Rainfall intensities (mm/hr): Historical Data ARI AEP 10m 20m 30m th 2h Streambed Characteristics Mountain streams with rocky beds Roughness Coefficient 004-005 1.58 0.633 50.6 39.8 345 273 215 141 0.500 56.7 435 378 299 234 15.4 Winding natural streams with weeds 0.035 5 0.200 739 573 46 389 304 17 Natural streams with litle vegetation 0.025 10 0.100 88.2 680 58.7 459 368 23.0 Straight lined earth canals 0.020 20 0.050 104 795 086 533 412 264 300003 113 7 747 579 447 25 Smoothed conte Runoff Coefficients for Land Use Types Land Use Type of Surface Downtown busines Range of "C" Valu 0.012 07005 08010390 0.0075 05000 Neighborhood buen 050070 Cultivated lands with any so 040045 Suburban residential 025040 Playgrounds 0.2003 General unimproved and 010000 010025 010015 A straight, unlined earth drain is to be constructed in a light industrial area. The drain is to be designed for a flood of once in 30 years event and time of concentration of 30 minutes. From the above tables, what are the design values of runoff coefficient (C), Manning's Coefficient of drain, and design rainfall intensity (i)? Oa. 0.40, 0.012, 41.2mm/hr O b. 0.70, 0.020, 68.6mm/hr O c. 0.70, 0.020, 74.7mm/hr d. 0.70, 0.025, 74.7mm/hr