Techniques and Methods 6-A19

U.S. GEOLOGICAL SURVEY
Techniques and Methods 6-A19

Table 4. Method for calculating stream depth and width, inflow rates, streambed properties, stream dimensions, and Manning’s roughness coefficients for stream segments used in test simulation 2.

[Stream: Streambed properties and stream dimensions for each stream segment are specified for the first and last reach in each segment. A linear interpolation is used to determine each value at the midpoint of each reach. Stream segment no: Segment 3 is a diversion from segment 2 assuming all available flow to the rate specified is diverted. Method determines how stream depth and width are calculated for each reach in a segment. Stream depth and width are specified when ICALC is 0; stream depth is calculated from Manning’s equation assuming a wide rectangular channel when ICALC is 1; stream depth and width are calculated from Manning’s equation using an eight-point cross section when ICALC is 2; depth and width are calculated from a power function when ICALC is 3; and depth and width are calculated from a table of values when ICALC is 4. See appendix 1 in Prudic and others (2004). Inflow rate: Inflow calculated from 1 or more tributary segments. Manning’s roughness coefficient is not used for calculating stream depth or width when ICALC is 0, 3, or 4, and Manning’s roughness coefficient for the overbank is not used when ICALC is 1. Abbreviations: ft, foot; ft/s, foot per second; ft3/s, cubic foot per second]

Stream Method (ICALC) Inflow rate (ft3/s) Streambed hydraulic conductivity (ft/s) Streambed thickness (ft) Elevation of streambed (ft) Stream depth (ft) Stream width (ft) Manning’s roughness coefficient (unitless)
Segment No. First and last reach Channel Over bank
1 1 4 25 0.00003 3 1,095
4 .00003 3 1,075
2 1 1 .00003 3 1,075 12 0.030
5 .00003 3 1,050 12
3 1 0 10 .00003 2 1,075 2 10
6 .00003 2 1,060 1 6
4 1 1 10 .00003 3 1,080 10 .030
3 .00003 3 1,060 10
5 1 3 .00003 3 1,060
4 .00003 3 1,045
6 1 1 .00003 3 1,045 12 .030
5 .00003 3 1,025 12
7 1 2 150 .00003 3 1,040 .025 0.045
3 .00003 3 1,025
8 1 2 .00003 3 1,025 .025 .045
6 .00003 3 990