The program ONLINE_COLBY calculates the discharge of sands by the Colby [1964] method.

1. The input data is the following: mean velocity [v], mean flow depth [d], channel width [B], water temperature [T], bed material size [d₅₀], and wash load concentration [C_w].

2. The program is executed in U.S. Customary units [default units]. However, the program can also take SI (metric) units and convert them to U.S. Customary units [during pre- and post-processing].

3. The input data is restricted in the following ranges:

    •  bed material size:   0.1 mm ≤ d₅₀ ≤ 0.8 mm

    •  wash load concentration:   0 ppm < C_w ≤ 200,000 ppm

4. When specifying U.S. Customary units, the input data is restricted in the following ranges:

    •  mean velocity:   1 ft/s ≤ v ≤ 10 ft/s

    •  mean flow depth:   0.1 ft ≤ d ≤ 100 ft

    •  channel width:   0 ft < B ≤ 20,000 ft

    •  water temperature:   32 ^oF ≤ T ≤ 100 ^oF

5. When specifying SI (metric) units, the input data is restricted in the following ranges:

    •  mean velocity:   0.3048 m/s ≤ v ≤ 3.048 m/s

    •  mean flow depth:   0.03048 m ≤ d ≤ 30.48 m

    •  channel width:   0 m < B ≤ 6,096 m

    •  water temperature:   0 ^oF ≤ T ≤ 37.777778 ^oF

6. Input data outside of the given range will trigger an error message and stop execution.