Module 1-2 Introduction and Hydrologic Cycle PDF

CHAPTER 1. INTRODUCTION TO HYDROLOGY Introduction to Hydrology Hydrology is the branch of science concerned with the study of water in the environment, encompassing its occurrence, movement, distribution, and the properties of the Earth's water resources. It plays a crucial role in understanding the...

CHAPTER 1. INTRODUCTION TO HYDROLOGY Introduction to Hydrology Hydrology is the branch of science concerned with the study of water in the environment, encompassing its occurrence, movement, distribution, and the properties of the Earth's water resources. It plays a crucial role in understanding the water cycle and its interactions with the natural and built environment. As water is an essential resource for human life, agriculture, industry, and ecosystems, the study of hydrology is vital for the sustainable management of water resources, predicting and mitigating the effects of floods and droughts, and designing water-related infrastructure. Importance of Hydrology 1. Water Resource Management: Hydrology helps in assessing and managing water resources, ensuring that there is a Y balance between water availability and the needs of human populations, agriculture, and ecosystems. This includes the planning and operation of reservoirs, irrigation systems, and urban water supplies. P O 2. Flood and Drought Prediction: Hydrologists use their knowledge of the water cycle to predict and mitigate the impacts of extreme weather events, such as floods and droughts. By understanding how water moves through the environment, hydrologists can develop models to forecast these events and design infrastructure to reduce their impact. C 3. Environmental Protection: Hydrology is essential for maintaining healthy ecosystems by understanding how water interacts T with soils, vegetation, and the atmosphere. This includes studying the effects of pollution on water quality and developing strategies to protect and restore aquatic ecosystems. N 4. Urban Planning and Infrastructure Development: Hydrology informs the design and construction of urban infrastructure, E such as stormwater drainage systems, sewage treatment plants, and flood protection measures. It ensures that cities can handle the demands of growing populations and changing climate conditions. D Related Terms in Hydrology U 1. The Water Cycle (Hydrologic Cycle): The continuous movement of water on, above, and below the surface of the Earth. The T water cycle includes processes such as evaporation, condensation, precipitation, infiltration, runoff, and subsurface flow. S 2. Precipitation: Any form of water, liquid or solid, that falls from the atmosphere and reaches the ground. Common forms include rain, snow, sleet, and hail. 3. Evaporation: The process by which water is converted from liquid to vapor and enters the atmosphere from water bodies, soil, and other surfaces. 4. Transpiration: The process by which moisture is carried through plants from roots to small pores on the underside of leaves, where it changes to vapor and is released to the atmosphere. 5. Infiltration: The process by which water on the ground surface enters the soil. The rate of infiltration depends on soil type, vegetation, and the degree of saturation. 6. Runoff: The part of precipitation that flows over the land surface toward streams, rivers, and eventually the ocean. Runoff is a major component of the water cycle and is influenced by land use, topography, and precipitation intensity. CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 1 of 21  8. Aquifer: A geological formation that can store, transmit, and yield water to wells and springs. Aquifers are essential sources of groundwater. 9. Watershed (Drainage Basin): An area of land that drains all the streams and rainfall to a common outlet, such as a river, bay, or other body of water. Watersheds are crucial for managing water resources and understanding the flow of water within a region. 10. Hydrological Modeling: The use of mathematical models to represent the movement, distribution, and quality of water within the hydrologic cycle. These models are used to simulate hydrological processes, predict water availability, and assess the impacts of environmental changes. References: Y Chow, V. T., Maidment, D. R., & Mays, L. W. (1988). Applied Hydrology. McGraw-Hill. P Linsley, R. K., Kohler, M. A., & Paulhus, J. L. H. (1982). Hydrology for Engineers. McGraw-Hill. O C Mays, L. W. (2010). Water Resources Engineering. John Wiley & Sons. Ward, R. C., & Robinson, M. (2000). Principles of Hydrology (4th ed.). McGraw-Hill. T N Hydrology E Hydrology is the scientific study of the distribution, movement, and quality of water on Earth. It encompasses the water cycle, including D the processes of precipitation, evaporation, transpiration, infiltration, and runoff, as well as the interactions between water and the environment. Hydrology is a key discipline in environmental science and engineering, focusing on understanding how water moves through the atmosphere, across the surface of the Earth, and beneath the ground. This knowledge is essential for managing water U resources, predicting and mitigating the effects of natural disasters like floods and droughts, and designing water-related infrastructure. T Hydrologist S A Hydrologist is a scientist or engineer who specializes in hydrology. Hydrologists study the distribution, circulation, and physical properties of water in the environment. Their work involves analyzing data related to rainfall, river flows, groundwater levels, and water quality. Hydrologists often use mathematical models and Geographic Information Systems (GIS) to predict water movement and assess the impact of environmental changes, such as climate change, land use, and pollution, on water resources. They play a crucial role in water resource management, environmental protection, and the planning and construction of infrastructure like dams, levees, and irrigation systems. Examples of Hydrology and Hydrologist Work 1. Flood Risk Assessment: A hydrologist might study a river basin to predict how heavy rainfall could lead to flooding. They use historical data, computer models, and field measurements to assess flood risks and recommend measures such as levees, floodwalls, or improved drainage systems to protect communities. CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 2 of 21  3. Urban Stormwater Management: Hydrologists working in urban areas might design systems to manage stormwater runoff, reducing the risk of flooding and water pollution. This could involve creating green infrastructure like rain gardens or permeable pavements to enhance water infiltration and reduce surface runoff. 4. Water Quality Monitoring: Hydrologists monitor the quality of water in rivers, lakes, and groundwater sources to ensure they meet safety standards. They may study the effects of pollutants from industrial, agricultural, or urban sources and develop strategies to mitigate contamination. 5. Climate Change Impact Studies: Hydrologists are often involved in research to understand how climate change affects water resources. They might analyze trends in precipitation, snowmelt, and river flows to predict how changes in climate will impact water availability and the frequency of extreme events like floods and droughts. Y References: P Chow, V. T., Maidment, D. R., & Mays, L. W. (1988). Applied Hydrology. McGraw-Hill. O Linsley, R. K., Kohler, M. A., & Paulhus, J. L. H. (1982). Hydrology for Engineers. McGraw-Hill. C Ward, R. C., & Robinson, M. (2000). Principles of Hydrology (4th ed.). McGraw-Hill. T Pronunciation Guide N 1. Hydrology: E D ◦ Pronounced as hahy-DROL-uh-jee. U ◦ Breakdown: T ▪ hahy (like "high") S ▪ DROL (rhymes with "troll") ▪ uh (a short "uh" sound) ▪ jee (like "gee") 2. Hydrologist: ◦ Pronounced as hahy-DROL-uh-jist. ◦ Breakdown: ▪ hahy (like "high") CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 3 of 21  ▪ uh (a short "uh" sound) ▪ jist (like "gist") These pronunciations follow standard English phonetic rules. Hydrology (hi-DRAH-luh-jee): The study of water, including its distribution, movement, and properties within the Earth's environment.The pronunciation hi-DRAH-luh-jee is an alternative way to pronounce "Hydrology," and it effectively conveys the same sound. Importance of water Water is one of the most vital resources on Earth, essential for the survival of all living organisms and the functioning of ecosystems. Its Y importance extends across various aspects of life, society, and the environment. Here are some key reasons why water is so important: P 1. Sustaining Life O Biological Necessity: Water is crucial for all living organisms. It is a major component of cells and tissues, and it plays a C fundamental role in physiological processes such as digestion, circulation, temperature regulation, and waste elimination. Human Survival: Humans can survive for weeks without food but only a few days without water. It is essential for T maintaining hydration, nutrient absorption, and overall health. N 2. Agriculture and Food Production E Irrigation: Water is essential for growing crops and raising livestock. Irrigation systems are critical for food production, D particularly in arid and semi-arid regions where natural rainfall is insufficient. U Aquaculture: Water bodies are used for fish farming and other forms of aquaculture, which provide a significant source of protein and income for many communities. T 3. Economic Development S Industry: Many industries rely on water for manufacturing processes, cooling, cleaning, and as a raw material. Water is essential in the production of goods such as food, beverages, textiles, chemicals, and electronics. Energy Production: Water is used in hydropower plants to generate electricity. It is also crucial for cooling in thermal power plants and in the production of biofuels. 4. Environmental and Ecosystem Health Habitat for Biodiversity: Water bodies like rivers, lakes, wetlands, and oceans provide habitats for a diverse range of plant and animal species. Healthy aquatic ecosystems are crucial for maintaining biodiversity. Nutrient Cycling: Water plays a key role in the cycling of nutrients within ecosystems. It helps transport nutrients and organic matter within and between ecosystems, supporting plant growth and sustaining food webs. CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 4 of 21  Drinking Water: Access to clean and safe drinking water is fundamental to public health. It prevents waterborne diseases and supports overall well-being. Sanitation: Water is essential for sanitation and hygiene practices, such as washing hands, bathing, and cleaning, which are crucial for preventing the spread of infectious diseases. 6. Climate Regulation Weather Patterns: Water in the atmosphere, in the form of vapor, clouds, and precipitation, influences weather patterns and climate. The water cycle plays a significant role in distributing heat and regulating global temperatures. Carbon Sequestration: Wetlands, oceans, and other water bodies act as carbon sinks, absorbing carbon dioxide from the atmosphere and helping to mitigate the effects of climate change. Y 7. Cultural and Recreational Value P O Cultural Significance: Water has cultural and spiritual significance in many societies. It is often associated with purification, renewal, and life. C Recreation: Water bodies provide opportunities for recreation and tourism, including activities like swimming, boating, fishing, and diving. These activities contribute to human well-being and economic development. T 8. Transportation N Navigation: Rivers, lakes, and oceans have historically been vital for transportation and trade. Even today, many goods E are transported by ships and barges, making water an essential medium for global commerce. D Conclusion U Water's importance cannot be overstated. It is indispensable for life, economic development, environmental health, and social well- T being. Ensuring the sustainable management and equitable distribution of water resources is essential for meeting the needs of current and future generations. S Importance of Water Water is the most common substance on the surface of the earth, with the oceans covering over 70 per cent of the planet. Water is one of the few substances that can be found in all three states (i.e. gas, liquid and solid) within the earth’s climatic range. The very presence of water in all three forms makes it possible for the earth to have a climate that is habitable for life forms: water acts as a climate ameliorator through the energy absorbed and released during transformation between the different phases. In addition to lessening climatic extremes the transformation of water between gas, liquid and solid phases is vital for the transfer of energy around the globe: moving energy from the equatorial regions towards the poles. The low viscosity of water makes it an extremely efficient transport agent, whether through international shipping or river and canal navigation. These characteristics can be described as the physical properties of water and they are critical for human survival on planet earth. CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 5 of 21  Y P O Fresh water C Fresh water takes many forms, including clouds, rivers, icebergs, most lakes, and the water in your glass. Because of this wide range, it’s often de ned as what it’s not: salty. T Fresh water has less than 500 milligrams of salt per litre, or 500 parts per million (ppm) of salt, according to Environment Canada. This N is equivalent to 0.05%. The United States Geological Survey uses a slightly di erent de nition: less than 1,000 ppm, or 0.10%. Across organizations, it’s almost always de ned as less than 1% salt and often—as in these two examples—well below that. E D U According to Environment Canada, fresh water has less than 500 milligrams of salt per litre, or 500 parts per million (ppm) of salt. T Note: 500 mg of salt is equivalent to 1/4 of teaspoon Source: https://www.iisd.org/ela/blog/back-to-basics-what-is- fresh-water/ S Physical Properties and Importance of Water Water is an extraordinary substance, unique in its properties and crucial to the existence of life on Earth. It is the most common substance on the planet's surface, with oceans covering over 70% of the Earth's surface. The abundance of water and its presence in all three states of matter—solid, liquid, and gas—under Earth's climatic conditions make it a key factor in maintaining a habitable climate. 1. Presence of Water in All Three States Water is one of the few substances naturally present on Earth in all three states: solid (ice), liquid (water), and gas (water vapor). This ability to exist in multiple states is due to the unique molecular structure of water, which allows it to transition between these forms CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 6 of 21 fi fi ff fi  Solid (Ice): Found in glaciers, polar ice caps, and snow, ice plays a crucial role in reflecting sunlight, helping to regulate the Earth's temperature. Ice also serves as a reservoir of freshwater, slowly releasing it into rivers and oceans through melting. Liquid (Water): As the most prevalent form of water, liquid water is essential for all known forms of life. It serves as a solvent for biochemical reactions, a medium for nutrient transport, and a habitat for aquatic life. Liquid water is also crucial for weathering processes and the hydrological cycle. Gas (Water Vapor): Water vapor is a significant greenhouse gas, trapping heat in the atmosphere and contributing to the greenhouse effect. It is also critical in the formation of clouds and precipitation, playing a key role in weather patterns and the distribution of water resources globally. 2. Climate Regulation and Energy Transfer Y Water's ability to transition between its three states is vital for climate regulation and energy transfer on Earth. The processes of P evaporation, condensation, and freezing/melting involve significant energy exchanges that help moderate Earth's climate: O Evaporation: When water evaporates, it absorbs a large amount of heat from the surrounding environment, which cools the surface. This process also increases humidity in the atmosphere, influencing weather patterns. C Condensation: As water vapor rises and cools, it condenses into liquid water, releasing stored heat (latent heat) into the T atmosphere. This release of energy helps drive atmospheric circulation and weather systems. N Freezing and Melting: The transition of water from liquid to solid (freezing) and solid to liquid (melting) also involves the E absorption and release of heat. These processes are particularly important in polar and high-altitude regions, where they influence global ocean currents and energy distribution. D U These phase changes are not only critical in moderating climatic extremes but also in the global transfer of energy. Water moves energy from equatorial regions, where it is abundant due to high solar radiation, toward the poles, helping to balance the global climate. T S 3. Water as a Transport Agent Water’s low viscosity makes it an extremely efficient medium for transportation. Whether through the natural flow of rivers and streams or human-made canals and shipping routes, water facilitates the movement of goods, people, and organisms. The global economy relies heavily on maritime transportation, with the vast majority of international trade conducted via ocean shipping. Rivers and canals have also historically served as crucial routes for inland trade and transportation, connecting distant regions and fostering economic development. The efficiency of water as a transport agent is also evident in natural systems. Water's ability to flow easily allows it to transport sediments, nutrients, and organisms across vast distances, playing a vital role in shaping landscapes and supporting ecosystems. 4. Critical for Human Survival The physical properties of water, including its presence in all three states, its role in climate regulation, and its efficiency as a transport medium, are fundamental to human survival. Without water, Earth’s climate would be far more extreme, with greater temperature CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 7 of 21 References (APA Style): Chaplin, M. (2006). Do We Underestimate the Importance of Water in Science? https://www1.lsbu.ac.uk/water/water.html Kleidon, A., & Renner, M. (2013). A Simple Explanation for the Hydrological Cycle Based on Maximum Entropy Production. Earth System Dynamics, 4(2), 455-476. doi:10.5194/esd-4-455-2013 Montanari, A., Young, G., Savenije, H. H. G., Hughes, D., Wagener, T., Ren, L., Koutsoyiannis, D., Cudennec, C., Toth, E., Grimaldi, S., Bloeschl, G., Sivapalan, M., Beven, K., Gupta, H., Hipsey, M., Schaefli, B., Arheimer, B., Boegh, E., Schumann, A., & Post, D. (2013). “Panta Rhei—Everything Flows”: Change in Hydrology and Society—The IAHS Scientific Decade 2013–2022. Hydrological Sciences Journal, 58(6), 1256–1275. doi:10.1080/02626667.2013.809088 Y P Saltwater O Saltwater refers to water that contains a significant concentration of dissolved salts, primarily sodium chloride (NaCl). Saltwater is C commonly found in oceans and seas, where the salt content, known as salinity, typically averages around 35 parts per thousand (ppt). This means that for every 1,000 grams of seawater, approximately 35 grams are dissolved salts. While saltwater covers about 97% of the Earth's surface water, it is not suitable for direct consumption by humans or most terrestrial organisms due to its high salinity. T Reasons Why Saltwater Should Not Be Drunk N 1. Dehydration E D ◦ Drinking saltwater leads to dehydration rather than hydration. The high salt content in saltwater requires the body to use more water to dilute the salts and excrete them. The kidneys must work harder to remove excess salt, leading to U increased urine production and a net loss of body water. As a result, drinking saltwater actually depletes the body's water reserves, worsening dehydration. T 2. Hypernatremia S ◦ Consuming saltwater can lead to hypernatremia, a condition characterized by an excessively high concentration of sodium in the blood. This can cause severe symptoms such as confusion, muscle twitching, seizures, and even coma. The body’s cells become dehydrated as water is drawn out of them to balance the high sodium levels in the bloodstream, leading to cellular dysfunction and damage. 3. Kidney Damage ◦ The kidneys play a critical role in filtering blood and maintaining fluid and electrolyte balance. Drinking saltwater places an enormous strain on the kidneys, as they must work overtime to expel the excess salt. Over time, this can lead to kidney damage or failure, particularly in individuals with pre-existing kidney conditions. 4. Gastrointestinal Issues CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 8 of 21  5. Incompatibility with Human Physiology ◦ The human body is not adapted to handle the high salt concentration found in seawater. Our bodies are designed to process freshwater, which has a very low salt content. Drinking saltwater disrupts the delicate balance of electrolytes, leading to severe health problems. Unlike marine animals, which have specialized adaptations to excrete excess salt, humans lack such mechanisms, making saltwater unsafe for consumption. References: National Ocean Service. (2021). Why Can’t People Drink Seawater? National Oceanic and Atmospheric Administration (NOAA). https://oceanservice.noaa.gov/facts/drink-water.html Y Mayo Clinic. (2023). Hypernatremia: An Overview. https://www.mayoclinic.org/diseases-conditions/hypernatremia/symptoms- P causes/syc-20373711 O World Health Organization. (2003). Total dissolved solids in Drinking-water: Background document for development of WHO C Guidelines for Drinking-water Quality. https://www.who.int/water_sanitation_health/dwq/chemicals/tds.pdf T Hydrology: Global Perspective and the Philippines N Hydrology, the science of water, encompasses the study of its distribution, movement, and properties across the Earth's surface, E subsurface, and atmosphere. Understanding hydrology is crucial for managing water resources, predicting weather patterns, and preparing for natural disasters. This discussion covers global hydrology with a special focus on the Philippines, highlighting key aspects D and challenges. U Hydrology is the study of water movement, distribution, and properties on Earth. It is a multidisciplinary field that encompasses the analysis of the water cycle, surface water, groundwater, watersheds, and the impact of human activities on water resources. T Understanding hydrology is crucial for water management, disaster preparedness, and environmental protection. Below are detailed explanations of key hydrological concepts, illustrated with examples and photos from both global perspectives and the Philippines. S 1. The Water Cycle (Hydrologic Cycle) Global Perspective: Image Description: A detailed diagram showing the global water cycle, with processes like evaporation from oceans, condensation into clouds, precipitation over land, and runoff back to the sea. The water cycle is the continuous movement of water on, above, and below the Earth's surface. It starts with the evaporation of water from oceans and other bodies, which then condenses to form clouds. These clouds eventually release water as precipitation (rain, snow, sleet), which can either runoff over the land into rivers and lakes or infiltrate the ground, replenishing groundwater supplies. Image from https://www.sciencelearn.org.nz/ CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE image_maps/36-dynamic-and-complex-the-global- URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 9 of 21  ◦ The Amazon River Basin: The largest river basin in the world, located in South America, plays a critical role in the global water cycle. The Amazon River discharges more water into the ocean than any other river, contributing significantly to global moisture and weather patterns. ◦ The Himalayan Glaciers: Known as the "Third Pole," these glaciers are crucial for feeding major rivers in Asia, such as the Ganges, Indus, and Brahmaputra. These rivers are essential for the water supply of billions of people across several countries. Philippines Context: Image Description: A photo of a heavy monsoon rain in the Philippines, contributing to local rivers and groundwater. Y Monsoon P Northeast Monsoon (AMIHAN) O ◦ Cold winds from the northeast that bring rains over the eastern side of the country C Southwest Monsoon (HABAGAT) T ◦ Warm moist winds from the southwest causing rains over the western portion of the country from May to September N In the Philippines, the water cycle is heavily influenced by monsoon rains E and typhoons. These intense weather systems bring substantial amounts of precipitation, which is critical for replenishing rivers, lakes, and groundwater but also poses risks such as flooding and landslides. D Image from Amihan Habagat Monsoon. (n.d.). Retrieved from h t t p s : / / w w w. d i v e s c o t t y. c o m / u n d... / a m i h a n - h a b a g a t - U 2. Surface Water T S Surface water includes rivers, lakes, and reservoirs that collect precipitation and runoff. It is a critical resource for drinking water, agriculture, industry, and recreation. ◦ Examples: ▪ The Nile River: The longest river in the world, flowing through northeastern Africa, is the lifeblood of Egypt, providing water for irrigation, drinking, and transportation. The Nile River flows over 6,800 kilometers (4,000 miles) before emptying into the Mediterranean Sea. For thousands of years, the river has provided a source of irrigation to transform the dry area around it into lush agricultural land. Today, the river continues to be a vital freshwater resource for millions of northeast Africans who rely on it for irrigation, drinking water, fishing, and hydroelectric power. Image Description: A photograph of the Amazon River, the world's largest river by discharge, flowing through a dense rainforest. The Amazon River is a vital surface water resource in South America, supporting diverse ecosystems and providing water for millions of people. Its vast basin is crucial for maintaining CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 10 of 21  ▪ Lake Baikal: Located in Russia, it is the world's deepest and oldest freshwater lake, holding about 20% of the Earth's unfrozen freshwater. Philippines Context: ◦ Major River Systems: The Philippines has several significant rivers, including the Cagayan River, the longest and largest river in the country, crucial for agriculture and irrigation in the northern Luzon region. Image Description: A photo of the Cagayan River, the longest river in the Philippines, crucial for agriculture and livelihoods. Explanation: The Cagayan River is the Philippines' longest river, running through the Cagayan Valley in Luzon. It is essential for irrigation, supporting the region's agriculture, which is a major economic activity. However, the river is also prone to flooding during the Y rainy season, which can cause significant damage to crops and infrastructure. P ◦ Lakes: Lake Laguna de Bay, the largest lake in the Philippines, is a vital water source for drinking, irrigation, and O fisheries. However, it faces challenges from pollution and over-extraction. 3. Groundwater C Global Perspective: Groundwater is the water stored beneath the Earth's T surface in aquifers. It is a crucial source of freshwater, especially in arid and semi-arid regions where surface water is scarce. N Image Description: A cross-section diagram showing an aquifer, with water E infiltrating through soil layers and being pumped for use. D Groundwater is stored in aquifers, which are porous layers of rock or sediment. It is U a crucial source of freshwater for drinking, agriculture, and industry, especially in regions where surface water is scarce. The Ogallala Aquifer in the United States, for example, provides water for one of the most productive agricultural areas in the T world. S ◦ Examples: ▪ The Ogallala Aquifer: This vast aquifer underlies much of the Great Plains in the United States, providing water for agriculture in a region known as the "breadbasket of the world." ▪ The Nubian Sandstone Aquifer System: Located in North Africa, it is one of the world's largest fossil water reserves, crucial for the water supply in Egypt, Libya, Sudan, and Chad. Philippines Context: ◦ Groundwater Resources: The Philippines relies heavily on groundwater, especially in urban areas like Metro Manila, where it provides about 30% of the water supply. Groundwater is also crucial for rural communities, particularly in areas with limited surface water. Traditional hand dug wells in Barangay Libo, Panukulan, Polillo Island for hygienic activity (leftmost photo) and human consumption (middle photo). CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 11 of 21 Image Description: A photo of a groundwater well in a rural Philippine village, showing how local communities access water. Y In the Philippines, groundwater is a vital resource, especially in rural areas and islands where surface water may not be readily P available. Many communities rely on deep wells to access groundwater for drinking, cooking, and irrigation. However, over-extraction and contamination are significant concerns, particularly in densely populated regions like Metro Manila. O 4. Watersheds and River Basins C T Global Perspective: Watersheds and river basins are land areas where all the precipitation drains into a common outlet, such as a river or lake. They are essential for managing water resources and understanding hydrologic processes. N ◦ Examples: E ▪ The Mississippi River Basin: The largest river basin in North America, draining 41% of the continental United D States, is crucial for agriculture, industry, and transportation. U T S CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 12 of 21  Y P O C Image: Mississippi River (Source: https://biggerpieforum.org/environment/the-mississippi-river-is-backing-up/) T ▪ The Mekong River Basin: Flowing through six countries in Southeast Asia, it supports millions of people through agriculture, fishing, and transportation. N Philippines Context: E D ◦ Cagayan River Basin: The largest river basin in the Philippines, covering several provinces in northern Luzon, is essential for agriculture, hydroelectric power, and flood control. U ◦ Agno River Basin: Another significant basin in Luzon, which is crucial for irrigation and flood management. The basin faces challenges such as deforestation, which increases the risk of flooding and soil erosion. T Location S Country Philippines Regions Central Luzon Cordillera Administrative Region Ilocos Region Provinces BenguetPangasinanTarlac Cities/municipality BuguiasKabayanBokodItogonSan ManuelSan NicolasSanta MariaAsinganVillasisRosalesSanto TomasA lcalaBayambangBautistaCamilingUrbiztondoMangataremSan CarlosAguilarBugallonLingayen Length 248 km (154 mi) Basin size 5,952 km2 (2,298 sq mi)[ Source: https://upload.wikimedia.org/wikipedia/commons/2/2c/Agno_river_watershed.png 5. Flooding and Typhoons CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 13 of 21  Y P O C T ◦ Examples: N ▪ The 2010 Pakistan Floods: Caused by unprecedented monsoon rains, it affected over 20 million people, highlighting the need for improved flood management and infrastructure. E ▪ Hurricane Katrina (2005): In the United States, this devastating hurricane caused widespread flooding in New D Orleans, leading to significant loss of life and property. U Philippines Context: T ◦ Typhoon Impact: The Philippines is highly susceptible to typhoons, with an average of 20 typhoons entering its area of responsibility each year. Typhoons often cause severe flooding, landslides, and storm surges. S ◦ Examples: ▪ Typhoon Haiyan (Yolanda) in 2013: One of the strongest tropical cyclones ever recorded, it caused catastrophic flooding and storm surges, particularly in the Visayas region, resulting in over 6,000 deaths and widespread destruction. ▪ Typhoon Ulysses (Vamco) in 2020: Brought severe flooding to Metro Manila and other parts of Luzon, displacing thousands of people and causing significant economic damage. The Philippine Atmospheric Geophysical and Astronomical Services (PAGASA) on Tuesday released the names that will be assigned to tropical cyclones that will enter the Philippine Area of Responsibility (PAR) in 2024. The names are re-used every four years, excluding those of tropical cyclones that have a severe impact and cause considerable damage to the country. CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 14 of 21 Sources: PAG-ASA and https://www.gmanetwork.com/news/scitech/weather/892923/pagasa-releases-philippine-tropical-cyclones- names-in-2024/story/ The first tropical cyclone this year will be named Aghon followedin alphabetic order by: Butchoy Leon Vicky Carina Marce Warren Dindo Nika Yoyong Enteng Ofel Zosimo Ferdie Pepito Gener Querubin Y Helen Romina Igme Siony P Julian Tonyo O Kristine Upang C 6. Human Impact on Hydrology T Global Perspective: Human activities such as deforestation, urbanization, agriculture, and dam construction have profound N effects on hydrological systems. These impacts can alter natural water flows, reduce water quality, and increase the risk of floods and droughts. E ◦ Examples: D U ▪ The Aral Sea: Once the fourth-largest lake in the world, it has shrunk dramatically due to water diversion for irrigation in Central Asia, leading to ecological disaster and economic hardship. T Image: Aral Sea (Source: https://www.columbia.edu/~tmt2120/introduction.htm) S CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 15 of 21  ▪ Deforestation in the Amazon: Reduces the region's ability to regulate water cycles, contributing to more severe droughts and floods. The Amazon is the largest rainforest in the world. It covers 6.9 million square kilometers (2.72 million square miles), with two-thirds of it situated in Brazil. The rainforest contains approximately 16,000 tree species and 2.5 million insect species, with half of all species living in the canopy. Its 390 billion trees act as a major carbon storage sink, by drawing carbon dioxide from the atmosphere to make food, mainly glucose, through photosynthesis. This locks carbon dioxide in, so it does not contribute to the greenhouse effect, which warms the planet. Y P O C T N E D U Image: Amazon rainforest (Source: https://www.azocleantech.com/article.aspx?ArticleID=1491) T Philippines Context: S ◦ Deforestation and Land Use Changes: The Philippines has experienced significant deforestation, particularly in upland areas, which has increased the risk of soil erosion, landslides, and flash floods. ◦ Urbanization: Rapid urbanization, especially in Metro Manila, has led to increased runoff, reduced infiltration, and more frequent flooding. The construction of impervious surfaces and inadequate drainage systems exacerbate these issues. ◦ Pollution: Industrial, agricultural, and domestic activities contribute to the pollution of both surface and groundwater. For example, the Pasig River in Metro Manila has suffered from severe pollution due to untreated wastewater and solid waste disposal. Conclusion Hydrology plays a critical role in understanding and managing the Earth's water resources. Globally, it influences weather patterns, supports ecosystems, and sustains human life. In the Philippines, the study and management of hydrology are particularly important due to the country's vulnerability to natural disasters such as typhoons, floods, and droughts. Effective management of water resources, CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 16 of 21 BODIES OF WATER Bodies of water are significant geographical features that hold various forms of water, such as rivers, lakes, seas, oceans, and more. Each type has unique characteristics and plays an essential role in the Earth's hydrological cycle and ecosystems. Here’s a detailed discussion of different bodies of water, along with examples and their locations: 1. Oceans Definition: Oceans are the largest bodies of saltwater, covering about 71% of the Earth's surface. They are crucial in regulating the Earth's climate and supporting a diverse range of marine life. Examples: Y ◦ Pacific Ocean: The largest and deepest ocean, it borders the Philippines to the east, providing the country with P extensive marine resources. O ◦ Atlantic Ocean: Located between the Americas and Europe-Africa, it is the second-largest ocean and plays a crucial role in global trade routes. C Example: The Pacific Ocean as seen from the Philippines, which lies in the Coral Triangle, known for its rich marine biodiversity. T 2. Seas N Definition: Seas are smaller than oceans and are partially enclosed by land. They are usually connected to an ocean and contain saltwater. E Examples: D U ◦ South China Sea: Located to the west of the Philippines, this sea is a critical area for maritime trade and fishing. ◦ Caribbean Sea: Situated in the Atlantic Ocean, this sea is bordered by Central America and the Caribbean islands, T known for its clear waters and coral reefs. S Example: The South China Sea, near the Spratly Islands, which are subject to territorial disputes but rich in marine resources. 3. Lakes Definition: Lakes are large, inland bodies of water that can be freshwater or saline. They are crucial for drinking water, irrigation, and supporting local ecosystems. Examples: ◦ Lake Taal: Located in Batangas, Philippines, this lake is known for its unique feature of having an island (Taal Volcano) within a lake, which is within a larger island (Luzon). ◦ Lake Baikal: In Siberia, Russia, it is the world's deepest and oldest freshwater lake, containing about 20% of the world's unfrozen freshwater. Example: Lake Taal in the Philippines, with Taal Volcano in the center. CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 17 of 21  Definition: Rivers are natural flowing watercourses, usually freshwater, flowing towards an ocean, sea, lake, or another river. Examples: ◦ Cagayan River: The longest river in the Philippines, flowing through the Cagayan Valley in Luzon and playing a vital role in agriculture and transportation. ◦ Nile River: The longest river in the world, flowing north through northeastern Africa, essential for the civilizations that have flourished along its banks. Example: The Cagayan River, a vital waterway in the northern Philippines. 5. Bays Y Definition: Bays are coastal bodies of water that are partially enclosed by land, with a wide opening to the sea. They are often protected from strong winds and waves, making them ideal for harbors. P Examples: O ◦ Manila Bay: A natural harbor that serves as the main port of the Philippines, known for its beautiful sunsets. C ◦ San Francisco Bay: A large bay in California, USA, surrounded by major cities and connected to the Pacific Ocean. T Example: Manila Bay, a vital port area in the Philippines, famous for its sunset views. N 6. Gulfs E Definition: Gulfs are large, deep inlets of the sea, often larger than bays, and usually surrounded by land on three sides. D Examples: U ◦ Gulf of Mexico: A major body of water in North America, rich in oil reserves and important for biodiversity. T ◦ Davao Gulf: Located in Mindanao, Philippines, this gulf is crucial for fishing and tourism. S Example: Davao Gulf, with the city of Davao in the background, an important economic hub in the southern Philippines. 7. Straits Definition: Straits are narrow passages of water that connect two larger bodies of water, often critical for navigation. Examples: ◦ Strait of Malacca: One of the most important shipping lanes in the world, located between the Malay Peninsula and Sumatra. ◦ San Juanico Strait: The narrowest strait in the world, located between the islands of Samar and Leyte in the Philippines. Example: San Juanico Strait, with the San Juanico Bridge connecting Samar and Leyte. CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 18 of 21  Definition: Estuaries are coastal areas where freshwater from rivers meets and mixes with saltwater from the sea, creating unique and productive ecosystems. Examples: ◦ Pasig River Estuary: Where the Pasig River meets Manila Bay, an area important for commerce but also challenged by pollution. ◦ Chesapeake Bay: The largest estuary in the United States, known for its rich biodiversity. Example: The Pasig River estuary, an important historical and commercial waterway in Manila, Philippines. 9. Lagoons Y Definition: Lagoons are shallow bodies of water separated from a larger sea or ocean by sandbars, coral reefs, or barrier islands. P Examples: O ◦ Laguna de Bay: The largest lake in the Philippines, located near Metro Manila, used for fishing, irrigation, and water C supply. ◦ Venice Lagoon: A famous lagoon in Italy, home to the historic city of Venice. T Example: Laguna de Bay, a vital water resource for the surrounding provinces in Luzon, Philippines. N E Conclusion D U Understanding these different bodies of water and their significance is crucial for appreciating their role in ecosystems, human activities, and the global environment. Each type of water body, from oceans to lagoons, contributes uniquely to the planet’s hydrology and biodiversity. T S CHAPTER 2. THE HYDROLOGIC CYCLE The hydrological cycle, also known as the water cycle, is a continuous process by which water circulates through the Earth's atmosphere, land, and oceans. This cycle is crucial for maintaining life on Earth and plays a significant role in weather patterns, climate regulation, and the availability of fresh water. The hydrological cycle involves several key processes, each with distinct meanings and functions. Process of the Hydrological Cycle 1. Evaporation: Evaporation is the process by which water changes from a liquid to a gas or vapor. This occurs primarily on the surface of oceans, lakes, rivers, and other bodies of water, where solar energy heats the water. As the water molecules absorb CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 19 of 21 In the Philippines, which is an archipelago with extensive coastlines, evaporation is significant. Water from the oceans, seas, and other bodies of water turns into vapor due to the sun's heat. Example: Evaporation from the sea in the coastal areas of Palawan. 2. Condensation: Condensation occurs when water vapor in the atmosphere cools and changes back into liquid droplets, forming clouds. This cooling happens when warm, moist air rises and encounters cooler temperatures at higher altitudes. The process of condensation releases latent heat, which helps to drive atmospheric circulation and weather patterns. Clouds formed through condensation are critical for the eventual precipitation that returns water to the Earth's surface. As water vapor rises, it cools and condenses to form clouds. The Philippines experiences high levels of condensation, especially during the monsoon season, leading to cloud formation over land and sea. Y Example: Cloud formation over the mountainous regions of Luzon. P 3. Precipitation: Precipitation occurs when the water droplets in clouds become too heavy to remain suspended in the O atmosphere. These droplets fall to the Earth as rain, snow, sleet, or hail, depending on the temperature and atmospheric conditions. Precipitation is the primary way that water is returned from the atmosphere to the Earth’s surface. It replenishes freshwater resources in rivers, lakes, and groundwater and is essential for sustaining ecosystems and human activities. C The condensed water in clouds eventually falls back to Earth as precipitation, which can be in the form of rain, snow, sleet, or hail. In T the Philippines, precipitation is predominantly in the form of rain due to its tropical climate. Example: Heavy rainfall during the southwest monsoon (Habagat) in Metro Manila. N 4. Runoff: Runoff occurs when water from precipitation flows over the ground surface and collects in rivers, lakes, and oceans. E Runoff is influenced by factors such as soil saturation, land slope, and the amount of vegetation. In urban areas, where surfaces are often impermeable (e.g., concrete), runoff can be higher, leading to increased risk of flooding. Runoff plays a key role in the D redistribution of water across the Earth's surface and is a major component of the water cycle. U The water from precipitation flows over the land, contributing to rivers, lakes, and eventually the ocean. The rugged terrain of the Philippines leads to significant runoff, especially during heavy rains, contributing to river systems and sometimes causing floods. T Example: Runoff contributing to the flow of the Cagayan River, the longest river in the Philippines. S 5. Infiltration Infiltration is the process by which water on the ground surface enters the soil. This water may be absorbed by the soil and become part of the groundwater, or it may continue to move through the soil to recharge aquifers, which are underground layers of water-bearing rock. The rate of infiltration depends on factors such as soil composition, vegetation cover, and land use. Infiltration is crucial for maintaining groundwater levels, which supply wells and springs with water. Some of the water from precipitation infiltrates the soil, replenishing groundwater supplies. This process is crucial for maintaining the water table and ensuring a steady supply of freshwater for agriculture and human consumption. Percolation Percolation refers to the downward movement of water through the soil and rock layers, often reaching the groundwater. This process is part of the infiltration process but specifically refers to the movement of water deeper into the ground, through porous soil, and into aquifers. Percolation helps to purify water as it moves through soil layers, filtering out impurities and replenishing groundwater supplies. CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 20 of 21 Example: Groundwater recharge in rural areas where deep wells are used for irrigation and drinking water. 6. Transpiration: Transpiration is the process by which water is absorbed by plants' roots, moves up through the plants, and is released into the atmosphere as water vapor through small pores in leaves known as stomata. Together with evaporation, transpiration contributes to the overall process known as evapotranspiration. This process is essential for plant life and plays a significant role in regulating the temperature and humidity of the atmosphere. Plants absorb water from the soil and release it into the atmosphere through transpiration. This process is significant in the Philippines' agricultural regions, where crops contribute to the water cycle. Example: Transpiration from rice fields in Banaue, Ifugao. Examples and Specific Context in the Philippines Y Monsoon Rains: The southwest monsoon, known locally as "Habagat," brings heavy rainfall to the western parts of the country, P leading to significant river discharge and groundwater recharge. Example: Intense monsoon rains in the Philippines. O C Typhoons: The Philippines is frequently hit by typhoons, which are powerful drivers of the hydrological cycle, causing heavy rainfall and flooding. Typhoons significantly influence the annual precipitation and water availability in the region. Example: Typhoon Pablo (Bopha) in 2012, which caused widespread flooding and landslides. T N Conclusion E This comprehensive view of the hydrological cycle highlights the interconnectedness of Earth's systems and the importance of water as a vital resource.The hydrological cycle in the Philippines is dynamic and influenced by its tropical climate, monsoon seasons, and D frequent typhoons. Understanding this cycle is essential for managing water resources, preparing for natural disasters, and sustaining agricultural productivity in the region. U T S CE 118-HYDROLOGY PANGASINAN STATE UNIVERSITY RIZALYN C. ILUMIN, MSME, MSCE URDANETA CAMPUS (1st Sem, AY 2024-2025) Instructor Page 21 of 21