CEE 1030 1nd Edition Lecture 16 Running Water Outline of Last Lecture I Mass wasting a Role of particle size and shape b Role of water c Role of underlying surface II Other factors of mass wasting III Review IV Mass wasting processes Outline of Current Lecture I Hydrolic cycle II Running water III Divides and drainage networks IV Vocab terms V Stream erosion transport and deposition Current Lecture I II Hydrolic cycle a Hydrolic cycle the continuous circulation of Earth s water among oceans atmosphere and continents b Hydrolic processes i Evaporation the process of water turning from a liquid to a vapor ii Transpiration the release of water vapor to the atmosphere by plants iii Precipitation water that falls to the ground from the atmosphere to the hydrosphere iv Infiltration surface water draining into the ground through cracks and pore spaces in the regolith v Runoff water flowing over land rather than infiltrating the ground Running water a One of the most important erosional agents on Earth s land surface b Infiltration vs runoff i Infiltration capacity max amount of water soil can absorb ii Runoff begins as sheet flow water draining in shallow unconfined sheets across the ground 1 Sheet flow erodes in narrow shallow channels called rills These 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 III IV V 2 Runoff may widen and deepen rills to become gullies ravines etc iii Water flowing in channels are called streams creeks etc 1 Erosion of channels 2 Transport of sediments 3 Deposition of sediment iv Streamflow types 1 Laminar flow water particles move in straight line paths downstream 2 Turbulent flow water flows erratically v Factors of streamflow velocity 1 Gradient of channel 2 Channel morphology 3 Discharge a Measure discharge by calculating width x depth x velocity of channel vi Drainage basin the area where runoff drains downhill into water way or body of water Divides and drainage networks a Drainage networks interconnected system of tributaries creeks streams and rivers in a drainage basin that feed into the main waterway b Divide each drainage basin separated topographically from adjacent basins c Continental Divide mountainous line that forms the border between two major watersheds of North America Vocab terms a Stream profile a cross section of a stream that shows the gradient channel morphology and discharge b Base level the lowest point to which a stream can erode sea level the ultimate base level c Stream valleys young V shaped or mature U shaped d Alluvial fans depositions of sediments on land and in a fan shape e Delta like an alluvial fan but deposited in a larger body of water Stream erosion transport and deposition a Stream erosion i Streams cause erosion by 1 Lifting loosely consolidated particles 2 Abrasion mechanical weathering 3 Dissolution chemical weathering ii Evidence of stream erosion potholes gorges b Sediment transport i Stream s load the transported material ii Dissolved load suspended load bed load iii Sediment load 1 Capacity maximum load a stream can transport 2 Competence largest particle a stream can transport 3 Capacity and competence determined by velocity c Sediment deposition i When streamflow velocity decreases competence is reduced and sediments are deposited ii Alluvium sediments deposited by streams iii Channel deposits sediment accumulation within a channel 1 Bar sand and gravel deposit 2 Braided stream stream consisting of numerous intertwining channels iv Floodplain deposits 1 Natural levee elevated landform composed of alluvium 2 Backswamp poorly drained area of floodplain 3 Yazoo tributary tributary flowing parallel to the main stream