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Fresh water


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Fresh water

  1. 1. FRESH WATER Marj Acuesta Lara Advincula Katrina Arcellana
  2. 2. Water Cycle Earth's water is always in movement, and the water cycle, also known as the hydrologic cycle, describes the continuous movement of water on, above, and below the surface of the Earth. Since the water cycle is truly a "cycle," there is no beginning or end. Water can change states among liquid, vapor, and ice at various places in the water cycle, with these processes happening in the blink of an eye and over millions of years.
  3. 3. 6 process of water cycle Evaporation The sun is the energy that powers this remarkable process. It's energy in the form of light, and heat causes water to EVAPORATE from oceans, rivers, lakes and even puddles. "Evaporate" means it turns the water from a liquid to a gas, or "vapor." Warm air currents rising from the earth's surface lift this water vapor up into the atmosphere. Condensation When the air currents reach the cooler layers of the atmosphere, the water vapor condenses around and clings on to fine particles in the air. This step is called CONDENSATION. When enough vapor attaches itself to tiny pieces of dust, pollen or pollutants, it forms a cloud. Clouds do not last forever. Old clouds constantly re-evaporate and new ones form, creating ever-changing patterns in the sky.
  4. 4. Precipitation As the air gets more and more moist, the droplets that form the clouds grow larger and larger. Eventually they will get so big that the swirling atmospheric winds can no longer hold them up. The droplets then fall from the sky as PRECIPITATION. Precipitation can be in the form of rain, snow, sleet or hail depending on other atmospheric conditions such as temperature. Surface Run-Off Once the precipitation reaches the ground, several things can happen to it. First, it might be re-evaporated. For instance, we've all seen the mist rising off hot roads after a summer shower. If it isn't re-evaporated, much of the water will become RUN -OFF that goes into streams and rivers as it flows back to the ocean.
  5. 5. Infiltration Some of the precipitation will be absorbed into the ground. This is called INFILTRATION. Once in the ground, the water can join the earth's ground water supply. This is one of the world's largest storehouses of water. The water could also be absorbed from the ground by the roots of plants. Transpiration Another form of evaporation that contributes to the water cycle is TRANSPIRATION. Here, water given off through the pores of plants and animals joins the atmosphere as a vapor. Check, for instance, your own breath on a cold day. What you are seeing is water vapor being given off by your body.
  6. 6. GROUNDWATER Water residing in the saturated zone where all the open spaces between sediments and rocks and even the spaces between mineral grains inside rocks are filled with water
  7. 7. Purposes of Groundwater <ul><li>It supplies streams, lakes, swamps and other surface waters. (Not all surface waters are from runoffs.) </li></ul><ul><li>It provides water to the surface during dry periods. </li></ul><ul><li>Wells pump groundwater to the surface where it is used for drinking, agriculture and industry purposes. </li></ul>
  8. 8. Water Table The upper boundary of the saturated zone is the WATER TABLE. - It’s level beneath the Earth’s surface varies with precipitation and climate. - It tends to rise and fall with surface topography. - It intersects with the surface of the lands where we find marshes, swamps and springs.
  9. 9. Porosity The amount of groundwater that a material can store depends on its POROSITY. It is the percentage of the total volume of rock or sediment that consist of pore spaces (open spaces). Pore spaces are usually found between sediments, but fractures in rock, spaces between mineral grains within a rock and pockets formed in soluble rock also contribute to porosity.
  10. 10. Permeability Rock or sediment may be very porous, but, if the pore spaces are small and not interconnected, groundwater cannot freely move through it. PERMEABILITY is the ease with which fluids flow through pore spaces within a rock or between rocks or sediments. Sand and gravel- highly permeable because they have rounded particles that do not fit together tightly Clay sediments- have flat particles that fit together that’s why clay which can be quite porous is practically impermeable
  11. 11. Aquifer Aquifer is a zone of water bearing rock through which groundwater can flow. -It has high porosity and high permeability -It underlies the land surface in many places containing an enormous amount of groundwater. Why is an Aquifer important? It is important because wells can be drilled into them, and water can be removed.
  12. 12. A Groundwater is a NONRENEWABLE RESOURCE. The process of restoring groundwater called recharging which is very slow. An aquifer constantly gains water form it recharge zone (the area of land from which the groundwater originates), but only a small amount of water reaches each year. This process of recharging a depleted aquifer may take thousands or even millions of years.
  13. 13. GROUNDWATER CONTAMINATION Sewage is a major cause of groundwater pollution. Sewer water contains bacteria that if not treated can cause: -typhoid -cholera -infectious hepatitis And other waterborne diseases.
  14. 14. The work of Groundwater Land subsidence is a lowering of the land-surface elevation cause be changes underground, including changes caused by the over pumping of aquifers. PERCOLATE- FILTER
  15. 15. - Water found on the surface of continents and islands. - Water that are found in lakes, ponds, rivers, streams, springs, and puddles. - Contains most bacteria and other microorganisms. -Surface water makes up only one fourth of one percent or 0.25% of the total water found on Earth. Surface Water
  16. 16. Surface Runoff <ul><li>Water that moves over the Earth’s surface </li></ul><ul><li>Whatever the ground cannot absorb becomes a runoff. </li></ul><ul><li>plays an important role in the recycling process. It replenish lakes, streams, and groundwater and creates the landscape by eroding topography and transporting the material. </li></ul><ul><li>The proportion of rainfall that becomes a runoff depends on: </li></ul><ul><li>1. Type of soil and it’s moisture </li></ul><ul><li>2. Steepness of slope </li></ul><ul><li>3. Presence of plant life </li></ul><ul><li>4. Rate at which the rainfalls </li></ul>
  17. 17. Streams - any body of flowing surface water - runoff collects in sheets that move downhill and merge streams to forum. - As streams move downhill, they merger with other streams and the grow quite large and most streams eventually discharge into the sea
  18. 18. Watershed - also called as the drainage basin - area of lands that drains into a stream - every stream, river, tributary and large rivers that gather streams has one. And watershed of a large river is a part of many smaller watersheds that service the smaller streams. - they are separated from one another by divides.
  19. 19. Watershed’s Divides - Divides are lines that trace the highest grounds between streams - Rain that falls on one side cannot flow into an adjacent basin - A divide can be hundreds of kilometres long if it separates 2 large watersheds/ it can be just a short mountain ridge separating two small gullies.
  20. 20. Questions 1-4. Name 4 of the water cycle process? 5. What is ground water? 6. Whats the cause of ground water pollution? 7. What is surface water? 8-10. The proportion of rainfall that becomes a runoff depends on? (give 3)