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; ft^{3}/s, cubic foot per second]

Stream | Method (ICALC) | Inflow rate (ft^{3}/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 | – | – |