Question

2. [10 points] Determine the 4-hr unit hydrograph using the following data for a watershed having a drainage area of 200 km, assuming a constant rainfall abstraction rate of 1 cm per time period and a constant baseflow of 20 m3's. The ordinates of the unit hydrograph are in units of m s cm Four-hour period | 1 | 2-1 3 i 41 5 6 7 8 9 10| 11 Rainfall (cm) Streamflow (m s) 20 35 60 95 130 175 195 165 103 2 382 20 İ 3.5.4.5 120

Answer 1

given that 20m's base flbw 20 drainage Area CA): 200kw,- four- hours period2 Rainfal (m) 352-0 At Volume 아rainfal) = -2 tirsh +last 2( remainin ordinate extey Fist and last all (ms sec A t -fouy-hours pevo Se c 2x1b volume Volume 아 raintal) n) 2.

@tず 19 I Cm 200 xID 4 Direct na n op hJdograph = stream lolo Base flou unit runoH hydrograph Direcl rumoJH RunoH

In ne prole m iven 0- houy Stream flow hydrograph and asked to find but Unil D → 4 hour s T→ Y hours

unit hy roy9% tour nours stream Direct period 2 20 I S 3 S 2. 60 40 AS 刊- ID I o 13 D ISS ISS 1구5 161 82 10320 83.1 63.2 to 3 82 382 3 8 2 20