EES 1030 Lecture 16Outline of Last Lecture I. Mapping the ocean floorII. Features on the Ocean FloorIII. Passive Continental MarginIV. Active Continental MarginV. ContinentsVI. Continental ShieldsVII. Mountain BeltsVIII.Mountain BuildingIX. Three types of plate boundariesX. Convergent Plate BoundariesXI. The Appalachian Fold BeltXII. Continental vs. Oceanic CrustOutline of Current Lecture XIII. Hydrolic ProcessesXIV. Running WaterXV. Infiltration and RunofXVI.Rivers and StreamsXVII. Stream Flow TypesXVIII. Divides and Drainage NetworksThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best Used as a supplement to your own notes, not as a substitute.XIX.Stream ProfileXX. Stream ErosionXXI.Sediment TransportXXII. Sediment LoadXXIII. Alluvial FanXXIV. DeltaXXV. Flood Control ApproachesCurrent Lecture- Hydrolic Processeso Hydrolic Cycle: Continuous circulation of Earth’s water among oceans, atmosphere, and continentso Evaporation: the process of water turning from liquid to vapor, moving from the hydrosphere to the atmosphereo Transpiration: Release of water vapor to the atmosphere by plants through pores in leaves; plants absorb water from ground through rootso Precipitation: Water, that falls to the ground from the atmosphere to hydrosphereo Infiltration: Surfacde water draining into the ground through cracks and pore spaces in the regolitho Runof: Water flowing over land rather than infiltrating the ground- Running Watero Running water is one of the most important erosional agents afecting Earth’s land surface- Infiltration vs. Runofo The maximum amount of water that the soil can absorb is its infiltration capacityo The infiltration capacity is controlled by: Intensity and duration precipitation Soil saturation level prior to precipitation Soil texture Slope of the land Vegetation type and extento Runof: Increased runof can be caused by: High velocity water flow Steep slope Saturated regolith Impermeable groundo Stages of Runof Sheet flow: runof begins as sheet flow: water draining in shallow, unconfined sheets across the groundo Erosion by runof Sheet flow often erodes narrow, shallow channels called rills Rills are common features of agricultural land and non-vegetated areas Over time, runof may widen and deepen rills until they grow to become guilles- Rivers and Streamso Water flowing in a channel is called by many names: rivers, streams, creeks, tributarieso All have efects on landscape formation: Erosion of channels (small to large in the land) Transport of sediments provided by weathering and mass wasting Deposition of sediment in a variety of landforms- Stream flow Typeso Laminar flow: Water particles move in straight line path downstreamo Turbulent flow: Water flows erratically often with swirling whirlpool-like eddieso Steamflow Discharge Discharge of a stream: volume of water flowing past a certain point in a given unit of time Discharge is usually measured in cubic meters per second (m3/sec) Discharge = channel width x channe; depth x velocity Discharge = 10m x 5m x 1m/sec = 50 m3/second- Divides and Drainage Networkso Drainage Network: interconnected system of tributaries, rivers, etc. in a drainage basin that feed into a main waterwayo Divide: Each drainage basin is separated topographically from adjacent basins by a ridge,hill, or other topographic high lineo The Great Divide: mountainous line that forms the border between two major watersheds on the North American continent- Stream Profileo The gradient, channel morphology, and discharge of a stream change between the head (upstream) to the mouth (downstream)o Base Level: lowest point to which a stream can erodeo Types of Base Levels: Ultimate Base level: Sea level Local Base Level: level of a lake, resistant rock layer, or any other base level that stands above sea levelo Changing Base Level: changing conditions cause readjustment of streamflowo General rules: raising the base level causes deposition of sedimentso Lowering the base level causes erosion- Stream Erosiono Streams cause erosion by: Lifting loosely consolidated particles Abrasion: physical weathering Dissolution: chemical weathering- Sediment Transporto Transported material is called the stream’s loado Types of load: Dissolved load: sediment in solution Suspended load: sediment in suspension Bed load: sediment moved along channel bottom- Sediment Loado Capacity: maximum load a stream can transporto Competence: largest particle a stream can transporto Capacity and competence are determined by velocity- Alluvial Fan: fan-shaped deposit of sediment formed on land, when stream’s slope is abruptly reduced alluvial fans develop where a high-gradient stream leaves a narrow valley- Delta: fan shaped deposit of sediment formed where a stream enters a lake or ocean and slows- Flood Control Approacheso 1. Engineering Eforts: Artificial levees, flood control dams, channelizationo 2. Nonstructural approaches through intelligent floodplain