Drainage basin hydrology Definitions: Tributary: ● A tributary is a stream or river that flows into a larger main river or body of water. It contributes its water to the larger watercourse. Confluence: ● A confluence is the point at which two or more rivers or streams meet and merge into a single channel. It is the location where the tributaries join the main river. Source: ● The source of a river or stream is the point where it originates, typically in the form of a spring, glacier, or mountainous area. It is the starting point of a river's flow. Watershed: ● A watershed, also known as a drainage basin or catchment area, is an area of land that drains into a common outlet, such as a river, lake, or ocean. It is defined by the highest elevations that surround it, and all precipitation that falls within the watershed eventually flows to a common point. Floodplain: ● A floodplain is a flat or gently sloping area of land adjacent to a river or stream that is subject to periodic flooding. Floodplains are often fertile due to sediment deposition during floods, making them suitable for agriculture, but they are also prone to flooding during periods of high water flow. Mouth: ● The mouth of a river is the point where it flows into a larger body of water, such as an ocean, sea, lake, or another river. It is the opposite end from the source and is often characterized by the river's discharge into the larger water body. Precipitation: ● Water, in liquid or solid form, falling from the atmosphere to the Earth's surface, including rain, snow, sleet, and hail. Infiltration: ● The process by which water soaks into the soil from the ground surface. Overland Flow: ● Water movement on the surface of the land when precipitation exceeds infiltration capacity, leading to runoff. Throughflow: ● Lateral movement of water within the soil, parallel to the land surface. Groundwater Flow: ● The movement of water within the saturated zone beneath the Earth's surface. Stemflow: ● Water running down plant stems and trunks during precipitation. Water Table: ● The level at which the ground is saturated with water, separating the unsaturated zone above from the saturated zone below. Aquifer: ● A permeable geological formation that can store and transmit groundwater. Evaporation: ● The process by which water changes from a liquid to a gas (water vapor) due to heat energy. Evapotranspiration: ● The combined loss of water from both evaporation and transpiration (water release from plants). Interception: ● The capture and temporary storage of precipitation by vegetation before it reaches the ground. Throughfall: ● Water dripping from leaves and branches of vegetation to the ground during precipitation. Channel Flow: ● The movement of water within a defined natural or artificial watercourse. Percolation: ● The downward movement of water through soil and rock layers. Channel: ● A natural or artificial watercourse that conveys water. Groundwater Store: ● The subsurface reservoir of water held in the saturated zone beneath the Earth's surface. Base Flow: ● The relatively constant, sustained flow of a river fed by groundwater, contributing to streamflow between precipitation events. Surface Store: ● A temporary accumulation of water on the Earth's surface, such as ponds, lakes, or reservoirs. How much of the water on earth is freshwater? 2.5 Where is most of the freshwater stored? Glaciers and icecaps The cyrosphere: What is the cryosphere? Refers to the parts of the earth where water is found in its frozen form, part of the hydrosphere What does it consist of? Glaciers, snow, ice caps, permafrost, icebergs, sea ice etc What are the positive effects of the cytoshere on Earth's temperature? ● Keeps earth cool (hydrosphere) because the solar energy reflects (90%) back into space What are the consequences of the melting of the ice because of climate change? ● Air pollution ● temperature rising -> sea level rising. ● Ocean current ● Weather temperature ● Darker surfaces -> more heat is absorbed, loss of habitat (penguins) What are the difference between porosity and permeability? Porosity: ● Definition: Porosity refers to the volume percentage of open spaces (pores) in a rock or sediment relative to its total volume. ● Measurement: It is expressed as a percentage and is calculated by dividing the volume of void spaces by the total volume of the rock or sediment. ● Significance: Porosity indicates how much space is available for fluids to be stored within a material. However, it doesn't directly address the ease with which fluids can flow through the material. Permeability: ● Definition: Permeability is a measure of how easily fluids can flow through the interconnected pore spaces of a rock or sediment. ● Measurement: Permeability is typically measured in units of darcies or millidarcies. It is determined through laboratory tests that measure the rate at which fluids can pass through a sample under certain pressure conditions. ● Significance: Permeability provides information about the connectivity and interconnectivity of the pore spaces, indicating how easily fluids can move through the material. High permeability means that fluids can flow more easily through the rock. What is meant by an aquitard? ● Slit and clay -> very slowly allows water to flow through it ● Transmits water at a very slow rate (slit and clay) Define aquiclude A layer that absorbs and holds water, it does not transmit any water to aquifers What is an artisan discharge area? A well or a spring that brings groundwater to the surface because of higher pressure What's the difference between a phreatic zone and an aeration? The phreatic zone is saturated with water, while the unsaturated zone, also known as the aeration zone, contains both air and water but is not fully saturated. Name and describe the different erosional process? Hydraulic Action: ● Description: The force of moving water wears away and erodes rock and soil from riverbanks or coastlines. Abrasion: ● Description: Rocks and sediment carried by water or wind scrape and wear down surfaces they come in contact with. Attrition: ● Description: Rocks and particles carried by water or wind collide, causing them to break and wear down into smaller pieces. Solution: ● Description: Chemical dissolution of minerals in rocks by acidic water, leading to their gradual breakdown and removal. What factors affect rates of erosion? ● Velocity ● Load ● Ph ● Human impact ● Transportation ● Deposition ● Size Name and describe the different transportation processes? Traction: ● Description: Large and heavy particles like boulders are rolled along the riverbed by the force of the flowing water. Saltation: ● Description: Small and medium-sized particles, like pebbles, are lifted and bounced along the riverbed by the flow. Suspension: ● Description: Fine particles, such as silt and clay, are carried in the flow without directly contacting the riverbed, remaining suspended in the water. Solution: ● Description: Dissolved minerals and ions are transported within the water without forming visible particles, contributing to the river's chemical load. The Hjulström curve: Landforms: A. V Shaped valley Meander = a bend in a river, they change over time middle (small) and lower course (large meaders). Formation of a oxbow lake Formation of potholes Formation of deltha Leeves-lower course: Powerpoint: ● ● ● Open system = Allows movement of energy and matter across its boundaries. Most drainage basins are such a system. Closed system = Can only exchange energy with its surroundings, no matter. The hydrological cycle or Earth is such a system. ● Isolated system = cannot exchange either energy or matter with its surroundings. An insulated drinking cooler is an example. ● Input = irrigation, water transfer schemes (channeling, dams,…), desalinated water. ● Output = leakage = occurs from the deeper subsurface to other drainage basins. ● Most important factor of evaporation = temperature. ● Infiltration capacity = the maximum rate at which rain can be absorbed by a soil in a given condition (type of soil, vegetation,…). ● Evapotranspiration = the most important aspect of water loss (counts for nearly 100% of precipitation loss in arid areas, 75% in humid areas). ● Groundwater = subsurface water ● Water table = - Varies seasonally (in winter mostly higher). - Found within the first few hundreds of meters. - Accounts for 96,5% of all fresh water - Some is recycled within days, other can be stored for 20.000 years. - permanently saturated zone = phreatic zone.
