Runoff Intro Flashcards
What is a hydrograph?
A graph showing the rate of flow (discharge) versus time past a specific point in a river
What are the three scales we can view hydrographs at?
Pluvial (are systems that are rainfall dominated see spikiness associated with rainfall events)
Nival (are broad long slow water inputs like a melting snowpack)
Glacial (are water inputs for glaciers, gonna be really slow)
What is the difference between the peak rainfall and peak discharge called?
The lag time
What is baseflow in a hydrograph?
Is the flow that the river always has and is sustained by slow groundwater paths
What is channel precipitation?
Is water flowing straight on river, is the fastest way for precipitation to reach river.
What is overland flow?
Is when the input rate exceeds the infiltration rate causing pooling and then due to topographical differences flows down. Is second fastest way for water to get to river.
Why is overland flow not important over natural landscapes versus urban ones?
Most surfaces have high infiltration rate, but in urban areas due to concrete this decreases increasing overland flow
What is throughflow?
Is the flow of water through the unsaturated zone which then reaches and flows into a river, is the third fastest flow path
Why are macropores big for throughflow?
Because throughflow might occur through macro pores- big connected pores that might be related to burrowing, as water flows through it the macropores get bigger and more connected increasing throughflow
What is piston hypothesis?
idea that water falling on the soil doesn’t necessarily have to make the whole transit to the river, but it can push existing water out, and into the river.
What is the runoff mechanism of groundwater?
It happens when the water table is high, so additional water percolating down allows ground water to flow by pushing it and makes the groundwater discharge area bigger. Is slowest path of flow.
What kind of runoff mechanisms contribute to fast floods?
The soil gets a crusty glaze which cause the water to runoff, steep slopes get water to go into rivers fast, sparse vegetation causes water to flow fast.
What is an intermittent stream? How does it dry up?
is a stream that receives no baseflow, and only runs at ppt events
What makes hydrographs steeper? Reach peak discharge faster?
Steep slopes, small drainage basins
What makes hydrographs less steep? Reach peak discharge slower?
forests, large drainage basins
