Problem 1-1

During a given year, the following hydrologic data were collected for a 2500-km² basin: total precipitation, 900 mm; total combined loss due to evaporation and evapotranspiration, 450 mm estimated groundwater outflow (including groundwater depletion), 100 mm; and mean surface runoff, 250 mm. What is the change in volume of water (in hm³) remaining in storage in the basin during the elapsed year?

Problem 1-2

During a given year, the following hydrologic data were measured for a certain 60-mi² watershed: total precipitation, 15 in.; and estimated losses due to evapotation, evaoptranspiration, and infiltration, 13 in. Calculate the mean annual runoff (in ft³/s). Neglect changes in surface water storage and groundwater effects.