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Water resources
- 2. Learning Objectives: After the session, participants/learners will be able to: 1. Discuss briefly the hydrologic cycle. 2. Recognized how water distributed on earth; 3. Identify the various water resources on earth; 4. Explain how different activities affects the quality and availability of water. 5. Suggest ways on conserving and protecting water resources.
- 5. Evaporation and transpiration Evaporation Stream Infiltration Water tableInfiltration Unconfined aquifer Confined aquifer Lake Well requiring a pump Flowing artesian well Runoff Precipitation Confined Recharge Area Aquifer Less permeable material such as clay Confirming permeable rock layer Water Cycle – continuously collected, purified, recycled and distributed
- 6. How muchHow much water dowater do we have?we have?
- 7. Supply of Water Resources Small fraction (.014%) is readily available for human use
- 8. Glaciers
- 9. Glacier: large natural accumulation of land ice affected by present or past flowage • Glacial ice has shaped many landforms in middle and high latitudes • Glacial ice sheets affect global climate •Glaciers reflect sunlight •Glacial ice affects global heat transport •Volume of glacial ice affects sea levels • Large bodies of ice are plastic because of pressure on ice at bottom of mass •Large body of ice can flow in response to gravity • Ice on a slope can slide downwards
- 11. Why there is groundwater?
- 12. S t r e a m s Earth scientists use the term stream for all water flowing in a channel, regardless of the stream’s size. The term river is commonly used for any large stream fed by smaller ones, called tributaries. Most streams run year-round, even during times of drought, because they are fed by ground water that seeps into the streambed.
- 13. 3 factors that control the stream velocity Discharge Gradient Channel Characteristics
- 14. Lake A lake is a large, inland body of standing water that occupies the depression in the land surface.
- 16. Wetlands Wetlands are areas where water covers the soil, or is present either at or near the surface of the soil all year or for varying periods of time during the year, including during the growing season.
- 19. Marine/Coastal Wetlands • Intertidal marshes; includes salt marshes, saltings, raised salt marshes; includes tidal brackish and freshwater marshes. • Intertidal forested wetlands; includes mangrove swamps, nipah swamps and tidal freshwater swamp forests. • Coastal freshwater lagoons; includes freshwater delta lagoons.
- 20. Inland Wetlands • Permanent rivers/streams/creeks; includes waterfalls. • Seasonal/intermittent/irregular rivers/streams/creeks. • Permanent freshwater lakes (over 8 ha); includes large oxbow lakes. • Seasonal/intermittent freshwater lakes (over 8 ha); includes floodplain lakes. • Permanent saline/brackish/alkaline lakes. • Seasonal/intermittent saline/brackish/alkaline lakes and flats.
- 21. Human-made wetlands • Aquaculture (e.g., fish/shrimp) ponds • Ponds; includes farm ponds, stock ponds, small tanks; (generally below 8 ha). • Irrigated land; includes irrigation channels and rice fields. • Seasonally flooded agricultural land (including intensively managed or grazed wet meadow or pasture). • Salt exploitation sites; salt pans, salines, etc.
- 22. • Water storage areas; reservoirs/barrages/dams/impoundments (generally over 8 ha). • Excavations; gravel/brick/clay pits; borrow pits, mining pools. • Wastewater treatment areas; sewage farms, settling ponds, oxidation basins, etc. • Canals and drainage channels, ditches.
- 23. Farming (41%) Public (10%) Industry (11%)Power- Plant (38%) Farming (85%) Public (6%) Industry (7%) Power- Plant (2%) U.S.A. China As is evident from the comparison of water use in the U.S. and China, economic growth necessitates increasing use of water for power generation. Source: Worldwatch Institute
- 24. The availability of water too is a limiting factor. An average human needs about 300,000 gallons of water annually, including 250,000 gallons for growing food. Indeed, nations with under 150,000 gallons of annual per capita water supply face severe limits to their growth.
- 25. Use of Water Resources Humans directly or indirectly use about 54% of reliable runoff Withdraw 34% of reliable runoff for: • Agriculture – 70% • Industry – 20% • Domestic – 10% Leave 20% of runoff in streams for human use: transport goods, dilute pollution, sustain fisheries Could use up to 70-90% of the reliable runoff by 2025
- 26. Activities affects the quality andActivities affects the quality and availability of wateravailability of water 1.1. Deforestation and removal of naturalDeforestation and removal of natural vegetationvegetation • Complete removal of natural vegetation fromComplete removal of natural vegetation from large stretches of land by converting forest intolarge stretches of land by converting forest into agricultural land, road construction, and uplandagricultural land, road construction, and upland developmentdevelopment • Deforestation leads to loss of wildlife habitats,Deforestation leads to loss of wildlife habitats, micro-climate changes, loss of productionmicro-climate changes, loss of production potential from a range of wood and non-woodpotential from a range of wood and non-wood renewable resources, and potentially to erosionrenewable resources, and potentially to erosion and loss of nutrientsand loss of nutrients
- 27. 2. Over-exploitation of vegetation for domestic use and commercial scale • Contrary to “deforestation and removal of natural vegetation”, this does not involve the (near) complete removal of the “natural” vegetation, but rather a degradation of the remaining vegetation;
- 28. 3. Inappropriate agricultural activities • Improper management of cultivated arable land; • It includes a wide variety of practices, such as absence or poor maintenance of control measures, improper crop rotation, shortening of the fallow period in kaingin cultivation, insufficient or excessive use of fertilizers and overuse of irrigation water; • Degradation types commonly linked to this causative factor are soil erosion, soil compaction, soil nutrient loss, and water pollution (by sediments, pesticides, fertilizer)
- 29. 4. Inappropriate forestry activities • These activities reflect to the improper management of natural forests and tree plantations; • This category would also include the replacement of a mixed natural forest with plantations of a very limited range of exotic species; and
- 30. 5. Overgrazing • The effect is usually soil compaction and/or a decrease of plant cover, both which may, in turn give rise to soil erosion and reduced infiltration of rainwater
- 31. 6. Poor water resource management • The over extraction of water (for irrigation, urban and industrial use) from rivers and other surface water resources has led to reduced downstream availability; • Inefficient irrigation practices, wasteful urban/industrial water use and leakages from water delivery systems all contribute to water shortage problems, as does over- pumping of the aquifers; • In coastal areas, over-extraction of groundwater has resulted in salt water intrusion into the freshwater aquifer (a growing problem in parts of Cebu)
- 32. 7. Unregulated land conversion • Uncontrolled land development for agricultural, residential, commercial and/or industrial purposes may contribute to degradation should such land uses or the management practices followed be unsuitable; • Unregulated urban and industrial expansion within lowland agricultural areas may be contributory to watershed degradation
- 33. 8. Industrial activities • All human activities of a (bio)industrial nature: timber processing, factory farming (e.g. large-scale commercial poultry and piggery farms), power generation, mining, infrastructure and urbanization, waste handling, etc. • It is most often linked to pollution of different kinds (either point source or non-profit); and • In addition to possible chemical and organic pollutants, uncontrolled rainwater run-off from mine spoil heaps, unconsolidated roadside cuttings and embankments, urban and industrial sites can be the source of significant quantities of downstream sediments.
- 34. 9. Inappropriate conservation technologies • While the range of soil and water conservation, agroforestry and forestry technologies have been developed for upland areas, it implementation typically requires substantial investments in labor, time, money and material resources – items that many households do not have; • Even when aware of the need to adopt specific sustainable land management practices, a household’s socio-economic constraints may prevent it from being in a position to do so; and • There is a strong need to develop strategies and technologies that are cost effective, socio-culturally adaptive and ecologically friendly.
- 36. Assignment: Search, list and at least 5 ways in conserving and protecting water resources
Notas del editor
- Almost all of the water on Earth, more than 97 percent of it, is seawater in the oceans. The rest is called fresh water, because it does not have a high salt content.
- The hydrologic cycle, or the water cycle, describes the continuous circulation of water among the four spheres: the hydrosphere (or watery part of the planet), the geosphere (the land), the biosphere (life-forms in the sea, on land, and in the air), and the atmosphere. About 1.3 billion cubic kilometers of water exist at Earth’s surface. Of this huge quantity, 97.5 percent is salty seawater, and another 1.8 percent is frozen into the great ice caps of Antarctica and Greenland. Thus, although the hydrosphere contains a great amount of water, only 0.64 percent is fresh and available in streams and rivers, ground water, lakes, and wetlands. Water evaporates from the seas and from land to form water vapor in the atmosphere. This vapor eventually condenses and falls back to the surface as rain or snow. Most precipitation lands on the ocean, partly because the oceans cover most of the planet. The precipitation that falls on the continents follow four paths.
- The hydrologic cycle, or the water cycle, describes the continuous circulation of water among the four spheres: the hydrosphere (or watery part of the planet), the geosphere (the land), the biosphere (life-forms in the sea, on land, and in the air), and the atmosphere. About 1.3 billion cubic kilometers of water exist at Earth’s surface. Of this huge quantity, 97.5 percent is salty seawater, and another 1.8 percent is frozen into the great ice caps of Antarctica and Greenland. Thus, although the hydrosphere contains a great amount of water, only 0.64 percent is fresh and available in streams and rivers, ground water, lakes, and wetlands. Water evaporates from the seas and from land to form water vapor in the atmosphere. This vapor eventually condenses and falls back to the surface as rain or snow. Most precipitation lands on the ocean, partly because the oceans cover most of the planet. The precipitation that falls on the continents follow four paths.
- Glacial ice builds up when snowfall in winter exceeds snow melted in summer Each annual layer of snow, melts, refreezes, forms ice Weight of ice compresses the lower layers into hard crystalline ice When the ice mass becomes thick enough, the lower layers flow plastically Glacial ice forms where temperatures are low and snowfall is high
- People probably think there is some kind of magic happening here ... they pull down a lever and out of the ground below their feet comes clear, cool freshwater. They (and maybe you) may not realize that there is an immense amount of water in aquifers below the earth's surface. In fact, there is a hundred times more water in the ground than is in all the world's rivers and lakes. Some water underlies the Earth's surface almost everywhere, beneath hills, mountains, plains, and deserts. It is not always accessible, or fresh enough for use without treatment, and it's sometimes difficult to locate or to measure and describe. This water may occur close to the land surface, as in a marsh, or it may lie many hundreds of feet below the surface, as in some arid areas of the West. Water at very shallow depths might be just a few hours old; at moderate depth, it may be 100 years old; and at great depth or after having flowed long distances from places of entry, water may be several thousands of years old.
- Why is there groundwater? A couple of important factors are responsible for the existence of groundwater: (1) Gravity Nothing surprising here - gravity pulls water toward the center of the Earth. That means that water on the surface will try to seep into the ground below it. (2) The Rocks Below Our Feet The rock below the Earth's surface is the bedrock. If all bedrock consisted of a dense material like solid granite, then even gravity would have a hard time pulling water downward. But Earth's bedrock consists of many types of rock, such as sandstone, granite, and limestone. Bedrocks have varying amounts of void spaces in them where groundwater accumulates. Bedrock can also become broken and fractured, creating spaces that can fill with water. And some bedrock, such as limestone, are dissolved by water -- which results in large cavities that fill with water.
- Three factors control stream velocity: gradient, discharge, and channel characteristics. Gradient is the steepness, or vertical drop over a specific distance, of a stream. Obviously, if all other factors are equal, water flows more rapidly down a steep slope than a gradual one. A tumbling mountain stream may drop 40 meters or more per kilometer, whereas the lower Mississippi River has a gradient of only 0.1 meter per kilometer. Discharge - is the amount of water flowing down a stream. It is expressed as the volume of water flowing past a point per unit time, usually cubic meter per second (m3/sec). At a given point stream, the velocity of a stream increases when its discharge increases. Thus, a stream flows faster during flood. Even though its gradient is unchanged. Channel characteristics – refer to the shape and roughness of a stream channel. The floor of the channel is called a bed, and the sides of the channel are the banks. Friction between flowing water and the stream channel slows current velocity. Consequently, water flows more slowly near the banks than near the center of a stream. If you paddle a canoe down a straight stream channel, you move faster when you stay away from the banks. The amount of friction depends on the roughness and shape of the channel. Boulders on the banks or in the streambed increase friction and slow a stream down, whereas the water flows more rapidly if the bed and banks are smooth.
- A lake is a large, inland body of standing water that occupies the depression in the land surface. Streams flowing into the lake carry sediment, which fills the depression in a relatively short time, geologically speaking. Soon the lake becomes a swamp, and with time the swamps fills with more sediment and vegetation and becomes a meadow or forest with a stream flowing through it.
- Oligotrophic Lake. A deep lake surrounded by mountains. Any nutrients drop to the bottom where there is no light. Eutrophic lake. Shallow lake with plenty of vegetation around the edge and even in the middle light reaches the bottom.
- Wetlands are areas where water covers the soil, or is present either at or near the surface of the soil all year or for varying periods of time during the year, including during the growing season. Water saturation (hydrology) largely determines how the soil develops and the types of plant and animal communities living in and on the soil. Wetlands may support both aquatic and terrestrial species. These complex habitats act as giant sponges, soaking up rainfall and slowly releasing it over time. Wetlands are like highly efficient sewage treatment works, absorbing chemicals, filtering pollutants and sediments, breaking down suspended solids and neutralising harmful bacteria.
- B — Marine subtidal aquatic beds; includes kelp beds, sea-grass beds, tropical marine meadows.