Mean annual discharge(Qmean) at any point A along river where drainage basin area BA is found by assuming total depth of runoff R of every m2 of BA in a year, all flows out by point A over same water year. Annual total R(in depth units, cm) is just(P –Et);P=annual depth of precipitation & Et=annual depth of evapotranspiration. Over regions of few 100km radius, P,Et & R are generally constants. Mean annual flood Q(= 2-3yr flood Q) at point A (is greater than the Qmean at A) depends on how concentrated are flood waves that, after strong runoff, travel down the watershed before reaching point P
Along YRiver, Qmean=20 m3/s and Q2-3 yr=200 m3/s at a point A, where YRiver’s watershed area BA=500 km2. An adjacent larger river flowing nearby is the XRiver. Lakes along XRiver, but not along YRiver.
1)Give approximate values of Qmean & Q2-3 yr at a point B along XRiver, where BA=2000km2 ? If can’t give value for Q2-3 yr, estimate a min/max value it might reach.Give reason & calc.
2)What is R(in cm) in this region?