In a given month a watershed with an area of 5 acres receive

In a given month, a watershed with an area of 5 acres received 5.2 in of precipitation. During the same period, the loss due to evaporation was 2.5 in. lgnoring losses due to transpiration and infiltration and assuming S = 1.5 inches, determine the average rate of flow measured in a gauge at the outlet of this watershed in ft3/day.

Solution

Solution:-

                 Inflow - Outflow = Change in storage + Evaporation loss

               O = I - S – E

              O = 5.2 – 1.5 – 2.5

              O = 1.2 inches

Average rate of flow at outet = Area x O /Month

                                                  = ( 5 x6272640 x 1.2 )/30

                                                 = 1254528 inch³/day

                                                 = 726 feet³/day         Answer

              Where 1 Acre = 43560 feet²

                            1 Acre = 6272640 inch²