

Unconfined aquifers- An unconfined aquifer is a aquifer not confined by impermeable material and its water table cannot be confined from the effects of atmospheric pressure.

Ex: Roswell Basin aquifer, Ogallala Aquifer, FLoridan aquifer

Perched aquifer- A perched aquifer is an aquifer that occurs above the regional water table, in the vadose zone. This occurs when there is an impermeable layer of rock or sediment or relatively impermeable layer above the main water aquifer but below the surface of the land.

Ex: Arkansas River aquifer, Dakota aquifer
3. The global (closed) system in conjunction with more localised open system, which could be a local drainage basin. It is possible to undertake the local element of this study through field work. 3 drainage basins worldwide
The three water basins I’ll talk about is the Great Basin, Sistan Basin, and the Chad Basin. The Great Basin is the largest area of contiguous endorheic watersheds, located in North America. It spans from the United States highest to lowest point, going through several physiographic divisions, ecoregions, and deserts. Some rivers that are part of the Great Basin’s system include the Amargosa River in California, American Fork River in Utah, and the Bear River in Wyoming. The Sistan Basin is an inland endorheic basin which encompasses parts of southwestern Afghanistan. The basin is feed by a lot of melted snow from the mountains of Hindu Kush. The basin lead to through a large watershed of rivers such as Helmand River, Khash River, and Farah River. The final basin is the Chad Basin. This is the largest endorheic drainage basin in Africa centered in the center of Lake Chad. The Basin spans past 7 countries. Some rivers that are part of Chad’s watershed are Hadejia River, Yedseram River, and the Chari River.
4. Examples of natural aquifers can be on a small local scale or of the scale of the Australian Basin. (3 large worldwide, 2 small)

  • The Great Artesian Basin is the world’s largest and deepest aquifer – it covers more than 1.7 million square kilometres and is over 3,000 metres deep in some parts.

  • The Ogallala Aquifer is a shallow water table aquifer located beneath the Great Plains in the United States. One of the world's largest aquifers, it underlies an area of approximately 174,000 sq mi (450,000 km2)

  • The Amazon basin is the part of South America drained by the Amazon River and its tributaries. The Amazon drainage basin covers an area of about 7,500,000 km2 (2,900,000 sq mi)

  • The Floridan aquifer is a portion of the principal artesian aquifer that extends into Florida and is composed of carbonate rock and located beneath the coastal regions of the Southeastern United States and is one of the world's most productive aquifers.

  • The Biscayne Aquifer, named after Biscayne Bay, is a surficial aquifer. It is a shallow layer of highly permeable limestone under a portion of South Florida. The area it underlies includes Broward County, Miami-Dade County, Monroe County, and Palm Beach County, a total of about 4,000 square miles (10,000 km2).

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