6.3 A watershed has a drainage area of 15 km2. In May, 2009, a storm produced the rainfall-time distribution and the streamflow rate distribution given by Table 6.10. (1) Assuming that equation (6.4) is valid, find the inflection points on the recession limb of the hydrograph. (2) Calculate the groundwater recession constant, k. (3) Plot the streamflow hydrograph and locate the first and last inflection points. 6.4 In problem 6.3, (1) calculate the SRV (m), and (2) the effective precipitation depth (mm).