The two watersheds shown below have the same area (AW) 0.32 sq km (0.125 sq mi) but have d...

The two watersheds shown below have the same area (AW) 0.32 sq km (0.125 sq mi) but have different shapes and channel configurations. Compute the runoff hydrographs from each watershed for a 6-hr duration storm (DUR = 6.0), with a computational time step of 5 minutes (DT = 0.0833) using the rainfall intensity equation from Prob­lem 6.8. Both watersheds have sandy clay loam soils (soil code = 6) with 10 percent impervious. Use an initial rainfall abstraction of 12.7 mm (0.5 in.) and a volumetric soil moisture content of 0.2. Watershed (a) has 12 channels (NOC = 12), including 8 first-order channels and 5 junctions (NOJ = 5). Watershed (b) has 13 channels (NOC = 13), including 8 first-order channels and 6 junctions (NOJ = 6).

Use the following cross-section for channels la, 2a, and lb with a slope of 0.002 and a length of 457.3 m (1,500 ft).

Use the following cross-section for channels 3a, 4a, 2b, 3b, 4b, and 7b with a channel slope of 0.003 and a length of 274.4 m (900 ft).

For all first-order channels, use the following cross-section with a channel slope of 0.004 and a channel length of 152.4 m (500 ft).

All channels have Manning "n" values of 0.06 for the channel and 0.10 for the over-bank with lateral inflow from both sides. Use a minimum base flow (BFM) of 0.11 cms (4 cfs).

For all overland flow surfaces, use a three-segment model with slopes of 0.01, 0.02, and 0.01, respectively. Each segment is 18.3 (60.0 ft) long with a Manning "n" value of 0.20.