A triangular shaped swale is to retain the runoff from a catchment with a design runoff rate of 0.01 m3/sec. The longitudinal slope of the swale is to be 1.5% with side slopes of 5:1 (H:V). If the grassed swale has a Manning's n of 0.030 and a minimum infiltration rate of 200 mm/hr,
determine the length of the swale required.