Module 9 Flashcards
Describe the movement of water at and beneath the Earth’s surface
Stream flow:
Perrenial streams flow all year long
Ephemeral streams contain water only for a short time
Within drainage basins, water moves downslope as overland flow, and beneath the ground surface as interflow and base flow
-Within a drainage basin, runoff and groundwater flow into streams that funnel into the largest stream, a trunk stream
Discuss the factors that contribute to variations in stream discharge over time displayed in flood hydrograph
Variables: w is channel width, d channel depth, v velocity of water, and s slope (gradient)
Calculated as: Q = w × d × v
Stream Hydrograph:
A graph of stream discharge over time for a specific place is called a hydrograph
-Rising limb–surface runoff
-Recession limb– interflow, baseflow
Discuss how fluvial erosion occurs within stream channels
Hydraulic action–related to stress applied by flowing water to bed and banks of the stream channel
Abrasion– sediment particles loosened and detached by hydraulic action mechanically erode the stream channel
Corrosion– chemical weathering within the stream channel release material into solution
Discuss how transport and deposition occur within stream channels
(1) Dissolved load (solution): chemical weathering
(2) Suspended load: fine-grained particles
(3) Bed load: course-grained materials
Define the terms stream capacity and stream competence
Increase in discharge (Q) leads to an increase in erosion and transport
Stream capacity– total load of material that can be transported at a given Q
Stream competence– largest particle that can be transported at a given Q
Identify and describe typical landforms created by fluvial processes
Straight and braided channels tend to occur in headwater areas where gradient and/or sediment load is high
In lower-gradient areas with finer sediments, meandering or anabranching channels are more common
Characteristic landforms:
Pools, cutbanks–erosional
Point bars, levees–depositional
Oxbow lakes
