class 11

a bucket and a stopwatch can measure

streamflow

• only works with small streams

• tells you flow during moment of measurement

• labor

weirs provice a control section:

an area with a unique relationship between stage and discharge

• calibrated

• easy to measure

• labor intensive to install

• hard to calibrate large weirs

stage

the level of a river above some “datum”- some arbitrary point that is decided on as 0

we measure stage, we want to measure

streamflow/ discharge (do math)

velocity- area relationships provide practical way to estimate discharge in real world settings

each set of blocks of known width of a stream, calculate velocity times area → sums discharge for each block

a rating curve is a

unique relationship between stage and discharge

rising limb and falling limb

increasing and decreasing flow around the peak flow; falling limb is also called recession limb

lag time

the time between peak precipitation and peak flow

bankfull discharge

discharge when the river is at bankfull stage

flood discharge

discharge when the river is above bankfull stage

storm flow

discharge from the fast flow of water during a storm

baseflow

discharge from the slower flow of water through the subsurface; often increases after a storm because of an increase in the water table

hysteresis

the state depends on its history