Culvert Information

The Culvert Information portion of the Input Window allows you to specify each culvert’s shape, size, material, and placement.

Culvert Number

For crossings with multiple culverts, this field informs you which culvert is currently displayed and the total number of culverts at the crossing. When inputting multiple culverts, its standard practice to go from left to right (looking in the downstream direction).

 Add an Additional Culvert. Inserts a new culvert with the data fields left blank.

 Copy Currently Displayed Culvert.  Adds a new culvert with the same data as the currently displayed culvert.

 Delete Culvert.  Removes the currently displayed culvert from the crossing.

 Scroll through multiple culverts.

Note: The culvert data that is actively displayed at the time of Calculation will be the culvert analyzed for fish passage.

Shape

Choose a culvert shape from the drop down list. Options are;

• Circular,

• Horizontal ellipse,

• Metal box,

• Box,

• Pipe-arch,

• High or low-profile arch, and

• Single radius arch.

If selecting a high or low profile arch, pipe-arch, or metal box, a window containing a list of predefined sizes to select from will open. After a size is selected, the dimensions can be reviewed and changed by pressing the Details button. For a description of the different culvert types and shapes, see Culvert Shapes.

Details

When a culvert shape that has pre-defined dimensions (high and low profile arches, pipe-arches, or metal boxes) is selected, use the Details button to change culvert dimensions.  The button will open another window that displays a list of the different culvert dimensions available.

Dimensions

Culvert dimensions can be entered in feet, inches or centimeters for:

• Diameter (circular culverts)

• Span and Rise (arch, metal box, and elliptical culverts)

• Height and Width (box culverts)

When a culvert shape with pre-defined sizes (high and low profile arches, pipe-arches, or metal boxes) is selected, the Details button will open another window that lists the available dimensions for that culvert type. Use the Details button to change culvert dimensions. For a description of  how the dimensions are defined for the different culvert shapes, see Culvert Shapes.

Material

Use the drop down menu to select the culvert construction material.  If the culvert consists of corrugated metal, select the appropriate corrugation dimensions.  The selected material will determine the default Mannings roughness coefficient (n) for the culvert.  If your culvert material is not in the drop down menu, you may enter a text description into the field and input your own roughness coefficient.   See Culvert Material and Construction and Corrugations for more information.

Installation

The installation field has two options, At Grade and Embedded:

At Grade - Standard installation, with the culvert bottom (invert) placed on the surface of the channel bed.   Except for arches and metal boxes, which have open bottoms, the At Grade option assumes the bottom material is the same as the rest of the culvert.

Embedded - Culvert bottom (invert) is depressed (countersunk) below the streambed to retain stream material, producing a natural channel bottom throughout the culvert. The embedded installation can also be used if the culvert bottom has been lined with concrete or other material.  

After selecting the Embedded option enter either the depth the culvert bottom is placed below the streambed material (if it is concrete lined, enter the thickness of the concrete) or enter the percent of the total culvert height that is embedded.  FishXing will auto-calculate the corresponding depth. For additional information see Entering Embedded Culvert Data.

Note: FishXing assumes that the embedded depth is uniform throughout the length of the culvert. The program does not directly allow for a partially embedded culvert or where the embedded depth varies.

Culvert Roughness

Enter or select a roughness coefficient for the selected culvert material.  FishXing uses Manning's Roughness Coefficient (n) by default, but you can also choose to use the Darcy Friction Factor (f) or the Chezy Coefficient (C) from the Options pull-down menu on the Navigation Bar.  Default values are entered automatically when you select the culvert Construction Type. The ellipsis button (...) will open a new window with an expanded T of Manning's n values.

Bottom Roughness

Enter or select a Manning's roughness coefficient (n) for the material along the culvert bottom.  It may be natural streambed material, engineered rock and streambed material, smooth or roughened concrete or other materials. The ellipsis button (...) will open a new window with an expanded Table of Manning's n values.

This field is only activated for embedded or open-bottom culverts.  Open-bottom shapes available in FishXing are:

• Single radius arches

• High and low profile arches

• Metal boxes

Culvert Length

Enter the total length measured from the culvert inlet bottom to the culvert outlet bottom.

Culvert Elevations and Slope

FishXing allows you to choose between:

(1)   Entering the inlet and outlet bottom elevations and have the software auto-calculate the slope or

(2)   Entering the outlet bottom elevation and the culvert slope and have the inlet bottom elevation auto-calculated.

Select the field you wish to enter, by activating the radio button.  The non-selected field will be grayed-back and display the auto-calculated value. The inlet and outlet elevations should correspond to the locations used to determine the culvert length.

Inlet Bottom Elevation - Enter the elevation of the inlet bottom (invert).  If the culvert is embedded or is an open-bottom culvert, enter the elevation of the channel bed at the inlet.

Culvert Slope - Enter the percent slope of the culvert bottom.  If the culvert is embedded or is an open-bottom arch, enter the slope of the bed within the culvert.

Outlet Bottom Elevation - Enter the elevation of the culvert outlet bottom (invert).  If the culvert is embedded or is open-bottom enter the elevation of the channel bed at the outlet.

FishXing assumes the bottom slope of an embedded or open bottom culvert is the same as the culvert slope. FishXing cannot directly model hydraulics of culverts containing a bottom slope substantially different from the slope of the installed culvert.   See Embedded Culverts for more information.

Note:  All elevations entered in FishXing should be tied to a common datum.

Entrance Loss

The Entrance Loss Coefficient (Ke) is a constant used to determine the amount of energy loss as the water enters the culvert inlet.  The entrance loss coefficient is based on the culvert inlet configuration.  The coefficient can range between 0 and 1, with larger values associated with greater energy loss. See Inlet Head Loss Coefficient for more information.